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A
ccording to IBT fundi, Dr Jeff
Mahachi from the National
Home Builders Registration
Council (NHBRC), one of the funda-
mental reasons for erecting buildings
is to create a shelter against the varia-
tions of the outdoor climate.
He highlights that innovation in
the building system in terms of mate-
rials or methods of construction has
the potential to be able to achieve
improved thermal performance due
to its integratednature of the technol-
ogy components for relevant climatic
zones. There has been little research
on the performance of IBT envelopes
in the South African low-income and
gap housing market. More atten-
tion should be paid when designing
and constructing homes to address
comfort temperatures and energy
efficiency savings that will induce
benefits in the longer term.
Due to the shortfall of housing
for the poor, more efficient ways of
delivering homes are being sought
through the use of IBT. To contrib-
ute to wider development goals of
sustainability, it is critical to create
a shelter against the vicissitudes of
the outdoor climate that simulta-
neously addresses environmental
concerns such as energy efficiency.
The aim of climate conscious design
is thermal comfort, on which this
research is based. Thermal comfort
or thermal neutrality is the series of
conditions in which householders
feel neither too hot nor too cold. The
research includes whether the indoor
temperatures of the constructed
IBTs fall within acceptable comfort
temperature ranges. The NHBRC
logged data for summer and winter
including minimum and maximum,
average temperatures and humidity
at 25 IBT houses at the NHBRC Eric
Molobi Housing Innovation Hub in
Soshanguve, Pretoria.
Temperature and humidity loggers
were set up in IBT houses ranging
in size from 30 m² and 110 m² and
the data collected was to ascertain
whether the indoor temperatures
werewithinAmericanSociety of Heat-
ing, Refrigerating, Air-conditioning
Engineers (ASHRAE) 55-2013 adaptive
method comfort ranges of naturally
ventilated buildings. The adaptive
chart relates indoor comfort tem-
perature to prevailing outdoor tem-
perature and defines zones of 80%
and 90% satisfaction. The results
indicated that only a marginal per-
centage of the maximum and mini-
mum dry-bulb temperatures, over
a one month period, complied with
ASHRAE standard 55-2013. However,
the average dry-bulb temperatures
for all the IBT homes in summer
complied, whereas most IBT houses
in winter did not comply. This is the
temperature of air measured by a
thermometer freely exposed to the
air but shielded from radiation and
moisture. HolmandEngelbrecht state
that building design that achieves
thermal comfort with a minimum
of artificial heating or cooling is an
energy-efficient building. It is also
likely to be the buildingwith themini-
mumnegative environmental impact
and the lowest running energy cost.
A fundamental reason for erecting
buildings is to protect householders
against extreme climate changes and
create indoor environmental condi-
tions that are better than outdoors
and within the comfort range.
International standards com-
monly used to evaluate thermal
environments include ISO 7730
(2005), ASHRAE 55 (2013) and EN
15251(2007). ASHRAE Standard 55
(Thermal Environmental Conditions
for Human Occupancy). These stan-
dard that providesminimum require-
ments for acceptable thermal indoor
environments.
The study aims to monitor the
thermal comfort of 25 different IBT
houses at Eric Molobi Innovation Hub
to establish the live-ability of houses
in terms of comfortable internal
temperatures. It therefore estab-
lishes whether the IBT houses are
thermally comfortable in terms of the
indoor temperatures versus outdoor
temperatures. Bearing in mind that
the IBT houses are show units, the
performance of the envelope of the
building becomes relevant in the
exercise. To obtain optimal results
Thermal comfort of
Innovativebuilding technologies (IBTs) demonstrate significant
value-adding attributes to construction products and building
systems, whichcouldplay amore significant role in thedelivery
of subsidised houses in South Africa.