LEMBAGA JURUTERA MALAYSIA BOARD OF ENGINEERS MALAYSIA
KDN PP11720/01/2010(023647) ISSN 0128-4347 VOL.41 MAR - MAY 2009 RM10.00
contents Volume 41 March - May 2009
4 President’s Message Editor’s Note 6 Announcements
Cancellation Of Registration Of Registered Engineer And Removal From Register
Invitation To Serve In Investigating Committee
Cover Feature Solid Waste Management: Towards Better Treatment And Disposal Facilities
13 Aquaponics: The Future Of Agriculture 17 Building Structures For The Future – The Green Way?
Engineering & Law 27 The JKR/PWD Forms (Rev. 2007): An Overview (Part 2)
Feature 34 Incorporating Electro-Magnetic Compatibility Design
Into Mission Critical Facilities 42 Riding The Economic Tsunami: Investing In Local Workforce And IBS Construction Technology 46 Utilisation Of Rice Husk Waste And Its Ash (Part 1)
Lighter Moments 51 Sudoku : A Mental Callisthenics Engineering Nostalgia 54 Bertam Valley New Village, Cameron Highlands
KDN PP11720/01/2010(023647) ISSN 0128-4347
Vol. 41 March - May 2009 MEMBERS OF THE BOARD OF ENGINEERS MALAYSIA (BEM) 2009/2010 President YBhg. Dato’ Sri Prof. Ir. Dr Judin Abdul Karim Registrar Ir. Dr Mohd Johari Md. Arif Secretary Ir. Ruslan Abdul Aziz Members YBhg Tan Sri Prof. Ir. Dr Mohd Zulkifli bin Tan Sri Mohd Ghazali YBhg Dato’ Ir. Hj. Ahmad Husaini bin Sulaiman YBhg. Dato’ Ir. Abdul Rashid Maidin YBhg. Dato’ Ir. Dr Johari bin Basri YBhg. Datuk (Dr) Ir. Abdul Rahim Hj. Hashim YBhg. Brig. Jen. Dato’ Pahlawan Ir. Abdul Nasser bin Ahmad YBhg. Dato’ Ir. Prof. Dr Chuah Hean Teik YBhg. Datuk Ir. Anjin Hj Ajik YBhg. Datuk Ar. Dr Amer Hamzah Mohd Yunus Ir. Wong Siu Hieng Ir. Mohd Rousdin bin Hassan Ir. Prof. Dr Ruslan bin Hassan Ir. Tan Yean Chin Ir. Vincent Chen Kim Kieong Ir. Chong Pick Eng Jaafar bin Shahidan EDITORIAL BOARD Advisor YBhg. Dato’ Sri Prof. Ir. Dr Judin Abdul Karim Secretary Ir. Ruslan Abdul Aziz Chairman YBhg. Dato’ Ir. Abdul Rashid bin Maidin Editor Ir. Fong Tian Yong Members Prof. Sr. Ir. Dr Suhaimi bin Abdul Talib Ir. Ishak bin Abdul Rahman Ir. Prof. Dr K.S. Kannan Ir. Mustaza bin Salim Ir. Prem Kumar Ir. Rasid Osman Ir. Dr Zuhairi Abdul Hamid Ir. Ali Askar bin Sher Mohamad Executive Director Ir. Ashari Mohd Yakub Publication Officer Pn. Nik Kamaliah Nik Abdul Rahman Assistant Publication Officer Pn. Che Asiah Mohamad Ali Design and Production Inforeach Communications Sdn Bhd Printer Art Printing Works Sdn Bhd 29 Jalan Riong, 59100 Kuala Lumpur The Ingenieur is published by the Board of Engineers Malaysia (Lembaga Jurutera Malaysia) and is distributed free of charge to registered Professional Engineers. The statements and opinions expressed in this publication are those of the writers. BEM invites all registered engineers to contribute articles or send their views and comments to the following address: Commnunication & IT Dept. Lembaga Jurutera Malaysia, Tingkat 17, Ibu Pejabat JKR, Jalan Sultan Salahuddin, 50580 Kuala Lumpur. Tel: 03-2698 0590 Fax: 03-2692 5017 E-mail: email@example.com; firstname.lastname@example.org Website: http://www.bem.org.my Advertising Subscription Form is on page 33 Advertisement Form is on page 37
4 THE INGENIEUR
president’s message Industries thrive on innovation and cutting edge technology. The engineering input towards new technologies that satisfy clients’ needs which are closely related to state-of-art technology, is without doubt the most important aspect of the whole formula. However, such input has to keep up with the fast pace of innovation and discovery to stay competitive in this borderless world. As the world’s economic trend moves from agriculture, industry, ICT and then to the nanotechnology era, we expect to see more emerging technologies introduced to industrial and household products. Some of these are already at our doorsteps. If one has not been to Cameron Highlands for the last 10 years, one will be surprised to see the new trend of tomato cultivation in bags laid on top of concrete floors fed with tubes of nutrient water, called vertigation. Flower beds are lighted up at night to stop buds from blooming until ready for harvesting Malaysia, via its Science and Technology Policy for the 21st Century, has set an objective of spending 1.5% of GDP to enhance national capacity in R&D and to achieve a competent work force of 60 RSEs (researchers, scientists and engineers) per 10,000 labour force by 2010. This should be a good platform for innovative engineers to tap into and move further up the value chain of industrial products. I hope more research groups will collaborate with locally trained engineers to move into emerging technologies as the potential is immensely beneficial to the nation. Dato’ Sri Prof Ir. Dr. Judin bin Abdul Karim President BOARD OF ENGINEERS MALAYSIA
editor’s note The increasing pace of scientific and technological innovation has kept engineers on their toes to update themselves with the latest codes of practices, technologies and scientific breakthroughs. Engineering, as an applied science, has improved the quality of life for man through the introduction of new and improved products. Emerging engineering technology holds an important place for the nation and practising engineers to stay relevant in the manufacturing and construction industry. This issue of the publication looks at green ways of building structures for the future and some of the policies towards Industralised Building System (IBS) construction technology. Innovations in agriculture that integrate aquaculture and hydroponics offer wide economic potential for local industrial players and practising engineers to ponder about. Technology on incineration of solid waste is relatively new to Malaysia. The article dedicated to this technology should provide readers some insight into the wide range of technologies available to incinerate solid waste. Ir Fong Tian Yong Editor
INVITATION TO SERVE IN INVESTIGATING COMMITTEE
announcement Registration Of Engineers Act 1967
Cancellation Of Registration Of Registered Engineer And Removal From Register Pursuant To Section 15 And Paragraph 16(c) IN ACCORDANCE with subsubparagraph 6(2)(a)(i)(B) and subparagraph 6(2)(a)(ii) of the Registration of Engineers Act 1967 [Act A138], the Registrar publishes the particulars of the registered Engineer as stated in Schedule whose registration has been cancelled and removed from the Register pursuant to paragraphs 15(1)(g), 15(1A)(d) and 16(c) of the Act with effect from 1 August 2008. SCHEDULE No.
Name, Address and Qualification
Leong Pui Kun No. 52 Tengkat Tong Shin 50200 Kuala Lumpur BE (Civil)
Registration Number 4112
Dated 12 November 2008 [KKR.PUU.110-1/4/3/1 Jld.2; PN(PU2)47/X] - SGD Ir. Dr. Mohd Johari Bin Md Arif Registrar of the Board of Engineers Malaysia
The Board of Engineers Malaysia would like to invite all Professional Engineers of not less than ten years standing as Professional Engineers to serve as members in Investigating Committee. The Committee’s prime duty is to investigate into complaints involving professionalism and breach of ethics of professional engineers. If you are interested in serving this Committee, kindly fill in the form below and return to the Secretariat. Training would be given to potential members.
To: Chairman Professional Practice Committee Board of Engineers Malaysia 17th Floor JKR HQ Building Jln. Sultan Salahuddin, 50580 Kuala Lumpur. Tel. No: 03-26912090 Fax. No: 03-26925017 e-mail: email@example.com I am interested to serve as a member of Investigation Committee. Name: PE Registration: Discipline: Date Registration: Tel. No.: Fax. No.: E-mail: Office Address: Home Address: Specialization:
June 2009: PUBLIC AMENITIES Sept 2009: SAFETY & HEALTH Dec 2009: SUSTAINABLE DEVELOPMENT
Solid Waste Management: Towards Better Treatment And Disposal Facilities By Nadzri Bin Yahaya (PhD) Director-General, Department of National Solid Waste Management, Ministry of Housing and Local Government
o l i d Wa s t e M a n a g e m e n t (SWM) in Malaysia, as in most countries worldwide, has traditionally been a task for Local Authorities (LA). It falls under sanitation which is listed as an item under the concurrent list of the Federal Constitution. Items listed in the concurrent list indicate that both the State and the Federal Governments have jurisdiction over it.
RDF Plant in Semenyih 8 THE INGENIEUR
I n t h i s r e g a r d , Th e L o c a l Government Act (Act 171) empowers the LAs to establish, maintain and carry out sanitary services with regard to solid waste and public cleansing for areas within their jurisdiction. Another piece of legislation that empowered the LAs relating to the maintenance, repair and provision of ash pits, dustbin and like receptacles is the Street,
Drainage and Building Act, 1974 (Act 133). Th e Fe d e ra l G ove r n m e n t â€™s engagement in the se ctor is traditionally restricted to financing of facilities, equipment and collection vehicles, based on applications from local authorities, and establishing policies and awareness. In addition, the States play an important role as the authority on land and hence responsible for the allocation of land for landfills and other facilities. Th e m a n a g e m e n t o f s o l i d waste by LAs has given rise to increasing criticism from the public, due to poor quality in some places. The quality of the service to a large degree depends on financial resources. LAs are also handicapped in handling the latest technologies for disposal and treatment of solid waste. Lack of human resources also hamper good quality enforcement. All these factors contributed to the deterioration in the quality of the environment, in particular, those surrounding the landfill sites. In its effort to ensure a coordinated, effective and efficient solid waste management, the Federal Government embarked on
a two-prong strategy; federalising the SWM through the enactment of the Solid Waste and Public Cleansing Management Act 2007 and privatising the collection and transportation of the household solid waste to reduce financial pressure on LAs. The enactment of the Act saw the establishment of the Department of National Solid Waste Management and the Corporation on Solid Waste and Public Cleansing Management as dedicated agencies to manage solid waste in the country.
Policy and National Strategic Plan on Waste Management The importance of technologies in the management of solid waste in the country was clearly defined by the 3rd Outline Perspective Plan (2001-2010). The 3rd OPP reported that the Government will install incinerators for safe and efficient disposal of solid waste. The National Policy on Solid Waste Management which was approved by Cabinet in 2006 as well as the National Strategic Plan on Solid Waste Management which was approved by Cabinet in 2005 put great emphasis on the importance of technologies to improve the quality of solid waste management. The National Strategic Plan laid down the provision of sustainable technologies as its fourth strategy to achieve the Planâ€™s objectives among which is to adopt an integrated management of solid w a s t e . Th e N a t i o n a l Po l i c y provides clear guidance on the criteria of technologies to be used. Its 5 th thrust emphasizes that only technologies which are environmental-friendly, cost effective and proven should be adopted for use in this country. Another criterion is that local
Mini incinerator in Pulau Tioman
technologies will be given priority. To ensure that solid waste management technologies which are proposed for implementation in the county comply with the criteria laid down by the National Policy and National Strategic Plan, a National Committee to evaluate solid waste technologies was formed under the Chairmanship of the Secretary-General of Ministry of Housing and Local Government. Its members among others consist of professionals and academicians from various universities and research institutions that are well versed in solid waste management technologies. The Committee will analyse not only the technical and technological features of the proposed facilities, but also the economic and financial aspects. Cost which includes capital and operating expenditure remains a crucial criterion in any proposal to built solid waste management
facilities in the country. Hence, the reason behind the termination of the Brogaâ€™s Incinerator as announced by the Deputy Prime Minister in 2007. He cited high cost as the main reason for the cancellation of the project.
Provision on technologies in the Solid Waste and Public Cleansing Act 2007 The Act besides laying down the various provisions on general management of solid waste has also recognized the importance of standards and specifications in the building of facilities to treat and dispose solid waste. Under Section 108 of the Act, the Minister may prescribe the standards and specifications for the design, construction, operation and maintenance of any prescribed solid waste management facilities. The Minister also may order any solid waste generator to reduce THE INGENIEUR 9
the generation of solid waste, to use environment-friendly materials as well as use specified amount of recycled materials. All the requirements as laid down by the Act can only be achieved if research and development activities are carried out in search of emerging environmentally sound technologies as well as new approaches in production processes. Best available technology (BAT) and ‘Best available technology not at excessive cost’ (BATNEC) will be the main guiding principle in the search for emerging technologies under the new National Solid Waste Management Department.
