Monthly Archives: November 2018

For a bright bathroom

It has to be designed carefully, with proper ventilation too.

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In the Indian context, ‘bright bathroom’ sounds like a contradiction! Majority of bathrooms in urban houses, with attached toilet, are ill-lit and badly ventilated.

Of course, we have quick fix solutions, without studying the root causes for the above experience. Fit a high wattage electric bulb and have an exhaust fan. Despite these two devices which consume electricity, many toilets and bathrooms are still dark during the daytime.

Actually the bathroom needs a large opening to brighten it up. There is a belief that larger the opening, lesser the privacy, which has no basis at all – a large window with translucent glass can ensure total privacy while a thin gap between the ventilator frame and the shutter can be a clear peephole. Ventilators in most buildings being rather low, most users keep them shut for the fear of privacy, incidentally blocking both air and light.

The generation before us knew the principle of ventilation that the warmer stale air moves upwards, being light in weight; hence the early toilets were provided with voids just below the roof level. During those days, with no steel and glass, these wall top openings were left with no shutters, which facilitated total movement of stale air.

The idea of continuous lintel band at 7 feet level coupled with the trouble of clearing cobwebs from this high opening made people stop the toilet ventilators at 7 feet height. With no escape, the stale air above this level comes to stay inside itself.

Most exhaust fans are operated when we are using the toilet with the doors shut, so no fresh air passes through the whole depth of the toilet. All that the exhaust fans throw out is the air immediately around them which often is fresh, so the stink continues.

Besides the general reasons, light is a prerequisite in a bathroom while fresh air is needed both for health and dry interiors. Bathrooms and toilets have been subjects of so many hilarious essays, that we may never realise how much they have in them for a serious ecological analysis too!

How to let the wind in, and out

Among the major hurdles for air movement is the larger indoor spaces we are creating in our buildings.

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Let us try this quiz – ask a hundred people if they appreciate traditional homes, and possibly the majority would say ‘yes’. Now ask if these houses get fresh air inside, and possibly the majority would say ‘no’.

Traditional homes would have few windows in the external walls and often a central court, together ensuring air circulation. Most owners cancelled courtyards, the poor built smaller houses and in some regions courts were anyway uncommon – so the stale air stayed in.

The best means of ensuring air circulation continues to be having an opening to the sky – a skylight if covered with glass, with or without a sunken courtyard. Enclosed rooms like bedrooms that cannot get a skylight, can have tall windows going up to roof level with vent at top.

In earlier times, most houses were rectangular in plan, with rooms distributed all around in geometrical shapes. Thus, one external wall of one room would get only one window. Now, let us try staggering them – push one room inside and pull one room outside. Thus, the external wall of the house would not be a rectangle with the wall line going in and out. We realise there can be many more windows in all orientations, many more corners for the room and generally much better air circulation inside.

Wind does not move in all orientations equally. Every region has its dominant directions, e.g. Kerala gets largely south-west wind, while Chennai has it from south-east. These larger trends further change directions due to trees, buildings, ground levels, seasons and such others, causing microclimatic modifications. As such, every site will have certain windward directions where pressure is high and leeward directions, where pressure is low. Wind blows from the higher to the lower pressure areas, hence windows can be located in such directions to get better indoor air movement.

Among the major hurdles for air movement is the larger indoor spaces we are creating thanks to technology. Smaller the room width, better the air circulation, but we are building large spaces necessitating ceiling fans. Even worse condition can be experienced in closely built crowded areas. The compactness nullifies all possible green cover and wind around the building, finally demanding an air conditioner. As such, both the house planning and city planning play major roles in indoor air.

Diagrams

Scientifically drawn-up data called wind rose diagrams are freely available today, though they may not be accurate for every site in a compact layout, but the general ideas can improve the situation largely. Roof-top fans called turbo ventilators are today popular, which need no electricity.

Past societies learnt how to live with wind, with sailors in the sea and farmers on land being the best examples. It was an animal instinct displayed by all, be it birds when they migrate or humans when they build vernacular structures. Somewhere down our modernising process, we seem to have lost this knowledge. It’s time to regain it.