Indoor quality arises because structures and the buildings have to take into account the health of the dwellers and avoid Sick Buildings, even as the key focus remains cost-cutting in mass affordable housing.
Kenya’s urban population was by 2018 estimated at about one-third of the country’s total population, and growing by over four percent annually. With the State-instigated plans to build a million homes by 2022, the quality of the indoor built-environment has come into sharp focus, notably being a key component of the State-backed Green Mark Standard, whose formulation kicked off in 2010.
In 2018, the Government announced plans to build one million houses by 2022 through two programmes – social housing and affordable housing. Low-cost housing is one of President Uhuru Kenyatta’s Big Four legacy agenda. The number of houses has now been revised to 500,000 (half a million) by 2022.
Briefly, the Green Mark Standard addresses indoor air quality testing, internal lighting, glare control and view outs, natural lighting and ventilation, artificial lighting and ventilation, internal noise level, and tobacco control, among others.
The indoor quality arises because the structures and the buildings have to take into account the health of the dwellers — who spend 90 percent of their time indoors—and avoid Sick Buildings, even as the key focus remains cost-cutting in mass affordable housing. That essentially implies that the materials, structures and even energy supply have to address toxicity, pollutants and other quality issues arising from the construction process. In Kenya, the high rate of cancer disease is a constant reminder of the indoor environmental quality primacy, with the obvious early solution being the elimination of asbestos roofing in public buildings. Asbestosis a leading cause of cancer. The plumbing for both the clean and waste water, and natural and mechanical ventilation in buildings, is another contributor to pollution, with professionals and statutory regulations and standards requiring enforcement. Paint, especially the lead-poisonous type, and the quality of cooking stoves, where the Government Green Mark Certification has emphasised on clean energy, all come into play for the sake of healthy living.
500,000 – Low cost houses planned for construction by the Government by 2022 as part of the Big 4 Agenda
Overall, the World Health Organisation (WHO) estimates some four million people die annually from household air pollution, mainly through respiratory diseases like pneumonia.
The air quality issue — often contributed to by low-quality energy sources like charcoal, firewood and kerosene stoves — is, however, the narrowest aspect of the indoor air quality by built-environment professionals. Even for mass housing, a lot of effort has to go into natural lighting and ventilation. The windows should be able to capture the daylight, which also helps in reducing energy spending for lighting, cutting the carbon foot-print while giving the inside of buildings ‘thermal’ comfort and relaxation. A good daylight construction avoids uneven glare of light that ends up increasing discomfort to the residents.
Increasingly in Kenya and globally, homeowners are opting for one-way or tinted windows that reduce the light and heat. This can significantly reduce the need for mechanical ventilation.
In terms of comfort and fresh air, balconies and large windows that offer open views have come to be appreciated, more so in multi-storey mass buildings. They help in improving both psychological and physical health of the occupants.
House designs with wide glass windows help tap the daylight. Reflective colours, including for ceilings and walls, equally reduce the need for light during the day and are part of the energy-saving sustainable buildings. In terms of structure, the building industry has come to avoid materials that negatively affect indoor air quality (IAQ). This would include soft blocks that easily absorb and retain water, resulting in high moisture and unhealthy toxicants. Built-environmental experts have identified “sick building syndrome” (SBS) resulting from accumulation of toxins and bad air, leading to recurrent flus and colds in particular homes and buildings. It is now known that in construction, mites, cockroaches and dust will affect the health of inhabitants, with the latter contributing to asthma, among other conditions.
Depending on the environment, quick-drying cement in wet areas and water-proofing cement can be required. The finishing of buildings has also come to be recognised as a major comfort issue, besides the type of roof selected. For the latter, baked clay tiles and concrete roofs can provide good comfort. But to avoid Volatile Organic Compounds (VOCs), timber or tile floors are good finishing materials, apart from quality paint.
Another important point is that dust brought in by footwear needs to be kept at a minimum by either building good pavements or providing “wipers” at the entry to homes.
The rules and regulations that govern indoor environment quality in Kenya include Noise and Excessive Vibration Pollution Control Regulations, Toxic and Hazardous Industrial Chemicals and Materials Management Regulations, Air Quality Regulations, Health Acts, and Public Health and Occupational Safety Act.
A building needs to take into account both the internal and external noises for comfort, while letting natural air, especially from green spaces hosting plants, whether in the surrounding areas or potted ones. Ventilation helps prevent accumulation of odours, carbon dioxide and toxins. In the Kenyan context, particularly where septic tanks are in use, exhausts are important to prevent pollution. These are normally put at the highest point, or where they least affect the residents. The contractors should also seal ventilations during building to avoid accumulation of dust ahead of occupation. Experts should be engaged in installing septic tanks to avoid backflow of pollution and, where possible, use of bio-digesters is advised.
Experts also advise that adhesives, commonly used in sealing waste pipes and other exhaust channels, should be placed in areas where they can be ventilated. The experts also caution on the quality of sealants used to avoid exacerbating the problem. Just like sealants plumbing, those of tiles should have minimal volatile organic compounds (VOC) and formaldehyde, and should be of low-emitting quality. Noise pollution is a poignant point in affordable mass houses hosting up to thousands of residents; the walls and windows need to be constructed accordingly.
The construction process itself generates a lot of pollution, more so for people occupying buildings or in the neighbourhood. Building of infills has become common for public mass housing in particular. The residents have to be insulated from dust and other pollutants and the buildings need to be flushed for moulds and dust before occupation.
In America, studies have shown links between productivity and airy work spaces against the background of the majority time spent in offices and homes. Some countries have regulators for indoor and outdoor pollution, including Kenya’s National Environmental Management Authority (Nema) and the GreenMark Standard. In the US, air and indoor quality issues are regulated by ASHRAE (previously called the American Society of Heating, Refrigerating, and Air-Conditioning Engineers.