Strategies towards sustainable solid waste management As reported by the 9th Malaysia Plan, 17,000 tonnes of solid waste were generated each day in 2002 of which 45% is food waste, 24% plastics, 7% paper and 6% iron. The Plan forecasted that in 2020, we will generate about 30,000 tonnes per day if no new effort is put in place to address the ever increasing generation of solid waste. In this regard, the Department of National Solid Waste Management has put in place two strategies: prevention at source and providing facilities for solid waste management treatment and disposal. To address this menace, high priority is given to reducing, reusing and recycling (3R) solid waste. Whilst lifestyle can largely contribute to the reduction of household solid waste, manufacturing process and technologies play a key role in the reduction of other types of solid waste, in particular, industrial and commercial waste as well as in recycling activities. Facilities under the solid waste management concept include 10 THE INGENIEUR
the various thermal treatment technologies such as incineration, pyrolysis and gasification technologies as well as material recovery facilities and mechanical and biological treatment, mechanical heat treatment; renewable energy and waste technologies. Sanitary landfill is still the most common disposal facility in the country. Incineration is the most established and matured thermal treatment technology whereas pyrolysis and gasification technologies are termed as the emerging, advance technologies in solid waste treatment and disposal. Incineration usually involves the combustion of mingled solid waste with the presence of air or sufficient oxygen. Typically, the temperature in the incinerator is more than 850ºC and the waste is converted into carbon dioxide and water. Dioxin is the main concern but is destroyed with high temperature. An incinerator
will give rise to two types of ash; fly ash and bottom ash. Fly ash is categorised as scheduled wa s t e a n d c o n t r o l l e d u n d e r the Environmental Quality Act 1974 and can only be disposed off at prescribed facilities as designated by the Department of Environment. The bottom ash consist of any non-combustible materials that contain a small amount of residual carbon. This can be used as materials in road making as well brick making. In contrast to incineration, pyrolysis is the thermal degradation of a substance in the absence of oxygen. This process requires an external heat source to maintain the temperature required. Typically, relatively low temperatures of between 300ºC and 850ºC are used during pyrolysis of materials such as solid waste. The products produced from pyrolysing materials are a solid residue and a synthetic gas (syngas). The solid residue
(sometimes described as char) is a combination of non-combustible materials and carbon. The syngas is a mixture of gases (combustible constituents include carbon monoxide, hydrogen, methane and a broad range of other VOCs). A proportion of these can be condensed to produce oils, waxes and tars. The syngas typically has a net calorific value (NCV) of between 10 and 20 MJ/Nm3. Gasification can be seen as between pyrolysis and incineration (combustion) in that it involves the partial oxidation of a substance. This means that oxygen is added but the amounts are not sufficient to allow the fuel to be completely oxidised and full combustion to occur. The temperatures employed are typically above 650Â°C. The process is largely exothermic but some heat may be required to initialise and sustain the gasification process. The main product is a syngas, which contains carbon monoxide, hydrogen and methane. Typically, the gas generated from
gasification will have a net calorific value (NCV) of 4 - 10 MJ/Nm3. While we are engaged in thermal treatment technologies, we are concerned with the existing method of disposal; the landfills. At present, we have about 261 landfills all over the country, 111 of these are no longer in operation and only 10 of the 150 operating landfills are sanitary landfills. Thus, the Departmentâ€™s strategies on landfill management are laid down as follows: (i) Decide location, types and size of landfills and coverage area of each landfill; (ii) Build regional landfills with centralised treatment plant; (iii) Safe closure of landfills in sensitive areas (iv) Safe closure of the nonsanitary landfills which are no longer operating; (v) Upgrade non-sanitary landfills that are still operating; and (vi) Build new sanitary landfills with Recycling Facilities
Although the technical specifications of sanitary landfill is not new, materials used for lining of landfill is now undergoing various changes, thanks to research and development to find better materials. Traditionally, lining material is made of HighDensity Poly Ethylene (HDPE). But new technologies have emerged suggesting other materials as alternatives. These new materials are expected to better prevent the leakages of leachate into the surrounding environment thus preventing pollution, in particular, of underground water, rivers and soil.
Waste to Energies Facilities Waste to energies facilities in solid waste management is quite new in Malaysia. Although this has caught on in the palm oil sector where waste from the industries are converted to energy, in solid waste management it has some hurdles to overcome before it can be made viable. The characteristics of waste which has high moisture content and its co-mingling nature make it difficult to harness its potential. Furthermore, incentives to encourage the private sector to venture into renewable energy are not very lucrative. In Europe, most solid waste treatment facilities are also power plants. They generate electricity and steam for central heating facilities.
Mini incinerator in Denmark
Solid waste management in Malaysia is undergoing a paradigm shift from being a local authority concern to a Federal Government responsibility. A structured approach has been established with policy, strategic THE INGENIEUR 11
The Themost mostinnovative innovativeand andrevolutionary revolutionarysoil soil monitoring monitoring and and reinforcement reinforcement system system developed developedinindecades! decades! • •The Theworld’s world’smost mostadvanced advancedand andcost costeffective effective
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plan and legislation in place as well as dedicated agencies. The policy will provide the general principles and guidance for management of solid waste. The law will provide the catalyst for the policy and strategic plan to be implemented in an integrated manner. However, the much needed push to ensure that solid waste being treated and disposed in an environment-friendly manner, cost effective and feasible depends on technology and technical know-how. Without expert and professional human resources, all the best policies and plans to ensure that solid waste management is carried out effectively and efficiently will not be successfully implemented. BEM
REFERENCE 1. Federalising Solid Waste Management In Peninsula Malaysia: Dr. Nadzri Bin Yahaya1 and Ib Larsen2 Director General, Department of National Solid Waste Management, Ministry of Housing and Local Government, Level 2 & 4, Block B North, Pusat Bandar Damansara, 50644 Kuala Lumpur, Malaysia 2 Chief Technical Advisor, Danish International Development Assistance (DANIDA) Solid Waste Management Component (SWMC), Level 4, Block B North, Pusat Bandar Damansara 50644 Kuala Lumpur 1
TenCate TenCate Geosynthetics Geosynthetics Asia Asia Sdn Sdn Bhd Bhd 14,14, Jalan Jalan Sementa Sementa 27/91, 27/91, Seksyen Seksyen 27,27, Shah Shah Alam Alam 40400, 40400, Selangor Selangor Darul Darul Ehsan, Ehsan, Malaysia Malaysia Tel:Tel: +6+6 03 03 5192 5192 8568, 8568,Fax:Fax: +6+6 03 03 5192 5192 8575 8575 Website: Website: www.tencate.com www.tencate.com
2. Advance Thermal Treatment of Municipal Solid Waste: Defra- Department for Environment, Food and Rural Affairs, UK
AQUAPONICS: The Future Of Agriculture By Lim Keng Tee INSAP
Figure 1: Overview of Aquaponics System
recent report from Farmerâ€™s Organisation Authority (FOA) Malaysia stating that the maximum potential marine capture fisheries has probably been reached, triggered increased attention on aquaculture, which will soon account for half of fish consumed. Based on world
population growth projection to 2030, an extra 27 million tonnes of fish will be needed to maintain the current consumption rate of 16.7kg per person per year. Fish farming or aquaculture is a system where commercial fishes are reared in a contained system e.g. ponds or tanks. The
water quality of the contained system will directly affect the growth rate as well as the feed conversion rate (weight of feed needed to convert a kilogramme of fish meat). Hence, aquaculture is said to be a highly polluting system due to the discharge of polluted water into the surrounding THE INGENIEUR 13
Figure 2: Aquaculture portion
Figure 3: Filtering system of the Aquaponics System
environment in order to improve water quality. However, over time many techniques have been invented to reduce the pollution, one of them is the AQUAPONIC system. Aquaponics is the combination of Aquaculture and Hydroponic systems whereby nutrient rich waste water from the Aquaculture system
is directed into the Hydroponic system. Plants will absorb the nutrient from the waste water and improve or purify the water quality for the aquaculture system. This provides an eco-friendly as well as sustainable system for the agriculture sector. This fantastic integrated farming system was invented by Dr James
Rakocy from the University of Virgin Island (UVI). Over time this system has been improved from a test system to an improved commercial system. UVI continuously improves its system with the focus on effective model design, which improves and optimizes water turnover rates. Figure 1, 2 and 3 show the actual site pictures of
The UVI Aquaponic System
Tank dimensions Rearing tanks: Diameter: 10 ft, height: 4 ft, Water volume: 2,060 gal each Clarifiers: Diameter: 6 ft, Height of cylinder: 4 ft, Depth of cone: 3.6 ft, Slope: 45o, Water volume: 1,000 gal Filter and degassing tanks: Length: 6 ft, Width: 2.5 ft, Depth: 2 ft, Water volume: 185 gal Hydroponics tanks: Length: 100 ft, Width: 4 ft, Depth: 16 in, Water volume: 3,000 gal, Growing area: 2,304 ft2
Sump: Diameter: 4 ft, Height: 3 ft, Water volume: 160 gal Base addition tank: Diameter: 2 ft, Height: 3 ft, Water volume: 50 gal Total system water volume: 29,375 gal Flow rate: 100 GPM Water pump: !s hp Blowers: 1 !s hp (fish) and 1 hp (plants) Total land area: Qi acre
Figure 4: Basic Layout of the Aquaponics System 14 THE INGENIEUR
the UVI Aquaponics System, while Figure 4 shows the basic layout of the UVI Aquaponics system. (Source: Rakocy et al, 2006) From the above figures, it can be seen that water is recirculating within the contained aquaponics system. Hence water wastage can be minimized, compared to the aquaculture system (frequent changing of fish water to ensure water quality) or plant cultivation on soil (roughly 10% of the water is absorbed by the plant, while 90% of the water is wasted). Along with saving water, the fertilizer and pesticide needed for plants can be further reduced, which directly contributes to operational cost savings. Besides that, labour needed is also reduced, as several operations such as watering plants, spraying fertilizer or pesticides can be minimized accordingly. In order to prevent solid sludge from clotting the system, a filtration system is installed between the aquaculture portion and the hydroponic portion. UVI has even improved the effectiveness by modifying the clarifier. Sludge will slowly sink to the bottom, whereby the operator can easily suck out
Figure 5: Cross-sectional view of modified UVI clarifier. (Source: Rakocy et al, 2006)
the sludge without disturbing the system. Figure 5 shows the crosssection of a modified clarifier which is easy to clean. Besides that, the filtrating system also plays a crucial role to allow the growth of beneficial bacteria which converts ammonia (waste from the fish) to nitrate and nitrite that plants are able to utilize for growth, as well as control the fruiting period.
Moreover, the solid sludge filtered out can be further processed to become bio-fertilizer. Figure 6 shows the Geotexile Technology/ Geotube 速 used to extract the solid sludge from the system. (Source: Danahar J, 2008) Land scarcity is a common issue for the agricultural sector, and cultivatable land is even more scarce. However this system does not require soil for cultivation.
Figure 6: Geotexile Technology used in extracting the solid sludge THE INGENIEUR 15
(b) Less pesticide as well as fertilizer is needed. (c) Less labour needed. (ii) Intensive production and maximizing space utilization. (iii) Scaleable and applicable to both ornamental and food fish/ plant. (iv) Environment-friendly system which produces healthy products. (v) No wastage of valuable byproducts (biomass and fertilizer). In view of the need for eco-friendly systems, scientist, agriculturalist as well as engineers should cooperate to invent and improve integrated agricultural systems. BEM
Figure 7: Multilayer cultivation of plants under the Aquaponic system. Hence, soil fertility is not an issue. Furthermore, plants can even be cultivated in multilayers to maximize the utilization of land as shown in Figure 7. The critical point of this system is to maintain the correct balance, so that one does not deviate from the optimized ratio. (Source: Ramos, 2009) Another beauty in this aquaponics system is scaleability, whereby the unit system can be scaled up to commercial sizes by retaining the same ratios of 16 THE INGENIEUR
each component. However, it is advisable to multiply the model units when scaling up as this allows flexibility in controlling the production rate, and gives constant supplies as well as standard produce. In a nutshell, the benefits of the Aquaponics system can be summarized below: (i) Operational cost will be reduced (a) Wa s t a g e o f w a t e r i s minimized.
Danaher, J. (2008). Evaluating Geotexile Technology To Enhance Sustainability Of Agricultural Production Systems In The U.S. Virgin Island. Aquaponic Journal, 50, 18-20. James E. Rakocy, M. P. (2006). Recirculating Aquaculture Tank Production System: Aquaponics Intergrating Fish and Plant Culture. Southern Region Aquaculture Centre, 454. Ramos, C. L. (2009). Aquaponic Development in Mexico. Aquaponic Journal, 52, 32-35.
Building Structures For The Future – The Green Way? By Ir. Chen Thiam Leong The need and urgency of sustainable development for the built industry is beyond the deliberation stage (or at least we hope so). Energy Efficiency can be deemed to be the prelude to Sustainability, and locally we did not fare too tardily having developed our MS1525 in 2001. It is only unfortunate that the incorporation of MS1525 into our Uniform Building By-laws (UBBL) has been delayed since 2003. However, of more significant concern (and damage) is our local modus operandi where Energy Efficiency (and now Sustainability) issues are more than often regarded as the sole responsibility of M&E Engineers. The sad reality is that not many Architects in Malaysia are conversant or have taken the lead role in sustainable design. Hence, it is not at all surprising that most Structural (Civil) Engineers have hardly heard of or have participated in sustainable structural designs. This paper will serve to highlight the role Structural (Civil) Engineers can and should play to realize the Sustainable (Green) agenda and the need for a holistic design approach by all relevant players. An introduction to the proposed Malaysian Green Building Rating tool will be included.
t is no more a matter of WHY we need to build green but rather HOW we can build green and it should be starting NOW. Unless we remain closeted (somehow), the effects of Global Warming (GW) cannot be unknown. GW has been attributed to the Ozone Hole; given gradual rise in the earth’s temperature; and leading to the Greenhouse Effect. The frightening statistic is temperatures in the far north have increased 570C in the last 50 years, and as the temperatures get warmer, the sea level rises causing a difference in the amount of precipitation. Th i s i n t u r n c a u s e s e x t r e m e
weather conditions to develop resulting in excessive storms with heavier rainfall. The ecosystem is then affected with difference in agricultural growth and harvest, leading to extinction of certain animal and plant species. The main Green House Gases (GHG) are CO2, methane and water vapour. While water vapour and methane are not present for very long in the earth’s atmosphere, CO2 can remain in the atmosphere for many years and when combined with the water vapour can escalate the rate at which GW takes place. Therein lies the need to stop GW by removing CO2 present in the atmosphere or at least not add
more to it. The Montreal Protocol and Kyoto Protocol are aimed at arresting or at least mitigating this man-made disaster. So what can we do about GW? Plenty! We can reduce consumption of energy to decrease GHG, starting with reducing use of electricity. It is amazing to know that about 11% of electricity is consumed by phantom loads alone. We are ready and have the capacity to use more efficient light bulbs. For instance, in US alone, if every household were to apply a compact florescent bulb instead of a glowing light bulb, we can realize a staggering reduction of 90 billion pounds of CO2 emission! THE INGENIEUR 17
In terms of Climate Change, apart from the great financial impact, the human impact is already being felt. Millions are starving throughout the globe, and with the World’s population increasing steadily, the situation will continue to deteriorate if temperature and climate changes are allowed to continue unimpeded. It will take years if not decades to put an end to the emission of GHG. This can only be achieved through a gradual transition to cleaner energy. In the meantime, mankind will have to live with the catastrophic effects that these temperature and climate changes are bringing upon us. Global GHG emissions have increased by 70% between 1970 and 2004 and the largest growth of this emission has come from the energy supply sector. So where do we stand locally? Malaysia’s population grew at a rate of about 2.8% from 23 million in 2000 to 27 million today. Rising population and changes in life style have accelerated the demand for energy. The Malaysian energy sector is still heavily dependant on non-renewable fuels. These non-renewable fuels are finite, gradually depleting and contributing significantly to the emission of GHG.
