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38
Thermal comfort is defined in British
Standard BS EN ISO 7730 as ‘that
condition of mind which expresses
satisfaction with the thermal
environment’. In layman’s terms,
this means being neither too hot nor
too cold.
Within a typical UK office, there is
relatively little change in humidity and
air movement, so the most critical factor
becomes the ambient air temperature.
Getting this right can feel like a never-
ending battle, as every individual has
a different comfort level, and this can
change from day to day depending on
what clothes are worn.
In the workplace, getting the
temperature right isn’t just a question of
comfort: if the office is too hot, occupants
may feel tired and drowsy and productivity
will suffer as a result. A dramatic heat
wave or broken air conditioning system
can cause stress and anxiety and, in some
cases, even affect safety.
So what is an acceptable workplace
temperature? The Health & Safety
Executive locates thermal comfort on a
scale from 13°C (56°F) to 30°C (86°F),
with the lower end more suited to
strenuous activities and the upper end
more appropriate for sedentary work. It
suggests that to be deemed ‘reasonable’
a thermal comfort level should ‘satisfy
80% of occupants’ at any one time.
For offices, the British Council for
Offices suggests a summertime range
of 21-23°C (69-73°F). Relative humidity
should be kept at around 50%: much
higher and the office will feel stuffy;
much lower and people will suffer
from dry skin and eyes and experience
electrostatic charges from office
equipment. The minimum fresh-air rate
should be 10 litres per second per person;
the optimum air movement should be
0.1-0.5 metres per second.
Easy wins
There are a number of things that
employees can do to improve their
thermal comfort during the summer
months. These include removing layers of
clothing; drinking plenty of water; eating
lighter meals with more water content,
such as salads and fruit; and using a desk
fan to increase air movement.
There are also actions that can be
taken by an employer, such as:
n
the hire or purchase of air
conditioning;
Office environment
How to stay cool this summer
Steve Reeve explains what employers and employees can do
to stay comfortable this summer.
n
fitting anti-sun blinds to reduce the
heating effect of the sun;
n
insulating hot pipes or machinery to
stop heat radiating into the office;
n
introducing flexi-time so that staff
don’t have to work or travel to and from
the office when temperatures are highest;
n
relaxing the dress code;
n
allowing outdoor meetings;
n
changing coffee breaks to ice-lolly
breaks; and
n
making sure all office equipment such
as photocopiers, computers and lighting
are switched off when not in use.
When it comes to thermal comfort,
you won’t please all the people, all
the time, especially at a time of global
warming and pressure to reduce
carbon emissions – according to one
survey, increasing the recommended
temperature in a 100,000 sq ft office
building by 2ºC could save six tonnes of
carbon emissions per year.
Very few offices can successfully
manage without air conditioning, but if
you make sure the office manager knows
how to operate the system and uses it
in conjunction with these tips, you will
be able to keep costs to a minimum
and keep a smile on everyone’s faces no
matter what the temperature is outside.
Steve Reeve is sales director at Andrew
Sykes, the UK’s largest specialist hire
company.With over 25 years’ experience,
Andrew Sykes serves virtually all industry
sectors with machinery sourced from the
world’s top manufacturers.
www.andrew-sykes.com 0800 211611
A single split has one outdoor
unit linked to one indoor unit, with
sophisticated control systems to set
temperature, timing and many other
functions. It used to be that splits could
only operate full on or full off, but most
now use ‘inverter’ technology to produce
infinitely variable output. This ensures they
only use the minimum energy required to
reach their target. As a result, running costs
are much lower than with ‘on or off’ splits.
Multi-splits are basically the same,
except that a single outdoor unit can serve
up to eight indoor units.
VRF systems can serve up to 64 indoor
units from a single outdoor condenser,
but this does not mean they are only
suitable for larger projects: some mini VRFs
are used for domestic installations. It all
depends on the exact circumstances; yet
another reason to consult an expert.
There are two types of VRF: two-pipe
that can either heat or cool at any one
time; and three-pipe that can heat and
cool different rooms at the same time.
One final reason for calling in an expert
is siting. Positioning the indoor units
correctly will affect the efficiency of the
system and the comfort of users, but the
siting of outdoor units can have an equal
impact on efficiency. There may also be
neighbours to keep happy and planning
regulations with which to comply.
Tony Nielsen is product and marketing
manager at FG Eurofred, the UK face of
Fujitsu air conditioning.
0208 731 3450
www.fgeurofred.co.uk
...continued
A dramatic
heat wave or
broken air
conditioning
system can
cause stress
and anxiety...
Positioning
the indoors
units correctly
will affect the
efficiency...