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MAINTENANCE OF VENTILATION SYSTEMS IN THE CIVIL, INDUSTRIAL AND COMMERCIAL SECTORS INTRODUCTION This publication has been compiled in order to provide technical/practical tips for carrying out correct hygiene maintenance services related to ventilation plant in locations that are open to the public or used as continuous work areas such as gymnasiums, swimming pools, shows, sales areas, offices, special production departments, ... For the drawing up of this report reference was made to three documents in particular: • for the epidemiological part: “The safeguarding and promotion of health in confined environments” • for the technical part: “Guidelines for defining technical protocols for predictive maintenance of air • conditioning plants” ( 256 03/11/2006) and • “Guidelines for the prevention and control of Legionnaires disease (G.U.S.G. no. 103 05/05/2000)” from which we report the following article: “To allow effective cleaning of the internal surfaces of ductwors, in order to avoid damaging their coatings, one can employ a special technique that uses a nozzle head with asymmetric holes, placed at the end of a flexible tube that is introduced into the purposely provided apertures. From this tube, compressed air is discharged in large quantities (up to 300cum/hr). The high flow-rate of the air creates a sort of air blade that causes the dislodgement of the dirt from the internal surfaces of the ductwork; the asymmetry of the holes then causes it to rotate and so the tube moves forward for its full length (up to 30 straight meters)”. From this guideline article published in the Italian Official Gazette of 2000 it can be deduced the importance of the management of air distribution ducting and that above all a simple, safe and cheap method for carrying out proper maintenance of air distribution ducting is finally recognised and certified.

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In the industrialised countries the population spends a considerable proportion of its time (up to 90%) in confined environments such as homes, public and private buildings and means of transport. Following the global energy resources crisis and the consequential necessity to contain consumption for heating, new technical planning criteria for civil buildings have been imposed, substantially improving insulation. At the same time there have been changes in the materials used for internal furnishings (furniture, coverings) and there has been an increase in electrical and electronic apparatus used inside the same environment (photocopiers, video terminals, printers, …). Of all this, accompanied, however, by an increase in outdoor pollution, has led to a substantial deterioration in living conditions inside closed indoor environments, that, although under the control of temeprature are trasformed into a sort of gas chamber full of various pollutants. Ventilation systems therefore have a double function: to ensure thermal comfort and, above all, to guarantee a reduction fo indoor pollutants. All these considerations lead to other conclusions: • if the ventilation system is not well designed and built it will not be able to guarantee thermal comfort and reduction of pollutants; • If the ventilation system is contaminated by pollutants it can itself become a source of indoor pollution; • If the ventilation system is not well maintained, it can partially malfunction or cause total breakdown of the system itself. The indoor pollutants are many and can be produced from several sources. The sources of pollution are divided into two large families that are identified as indoor sources and outdoor sources. In the national and international literature it has now become firmly established that the more worrying sources of pollution come from indoors: just remember


how many and which products are normally used in enclosed locations – detergents (often sprays). Toners for photocopiers and printers, glues, … Table 1*: list some pollutants and their respective effects on health:




Environmental tobacco smoke (ETS)

Tobacco smoking

Total suspended particulates (TPS)

Tobacco smoking Heating systems External pollutants Wood burning Cooking by gas Gas stoves Boilers Vehicles located in the surrounding areas Fireplaces Wood-burning stoves

Probable increase in the frequency of serious respiratory symptoms Probable decrease in the respiratory ventilation function Probable decrease in the respiratory ventilation function

Nitrogen dioxide

Wood smoke Formaldehyde

Construction materials Cleaning products and supplies Tobacco smoke Combustion processes

Increase in the frequency of chronic respiratory symptoms Uncertain effect on respiratory functions Increased risk of developing chronic obstructive lung disease Possible bronchial reaction phenomena in asthmatic subjects

*Source: Italian Ministry of Health – prevention department: Safeguarding health in confined environments


exceptional maintenance costs.

It is possible to become aware of the necessary and non-postponeable minimal system engineering alignments for the safety of HVAC. After over fifteen years spent in the fild of maintenance of ventilation systems, Aria SpA has found several troubling situations: • Insulation placed inside the ducting; • Projecting screws inside the ducting; • Filters often not installed or, if present, occluded by power to the point that was impossible for air to pass at the selected airflow; • Insect nests inside the delivery ducting; • External air inlets that were blocked and covered by panels installed over; • Air vents that were obstructed and so iunable to ensure the adeguate air flow. The above examples represents a small part of all the situations that may arise during HVAC maintenances.That shows how it is necessary to pay a lot of attention at the continuous monitoring of the HVAC systems in order to make step by step those small adjustments that avoid discomfort and other

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CONSIDERATIONS ABOUT THE PRODUCTION COSTS OF BADLY MANAGED SYSTEM Maintenance is often considered as a cost to be cut down or at least to limit as much as possible neglecting aspects like thermal comfort, the wholesomeness of the indoor air and the increase in pathologies connected with environments in which there is a high level of humidity. The lack of attention given to the internal duct surfaces during the maintenance of the system an increase in the days of lost work. This is a quantificable cost, but is not possible quantify the loss in productivity caused by an uncomfortable environment that brings discomfort to the occupants. Other dangerous factors for people arise from their contact with the public and overcrowded offices. In these situations the same system spread the pathogenic agents, either because they are already inside (in the case of plant to be flushed) or because of insufficient air change (system requiring improvement). Certainly the worst case is the one in which the ducts have internal insulation without any type of flaking protection. In this case the only possible solution is the replacement of the duct with another one built under the current manufacting standards. Internal insulation is firmly banishes in UNI EN12097:2007 (Requirements related to fitted components to facilitate the maintenance of ducting networks) and it is prohibited in the “Guidelines for the prevention and control of Legionnaires Disease” (G.U.S.G. no. 103 05/05/2000). The presence of particulate matter should not be understimated: indeed it is often in this imunities microbiological agents travel, so the cleaner are the airducts the lower will be the possibility of spreading micro-organisms.