What is meant by building Green? A Green or Sustainable building is one which is designed: ● To save energy and resources, recycle materials and minimise the emission of toxic substances throughout its life cycle, ● To h a r m o n i s e w i t h l o c a l climate, traditions, culture and the surrounding environment, and ● To be able to sustain and improve the quality of human life 18 THE INGENIEUR
Pusat Tenaga Malaysia - Zero Energy Office (ZEO) building
while maintaining the capacity of the ecosystem at local and global levels Building Green in the future is a necessity and not an option as the following statistics will attest; ● Buildings consume 40% of our planet's materials and 30% of its energy ● Their construction uses up to three million tonnes of raw materials a year and generates 20% of the solid waste stream Therefore, if we want to survive our urban future, there is no option but to build in ways which improve the health of ecosystems. Understanding the concept of ecological sustainability and translating it into practice as sustainable development is a key challenge for today's built environment professionals To quote Peter Graham; The skill and vision of those who shape our cities and
h o m e s i s v i t a l t o a ch i e v i n g sustainable solutions to the many environmental, economic and social problems we face on a local, national and global scale
How to build Green? The term ‘Green building’ is a loosely defined collection of land-use, building design, and construction strategies that reduce the environmental impact that buildings have on their surroundings. Traditional building p ra c t i c e s o f t e n ove r l o o k t h e inter-relationships between a building, its components, its surroundings, and its occupants. Typical buildings consume more of our resources than necessary and generate large amounts of waste. Green buildings have many benefits, such as better use of building resources, significant operational savings, and increased workplace productivity. Building green sends the right message about a company or organisation - that it’s well run, responsible, and committed to the future.
Elements of a Green Building There is not any one single t e ch n i q u e f o r d e s i g n i n g a n d building a green building, but green buildings often: ● Preserve natural vegetation ● Contain non-toxic or recycledcontent building materials ● Maintain good indoor airquality ● Use water and energy efficiently ● Conserve natural resources ● Feature natural lighting ● Include recycling facilities throughout ● Include access to public transportation ● Feature flexible interiors; and ● Recycle construction and demolition waste.
Who are involved in Green Buildings? A truly green building can only materialize and thereafter sustain itself when all parties involved with its birth are involved. Notice the choice of word – birth and not construction. If involvement by all commence only at the construction stage, then the end result would definitely be a tainted green at most. Obviously the starting point is the particular piece of land on which the building will stand. Hence, it starts with the owner/ developer who will probably consult the advice of the relevant experts which includes the professional architect or engineer (as the case maybe). It is at this stage that issues such as developing on a protected green lung, brown field and green field are relevant and decisive on achieving a green building. After the initial hurdle (which includes the social impact assessment) is successfully (and
greenly) navigated, the design team will be next to play their full role. From there on, the need to strike a balance between ‘company’s green policy’, value engineering, life cycle cost et al will determine the success or otherwise of the project. Nowadays when we talk about green buildings, the project team (helmed by the owner) will have to determine which Green Building Rating system to adopt. There is no right or wrong tool but rather the most appropriate tool to choose from. All green rating tools i n c o r p o ra t e b a s i c a l l y s i m i l a r criteria of assessments (albeit with differing weightings) and these criteria require the entire team’s participation. For instance, the owner will have to agree to pay to save the environment and commit that the end users will procure energy efficient appliances. The
designers will need to write into the contract conditions for the builder to undertake the protection of the environment (in terms of air and waste pollution) at commencement of construction. Vendors have to supply products that are environmental-friendly and so on. The simple chart below summarizes this integrated approach to achieving green.
Local Design Consultants/ Professionals The notorious modus operandi of the local consultant team needs to be highlighted at this juncture. We have to admit that it is an exception rather than the rule to experience a fully integrated design team working together in Malaysia (for a green project). With the advent of green buildings, the design team leader (architect for majority of building
THE INGENIEUR 19
Comparison of Selected Green Rating Tools Name Country Year
BREEAM UK Bldg Research Establishment Environmental Assessmt Method 1990
1. 2. 3. 4. 5. 6. 7. 8. 9.
LEED USA Leadership in Energy and Environmental Design 1996
Management Health & Comfort Energy Transportation Water Consumption Materials Land Use Ecology Pollution
1. 2. 3. 4. 5. 6.
Sustainable site Water Efficiency Energy & Atmosphere Materials & Resources Indoor Environmental Quality Innovation & Design / Construction Process
1. 2. 3. 4. 5. 6. 7. 8. 9.
t y p e s a n d c iv i l e n g i n e e r f o r industrial type buildings) must take the role to lead the whole team, failing which they can only blame themselves if they are subsequently made irrelevant in green matters by other allied professionals. A simple case in point would be architects not interested (or not conversant) in dictating the design development a n d c a l c u l a t i o n s f o r O ve ra l l Thermal Transfer Value (OTTV) of building envelopes. Local Civil (and Structural) engineers are similarly notorious in not venturing beyond their self-defined field, with many not being aware of their role in green building designs in the fields of construction process, material selection, innovation and so forth. Local Mechanical & Electrical engineers are also not spared this criticism with more than a handful of them contented to merely churn out basic fundamental designs and not bothering to catch up with technological advances. It is Author’s fervent hope that such a critical comment will elicit reaction from the local professional fraternity to practice 20 THE INGENIEUR
GREEN STAR Australia
GREEN MARK Singapore
Management Transport Ecology Emissions Water Energy Materials Indoor Environmental Quality Innovation
an integrated design approach to achieve beyond green buildings.
Green Building Rating Tools Advent of Green Tools In 1990, the Building Research Establishment of UK came out with the first Green Building Rating Tool or Assessment Method called BREEAM. This was quickly followed by other countries, and in the past year or so, this awareness has finally come to Malaysia’s shore. The following table depicts a comparison of selected established assessment methods. ●
Proposed Malaysia Green Building Index It is inevitable that some passionate and concerned individuals will eventually band together to initiate our own local Green Building Rating tool. Hence, after a few years of false starts, the Malaysian Green Building Council will soon be up and running and together with a parallel group from PAM and ACEM, the target of getting our tool ready should hopefully be ●
1. 2. 3. 4. 5.
Energy Efficiency Water Efficiency Environmental Protection Indoor Environmental Quality Other Green Features
realized by the second quarter of 2009. As highlighted at the onset, meeting the assessment criteria for any green building rating tool will involve all members of the building team. For the Green Building Index, the structural engineer’s input likewise will cover all the six criteria, but probably with more emphasis on; Sustainable Site & Management; and Materials & Resources;
Role of Structural Engineers in Building Green This section is extracted/reproduced from various website articles by eminent green professionals/organisations (See Reference). Structural Engineering Best ‘Green’ Practice Structural engineering ‘best practices’ incorporates strategies that embrace the tenets of sustainable design. Sustainable design is not a novelty; it is a mainstream approach that reflects good design. The necessity and importance of design integration, in general, ●
Comparison of Malaysia Green Building Index with other selected Tools LEED USA 1996
Name Country Year
1. 2. 3. 4. 5.
Sustainable site Water Efficiency Energy & Atmosphere Materials & Resources Indoor Environmental Quality 6. Innovation & Design / Construction Process
GREEN STAR Australia 2003 1. 2. 3. 4. 5. 6. 7. 8. 9.
Management Transport Ecology Emissions Water Energy Materials Indoor Environmental Quality Innovation
Green Star, Australia
is not a new idea. For decades, structural engineers have seen how close collaboration with other project team members has led to the creation of some very unique buildings. Unfortunately, design integration is often overlooked when teams collaborate on more t y p i c a l s t r u c t u r e s . S t r u c t u ra l engineers have traditionally been limited to providing input only after the core building concepts have been decided. However, structural engineers should not limit themselves to the perceived boundaries of their expertise. Sustainable design integration is a call to action for structural engineers to become more involved with the early conceptualization of a building project. Structural engineers need to be reminded of the significance of sustainable design with increased awa r e n e s s o f c o n s i d e r a t i o n s
GREEN MARK Singapore 2005 1. 2. 3. 4. 5.
GREEN BUILDING INDEX Malaysia 2008
Energy Efficiency Water Efficiency Environmental Protection Indoor Environmental Quality Other Green Features
Green Mark, Singapore
1. 2. 3. 4. 5. 6.
Energy Efficiency Indoor Environmental Quality Sustainable Site & Management Materials & Resources Water Efficiency Innovation
Green Building Index, Malaysia
associated with it. The following issues are presented in cursory form as is appropriate to generate interest: materials, resource conservation in design and construction, structural systems and performance based engineering, and collaboration opportunities with other design professions.
considering and exploiting the efficiency, availability, recycled content, reuse, and impact a material has on the environment. Consideration of benefits and disadvantages of some of the major building materials such as concrete, masonry, steel, and timber, are briefly outlined.
Materials Structural materials provide t h e s t r u c t u ra l e n g i n e e r w i t h real opportunities to contribute t o a p r o j e c t â€™s s u s t a i n a b i l i t y. Th e s t r u c t u r a l e n g i n e e r, i n u s i n g t h e t ra d i t i o n a l c r i t e r i a for material selection such as economy and appropriateness to project structural requirements, h a s a l r e a dy b e e n a n a c t iv e participant in sustainable design. Th e s t r u c t u r a l e n g i n e e r c a n further contribute to the overall sustainability of a project by
Concrete Concrete consists primarily of cement paste binder and aggregate. While concrete is an essential and structural material, cement production contributes approximately 1.5% of annual (US) carbon dioxide emissions, and as much as 7% of worldwide annual emissions. Cement production produces approximately one pound of CO2 for each pound of cement. Reducing the amount of cement used in concrete will reduce carbon dioxide emissions.
THE INGENIEUR 21
The amount of cement in concrete can be reduced by substituting fly ash or ground granulated blast furnace slag, or slag for short, for cement. Fly ash is a by-product of the combustion of coal in electric power generating plants, and slag is made from iron blast-furnace slag. Fly ash has less embodied energy than Portland cement. Typically, fly ash replaces cement at 15% to 25% by weight, and slag replaces cement at 15% to 40% by weight, with little effect on concrete mix design, placement, curing, and finishing. However, the following considerations are applicable: - Minimal cost impact - Improved workability - Less bleeding - Improved finishability - Improved pumpability - No change in plastic shrinkage - No change in abrasion resistance High Volume Fly Ash (HVFA) concrete mixes replace cement binder with fly ash at rates of 50% to 55% by weight. These m i x e s h av e b e e n d e v e l o p e d in recent years and have the advantage of reducing cement requirements while producing concrete with low permeability and lower heat of hydration. Masonry The use of concrete masonry has many sustainable benefits throughout the life of the structure. It is often obtained from local suppliers, and its thermal mass can be used for night time heat purge. Unlike light framed construction, masonry remains cool long after the air-conditioning has shut off, reducing cooling loads. Masonry also offers improved 22 THE INGENIEUR
indoor environmental quality by eliminating plaster or paint if an architectural finish is desired. The use of masonry construction also reduces the potential for mold growth because masonry does not provide a ready food source for mould. Additional benefits are gained by specifying lightweight or aerated concrete masonry units whenever feasible. These units decrease resource depletion, r e d u c e t ra n s p o r t a t i o n e n e r g y impact, and increase concrete unit masonry wall insulation values. Masonry construction also has benefits of recycled content including fly ash, slag cement, s i l i c a f u m e a n d r e cy c l e d o r
Sound reflecting of the soffit
salvaged aggregates, for all the same reasons cited for concrete [www.greenbuilder.com]. In addition to traditional concrete and clay masonry units, there are many alternative forms of masonry available today. Adobe is an especially environmentfriendly masonry product, using less than one-sixth the production energy of concrete block. Interlocking concrete masonry units for landscape retaining walls do not require mortar and are easy to disassemble and reuse or recycle. Use of salvaged marble reduces demand on nonrenewable virgin resources. Other salvaged materials such as brick and stone are readily available.
Sound reflecting of the flat soffit
Sound tansmiiting between work-cells
TRADITIONAL CEILING SOFFIT
Absorption control noise levels within work-cell
Coffers preventing shallow reflection propagating over distance
Acoustic screen making privacy between work-cells
THERMOCAST COFFERED SOFFIT
Steel Steel is the most recycled material used in modern building construction. In 2005 alone, almost 76 million tons of steel were recycled which corresponds to a recycling rate of 75.7% [www.recycle-steel.org]. Steel in all forms including cans, automobile parts and structural shapes is continually salvaged by various mills throughout the globe and can be made into new steel products of any form through one of two new technologies: the electric arc furnace (EAF) and the basic oxygen furnace (BOF). The primary method used in the production of structural shapes and bars is the EAF which uses 95-100% [www.aisc.org] old steel to make new. With this process, producers of structural steel are able to achieve up to 97.5% recycled content for beams and plates, 65% [www.recycle-steel. org] for reinforcing bars and 66% [www.aiacolorado.org] for steel deck. Total recycled content varies from mill to mill. Steel for products such as soup cans, pails, drums and automotive fenders is produced using the BOF process which uses 25-35% [www.aisc. org] old steel to make new.
