KARACHI: Even some inexpensive measures can help make indoors cool and comfortable in hot summer days. For instance, painting the exterior walls of a building white or in any other light colour, keeping inverted clay pots on the rooftop or simply putting clay tiles on the top, using insulation material available in the market for roofs and walls, using shading devices on windows and installing LED (light emitting diodes) lights, which consume less energy and emit little heat, can be quite effective.

These suggestions were shared by experts while responding to Dawn’s questions about how the existing or yet-to-be-built structures in the city could be made environment friendly and energy efficient.

According to these experts, climate-responsive architecture can be achieved by respecting the wind direction during site planning, understanding the sun path to create optimum shaded spaces, preventing direct sun on rooftops and walls, providing optimum inlet for natural wind, keeping the plan form simple and choice of appropriate techniques to withstand conduction, convection and radiation effects.

“In my opinion, environment-friendly construction is based on ‘minimalism’ which is about building spaces and using building material to the minimum possible extent.

‘Kitchen waste water can be collected in separate drums and used in gardening after some treatment’

“Whenever and wherever possible, we must rely on the power and capacity of natural elements such as landscaping and vegetation to achieve our design objectives,” said Prof Noman Ahmed, dean of the faculty of architecture and management sciences at NED University, when asked about the basic idea behind environment-friendly constructions.

Old architecture

Elaborating further, he said that if someone desired to have external shaded spaces around the home then creating wooden pergolas with creeper plants could be a better alternative than a concrete slab or a metallic projection.

“Additionally, materials that possess capacity to mitigate the extreme climatic effects should be preferred. For example, in places which brave very warm summers, wood and stone could be useful. Alternative industrial materials with the same properties may also be effective,” he said.

He suggested that some concepts followed in old buildings, for instance, keeping ceilings high and maintaining insulation in walls, helped in maintaining optimum air circulation and keeping interiors cool.

Asked about how much the city’s concrete development contributed to hot weather conditions, Prof Ahmed said that unplanned urban sprawl in the suburbs had deprived Karachi of the possibility of promoting urban forestry and agriculture that most master plans for the city had suggested.

Haphazard densification, planned and unplanned, he said, had altered the open-to-built space ratio to a great extent. “Now, we have much more built space — especially in the central areas of the city — than desirable. Common sense practices such as keeping adequate provisions for ventilation and diffused daylight are also ignored. And the biggest crime is the ruthless cutting of trees in the name of development.”

Answering a question about building laws, Prof Ahmed said that building bylaws did have some useful parameters related to site planning, ventilation and other attributes related to a climate-sensitive design.

“The Sindh Building Control Authority is already comprehensively revising the building and town planning bylaws. Hopefully, a more effective regulatory regime shall come out as an outcome of this exercise,” he noted.

Water conservation

According to Prof Ahmed, it is direly needed that people opt for water conservation strategies in their homes. By adjusting plumbing, kitchen waste water could be collected in separate drums and used in gardening and other landscaping after some treatment, he suggested.

“Similarly, the water consumed in ablution in mosques can be collected in separate chambers and reused for gardening and landscaping after some basic treatment. One such system is working in the NED university in our Masjid Bait-ul-Maamoor.”

Sharing his opinion, Prof Rizwan U. Farooqui, co-chair at the department of civil engineering at NED University, said the built environment in Pakistan faced many challenges, one of which was its sustainability and energy efficiency.

“Recently, there has been an increase in energy use in developing countries primarily because of the expanding use of air conditioning. Pakistan is no exception,” he said, adding that air conditioners helped cool indoors but increased temperature outside.

Reducing the energy needed to heat, cool, and light buildings would not only save money, reduce pressure on the power grid and climate change, but also increase occupant comfort as the thermal envelope became more efficient, he added.

According to him, many of the significant techniques for reducing energy consumption are low cost and some are even free.

“It’s unfortunate that components, which are very fundamental and significant contributors to developing environment-friendly structures, are often ignored during construction.

“These factors include natural ventilation, air flow, facades, length-width proportion, framing and glazing materials, insulation materials, exposure to climatic conditions, indoor air quality, lighting efficiency, air conditioning/heating efficiency, fresh and grey water consumption patterns, use of plants within the building and use of green rooftops,” he said.

A few examples of interventions in existing buildings, he recommends, can be use of false ceilings, bitumen coats with clay tile cladding, clay pots, façade treatment according to orientation, installation of DC (direct current) fans, use of porous hard landscape, use of high-efficiency plumbing fixtures, use of dual flush and high-efficiency toilets that use a gallon or less per flush, use of efficient showerheads and use of sensor faucets to limit the amount of water consumption.

In his opinion, limited awareness on part of the client/owners about the sustainability and energy efficiency benefits as well as lack of regulatory support towards energy-efficient construction has resulted in the absence of adequate push towards green and climate-friendly built environment in Pakistan.

Published in Dawn, June 3rd, 2018