Different pathogens are known to thrive
in particular conditions, e.g. in places with
relative humidity (RH) of below 40% and
above 60%; in dump spaces; in spaces with
poor conditions of lighting; in places with
low levels of ventilation allowing their
recirculation in the air and increasing
their probability of infecting humans.
Many pathogens also thrive in low
temperatures and in places where the
materials used in construction and finishes
provide conducive environments for their
propagation, a case in point is dust mites
that breed under carpets.
Healthy Buildings in
African Context
In the African context, most of the
issues raised in this commentary can
easily be dealt with through building
regulations. The problem is that most of
those regulations are not up to date, and
do not respond to the predominant local
conditions.
It is quite difficult to maintain building
standards specified in the codes in
informal settlements, where construction
is basic, lighting is compromised and
keeping out weather elements is not taken
into account.
Ironically, the challenge is also
experienced in expensive high-rise office
building blocks, where standards for many
“modern innovations” are missing. Natural
ventilation is absent favouring mechanical
heating, ventilation and air conditioning
(HVAC) systems, with no standards to
deal with the levels of volatile organic
compounds (VOCs), which they emit.
Unchecked levels of VOCs can cause eye,
nose, throat irritation, headaches, loss of
coordination and nausea. It can damage
the liver, kidney and central nervous
system. Some of these compounds have
been proven to cause cancer.
Wall to wall carpets are common in “big
people’s offices” and hotels all over Africa.
The carpets allow dust mites to thrive.
Poor lighting conditions imply reliance on
artificial lighting throughout the day with
the challenges highlighted earlier. The
buildings are literal green houses where
temperatures soar in absence of HVAC
systems.
Apart from basic accommodation,
buildings typologies have already been
developed in vernacular architecture in
Africa that take cognisant of prevailing
natural environments, including local
materials and construction approaches, to
provide healthy buildings. An example is
Swahili Architecture at the East African
Coast. Key elements of this are described
below.
Natural ventilation is dealt with through
the following strategies: Generous
openings, that have been optimized and
standardised through thousands of years
of practice, that are normally aligned
to external air movements of “Kusi”
but located to be shaded from the more
violent northern winds “kaskazi” that
come with driving rain; The high “makuti”
(palm leaves) breathing roofs help in air
circulation, in and out of the building;
Contemporary designs also include wind
driven fans, eliminating the need for air
conditioning.
Regulation of Diurnal Temperatures:
This is controlled mainly through partial
shading on western walls using verandas;
Thick coral walls are key to regulating
indoor temperatures, with very low diurnal
temperature range; The “makuti” or shaded
coral roofs being key to ensuring that the
building does not overheat.
Humidity is dealt with through building
construction techniques, including: Site
location on elevated areas, elevating the
ground floors; Use of lime plaster finish,
which is often coloured and smooth,
like marble, provides spaces that are
easily cleanable, eliminating spaces for
pathogens; Effective plumbing and
drainage techniques (Did you know
that some of the earliest plumbing and
drainage in buildings on earth was done
in the Kenyan coastal town of Lamu, soon
after it was established by the Swahili
around 1370 AD?)
Lighting is key in Swahili Architecture,
with strategies including the following:
Large openings for doors and windows
allowing adequate light into the spaces;
Courtyards allow adequate light deep
into building interior spaces; Building
orientation ensures sun shading from
hostile western sun while allowing the
morning softer eastern sun into the spaces.
Ambient lighting is mainly from North
and South facing openings; Even in very
dense spaces residents have access to the
roof, where they can get natural lighting;
Glare is dealt with through a system
of sun shading verandas, and louvered,
open-able, timber screens over doors and
windows.
Lessons for Covid-19
Studies have shown that though
environmental factors alone do not explain
the spread of Covid-19, it is a major
contributor nonetheless. The unhealthy
living and working environments described
in this write can help propagate the virus
by providing appropriate temperature,
humidity, surfaces and circumstances for
its propagation.
Further, lockdown in confined homes,
compelling people to stay in the same
internal environment for extended
periods of time would expose the
residents to other conditions that would
compromise their immunity and make
the impacts of the virus more lethal. Such
unhealthy environments would provide an
infrastructure for spread of the virus.
We note the following highlights in
terms of space and the spread of Covid
19: Smooth surfaces are better as they
are easier to clean and the virus may not
stick there for too long; Air recirculation
in poorly ventilated surfaces is perfect for
the spread of the virus, this is one of the
major reasons why the spread of the virus
was linked to air travels; Thermal comfort
with low w=swings in daily temperatures
from the norm is actually a good deterrent
of SARs; studies have linked drop in
temperatures increase in infection rates;
It is understandable that weather alone
does not explain the spread, but is a major
contributing factor.
As this write up indicates, there are useful
insights that one can glean from building
construction of vernacular architecture in
Africa, which will contribute to healthier
buildings. As more research reveals
the nature of Covid-19, this will be a
good basis to build on to contribute to
eliminating conditions that allow the virus
to spread, in addition to eliminating other
pathogens and promoting human health
generally.
Prof. Alfred Omenya, B.Arch,
M.Arch, PhD is an Architect and
Urban Development Expert and the
Chief Executive Officer of Eco-
Build Africa. You can engage him
on this or related matters via email
at: [email protected].