In addition to the recyclability and percent recycled content of the materials used in building construction, the deconstructability of a building can be considered when evaluating its sustainability. For instance, using all-bolted connections in the structural framing system is one method for facilitating ease of deconstruction. As another example, the use of butted steel deck under concrete fill as opposed to lapped and welded metal deck also aids in deconstruction. Wood Of the many material choices designers have at their disposal, timber at first glance may appear the least sustainable. Discussions
of timber harvesting conjure images of clear cutting and global de-forestation. However, timber holds the distinction of being the only conventional building material that is renewable. Additionally, it is biodegradable, non-toxic, energy efficient, recyclable, and reusable. With more than one quarter of the world’s consumption of wood used in building products such as lumber, plywood, veneer, and particleboard, a shift in the way structural engineers utilize timber could have far reaching ecological effects. The three primary areas the structural engineer can promote the sustainable use of wood are: efficient framing, alternative products, and sustainable material suppliers. Conventional wood f ra m i n g p ra c t i c e c a n b e r e examined so that it is more efficient and less wasteful. Rethinking the way we detail light framed wood construction can significantly reduce a project’s wood waste. ●
Resource conservation can be considered in all stages of a project. These considerations include, but are not limited to material use, material source, construction process, and the end of a building’s useful life. Material, design and construction
Wood roof trust THE INGENIEUR 23
decisions have an enormous impact on the sustainability of buildings. The structural engineer has the opportunity to weigh these decisions with respect to the beauty, efficiency, function, constructability and budget of a building project. Design During the design phase of a project, the structural engineer can affect the sustainability of a project through (i) the choice of locally available resources, (ii) t h e r e c y c l a b i l i t y a n d reusability of materials and systems, (iii) the efficiency of structural systems, and (iv) i n f o r m e d ch o i c e s a b o u t demolition and preservation. Resource location is a determining factor in material choice. Local resources minimize the use of fossil fuels in truck transportation and potentially increase the efficiency of the building process. The structural engineer should be aware of locally available materials, and make effort to design using these materials. These materials would ideally be both harvested and manufactured in the local area. During construction, using local materials can result in shorter lead times, which can simplify logistics and speed up the construction process. Choices concerning labour resources should be made similarly, though in fact the structural engineer often has little influence in contractor selection. For many of the same reasons as with material selection, a projectâ€™s overall sustainability will benefit when contractors and labour pools are in close proximity to the project location. 24 THE INGENIEUR
In order to fully consider sustainability in the building design process, options other than demolition at the end of a buildingâ€™s useful life should be considered in design. Though an owner or architect would primarily make this decision, the engineer can facilitate this process by providing options for adaptability of the structure for other uses or reconstruction. The condition of the structure is often not the determining factor when a building is no longer useful. Adapting a building for other uses will conserve resources associated with demolition and reconstruction and also eliminate construction waste. Examples of adaptability include the conversion of warehouses to residential lofts and industrial buildings to recreational facilities. To ensure that a structure can last into future building uses, it must
to be designed for durability in a seismic environment or any other natural hazards to which it may be subjected. The structural engineerâ€™s choice of structural systems during the design phase also affects how a building can be adapted for future use. Buildings often change u s e ove r t h e i r l i f e t i m e , a n d therefore require reconfiguration of partition walls, openings, etc. For example, designing a building with exterior perimeter structure, such as a perimeter moment frame, and interior partitions allows the building to easily change configuration. Deliberate placement of structure can integrate with the mechanical systems, openings for light and natural ventilation, all which allow for an energy efficient building even with changes of occupants and uses over time. When adaptability is not an
the present and future use of a building. The engineer also has the unique opportunity to communicate the benefits of performance-based engineering in the selection of a structural system and its impact to the life cycle cost analysis of sustainable design investment.
Construction in progress
option, deconstruction is the next best alternative to demolition. The goals of deconstruction are not only to design for ease of disassembling the structure but also for the members to be reused in other structures. Generally, the principles are similar to those for constructability of a structure. Design practices that lend themselves to disassembly include the use of bolted connections in steel structures, pre-cast members in concrete construction, and prefabricated shear walls and metal fasteners in wood construction. Some of these principles may not be appropriate in high seismic areas, but may be appropriate to implement in low to moderate seismic environments. Modifying and reusing members consumes less energy than recycling. Lastly, recycling is still an option if the building or member cannot be reused. Recycled steel only consumes one quarter the energy it takes to produce virgin steel. Construction Decisions that the structural engineer makes during the design phase affect resource conservation during the construction process a n d t h e e n d o f a b u i l d i n g ’s useful life. In order to be better informed about the decisions a f f e c t i n g s u s t a i n a b i l i t y, t h e structural engineer and the entire design team can benefit from a contractor’s input and
owner involvement during the design process. The contractor is often more informed of material availability and recyclability than the rest of the design team. The contractor can inform the design team of typical dimensions and size of materials that can affect design decisions. This may add an additional upfront cost, but over the duration of the project can provide a more streamlined process and end result, and therefore minimize cost. Another factor that affects the construction process is the use of prefabricated elements, and the efficiency is even greater if a single unit type can be used repetitively in a project. Because prefabrication is typically done offsite in a shop under controlled conditions, it is easier to obtain more precise elements and a therefore a more efficient use of materials. Cost and material efficiencies are often found through mass production. Also, by producing the elements in a shop’s controlled atmosphere, material waste can be better and more easily controlled. Conditions can be established to control dust, noise and air pollution, and therefore minimize it on the construction site. These factors likely decrease the overall cost as well. Structural Systems The structural engineer has the opportunity to evaluate structural systems for their suitability for
Adaptability for Future Use
It is not uncommon for existing buildings to be partly or completely demolished before the lifetime of the building is near its end. This is mainly the solution owners seek when their individual buildings no longer serve as a desirable space for occupancy, whether the owner desires flexibility in the tenant space, or the surrounding neighborhood redevelops to cater to a different set of customer altogether. In order to make t h e m o s t o f e n e r g y, l a b o u r, and materials used during new construction, it is beneficial to consider possible changes in use or occupancy that may occur over the lifetime of the building. Future possibilities for use should be discussed, established and accounted for in the initial layout and design process. To allow for changes in use, consideration of floor vibrations can be made to ensure serviceability for a wider variety of future uses. The design load for floor systems can be increased from the minimum code level, not only to damp out vibrations, but also to support potential increases in load. For partial overhauls of gravity or seismic systems, a higher floor-to-floor height can allow for either deeper beams or a more open tenant space. The structural system layout can be designed to accommodate unknown future tenant THE INGENIEUR 25
improvements that will almost certainly occur during the life of a building. Large open spans in an initial structural layout allow for more architectural options within that layout. The potential elimination of a column requires a redundant system, and if designing in steel, beams could be switched out for stronger ones if the connections are bolted. Performance-based Engineering ●
Th e i nve s t m e n t o f d e s i g n effort and thoughtfulness in the implementation of sustainable systems of a building deserves a corresponding amount of thoughtful design effort and owner investment in the structural system of the building. If the conscientious intent of sustainable design includes conserving operating costs and resources in the building, maintaining and prolonging the useful life of the building, then the design approach should extend beyond the building shell to the building contents as well. The building and its contents together comprise the sustainable design system. The consequences of the structural performance on the building contents and systems should be considered because the building performance can protect and prolong the benefits of the sustainable systems and of the other investments that the owner has committed to. ●
Structural engineering is an integral part of sustainable design on a number of fronts: judicious and selective use of materials, resourceful use and application of structural systems, and provisions for future adaptability 26 THE INGENIEUR
of the buildings that are designed today. Material selection can be optimized, recycled and reclaimed or salvaged materials can be used. The performance, reliability, and reparability of structural elements in the seismic force resisting system contribute to sustainable d e s i g n . Th e v i a b i l i t y o f t h e structural system and building shell to accommodate future renovation becomes important. Structural design that considers the eventual deconstruction of a building increases the likelihood that the building components can be reused in another form. Collaboration with other design professionals is critical to the structural engineer’s successful role in a project - understanding lighting, stacking, thermal mass, cooling and heat gain strategies enables the structural engineer to anticipate and respond to these issues in the building structure. S t r u c t u r a l e n g i n e e r s h av e the opportunity to become an i n s t r u m e n t o f ch a n g e i n t h e industry. By encouraging the responsible use of our natural resources, and considering total building performance over its life cycle, we can proactively collaborate and participate in the ‘best practices’ of structural engineering and sustainable design.
Conclusion As the world’s population continues to grow and the need increases for more food, comforts and luxuries, we must learn to do more with less energy and materials. We must begin developing alternative and renewable energy sources that will be available when the known supplies of fossil fuels are gone.
We must also learn to turn our garbage into a resource. Today’s designers have to develop a ‘cradle to grave’ attitude in their designs. By thinking initially about the full lifecycle of a product and how it might ultimately be reused, designers and in particular, engineers can make great strides in helping to close the energy and environmental cycles. Closing the energy and environment cycles is certainly not an easy task. However, it is a necessary commitment if the human race wants to ensure our very own sustainable existence. We simply have no choice but to work towards this goal of (at least) stretching our resources. For the built environment, the building industry which has served mankind extremely well (in terms of comfort convenience and the like), now need to be at the forefront of this effort since we will not likely sacrifice all the comfort and luxury that we have grown accustomed to. BEM
REFERENCES 1. G. S. Kang and A. Kren, Structural engineering strategies towards sustainable design < www.ruthchek.com> 2. D. Wood, The structural engineer and sustainable design <www.douglaswood.biz> 3. P.K. Mehta, Fly ash, silica fume, slag & natural Pozzolans in concrete 4. Portland Cement Association, (PCA), Design and Control of Concrete Mixtures, 2005. <http://www.cement. org/concretethinking> 5. M. Pulaski, C. Hewitt, M. Horman and B. Guy, Design for deconstruction, <http://www. recycle-steel.org>
engineering & law
The JKR/PWD Forms (Rev. 2007): An Overview (Part 2) By Ir. Harbans Singh K.S. P.E., C. Eng., Advocate and Solicitor (Non-Practicing)
This paper was presented on November 8, 2008 at a talk organised jointly by the Bar Council Malaysia, The Society of Construction Law (KL & Selangor) and The Chartered Institute of Arbitrators (Malaysia Branch). The first part of the paper was published in the December 2008 - February 2009 issue of Ingenieur. The final part will appear in June - August 2009 issue of Ingenieur.
2.20 Completion of Works: Clause 39.0 The new clause is a welcome revamp of the previous Clause 39; retaining the old subclauses in essence but expanding upon these in the form of 4 new sub-clauses.
(e) I t p r e s u m a b l y g i v e s e f f e c t t o t h e judicial pronouncement in KC Chan Brothers Development Sdn. Bhd. V Tan Kon Seng & Ors  4 CLJ 659.
2.21 Damages for Non-Completion: Clause 40.0
Amongst the principal changes are: (a) It obligates the Contractor to initiate the practical completion process vide sub-clause 39.2; and (b) S u b - c l a u s e 3 9 . 3 s t i p u l a t e s a d e f i n e d procedure inclusive of definite time periods for the S.O. to take the necessary actions inclusive of reaching a considered decision as to either issue or reject practical completion; (c) I t p r e s c r i b e s , p u r s u a n t t o s u b - c l a u s e 39.4, the follow-up procedures pursuant t o t h e S . O.’s r e j e c t i o n o f t h e C o n t ra c t o r ’s application; (d) It stipulates vide sub-clause 39.5, the criteria for establishing whether practical completion had been achieved: and
The new provision is a reformulation and amplification of the previous Clause 40 bearing the same labels. It appears to incorporate the effect of Section 56(3) of the Contracts Act 1950 and a line of legal authorities governing the procedural aspects pertaining to the topic of LAD; However, in the light of recent local legal pronouncements, in particular of Selvakumar v Thiagarajah, in its present form and content, the new provision may be readily and most likely, successfully challenged; and Nevertheless, it spells out a clear and definite procedure for the imposition and in the process outlaws the current practice of deducting such damages merely on a “provisional” basis pending the final deduction.
THE INGENIEUR 27
engineering & law
2.22 Delay and Extension of Time: Clause 43.0 This clause is essentially similar to the previous provision bearing the same number and label, except for the following principal differences: (a) Some of the previous events entitling the Contractor for extension of time (EOT) e.g.: (i) Sub-clause 43(d): Insurance contingencies, etc.; and (ii) Sub-clause 43(h): Strikes, riots, etc. have been omitted; (b) Two new delaying events have been included, these being: (i) Sub-clause 43.1(c): Suspension of Works under Clause 50; and (ii) Sub-clause 43.1(g): Work Progress being adversely affected by delay in payment by the Government. (c) Three new provisos have been added to the granting of EOT; these being: (i) Delays not to be caused by Nominated SubContractors, Nominated Suppliers, etc.; (ii) Contractor to mitigate the effect of the delay; and (iii) There is no default/breach of contract by the Contractor. Most of the changes are procedural in nature and are meant to give effect to a number of judicial decisions, in particular, the High Court’s pronouncement in Gasing Height’s Sdn. Bhd. v Pilecon Building Construction Sdn. Bhd. (2001) 1 MLJ 621. The new clause is still deficient, in that: (a) It places the onus on the Contractor to apply for, and justify all applications for EOT, be these caused by the Employer’s Acts of Prevention, or Neutral Events; 28 THE INGENIEUR
(b) The prescribed EOT application procedure is a single step or unitary one combining notification with substantiation which is impractical and difficult to implement in practice; (c) It does not give any guidelines to the Contractor and the S.O. for the EOT application and assessment process; (d) It does not stipulate adequately and with clarity, the required contents of a typical EOT application; (e) It does not prescribe a definite period for the S.O. to make its assessment and decision; leaving it open-ended; (f) It does not deal with issues such as culpable delays, concurrent delays and delays of a continuing nature; and (g) I t d o e s n o t r e f l e c t c o n t e m p o r a r y international practice as prescribed, for example, in the SCL Delay and Disruption Protocol.
2.23 Claims for Loss and Expense: Clause 44.0 In essence, this clause expands upon the previous Clause 44.0: Loss and Expense Caused by Delays, by spelling out in the new subclauses 44.2 & 44.3 additional procedures for the claim process and in the event of defaults. Despite these revisions, the said provision is still deficient in the following principal areas: (a) Nowhere is the term “direct loss and/or expense” defined and, neither are the claimable heads of entitlements suitably identified; (b) There are no express stipulations prescribed for the keeping of contemporary records by the Contractor; an item which is critical to substantiation of such claims;
engineering & law
(c) It falls rather short of the corresponding prescriptions contained in the SCL Delay and Disruption Protocol; and (d) Sub-clause 44.3 is vague in its effect as to whether the Contractor’s common law rights are extinguished, or otherwise.
