| Buildings
The provision of adequate
ventilation is arguably the most
important consideration when
designing a new building for
animal housing
Even at fairly modest wind
speeds, the ventilation of a typical
livestock building will be governed
by the “wind effect”, meaning that
sufficient fresh air will be supplied
naturally by the wind. A building
containing livestock must,
however, be adequately ventilated
even on the calmest of days,
relying on what is known as the
“stack effect” (warm air rising
replaced by cooler air). The
adequacy of stack effect
ventilation for a given building will
depend on the location and size of
the inlets (normally below eaves
height), the location and size of
the outlet vents (normally at the
ridge) and the heat generated by
the livestock. A detailed design
procedure for calculating stack
effect ventilation is given in the
RIDBA Farm Buildings Handbook.
Condensation
Condensation occurs on a
surface when the temperature falls
below the dew point for a given
relative humidity. Condensation
does not cause high humidity, but
may be a symptom of it if the
temperature is low enough.
Although condensation can be a
nuisance if it results in dripping
water, and can in some
circumstances lead to corrosion of
steel fasteners and fixings, it is
high humidity (i.e. moisture in the
air) that causes health problems in
livestock. The focus for the
building designer should,
therefore, be on reducing humidity
through good ventilation rather
than hiding the problem through
the use of absorbent materials.
Other considerations
Buildings used for housing
livestock should have adequate
levels of lighting, provided by
natural or artificial means, or a
combination of the two. Natural
daylight is normally provided by in-
plane rooflights, often arranged in
bands along the roof. Since
rooflights allow direct sunlight to
enter the building, there is a risk of
overheating in summer if the
percentage area of rooflights is too
great. It may be possible to use a
smaller area, and therefore reduce
the overheating risk, by specifying
cladding with a highly reflective
coating on the inside.
Surface finishes should be
smooth and without sharp
projections to avoid injury to
animals or people. Walls should
have a washable inner surface that
can easily be hosed down and
floors must be non-slip.
Conclusions
With careful consideration at the
design stage, it is possible to
create a healthy and pleasant
Dr Martin Heywood
environment, with adequate fresh
air, and lighting, humidity and
temperature levels that are
comfortable for the animals. Good
ventilation and careful
specification of materials are the
most important factors.
Visit us
Cereals at
20
Stand 2 18
58
www.farmingmonthly.co.uk
June 2018 | Farming Monthly | 29