Green Building

01…….Components of the roof top rainwater harvesting system •Roof catchment •Drain pipes •Gutters •Down pipe •First flush pipe. •Filter unit •Storage tank.

•Collection sump. •Pump unit Roof catchment •Catchment for collecting the rainwater •Style, construction and material of the roof determine its suitability as a catchment •Roofs made of corrugated iron sheet, asbestos sheet, tiles or concrete can be utilized as such •Thatched roofs are not suitable .

Drain pipes •Pipes of suitable size, made of PVC / Stoneware •To drain off the roof top water to the storm drains Gutters Channels fixed to the edges of roof all around to collect and transport the rainwater from the roof to the storage tank Shape: Rectangular or semi-circular Made of either plain Galvanized Iron sheets or cut PVC pipes or split Bamboo

Rectangular

semi-circular

Down pipe •Pipes that carries the rainwater from the gutters to the storage tank •Down pipe is joined with the gutters at one end, whereas the other end is connected to the filter unit of the storage tank •PVC or GI pipes of 50mm to 75 mm (2 inch to 3 inch) diameter are used

First flush pipe •Debris, dirt and dust collect on the roofs during nonrainy periods •A first flush system can be incorporated in the roof top rainwater harvesting systems to dispose off the ‘first flush’ water so that is does not enter the tank •A separate vertical pipe is fixed to the down pipe with a valve provided below the ‘T’ junction •After the first rain is washed out through first flush pipe, the valve is closed to allow the water to enter the down pipe and reach the storage tank.

Filter unit •Filtration forms the most important process in the purification of water •It involves allowing water to pass through a filter media e.g. sand. Filtration involves removal of suspended and colloidal impurities present in water.

•Depending on the type of filtration, the chemical characteristics of water may be altered and the bacterial content may be considerably reduced Storage tank •Used to store the water that is collected from the Roof tops •Small-scale water storage: Plastic bowls, buckets, jerry cans, clay of ceramic jars, cement jars, old oil drums etc.

•Large scale water storage: Bigger tank with sufficient strength and durability •Construction materials: RCC, masonry, Ferro-cement, PVC Collection sump •Small pit is normally dug in the ground beneath the tap of the storage tank for collecting water form the storage tank •Constructed in brick masonry •Size of collection pit shall be 60 cm x 60 cm x 60 cm Pump unit •Hand pump or a power pump fitted to the storage sump facilitates lifting of water to the user •Size of the pump has to be decided depending upon the consumption of the stored water.

6)Passive design technique Opening & device This passive design technique involves openings and devices designed to maximize daylight and natural ventilation. These are used as elements of the building’s envelope design, and include openings such as skylights and clerestory, light-inducing devices such as light shelves, and ventilation-inducing devices such as ventilation towers.

(1) Skylight and monitor roof

The Hearst Tower is a renovation project to be constructed with an atrium while preserving the skin of the existing building. Skylights designed to optimize the amount of daylight can be installed between the new high rise office building and existing historic building (Fig.18). This is a technique that introduces green design elements when two different masses are combined

The Sports Centre Pajol induces day-light and natural ventilation by bending and lifting the central parts of the monitor roof on the top of the gymnasium. Although from the exterior it is recognized as a simple cubic building rather than a monitor roof, in the interior it represents the aesthetic effect of a curved ceiling (Fig.19). This effect is possible in spaces with a long span such as gymnasiums as live loads are not stacked on the roof, allowing the shape of the roof to be relatively unburdened

(2) Clerestory Here air gathers in the higher levels through the stack effect induced by installing a sloped shed roof on one side, while ventilation is facilitated by way of an opening in the clerestory. IGES enables natural ventilation in the entire building by bringing the prevailing wind into the interior spaces and deliberating them through the atrium’s clerestory (Fig. 20). The Pocono Environmental Education Center controls sunlight using its tilted main roof to eliminate the opening on the north side and installing a curtain wall on the south side

(3) Daylight duct This light induction device is used to artificially draw sunlight into spaces that do not face to the south or into deep floor areas. The daylight duct of the Solaris building allows daylight to penetrate into the building’s interior. Although it is not represented on the façade, it creates a passage of daylight in a diagonal direction within the internal spaces(Fig.22). The Manchester Civil Justice Centre employed a method for drawing sunlight into internal spaces through the atrium, although such spaces are not directly facing the atrium. This is an example of the use of the adjacent room’s ceiling situated between the atrium as the daylight duct, which also creates ceiling height variation (Fig. 23)

4) Light shelves and daylight ceiling These are devices used to draw direct sunlight into the interior of the building or maintain equal intensity of indoor illumination within the deep floor by converting it into reflected light. In many cases, light shelves are a design element that is simply installed on the façade. IGES has produced a threedimensional façade by protruding the light shelves from the façade and the sloped ceiling (Fig.24).

(5) Ventilation duct and ventilation tower Ventilation induction devices are used to induce natural ventilation through the installation of a vertically extended duct. The ventilation tower vertically protrudes from the façade to represent a repetitive rhythm (Fig.26).

3)Benefits of conducting a building LCA In the construction sector conducting an LCA provides a number of tangible benefits: Reduce environmental impact by: •Evaluating building site options to select the lowest impact choice. •Comparing the environmental impacts of renovating rather than demolishing and building anew. •Comparing design alternatives to choose the lowest impact ones. •Identifying a building’s environmental hotspots and taking action to reduce them. •Calculating the lifetime impact of building materials and products to help find the most sustainable options.

Gain certification credits .

LCA is a significant credit in BREEAM, LEED v4 and many other certification schemes.

Comply with whole life carbon regulations.

Governments are increasingly recognising the need to legislate to reduce whole life carbon (that is operational and embodied carbon emissions) in construction. LCAs are a mandatory part of many of the new laws and policies.