2.24 Access For Works, etc.: Clause 46.0 This provision is a reformulation and expansion of the previous Clause 23.0: Access for S.O. to the Works, etc. It obligates the Contractor vide sub-Clause 46.1(b) to step-down a similar provision in all its sub-contracts. Sub-Clause 46.1(c) spells out the procedure and consequences of the removal and replacement of any person(s) under sub-clause 46.1(c) and (b) whereas sub-clause 46.2 covers the situation vis-à-vis access for other Contractors and Workmen.
2.25 Sub-Contract or Assignment: Clause 47.0
Clause 47.0 is a reformatting and revision of the previous Clause 27.0: Sub-letting and Assignment.
Principal deficiencies are: (a)
Nowhere is the term “defect” defined;
(b) There is no express guidance on the amount of time that should be prescribed by the S.O. in the written instruction for the Contractor to undertake the instructed rectification Works; (c) The stipulated remedies for the Contractor’s failure to rectify are not exhaustive e.g. can the defects liability period be extended unilaterally by the S.O.?, or can separate LAD be imposed on failure to rectify?, etc.; (d) There is no requirement for the Contractor to investigate the cause(s) of any reported defect; (e) Procedurally, the clause is inadequate in that there is no mention of the keeping of records, or maintaining a register of defects, signing-off of records/register upon completion of defect rectification, possible extension of equipment warranties/guarantees, etc.; (f) Procedures involved in the replacement of defective parts, rebuilding of defective work, removal of defective items for “off-site” rectification/replacement, etc. have not been expressly spelt out; and
The principal changes introduced are: (a) The previous sub-clause 27(c): Employment of Sub-Contractors from within the district where the Works are situated has been deleted; and (b) A new sub-clause 47.5 governing the Employer’s rights/remedies in the event of the Contractor’s breach in sub-contracting without the S.O.’s prior written consent has been introduced. It is unclear in its reading whether the said rights/remedies are in addition to, or as an alternative to the Employer’s rights under sub-clause 51.1.
2.26 Defects after Completion: Clause 48.0 Save for some cosmetic changes, the new Clause 48.0 is essentially similar to the previous Clause 4.05 bearing the same title.
(g) Important post-defect rectification activities e.g. retesting, readjustment, updating of O&M manuals and ‘as-built’ drawings, etc. have not been stipulated at all but left merely for, perhaps, necessary implication.
2.27 Suspension and Resumption of Works: Clause 50 This is a wholly new provision governing the exercise by the S.O. of the power to suspend, either part or the whole of the Works. It prescribes the procedures and obligations of the Contractor and some of the consequential redress available to the Contractor should such suspension be initiated not due any default/neglect of the Contractor. THE INGENIEUR 29
engineering & law
Apparent deficiencies/omissions of this clause include, inter alia, the following: (a) It is very wide in its ambit. No grounds are prescribed and neither is the S.O. obliged to give a reason/reasons for invoking the said suspension clause; (b) No time period(s) and/or manner of the suspension is stipulated but is left solely to the discretion of the S.O.; and (c) It appears to be one-sided as it entitles only the Employer to suspend and completely glosses over/avoids practical situations where the Contractor may be compelled to exercise a similar move. Many reasons have been proferred for the inclusion of this new clause, in particular, the Employer’s attempt to comply with the ruling in Pernas Construction Sdn. Bhd. v Syarikat Pasabina Sdn. Bhd. (2004) 2 CLJ 707 has been cited by the drafters.
2.28 Events and Consequences of Default by the Contractor: Clause 51.0 This Clause appears to be the repackaging and relabelling of sub-clauses 51(a), (b) and (c)(i) to (iv) of the previous Clause 51.0 entitled “Determination of the Contractor’s Employment”. The principal differences noted are: (a) i.e.
The addition of two new performance defaults
(i) Sub-clause 51.1(a)(i): failure to commence Work at Site within 2 weeks of the date of site possession; and (ii) Sub-clause 51.1(a)(viii): failure to comply with any terms and conditions of the contract (b) The reformatting of the financial defaults in sub-clause 51.1(a); (c) Alteration of the mode of notification of the default and termination;
30 THE INGENIEUR
(d) Replacement of the label “Determination of the Contractor’s Employment” with “Termination of this Contract”; and (e) An expansion and amplification of the consequences of the termination. Although some of the revisions are positive and are therefore most welcome, the new clause is however “pock-marked” with a number of omissions/deficiencies which include, the following major ones: (a) The most commonly invoked performance default i.e. “regularly and diligently” is still not defined; (b) The inclusion of the new performance default entitled “fails to comply with any terms and conditions of this Contract” is, prima facie, very wide in its ambit and can be subject to possible abuse; (c) There is inconsistency in the terminology used e.g. termination of this Contract, termination of this Agreement, etc.; and (d) It fails to address pertinent issues pertaining to matters such as equipment warranties/ guarantees, retention of title, liens, etc. of sub-contractors/ suppliers, etc. which frequently are contentious items following the termination/determination.
2.29 Termination on National Interest: Clause 52.0 A wholly new and very controversial provision that will predictably generate much contention in the foreseeable future. It blankets the Employer with unilateral and unfettered power to terminate any contract by following a prescribed procedure on grounds such as “national interest”, “national policy” and “national security” though providing a compensation formula. The final arbiter as to whether a matter claimed falls within the purview of such a classification is the Employer whose decision is to be “final and conclusive and shall not be open to any challenge whatsoever” apparently inclusive of any judicial review.
engineering & law
Reliance has been placed on decisions such as PDC v Teoh Eng Huat & Ors (1992) 1 MLJ 749 and B.A. Rao & Ors v Sapuran Kaur & Anor (1978) 2 MLJ 148. Perhaps, instead of its current form, the said clause should have been simply formulated and labeled along the typical “Termination by Convenience” or “Termination Without Default” provisions found in other contemporary Forms of Conditions of Contract used locally.
2.30 Termination on Corruption: Clause 53.0 Another new provision which apparently has been drafted pursuant to the recent policy of transparency and accountability, or as a feeble attempt at good governance. It appears to be very wide and vague in its ambit; the decision in Chow Chee Sun v PP (1975) 1 LNS 10 being cited as being part of its inspiration. How it is to be translated into practice and implementation is a moot point and left to be seen. Perhaps, it is a mere “window dressing” or even a mechanism for possible abuse or selective victimization depending on the professionalism and/or political will of the ultimate enforcers. But for the moment it is on paper and will have to be given due effect to.
2.31 Effect of Force Majeure: Clause 57.0 A new provision, expanding upon and replacing the previous Clause 52: Effect of War or Earthquake. Comprising a total of seven sub-clauses, it defines the term “Event of Force Majeure”, stipulates its effect and consequences on the parties’ performance of the Contract, etc. The inclusion of this new clause is a positive development as it brings the JKR Forms to be in tandem with other contemporary Forms of Conditions of Contract both locally and internationally.
2.32 Site Agent and Assistants: Clause 58.0 Clause 58 is the revision and relabelling of the previous Clause 19.0: Foreman and Assistants. The principal revisions include: (a) The anachronistic term “Foreman” has been replaced with the contemporary label “Site Agent”;
(b) The previous word “competent” has been expanded to also include “…………. efficient, suitably qualified, experienced and good character”; and (c) The responsibility for the default in providing such personnel by the Contractor has been shifted to the Contractor instead of the previous alternative for the Government to provide a suitable replacement. Despite these seemingly cosmetic changes, this very important clause is still deficient in the following aspects: (a) It is not in tandem with contemporary practice which expressly, and in no uncertain terms, proscribes the Contractor from either commencing work, or proceeding with any work started should there be no suitable Site Agent on Site; (b) The usual remedy for the Contractor’s default in providing a Site Agent full time on Site i.e. the Employer’s right to order Suspension of Work at the Contractor’s cost with a commensurate deduction so long as the Site Agent is absent from Site, has not been expressly prescribed; and (c) The S.O. is nowhere given the express power and authority, as is the contemporary practice in other Forms, to decide on the suitability and competency of the Site Agent for the purposes of the Contract in question.
2.32 Arbitration: Clause 65.0 This Clause is a revision of the previous Clause 54 bearing the same label. The principal changes include: (a) An increase in the number of sub-clauses from 9 to 11; (b) Redefinition of the term “dispute or difference” in respect of the invocation of this Clause; (c) The Employer can also now make a reference to Arbitration; (d) Parties are also expressly permitted to make any counter-claims; and THE INGENIEUR 31
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(e) The previous Arbitration Act 1952 (Rev. 1972) has been replaced with the recently enacted Arbitration Act 2005.
(b) Instead of the Employer bearing the Stamp Duty as was the case previously, the obligation is now transferred to the Contractor; and
Despite the said revisions, the new provision is still deficient, in that:
(c) It purportedly reflects the decision in the case of Koperasi Setiaguna Kebangsaan Bhd. v Pemungut Duti Setem, Wilayah Persekutuan, Kuala Lumpur (2003) 8 CLJ 223.
(a) It is very narrow in its ambit i.e. merely involving arbitration. It should have been formulated for a wider scope encompassing “Dispute Resolution” and should have been labeled as such; and (b) It does not include and reflect contemporary (both local and international) dispute resolution methods such as amicable settlement, mediation/ conciliation or adjudication, as a prelude or precondition to eventual resorting to Arbitration.
2.33 Notice, etc.: Clause 66.0 A redrafting of the previous Clause 6 spanning 4 sub-clauses and covering all the important facets of issues such as notices/communications between the parties inclusive of the form, mode of communication and the effects of such matters. Interestingly and unfortunately it has side-stepped such contemporary modes of communication such as facsimile transmission, electronic mail, etc.; which modes form the essential component of prevailing practice in the industry.
2.34 Amendment: Clause 67.0 Another new provision encompassing the question of, and effect of any modification, amendment or waiver of any parts of the contract. It mandates the necessity of mutual consent and formalisation through a supplementary agreement of such matters.
2.35 Stamp Duty: Clause 68.0 This Clause is a reformulation and revision of the previous Clause 55.0 bearing the same label. The principal changes include: (a) In addition to the Stamp Duty under the Stamp Act 1949, other costs such as legal costs and fees in the preparation and execution of the contract and other incidental costs are now included expressly; 32 THE INGENIEUR
2.36 Severability: Clause 70.0 A new provision has been introduced as a “saving provision” in the event of any clause/ clauses of the Contract been held to be illegal or invalid.
2.37 Waiver: Clause 71.0 Another new inclusion governing the issue of both express and, especially, implied waiver consequent to the act or omission to act by either party to the contract.
2.38 Laws Applicable: Clause 72.0 A new Clause reinforcing the previously implied position on the application of Malaysian Laws and resort to Malaysian Courts by the parties to the Contract.
2.39 Successors Bound: Clause 73.0 Another new provision governing the liabilities of the various parties, in particular, the successorsin-title.
2.40 Epidemics and Medical Attendance: Clause 74.0 A new clause dealing with important facets of health and safety issues.
2.41 Technology Transfer: Clause 75.0 Another new inclusion applicable in situations where foreign professionals (presumably also specialist sub-contractors) are engaged for the Works and the necessity for them to transfer the particular expertise or technology within their remit to the locals.
engineering & law
2.42 General Duties and Performance Standard: Clause 76.0 A wholly new provision, which perhaps is an afterthought but should have been part and parcel of Clause 10.0: Obligations of the Contractor. Encompassing a total of three sub-clauses, this clause mandates the Contractor to perform the Works under the Contract competently along good industry practice and with a primordial purpose of safeguarding the Employer’s interest. Essentially, it is a very nebulous and general provision whose actual effectiveness is left to be seen in practice.
2.43 Restriction and Procedures on Use of Imported Materials and Goods: Clause 77.0 Another new provision that was previously more often than not, included in the “Preliminaries”
section of the Contract Documents. As aptly labeled, it mandates the use of local goods/materials, the exceptions to this requirement and the attendant procedural requirement as to testing, approval, mode of importation, etc.
2.44 Time: Clause 78.0 A new clause stipulating that time whenever mentioned shall be of essence to the Agreement; which clause whose usefulness is dubious and whose legal ramifications is a moot point.
2.45 Appendix to the Conditions of Contract In line with the revision, reformulation and redrafting of the previous Conditions of Contract, the Appendix has been accordingly updated and amended. BEM
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Incorporating Electro-Magnetic Compatibility Design Into Mission Critical Facilities Case Example: Aljazeera English TV Studio & Broadcast Facility on Level 60, Tower 2, Petronas Twin Towers, Malaysia By Ir. Satha A. Maniam The mission critical facilities of today, contain large numbers of high speed computers and communication equipment which place significant demands on supporting infrastructure. An engineering facet that is often overlooked is that of Electromagnetic Compatibility (EMC). With today’s mission critical facilities, the incorporation of EMC design is no longer a choice, rather, it’s a MUST. EMC covers a broad spectrum of electrical engineering and includes Electromagnetic Interference (EMI), Radio Frequency Interference (RFI), Lightning & Surge Protection, Grounding & Bonding, Power Quality (PQ), and Electro-Static-Discharge (ESD). This paper is intended to provide a broad outline of some of these EMC considerations, and it discusses in depth the issues related to ‘Electrical Ground Noise’ management and ‘Clean Earths’. ‘Clean Earths’ are sometimes referred to as ‘technical earths’ or ‘system earths’ or ‘functional earths’. The paper will take an actual case example, that of Aljazeera English, a TV Studio & Broadcast facility built on Level 60 of Tower-2 of the Petronas Twin Towers (PTT), where the EMC measures were incorporated at the design stage. The term ‘equipment’ referred to in this paper, applies to that of the TV Studio and Broadcast equipment, and not that of the electrical infrastructure. 34 THE INGENIEUR
lectro-Magnetic Compatibility (EMC) is the ability of an equipment or system to function satisfactorily in its e l e c t r o m a g n e t i c e nv i r o n m e n t without introducing intolerable electromagnetic disturbances to anything in that environment. A product and its associated equipment often carry their i n d iv i d u a l ‘ C E ’ m a r k . It is essential that one realizes that the ‘CE’ mark is a statement of conformance by the manufacturer. The ‘CE’ mark does not carry the endorsement of any certifying body or authority that it actually is compliant. This mark is a self declaration by the manufacturer, where the manufacturer states that it has been designed and tested to meet the necessary EMC requirements in terms of immunity and emissions. Besides the product, it is essential that the system, and the installation too be compliant from an EMC stand-point. This would, besides the specific ‘CE’ equipment themselves, include the power supply distribution system, the grounding systems, the data and signal sub-systems, and even the topology of the cabling. Furthermore it is essential that the complete facility or system be electo-magnetic (EM) compliant in respect of the expected EM e n v i r o n m e n t i n wh i ch i t i s installed. For eg., the isokeraunic and corresponding lightning flash density levels in Malaysia are amongst the highest in the world, and due consideration should be given for this aspect of EM Interference.