INTERVENTION PROTOCOLS Recent studies have encouraged Aria SpA to establish procedures, above all, according to the type of system that it is involved. The following lists contain the procedures tipically followed by Aria SpA: WORK PROTOCOL FOR THE INSPECTION OF AERATION SYSTEM • Drawing up the agreed work plan and related documents; • Choice of sampling points for microbiological and gravimetric tests for particulates deposits in the ducting; • Making video recordings by means of high definition videocamera probe; • In-depth analysis of the film by technicians; • Creating a summary DVD of the general situation; • Drawing up reports with microbiological and gravimetric results and considerations.

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WORKPROTOCOL FOR THE SERVICE OF FLUSHING AERATION SYSTEMS • Drawing up the agreed work plan and related documents; • Identification of the critical points in the system in order to systematically undertake the service on • the whole plant avoiding non-flushing points and unnecessary procedures; • Site preparation with sectioning and fencing off the system; • Flushing procedure using an compressed air nozzle that spontaneously advances along the ducting remaining in constant contact with the internal surface of the duct; the nozzle creates a blade of air that dislodges and takes away the particulate matter that are present on the inside of the duct towards the high pressure closed cycle aspirator fitted with high– efficiency filters; • Nebulisation of a broad spectrum bactericidal in order to inhibit the growth of micro- organisms; • Acquisition of microbiological samples and gravimetrics post-flushing. • Refuse disposal; • Issuing the final technical report. WORK PROTOCOL FOR CARRYING OUT PERIODIC HYGIENE CLEANING OF AERATION SYSTEMS • Drawing up the agreed work plan and related documents; • Confinement of the premises or that part of the premises served by the system; • Positioning equipment for the distribution of the hygiene materials; • Setting the air handling unit to use only external air after completely scrubbing the air; • Issuing the final technical report. WORK PROTOCOL FOR FLUSHING THE AIR HANDLING UNIT (AHU) • Drawing up the agreed work plan and related documents; • Shutting down the AHU and preparing the worksite; • Visual analysis of the current state of the plant ; • Replacement of filters; • Cleaning and disinfection of fans and finned stacks; • Cleaning and disinfection of internal surfaces of the AHU; • Cleaning and sanitisation of condensation collection and/or dehumidifier vessels; • Check presence of straps; • Possible rebuilding of the external air intake; • Site cleaning; • Restarting the equipment; • Issuing the final technical report.


REGULATORY ENVIROMENT The European and italian regulatory enviroment is in continuous evolution because of the numerous and continuos improvements in the HVAC field. SPECIFIC DECREE G.U. no. 256 03/11/2006

SUBJECT “Guidelines for defining technical protocols for predictive maintenance of air conditioning systems”

Circ. Min. Health of 17/12/2004 Information on the guidelines for the protection of non smokers Law no. 3 16/01/2003 – Art. 51

Instruction codes for public administration matters - Protecting the health of non-smokers

Regional Law of Liguria n°24/2002

Disciplines for the construction, installation, maintenance and cleaning of airconditioning systems

Ordinary Section no. 252 G.U. no. 276 27/11/2001 G.U.S.G. no. 103 05/05/2000

Guidelines for the protection and promotion of health in indoor environments

D.Lgs. 81, 09 April 08

Security in the work environment

“Guidelines for the prevention and control of Legionnaires Disease”


Classifications, particulars and requirements of aeration systems for well-being

UNI ENV 12237:2004

Regulation replacing the previous 10381 Classification of planning and start-up of ducting

UNI EN 12097 :2007

Requirements related to fitted components to facilitate the maintenance of ductworks

UNI ISO 14644

Within the regulatory part are the criteria for building clean rooms.

UNI EN 15240:2008

Ventilation of buildings – Energy performance of buildings - Guidelines for the inspection of air conditioning plant

UNI EN 15780:2011

Ventilation for buildings. Ductwork. Cleanliness of ventilation systems

UNI EN 779:2012

Particulate air filters for general ventilation. Determination of the filtration performance

UNI EN 1822-1:2010

High efficiency air filters (EPA, HEPA and ULPA) - Part 1: Classification, performance testing, marking.

ISPESL GUIDELINES Guideline Final version 1 June 2006

Micro-climates, aeration and illumination in work places Requirements and standards Operational and planning information

FOREIGN REGULATIONS This section should be considered along with the above regulation. The regulations should be taken into sccount sldo in order to obtains new ideas to improve, and in order to understand how the future HVAC regulations will evolve in the future. NADCA ACR 2013

Assessment, Cleaning and Restoration of HVAC Systems


General specifications and particulars for the cleaning of heating, ventilation and air conditioning systems

CONCLUSIONS The maintenance operations described above must be take into strong considerations in order to maintain ventilation systems perfectly efficient and to provide also a comfortable environment for the workers that spend several hours each day inside the supplied areas. The protocols shown above have been adopted thanks to to the experience that our company has accumulated from years of work in the fild and have been modified according to the “ordinary” state and level of maintenance of systems to which they have been exposed.

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Maintenance of ventilation systems  

From this guideline article published in the Italian Official Gazette of 2000 it can be deduced the importance of the management of air dist...

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