Create cost-efficient benchmarks.

LCA can be totally automated from existing design data and fully integrated into the workflow without disrupting it or slowing it down. This enables costefficient benchmarking.

Improve transparency.

Clients, investors, tenants and others are increasingly seeking transparency over a building’s environmental impacts. LCA is the most reliable and transparent way to do this.

4)Principles for Managing water:

•Make buildings water efficient over entire life-cycle- embodied and operational use of water Promoting Slow the flow of water Promoting Economical and optimal use of water Minimizing wastage Minimizing leakage Promoting Multiple Usage (reuse and recycling) •Using water efficient fixtures •Using native plants and trees •Using low water embodied materials •Using materials requiring less water in making and using •Using low water construction technologies •Using water efficient landscape •Using native trees/plants •Mulching trees/-plants to retain moisture, prevent evaporation •Using alternate sources of water-Rainwater water harvesting

5)WATER MANAGEMENT STRATEGIES 1)Use integrated process to assess:

existing water resources, opportunities for reducing water demand, and alternative water supplies.

2)Promoting Green building to encourages : innovative water-saving strategies that help projects use water wisely.

3) Promoting effective water strategies include Installing efficient plumbing fixtures. Use dual plumbing Using non-potable water. Installing -meters. Choosing locally adapted plants. Using Xeri-scaping.

– a landscaping method developed especially for arid/semi-arid climates that utilizes water conserving techniques –use of drought-tolerant plants, mulch, and efficient irrigation.

7)WHAT IS A REED BED? •A reed bed is a natural filtration system that can be used to treat and improve water quality prior to discharging into the environment. It utilises the ability of a reed to transport oxygen to the soil, hence encouraging microorganisms to digest the contaminants in the effluent.

•Reed beds are gravel filled, contained, shallow beds, planted with plants (e.g. reeds), and specially design to treat wastewater including sewage, agricultural, industrial and road wastewaters.

•Wastewater, black or grey, is passed through the root zone of the reeds where it undergoes treatment. •Primary treated effluent from the house is initially filtered prior to entering the reed bed through an effluent filter fitted to the grey-water collection tank or septic tank outlet pipe then it is passes through reed bed system.

8)TYPES OF REED BEDS Horizontal Flow Reed Beds •The effluent enters at one end and travels horizontally through the reeds root zone, before being discharged on the far side of the bed.

•These reed beds works particularly well for low strength effluents, or effluent that have been pre-treated.

•They are also of no real use for reducing ammonia levels, but they can reduce the level of BOD (Biochemical Oxygen Demand) and SS (Suspended Solids) in sewage treatment plant effluent. They are particularly useful in converting nitrates into nitrogen.

Vertical Flow Reed Beds •The reed beds are lined with deeper structures made up of layers of various sized gravels planted with reeds. In this system effluent is delivered to the top of the bed in batches, floods the surface of the bed and drains through.

•Each batch traps oxygen in the bed leading to an aerated system.

•Vertical flow systems are more efficient than horizontal flow reed-beds and can handle stronger strength effluent.

•They can reduce ammonia as well as BOD and SS levels.

Pumped Reed Bed Systems A pumped reed bed system is either one of the above “vertical” or “horizontal” systems but with the water fed into it using a pump. This can be advantageous, especially within vertical flow systems as water can be lifted up to then disperse back down through a second filter bed.

Subsurface flow

•In subsurface flow constructed wetlands the flow of wastewater occurs between the roots of the plants and there is no water surfacing (it is kept below gravel). As a result, the system is more efficient, does not attract mosquitoes, is less odorous and less sensitive to winter conditions. Also, less area is needed to purify water. A downside to the system are the intakes, which can clog or bioclog easily, although some larger sized gravel will often solve this problem.

•Subsurface flow wetlands can be further classified as horizontal flow or vertical flow constructed wetlands. In the vertical flow constructed wetland, the effluent moves vertically from the planted layer down through the substrate and out (requiring air pumps to aerate the bed).[17] In the horizontal flow constructed wetland the effluent moves horizontally via gravity, parallel to the surface, with no surface water thus avoiding mosquito breeding. Vertical flow constructed wetlands are considered to be more efficient with less area required compared to horizontal flow constructed wetlands.

Subsurface flow •However, they need to be interval-loaded and their design requires more knowhow while horizontal flow constructed wetlands can receive wastewater continuously and are easier to build.

•Due to the increased efficiency a vertical flow subsurface constructed wetland requires only about 3 square metres (32 sq ft) of space per person equivalent, down to 1.5 square metres in hot climates.

•The "French System" combines primary and secondary treatment of raw wastewater. The effluent passes various filter beds whose grain size is getting progressively smaller (from gravel to sand)

9)Sick building syndrome (SBS) Occupants experience acute health and comfort effects that are linked to time spent in a building; no specific illness or cause can be identified SBS Symptoms Dry eyes Dry throat Headache Dry skin Mucus membrane irritation Lethargy Asthmatic symptoms

2)Kinetic & Responsive Building façade

•A kinetic façade is one that changes dynamically rather than being static or fixed, allowing movement to occur on a building’s surface. This helps to create what the architect Buckminster Fuller called a ‘skin-like articulation’ effect, and is an extension of the idea that a building's envelope is an active system rather than just a container.

•A kinetic façade can be used to manage light, air, energy, and even information. They can act to reduce solar gain as well as allowing the passage of fresh air into the building, helping to alter the interior environment. The moving elements of the façade can be programmed to respond to climatic or other environmental factors, time, levels and type of occupancy and so on to improve performance and efficiency.

•With advances in sensors, materials and building management technology, designers are increasingly able to consider kinetic components as design solutions.