Equipment Ports A device or equipment may be affected by impinging EM disturbances through one or more
‘entry’ paths called ports. These are the AC Power Port, DC Power Port, Control Port, Signal Port, Earth Port, and the Enclosure Port.
EM Coupling Mechanisms E M I n t e r f e r e n c e g e n e ra l l y occurs through one or more of the following mechanisms: Conductive or Resistive coupling, Inductive coupling (near effect), Capacitive coupling (near effect), and Electromagnetic or Radiated coupling (far effect). The acronym RICE sums it up nicely!
Typical Mission Critical Facility Quite often, an electrical designer’s perspective for a mission critical facility, would be in respect of redundancy in power supply ie. dual power intakes, dual standby gen-sets, dual UPS; a well Graded Protection System; ‘Star-Point Grounding’; ‘Clean Earths’; ‘1 Ohm Grounding’, etc. Interestingly how does one implement a ‘clean earth’ at Level 60 of the PTT?
Challenges Faced In This Project The two sources of electrical power had to be brought in from different floors, of which one source comprised a cable run of many floors. A facility such as this, would use a lot of single phase equipment, resulting in the generation of significant harmonics, including triplen harmonics. Triplen harmonics, a power quality issue, can cause excessive neutral current flow (up to 1.7 times that of the phase current), which would in turn effect cable voltage drops over the long run,
along with the associated elevated temperature. As a consequence of the i n c r e a s e d vo l t a g e d r o p , t h e equipment would also experience a higher common mode (NeutralEarth) voltage which could affect the correct operation of the equipment. As the equipment communications are based on a mix of balanced and unbalanced signalling, it was imperative that resistive or conducted coupling, and inductive and capacitive (near field) coupling to the cables be reduced, especially so in the case of data or video feed cables using unbalanced signalling. Besides the harmonics generated by the equipment, the dimmers too (which were being used for controlling the lights of studios), were yet again, another source of harmonics. Harmonics as we all know can be a potential source of EMI. The next challenge was the ‘clean’ or functional grounding system. A facility of this nature, would have significant electrical ground noise which could cause further EMI to equipment. Hence, when one looks at the design, from an EMC perspective, one can clearly see that there other challenges that need to be addressed. Some of the issues which were implemented in this project, are listed here.
‘Electrical Ground Noise’ There are many sources of ‘electrical ground noise’, eg: currents shunted to ground through the line-ground capacitances present in power supply modules and filters; currents shunted t o g r o u n d t h r o u g h t h e s t ray capacitances between the insulated windings of a motor and the frame THE INGENIEUR 35
of the motor which is grounded; currents shunted to ground through stray capacitances between cables and the ground itself. The lower frequency spectrum of noise ranges from that of the power supply frequency of 50Hz, up through the range of expected harmonics. The higher frequency noise is generally due to the higher clocking and signaling rates present in today’s electronic equipment, especially the abrupt change from one signal logic level to the next. All these ‘noise’ must eventually return to the driving source of the energy. In the case of power related ‘electrical ground noise currents’, or leakage currents, it must return to the source, ie. the star point of the upstream delta/wye transformer. If this star point were located some distance away, these ‘noise’ currents would flow ‘all over’ the multitude of ground paths via the network of grounding conductors to return to the neutral star point. However, as the electrical ground noise currents proceed through these numerous paths, they create potential differences between the equipment at different portions of the grounding network. It is these resulting potential differences that cause problems for equipment, especially for those that use low level common mode signaling. Hence the concept of ‘no-ground-loops’!
suited for low frequency analogue systems, and that too for small facilities such as rooms. With today’s facilities housing large numbers of high speed digital electronics, this concept is not suitable. For one, there is the issue of impedance of the grounding conductors. Next there is also the issue of parasitic capacitance between cables and the ground, and together with the self-inductance of cables, can result in resonance conditions. It should also be noted that implementing ‘ground-with-noloops’ is impractical in facilities with a multitude of interconnected equipment dispersed over a large area.
Impedance Vs. Resistance Resistance and impedance: the former is independent of frequency, and the latter is dependent on frequency. From a fault current carrying viewpoint, and considering the
relatively low power frequency, the typical ‘green’ electrical cables (ie. the circuit protective conductors or CPC) used are sufficient. Hence we normally associate these cables with resistance. However when we look at ‘electrical noise’ management, the impedance offered by these CPC, especially at the higher frequencies, is too high. Furthermore with just one CPC, resonance conditions may result in this grounding conductor going into open circuit – resulting in an open circuit for the noise currents in that range of frequencies. This brings about the need for functional conductors (in addition to the green CPC). Normally these are in the form of short flat straps or copper tapes which offer lower impedance. Quite often these functional conductors are bonded to mesh earth systems and the Common Bonded Network (CBN) offering a multitude of parallel low impedance ground paths (seemingly in direct contradiction
The concept of star point grounding was introduced to avoid the issues and problems caused by common mode currents in ground loops. However it must be appreciated that star point grounding is more 36 THE INGENIEUR
Star Point Grounding
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to the long held concept of ‘noground-loops’ !!!).
‘Clean Earth’ The term ‘clean earth’ needs to be clarified. For many, ‘clean earth’ is a network of grounding conductors different from that of the CPC, normally in star point configuration, and in some cases these grounding conductors use external ground rods that are not bonded into the common earth network. Even if they are bonded into the common earth network, the long runs of the earth cables (especially for those with higher currents) behave like antennae emitting radiated noise. First and foremost, in most situations, Common Earth Network is the way to go. Next, ‘clean earth’ is NOT a separate magic earth. A ‘clean earth’ is a network of grounding conductors of sufficiently low impedance such that even with noise currents flowing within the grounding conductors, the equipment connected at different portions of the grounding network do not see any potential difference between themselves. The grounding network should also minimize the risk of concentrated current flow which might result in radiated emissions from the grounding conductors themselves. Hence the direction, is towards multi-point grounding, rather than the star (single point) grounding. Th e r e a r e d i f f e r e n t w ay s of implementing a multi-point grounded system, and one of the more established ones is the Signal Reference Grid.
Signal Reference Grids Signal Reference Grids (SRG) are a marvelous engineering 38 THE INGENIEUR
answer to the issues described above. SRGs offer very low impedance (across a broad frequency spectrum) and hence result in very low potential difference. SRGs offer a multitude of alternate ground paths and hence allow for good low impedance connectivity even while one or more paths may be facing open circuit resonance conditions. SRGs also keep the current density very low resulting in minimal radiated noise from the grounding conductors. SRGs can also serve as a Parallel Earth Conductor (PEC) for cables laid on it, reducing the loop area of signal cables, and reducing the transfer impedance of cabling systems. In short, SRGs are an excellent solution for electrical noise management and ‘clean earths’. Does the SRG need an earth pit to make it ‘clean’. The answer in short, is ‘NO’. Does the SRG need to be bonded into building steel/earthing system? It really depends on the design purpose of the SRG. An SRG can serve many functions. As such, it is important that one understands the design purpose of the SRG, based upon which, the ‘earth-grounding’ schema for the SRG could be defined.
Isolation Transformers Isolation transformers are often used to establish a separately d e r ive d s o u rc e ( w i t h a n e w neutral), for say, a computer room of a facility. The type of isolation transformer selected is often governed by the need for power quality. For eg. K-rated delta/wye transformers are used to handle harmonic currents and trapping of triplen harmonics;
zig-zag configurations are used to offer lower impedance to harmonic currents. An isolation transformer with effective shielding between the input and output windings also offers reduction in the coupling of common-mode transients between the primary and secondary windings. Common-mode noise, ie. Neutral-Earth voltage is an important criteria for IT equipment. Quite often the neutral of an isolation transformer is ‘hauled’ all the way back and bonded to the main transformer neutral or to an external pit in the ground. This defeats the purpose of introducing a separately derived source to minimize Neutral-Earth voltage. Furthermore it should also be appreciated that the isolation transformer serves as a ‘current collector’ or ‘sweeper’ to ‘pick-up’ any electrical ground noise from downstream equipment powered by this isolation transformer. By the noise returning directly to this isolation transformer, we minimize the impact of stray noise currents (from these downstream e q u i p m e n t ) t rave l l i n g i n t h e grounding conductors of upstream grounding systems. For an isolation transformer to be effective in both these respects, ie. low common-mode voltage, and to also localize the travel of ‘noise currents’, it is essential that the Neutral-Ground of the transformer be grounded within the vicinity of the computer room. A Delta/Star isolation transformer a l s o s e r ve s t o ‘ t ra p ’ t r i p l e n harmonics generated by the loads from propagating upstream of the transformer. An isolation transformer selected properly, installed at the right location, and connected correctly, can result in improved power quality
management, improved isolation from upstream noise, reduced neutral-earth or common mode voltage/noise, reduced commonmode transients, localization of downstream electrical ‘ground noise’, and removal of triplen harmonic currents.
Isolation Transformers + SRG + CBN Isolation transformers are best used with SRGs, where the NeutralGround of the isolation transformer is bonded to the SRG within the vicinity of the computer room. For safety (as in the case of a fault within the transformer) the Neutral-Ground of the isolation transformer should also be connected via a CPC to the upstream Main-Earthing-Terminal, or the building Common Bonded Network (CBN).
Cable Layout Or Topology Cable layout or topology is another very important element that is often overlooked. To minimize the near and far effects of electromagnetic coupling, the phase, neutral and CPC should be bundled together. In the case of a single phase s u p p l y t h i s w i l l i nvo l ve t h e live, neutral, and CPC. In the case of a three phase system, it would include all the three phase conductors, the neutral conductor (if present), and the CPC. To f u r t h e r r e d u c e t h e susceptibility of cables to the EMI as mentioned above, the cables should be laid as close as possible to the Parallel Earth Conductor (PEC). The PEC will reduce the transfer impedance of the cables, as well as reduce the loop area of cable systems. The PEC could be implemented in the form of a
continuous cable tray grounded at both ends, or in the case of a SRG, the SRG itself. The above applies to power cables. In the case of signaling cables, similar principles apply.
Segregation Of Classes Of Cables It is essential that the different categories or classes of cables be adequately segregated such that they do not affect each other unduly. For eg. low level I/O cables should never be mixed together w i t h p ow e r c a b l e s . A n o t h e r example is in the case of very noisy cables such as those feeding the power of Variable Frequency Drives – these cables should be kept well away from less ‘noisy’ cables. In cases of cables with filters, the unfiltered portion of the cable a n d t h e d ow n s t r e a m f i l t e r e d portion of the cable should not be bundled together nor run adjacent to each other.
Bonding Bonds between painted or epoxy surfaces should not be accepted. It is essential that all bonds and joints provide electrically conductive low impedance paths across the bond.
Quality Of Racks & Typical Grounding Techniques If you take a rack from the 70’s or 80’s, you will observe the build quality in respect of the intent of grounding. Today’s equipment racks fall far short in this respect. It is essential that racks serve as a PEC, and that there is proper continuity between the elements of a rack. The epoxy-based racks
of today do not provide proper leakage paths for the leakage currents of equipment mounted on the racks. Racks with metallic conductive surfaces, such as galvanized or chromed surfaces, are more suited for this. Bonding of equipment within a rack by looping is a very poor approach to grounding and should be avoided. Ideally the equipment should be bonded to the rack by direct mating of the metallic conductive surface of the equipment against the metallic conductive surface of the rack. This constitutes a low impedance bond. Bonding of racks to racks (ie. looping) before returning to the main grounding point within the room is another poor approach which should never be used. This causes potential differences between interconnected equipment on different racks of the same row, as well as potential differences between interconnected equipment mounted on different rows.
Grounding Of Racks Via The SRG The CPC which are terminated on rack equipment, should be bonded to the rack as well. The equipment should have good electrically conductive bonding to the rack in which it is mounted. It is also essential that a low impedance functional grounding network be provided to bond the racks to the separately derived source. This purpose of the functional grounding network is to handle the ‘noise’ currents that may not flow through the CPC (as for example when the CPC offers high impedance). This is best done by implementing an SRG, and bonding the rack to the SRG through short wide flat bonding THE INGENIEUR 39
as we have very high lightning activity. It can manifest itself in terms of equipment mal-operation, equipment failure, as well as nuisance tripping. The mitigation of this EMI is yet again another element that appears to be like a â€˜Black Artâ€™ when really it is not! It must also be stressed that the Common Earth Network should include that of the lightning protection system.
Power Quality Lightning surge protector
straps. It is recommended that at least two such straps be used (of different lengths) for each rack.
Cable Shielding Shielding of cables is very dependent on the quality of the shield used, the manner of termination (for eg. pig-tails is not good), and the grounding of one or both ends. The choice of one or both ends should be done carefully as there is the risk of current flow through shields if both ends are grounded. Ideally both ends should be grounded at the respective grounded enclosures for maximum effectiveness, with the cable laid on a grounded PEC along its length. In the case where an SRG is implemented, the preferred approach is laying the cable on the SRG (SRG as PEC), and bonding both ends of the cable shield to the respective equipment, which are in turn grounded to the SRG. The SRG in this case offers a multitude of very low 40 THE INGENIEUR
impedance paths to noise currents which might otherwise flow on the cable shield. It should also be noted that shielding of cables is harder to achieve at low frequencies (as compared to higher frequencies), and the cheaper and more effective alternative in this case is by utilising spatial segregation.
Enclosure Shielding This is used to protect an equipment from the effects of external EMI. Shielding works on the principle of absorption and reflection of energy. Enclosure shields are normally used together w i t h f i l t e r s a n d wav e g u i d e s as cables enter and leave the enclosure, as well as for ventilation purposes.
Lightning & Surge Protection This is another large facet of engineering that needs to be integrated into the overall design of a facility. This is a major element that causes lots of problems in Malaysia
Poor quality too, is another critical aspect of engineering, which should be incorporated at the design stage of mission critical facilities. Th i s w o u l d i n c l u d e t h e topological approach to cabling; segregation of feeders for sensitive and heavy loads; choice/type/ location of isolation transformers; effective use of the separately derived source including that of the UPS; utilization of Surge Protective Devices to limit Switching Surges and Transients; active and passive filters to name a few.
Tripping Issues Tripping normally occurs as result of an actual fault condition, or a voltage dip. However, another problem that tends to occur is the inadvertent tripping of one or more protective devices be it RCCBs, or ELRs, or MCBs, or even cascading trips of MCCBs. These occur for a variety of reasons: poor discrimination; standing leakage currents; cascading MCCB trips during an earth-fault (with 3-pole MCCBs for 3-phase, and 1-pole MCBs for 1phase systems); tripping of MCCBs with Neutral pole due to excessive
This will involve humidity control, types of flooring especially the conductivity of carpets and tiles, grounding of raised floors, and provision of grounding points at equipment areas, amongst others.
Incorporation Of EMC Design
Moulded case circuit breaker
harmonic neutral current; tripping of multiple MCBs on recovery of DB bus voltage on clearing of a fault, etc. A mission critical facility is dependent on the continuous availability of power, and because of this, there is so much redundancy built-into the system, to make it extremely resilient. Yet, simple and common issues cause inadvertent tripping. Many of these issues may be addressed at the design stage. The protection system employed or implemented needs to be immune to the common issues that cause these unnecessary trips.
Electro-Static Discharge Electro-static Discharge (ESD) is another element that ought to be considered and implemented at the design stage.
The implementation of EMC does not just happen by chance. It needs to be engineered into place. Quite often it is not implemented at all! The practices of ‘yester-year’ are no longer applicable for the demands of today’s mission critical facilities. There are numerous documented cases of EMC related problems. Unfortunately, the mitigation measures are put into place only after the facility is built and problems are encountered. These subsequent measures are often limited in their effectiveness and are often implemented at much higher costs. EMC design requirements should be incorporated at the design stage of a facility.
System Engineering & Integration All of the EMC concepts mentioned earlier, need to be system engineered and integrated on a system-wide basis for all the relevant elements of the facility. This will not only include the electrical sub-system, and the facility ‘equipment’ (such as TV Studio & Broadcast equipment), but also the lightning protection system, and the support infrastructure such as the BMS, the Security, Voice & Data, etc. It is no longer a situation of independent systems, but rather inter-dependent systems,
that must co-exist in harmony in an increasingly challenging electromagnetic environment!
Supervision Of Facility During Construction The proper implementation of these requirements needs very stringent and experienced levels of supervision. It is essential that the supervision be done by one who is familiar with the subtle nuances of EMC.
Post Construction Change Control Once a facility is built and handed over, it undergoes changes during its lifecycle. This may be an interior design fit-out, or an expansion. It is essential that a facility built to these standards implement strict change-control measures to ensure that any future changes do not compromise the EMC integrity of the facility. BEM
ACKNOWLEDGEMENT I wish to thank Mr Keith Pierce of Aljazeera English, for his kind permission to use their facility at the Petronas Twin Towers as a case study.
BIODATA Satha A. Maniam, the Managing Director of Acuity System Consultants Sdn Bhd, has a B.Tech in Electrical Engg. from IIT Madras, and an M.Sc. in Comp. Sc. from UCL London. He has provided these ser vices for the following sectors: Aviation, Building, Water, Electrical, Oil & Gas, Rail, Telecommunications, Broadcast, and Satellite Earth Stations. He is contactable at: satha@acuity. com.my
THE INGENIEUR 41
Riding The Economic Tsunami: Investing In Local Workforce And IBS Construction Technology By Ir. Shahrul Nizar Shaari Technology Director, Innovacia Sdn Bhd
he current global economic tsunami that was started by the subprime borrowers’ crisis in the United States has finally hit our shores. According to the Ministry of Human Resource1, almost 18,000 factory workers have been retrenched in the period between October 2008February 2009. The latest figures released by Bank Negara stated that the economy grew 4.6% in 2008 compared with 6.3% in 2007 2 . The Gross Domestic Product (GDP) growth in the Final Quarter of 2008 registered 0.1% growth compared with 4.7% in Q3. The poor results were led by the massive decline in the manufacturing sector; especially in the electronics sector as orders from overseas were cancelled. The construction sector has always provided ‘early warning signals’ on the economic state; and for Q4 of 2008, it registered a negative growth of 1.6% (1.2% growth in Q3). It brings grave concern to industry players as the results were for 2008; right in the middle of the Ninth Malaysian Plan (9MP) 20062010. It was when the industry was supposed to be at its peak; as most of the projects should have been mid-way in implementation.
42 THE INGENIEUR
Are we ready enough to survive the economic tsunami? H i s t o r i c a l l y, d u r i n g t h e past downturns, the Malaysian Government has always been successful to quickly bring the
country out of recession through its stimulus packages. At the time this article was written, we were all anticipating the announcement of the second stimulus package or mini-budget that was formulated to complement the earlier RM7 billion (US$ 1.93 billion) package;
1 Penyata Rasmi Dewan Rakyat 2 Mac 2009, Parlimen Malaysia 2 Economic and Financial Developments in the Malaysian Economy in the Fourth Quarter of 2008, BNM Press Statement, Bank Negara Malaysia, 27 February 2009
wh i ch wa s c o n s i d e r e d q u i t e low compared to the packages announced by other countries. As highlighted in Table 1, the figures for Malaysia are the lowest among the four ASEAN countries quoted in the comparison. Nonetheless, it is expected that the second package will be more comprehensive and able to stimulate the Malaysian economy and support its entire population. Table 1: Comparison of Stimulus Packages (Total)3 (Before March 10, 2009) Country
* Before 2nd stimulus package
Issues on Workforce Economic downturns generate negative effects on the social wellbeing of affected communities. The risk for Malaysia is even higher due to higher dependency on foreign workforce. As at the Third Quarter of 2008 4 , the total Malaysian workforce is 11.1 million; out of which 343,700 Malaysian are without jobs, contributing to the 3.1% unemployment rate. While the country is depending on 10.78 million Malaysian workers, there are also a total of 2.06 million5 registered foreign workers in the country. As such, the total combined workforce in Malaysia
stands at 12.84 million and 16% of the workers are foreigners. The total figure is even more alarming should the number of foreign workers include the illegal ones. Using estimated figures of 600,000 Pekerja Asing Tanpa Izin (PATI) released by the Immigration Department, the foreign-to-local workers ratio stands at 1:4; leading to an astonishing figure of RM15.5 billion6 outflow of money through local banks. Imagine what would h a p p e n s h o u l d t h e M a l ay s i a economy plunge really deep into recession and jobs were cut massively. What would happen to the millions of foreign workers? Would they immediately leave the country or decide to stay? Would they find a decent alternative job? Issues affecting the local construction industry are even worse as it has among the highest percentage of foreign workers. The Malaysian construction has long been dependent on foreign labour. In fact, as presented in Table 2, the number of legal foreign workers increased from 49,080 in 1999 to 306,873 in 2008 7 ; which was more than a six-fold increase. These figures are very disappointing; considering that 343,700 Malaysians are without jobs. It is even more frustrating should the figure of foreign workers include those who are h e r e wo r k i n g w i t h o u t g o i n g through the proper channels. It is an undisputed fact that in any construction worksite,
3 4 5 6 7
Table 2: Number of Legal Foreign Workers in Construction Industry (1999-2008) Year
Foreign Workers (No.)
almost all of the wet trades are being executed by foreign workers. Even more worrying is the fact that more are being given larger responsibilities at sites by becoming site supervisors. The locals are generally working at the management level or as workers for the dry trades such as wiremen and crane operators. Now where do the local workers go? Did they opt for better workplace environment in other industries? The author beg to differ as currently we can see more and more businesses opting for foreign workers - from the concierge of established six-star shopping arcades to waiters at Mamak restaurants; and from attendants of public toilets in Pertama Complex to security guards attending to million Ringgit worth of properties in Mont Kiara.
J.S. Sidhu, Budgeting for Crisis, Starbizweek, The Star, 28 February 2009 Laporan Suku Tahunan Penyiasatan Tenaga Buruh Malaysia- Suku Tahun Ketiga 2008, Jabatan Perangkaan Malaysia Jumlah Pekerja Asing di Malaysia Mengikut Negara Asal, 1999-2008, Kementerian Dalam Negeri Malaysia 65,000 Pekerja Asing Dihantar Pulang, Berita Harian, 12 Januari 2009 Jumlah Pekerja Asing di Malaysia Mengikut Sektor, 1999-2008, Kementerian Dalam Negeri Malaysia THE INGENIEUR 43
can we, “theWhat engineers,
IBS Masterpiece - the Kuala Lumpur Convention Centre
Go IBS. Go Local. The issue is very serious as we would be losing a generation of local construction tradesmen. The number of foreign workers dwindled during the recession in mid-1980s and end 1990s but once the economy started to boom, there was a manic rush to get workers to complete construction projects; many of the workforce were obtained illegally. The new group of workers, unfortunately inexperienced and untrained, were recruited to complete the projects. Are we going to experience another cycle here? Yes, without a doubt. As a result, it would bring very negative repercussion to Malaysia economically and socially in the long run. Contractors need to spend more time and money training their workers; officially or in most cases, by experience. Low productivity and quality is still rampant in the industry. Rectification works delay handing over of projects; and repair works during defect liability period create disruption to businesses and generate greater problems for many parties. As such, it is very difficult for the Malaysian construction sector to be globally competitive. What actually encourages the high number of foreign workers in the Malaysian construction industry? Industry 44 THE INGENIEUR
stakeholders argue that the main reasons include poor enforcement by authorities, reluctance of locals to work in difficult environments and the relatively low salary that the foreigners are willing to receive compared to locals. What can we, the engineers, contribute in helping the nation to reduce dependency on foreign workers? Quite a lot. It is true that we are not able to directly eliminate the three main reasons stated above. However, indirectly, we can start by revisiting construction technology that affects the way we think, plan, design and construct. The Malaysian construction sector i s s t i l l c u r r e n t l y ve r y m u ch reliant on conventional or in-situ construction. Unfortunately, the traditional methods use a lot of manpower; thus leading us to dependency on foreign manpower and its negative consequences. As such, the industry must change by reducing wet trades in the process. This can be achieved by a construction method known as the Industrialised Building System (IBS). IBS is a construction technology that involves manufacturing of prefabricated components in a controlled environment that are
contribute in helping the nation to reduce dependency on foreign workers? Quite a lot
later brought to construction sites for assembly. According to CIDB Malaysia, there are five main IBS Groups identified as popularly being used in Malaysia: precast concrete, formwork, steel frames, prefabricated timber frames and blockwork systems8.
Better Quality & Productivity with IBS The co-ordinated initiative by the Malaysian Government in promoting IBS started six years ago with the formulation of IBS Roadmap 2003-2010. The Government has pledged a total of RM9.2 billion9 worth of projects to be executed using IBS. It is expected that IBS will again be given priority in the new projects that are to be announced in the upcoming second stimulus package. CIDB Malaysia has also established a dedicated reference centre for Government agencies and industry players, the IBS Centre, in Kuala Lumpur 10. Subsidised IBS trainings are being offered to professionals, contractors
8 Part of Second Stimulus Plan Will Focus on Construction, New Straits Times, 24 January 2009 9 IBS Centre, IBS Digest@MIIE’09, CIDB Malaysia, 2009 10 Abby Lu, To IBS…or not, New Straits Times, 13 February 2009
Subsidised “ IBS trainings are being offered to professionals, contractors and installers (workers). Besides that, tax and levy incentives are also being offered to industry players
and installers (workers). Besides that, tax and levy incentives are also being offered to industry players. Wi t h I B S , w e t t ra d e s c a n be greatly reduced, and with requirement of less labour due to the prefabricated components, it also promotes better quality, productivity and safety at construction sites. It also reduces the hidden costs associated with the high number of manual labour such as rectification, healthcare, security and accommodation costs. As construction processes are being simplified through IBS, it will reduce the 3-D ( D i r t y, D i f f i c u l t , D a n g e r o u s ) syndrome often associated with t h e c o n s t r u c t i o n s e c t o r. Th e structural building portions will join M&E works as ‘dry trades’. As a result, it will attract more locals to join the construction workforce. Th e G o v e r n m e n t i s v e r y committed in eliminating the 3-D
The IBS Centre, Kuala Lumpur
syndrome that has been plaguing the construction sector. As experienced by Dubai’s Dynamic Tower construction team, using IBS instead of conventional method, reduced the number of workers to only 30%. In order to highlight the potential savings, let us assume that a local IBS skill worker demands RM120 per day and a foreign worker gets RM40 per day. With 30 local workers, the cost per day is only RM3,600 while the cost of constructing an in-situ structure with 100 foreign workers sums up to RM4,000 per day. This is not even counting the hidden costs mentioned earlier. While one may argue that the cost of IBS components is higher than conventional items, the total construction costs will always be lower by using IBS. This is proven by successful implementation of development projects by big names such as SP Setia, PJD and MTD-ACPI using their own IBS systems. The total costs can
be lowered further by having the components produced in a controlled environment at sites instead of factories. Site-casting of precast concrete components using steel, aluminium and f i b r e g l a s s m o u l d s p r ov i d e a cheaper alternative by reducing transportation costs.
Conclusion In essence, IBS is the key in simplifying construction and attracting more locals to join the construction workforce. As a result, it provides more jobs to Malaysians; instead of relying on foreign workers. Economically, billions of Ringgit can be kept locally for domestic consumption. Socially, with improved standard and sustainable quality of life, the positive effects are priceless. We are ‘Nation Builders’. Do your part - Choose IBS and invest in local workforce for sustainable national development. BEM THE INGENIEUR 45
Utilisation Of Rice Husk Waste And Its Ash (Part 1) By M. Rozainee, S. P. Ngo, A. Johari, A. A. Salema and, K. G. Tan Department of Chemical Engineering, Faculty of Chemical Engineering & Natural Resources Engineering, Universiti Teknologi Malaysia
Rice husk is available abundantly in Malaysia in the form of waste from rice milling industries, with an annual generation rate of approximately 0.5 million tonnes. The current disposal methods of field dumping and open burning are not environment-friendly as these practices create serious environmental pollution and health problems. Rice husk has high calorific value (at 13â€“16 MJ/kg), which upon thermal degradation, releases a substantial amount of heat that is economically-viable when recovered. The recovered heat could be used for drying of paddy or to increase steam for electricity generation. It was estimated that the potential energy generation from rice husk is 263 GWh per annum in 2000. In addition, thermal treatment of rice husk also produces materials with commercial value in the form of siliceous rice husk ash (RHA) and activated carbon (AC). Depending on the type of thermal treatment applied, activated carbon could be generated in quantities ranging from 3â€“40 wt% in RHA. This paper presents research work that was undertaken in Universiti Teknologi Malaysia (UTM) to recover energy from rice husk and utilisation of its ash. The work involved controlled burning of rice husk in a fluidised bed to produce amorphous RHA which contains highly reactive silica and production of sodium silicate using RHA as raw material. Furthermore, the capability of RHA as an adsorbent and the effect of caustic digestion to produce sodium silicate on adsorption capacity of RHA were also conducted. Part 2 of this article will appear in the June - August 2009 issue of Ingenieur.
he annual paddy output in Malaysia in 2004 was 2.27 million tonnes (Department of Statistics Malaysia) and since rice husk accounted for 22% of this value, the amount of rice husk generated was approximately 0.5 million tonnes per annum. Rice husk is considered a form of waste from rice milling processes and are often left to rot slowly in the field or burnt in the open. These practices clearly pose 46 THE INGENIEUR
serious environmental problems as the slow-rotting process generates methane (a greenhouse gas which contributes to global warming) while open burning generates various pollutants (smoke, dust, acid gases and volatile organic compounds) that can have adverse impact on human health. Hence, the utilisation of rice husk and its ash is important to eliminate the aforementioned problems.
In this paper, the potential uses of rice husk and the available technologies for such purposes are presented. In addition, research work that have been conducted in UTM such as production of amorphous RHA through controlled burning of rice husk in fluidised bed, production of sodium silicate using RHA as a raw material and investigation on the capability of RHA as an adsorbent are also presented. Also included is
the effect of caustic digestion to produce sodium silicate on adsorption capacity of RHA.
Potential Use Of Rice Husk Rice husk is a good source of renewable energy due to its relatively high calorific value. Upon thermal treatment, its ash contains amorphous silica in excess of 95 wt%. Due to the high content of amorphous silica, RHA can be utilised to produce sodium silicate. Alternatively, the rice husk could be converted into carbon, which is also a good source of raw material for powdered activated carbon. Heat and Electricity Generation ●
Rice husk has an average lower heating value (LHV) of 13–16 MJ/kg, which in comparison is about one-third that of furnace oil, one-half of good quality coal and comparable with sawdust, lignite and peat. According the National Energy Balance Malaysia Report (2000) published by the Ministry of Energy, Telecommunications and Multimedia, Malaysia, the potential energy generation from rice husk is 263 GWh per annum. This translates into a potential capacity of 30MW. Power generation from renewable energy sources has been included in the Eighth Malaysia Plan (2001 – 2005) through the Five-Fuel Diversification Policy. Th e r e n e wa b l e e n e r g y f o c u s is on biomass and the target contribution towards the total electricity generation mix is 5% by 2005 and 10% by 2010. Due to its relatively high calorific value, the combustion of rice husk is autogenous (selfsustaining) and this minimises the requirements for auxiliary
fuel. Apart from offering the benefits of energy recovery, the combustion of rice husk in thermal treatment units will also solve its disposal problem. It is also more environmental-friendly as the combustion process reduces the greenhouse effect by converting emissions that would have been methane due to its slow-rotting into the less potent greenhouse gas carbon dioxide. ●
Rice husk contains silica in the range of 20%–25%, which upon thermal degradation, results in ash that contains more than 95 wt% of silica (Kaupp, 1984; Kapur, 1985; James and Rao, 1986). Thus, the ash content of approximately 15%–20% in rice husk makes silica recovery from it very economically-attractive. When rice husk is burnt under controlled conditions, the resulting ash is easily the cheapest bulk source of highly reactive silica in comparison with silica produced from conventional methods. Amorphous silica in rice husk ash (RHA) has commercial applications in cement and chemical industries. In the cement industry, it has been widely researched as mineral cement replacement material (MCRM). It has the potential to replace silica fume in the production of high quality concrete. The current price of silica fume is reported to be US$1,200 per tonne in India. Various studies have proved that RHA is more superior to silica fume in terms of increasing the compressive strength of concrete, r e d u c i n g t h e ra p i d ch l o r i d e penetrability, resisting surface scaling due to deicing salts and improving resistance to acid attack. The market for RHA in the cement
industry is not as well-developed compared to the steel industry, but there is a great potential due to the pozzolanic properties of RHA that are comparable to cement. In the US, RHA has already been used commercially by Pittsburg Mineral & Environmental Tech. Inc. (PMET), which is part of Alchemix Corporation in Arizona, as a substitute for silica fume in the production of specialist concrete. • Sodium Silicate Production I n t h e ch e m i c a l i n d u s t r y, amorphous RHA has been used widely due to its silica quality comparatively with other expensive sources of silica. The silica obtained from RHA is a good material for synthesis of fine chemicals (i.e. highly pure silicon useful for manufacturing solar cells for photovoltaic power generation and semiconductors, silicon nitride, silicon carbide, magnesium silicide and sodium silicate for manufacturing aerogel). The amorphous nature of silica makes it viable for extraction using sodium hydroxide to produce sodium silicate, which can replace the conventional process that is high energy-intensive. The current market price for sodium silicate or water glass is lucrative, retailing at approximately US$550-780 per tonne. Sodium silicate has diverse application in the industry due to its varying silicon dioxide to sodium oxide (SiO2: Na2O) ratio. Upon losing small amount of water, sodium silicate becomes tacky and can be used as a strong adhesive for fibre box and in making various paints and coatings. In addition, it is also used in making different kinds of cement including for acid-proof construction, refractory uses and binding thermal insulating material. THE INGENIEUR 47
Rice husk is also a good source of carbon, containing approximately 10 wt% of fixed carbon (char). Depending on the type of thermal treatment applied, activated carbon (AC) could be generated in quantities ranging from 3–40 wt% in RHA, with conventional combustion process being able to produce 3–13 wt% of activated carbon. Activated carbon is an adsorbent derived from carbonaceous raw materials that is widely used in industries for separation, purification and recovery processes due to their highly porous texture and large adsorbent capacity. It is also used as catalyst support, chromatography columns and electrode materials for batteries and capacitors. Its major application is for absorbing impurities in wastewater or waste gas streams, whereby it could be regenerated by heating and used repeatedly. To date, the most widelyused materials in the commercial manufacture of activated carbon include wood, coconut shells, peat, lignite/bituminous/anthracite coals, petroleum cokes and synthetic polymers.
Available Technology For Recovery Of Energy And Silica From Rice Husk Rice husk has high calorific value, thus energy in the form of heat can be recovered during its combustion. The recovered heat can be used for drying of paddy or to raise steam for electricity. Apart from energy recovery, the resulting ash from combustion of rice husk contains valuable amorphous silica. The quality of the produced amorphous silica depends on the technique of rice husk combustion. Existing 48 THE INGENIEUR
technologies for the preparation of amorphous silica with low carbon content include alkaline extraction and thermal treatment of rice husk in various types of furnaces ( i n c l i n e d s t e p - g ra t e f u r n a c e , cyclonic furnace, muffle furnace, fixed bed furnace, fluidised bed, rotary kiln, tubular reactor etc.). The alkaline extraction method is capable of producing high purity silica but involves a significant amount of time (one to two days) and many steps with the use of various types of chemicals, thus resulting in an extremely expensive p r o d u c t i o n c o s t . M e a n wh i l e , various drawbacks are associated with the preparation of silica via thermal treatment of rice husk in existing thermal treatment technologies. This includes the occasional crystallisation of the ash due to lack of mixing and hot-spots formation, lack of freeflowing air for complete oxidation of carbon and long reaction time. The residual carbon in the RHA from thermal treatment of rice husk from various thermal treatment technologies are significant and can be as high as 30 wt%. The fluidised bed technology, on the other hand, is capable of producing amorphous RHA with very low carbon content (consistently less than 2 wt %) at a very rapid reaction time (less than two minutes). Further, it offers continuous combustion of rice husk with good temperature control, has a very high throughput rate due to its rapid reaction time, high combustion efficiency, is self-sustaining (thus reducing the cost of auxiliary fuel) and the ash could be easily collected via entrainment by the fluidising air into a cyclone. It also offers the flexibility of producing ash with higher carbon content, as and when desired, by manipulating the
amount of fluidising air and rice husk feed. Thus, the same fluidised bed system used for producing low carbon content, amorphous RHA could be used for producing char meant for preparation of activated carbon through a simple change in the operating conditions, thereby resulting in lower capital investment.
Research Works In Universiti Teknologi Malaysia ●
Production of amorphous rice husk ash
Amorphous RHA can be produced through controlled burning of rice husk at temperatures below the crystallisation point of silica in the ash (i.e. below 700oC) in combustors such as the fluidised bed combustor. Such research has been carried out successfully in UTM (High Temperature Processing Research Laboratory), whereby 100% amorphous RHA with low residual carbon content (less than 2wt %) could be produced from the combustion of rice husk in fluidised bed combustors (Figure 1). The research group has been involved in research related to the production of energy and silica from rice husk since 1999. The amorphous nature of the produced RHA was proven by the x-ray diffraction (XRD) analysis, which showed a background hump at 20 degree of 22o and absence of any crystal peaks in the resulting diffractogram (Figure 2). Through careful manipulation of the ratio of air and rice husk feed in the fluidised bed combustor, different grades of RHA with different levels of carbon contents could be produced (Figure 3), ranging from black chars suitable for the manufacture of activated carbon to essentially carbon-
commercial utilisation. In addition, work has been done to develop optimum design of fluidised bed combustors by taking advantage of the highly reliable computational fluid dynamics (CFD) programme code of FLUENT (Figure 4). The application of CFD to combustor design is widespread in all the new research and development techniques in combustion technology. Additionally, studies were also carried out to optimise the design of fluidised bed (i.e, distributor plate, freeboard) as well as to study the combustion characteristics of rice husk in fluidised bed. â—?
Figure 1: The pilot-scale fluidised bed system developed by Universiti Teknologi Malaysia to produce energy and valuable materials (amorphous silica and carbon) from rice husk
free white ash. This is one of the main advantages of fluidised bed, which consequently leads to the enhanced flexibility of the system to produce different grades
of RHA depending on market demand. Research was conducted to develop and operate the fluidised bed combustor for combustion of rice husk to produce RHA for
Figure 2: X-Ray Diffraction (XRD) diagram showing the amorphous structure of the rice husk ash produced by the High Temperature Processing Research Laboratory in Universiti Teknologi Malaysia
Production of sodium silicate from RHA
The combustion of rice husk in fluidised bed also produced amorphous RHA of varying colours - black, grey and white. The residual carbon content varies according to the colour with black RHA containing the highest amount of carbon at 24%, followed by grey RHA, 3% and white RHA with the least carbon content of 0.2%. These amorphous RHA were used to produce sodium silicate and the quality of the product was compared to the commercial grade. Silica in RHA was dissolved using sodium hydroxide (NaOH) in an autoclave. The process is known as caustic digestion. It was found that grey RHA produced clear and colourless sodium silicate solution (Figure 5). It is believed that during the digestion process carbon residue in grey RHA helped to clean impurities in the solution. On the other hand, white RHA produced amber solution, while black RHA produced dark brown solution which was undesirable in the sodium silicate industry. THE INGENIEUR 49
Figure 3: (a) Black chars suitable for the manufacture of activated carbon obtained from the combustion of rice husk in fluidised bed combustor, (b) Amorphous rice husk ash with 6 wt % residual carbon suitable for the manufacture of sodium silicate (water glass), (c) Amorphous rice husk with 2.0 wt % residual carbon content, (d) The final siliceous rice husk ash product (pure, amorphous and residual carbon content of 0.2 wt %) suitable for the synthesis of aerogel
Note: (i) & (ii) single-stage standard cyclone
Figure 4: Computational Fluid Dynamics (CFD) modelling of the freeboard design of the fluidised bed combustor to increase residence time of gas by overcoming the buoyancy effect due to difference in temperatures
The results showed that certain amount of carbon was beneficial to produce clear and colourless sodium silicate solution. It was found that sodium silicate could be produced at temperatures as low as 115째C and concentration of 15% w/w (15 gram RHA in 100 ml NaOH solution). The silicon dioxide to sodium oxide (SiO 2: Na 2 O) ratio of sodium silicate obtained was 2.48 whereby the optimum ratio in industry is 3.22. A study was also carried out to produce sodium silicate using RHA obtained from rice mills (Table 1). 50 THE INGENIEUR
Figure 5: Effects of carbon content in RHA to the quality of sodium silicate solution. From left: Sodium silicate solution of white, grey and black RHA
Out of the four samples tested under similar conditions, only sample RHA 3 could be digested with NaOH to produce sodium silicate with SiO 2:Na 2O ratio of 3.00 at temperature of 120째C and concentration of 15% w/w. the solution was clear and colourless. It was found that not all RHA could produce sodium silicate because the ability to turn RHA into sodium silicate was largely depended on the properties of ash. Crystallisation of ash was another factor that hindered the formation of sodium silicate due to low activity and solubility. BEM
By Lim Teck Guan
Fig 1 An Ultimate Puzzle
Fig 2 The Solution THE INGENIEUR 51
Source: www.flickr.co m
Playing Golf 52 THE INGENIEUR
THE INGENIEUR 53
Bertam Valley New Village, During Emergency
54 THE INGENIEUR
Contributed by Old photos: Wong Fook Chai Present photos: Ng Kong Leong
THE INGENIEUR 55