Preparation and refinishing area
When planning your bodyshop, productivity, health,
safety, and environment regulations must all be taken
into consideration.
Start with the preparation area. There must be
space to pressure wash vehicles to get cleaner
paintwork before they enter the paint shop.
The dust created by sanding in the preparation
stage must be prevented from being drawn into
the paint area. The best solution is an efficient
extraction system or extraction tools. Avoid walls
or curtains as they lead to rigid space allocation
and are inflexible because they prevent bodyshops
reacting to variable workloads. If possible, design
the paint shop so that the vehicle moves forward
in a relatively straight line or an easy loop, and
try to keep it inside the workshop to avoid the
problem of coming into contact with dirty, dusty
air.
Ideally the refinishing area should form a selfcontained
area separate from the mechanical and
repair side of the workshop and the preparation
area. The main objective is to minimize the amount
of handling of the vehicles by arranging for a flow
system from the vehicle’s entry to its exit from the
spray booth, thus preventing any dust entering the
spray booth. Consequently spray booths and ovens
can be used to their full capacity throughout the
working day.
In the paint shop, health and safety regulations
will dictate many decisions and must be taken
into account in your plans. The ramifications of
the EPA and COSHH legislation are far reaching
for all bodyshops. In effect, any bodyshop currently
operating without a properly constructed
fully operational and well maintained spray booth
is operating outside the law and risks summary
closure.
A spray booth is in most cases the single biggest
purchase decision made by the bodyshop owner.
Most bodyshops are now fitting combi-booths.
A combi-booth is a combined spray booth and
low-bake oven with an electrically controlled operational
cycle which provides the correct temperature,
filtration and lighting requirements for the
spraying and baking of paint. The purpose of the
combi-booth is to provide an efficient, clean area,
free of humidity and within the temperature band
20–25 °C. The booth must be sealed off to prevent
overspray escaping into the workshop, and must be
force ventilated to remove solvent fumes and
microscopic paint particles whilst drawing in clean
and dust-free air. Once spraying is completed, the
combi-booth can be put into the bake cycle in
which the internal booth temperature is raised to
promote rapid curing of the paint. One important
point to consider is the choice of spray booth. This
must meet all the requirements of the EPA in relation
to the throughput of air and the placement of
the exhaust stack. This point is particularly important
in residential areas. The booth must operate
under negative pressure and to comply must be
fitted with a pressure gauge. As a further precaution,
emissions from spray booths should be tested
at least once a year to monitor particulate matter
emitted. The EPA stipulates that concentration of
total particulate matter in final discharge to air
from the booth should not exceed 10 mg/m3.
When constructing the paint store room, remember
to provide space for the mixing system and
for the safe storage of paint. Again, follow all the
necessary regulations.
Valeting
The vehicle should now be back at the valeting bay
for both interior and exterior valeting, to emerge as
good as new with the minimum wasted time.
Careful valeting work can transform the final
appearance of the vehicle, thus creating customer
satisfaction by returning the car looking like it did
when new. If the customer’s first impressions on
collecting the vehicle exceed expectations, he will
be more than willing to recommend the comapany’s
quality of service.
First aid
First aid equipment should be supplied at set
points throughout the workshop, and staff should
be encouraged to attend first aid classes. The
Health and Safety at Work Act requires that
where more than 50 personnel are employed, one
qualified first aid person must be appointed.
Fire fighting equipment
Consult the local fire officer regarding fire points
and types of fire appliances, exits, and fire doors.
Organize staff fire drill and training procedures,
Bodyshop planning 509
and make sure that all fire extinguishers are
maintained.
15.3 Bodyshop heating
The body repair shop can be a difficult building to
heat because of the very nature of the work that is
carried out. First, it needs to be a reasonable height
so that vehicle bodies can be elevated and moved
about easily; and secondly, doors are constantly
being opened and shut to allow for the movement
of vehicles in and out of the workshop.
Careful consideration of bodyshop heating
requirements will not only result in energy consumption
savings but also make the bodyshop
more comfortable. Whatever type of heating systems
are used, care should be taken to ensure that
heaters are placed where they will not interfere
with work in progress, will not take up unnecessary
floor space, and will provide employees with
the maximum benefit.
Most of the conventional methods of space
heating can be found in bodyshops, ranging from
portable gas fired units through wet systems to
radiant systems.
Radiant heating
Infrared (IR) heating is the transfer of energy by IR
electromagnetic radiation; this is the portion of the
electromagnetic spectrum between visible light
and the top section of the radio-radar wavebands.
Any object will emit IR energy; the higher
the temperature, the more IR radiation is emitted.
Therefore when two objects are adjacent to one
another and one is hotter than the other, there will
always be an exchange of heat from the hotter object
to the cooler one. Radiant heaters operate by the
transfer of heat to solid objects rather than by heating
the air itself; therefore high-ceiling buildings can be
heated with a high degree of efficiency. By installing
radiant heaters above a cold concrete floor, there
will be a transfer of IR radiant energy downwards
towards the cold concrete, which will absorb energy
until it becomes warm. Other objects at floor level,
such as vehicles, benches and machinery, as well as
the walls, will become warm either by receiving
direct IR energy or by the transfer of energy from the
floor. All of these items become secondary heat
sources, transmitting energy into the surroundings of
the workshop. Ceiling-mounted radiant heating units
are ideal for bodyshop use in that they do not take
up usable space and encroach into the working
area; however, they are not suitable where the ceiling
height is less than 3.5 metres. Also radiant heat
absorbed by its surroundings does not easily escape
through service doors: therefore heat loss is reduced
and a saving is made on energy costs. Furthermore,
heating the floor keeps it dry, and the fact that vehicle
bodies become heated reduces problems associated
with condensation as the cold vehicle bodies are
brought into a heated environment.
Electric heating
Electric spot heating allows comfortable heat to be
concentrated where and when it is wanted. Linear
quartz heaters can be used for the spot heating of
specific work areas, for zone heating of a particular
area of the bodyshop, or for full coverage heating.
For spot heating, the heaters should be positioned
about 3–5 metres apart, at a height of approximately
2.5–3.5 metres from the floor, depending upon the
heater rating. Heaters should be rated at 1.5 kW for
sheltered locations, rising to 3 kW or even 4.5 kW
for more adverse conditions. For zonal heating, the
heating requirement should be calculated on the
basis of 150–300 W/m2. The actual value selected
will depend upon the state of the building, internal
draughts, etc. If the zone is more than about
15 metres wide, then additional rows of heaters may
be required. For full coverage, the heaters should be
positioned around the perimeter of the building at
spaces of about 4–6 metres, using load densities of
100–200 W/m2 based upon heat loss calculations. If
the building is more than about 17 metres wide,
additional heaters can be installed.
When installing these heaters, the general principle
is for the heater to be angled down at about 45
degrees when wall mounted and up to 90 degrees
when mounted overhead.
As with all forms of heating, care should be
taken with these heaters if there is a risk of combustible
dusts or flammable gas hazards. The
lamp/filter assembly is the hottest part of the
heater, with surface temperatures of 750–800 °C,
broadly similar to the surface temperature of the
lamp in a tungsten halogen floodlamp. In case of
concern over this point, consultations should be
held with the factory inspector.
510Repair of Vehicle Bodies
Gas heating
Radiant gas heaters come in two forms: tubular and
ceramic plaque.
The radiant tube heater typically incorporates
single or twin emitter tubes through which hot
gases are drawn by a vacuum fan to produce the
IR heat. An automatic burner fires into the mouth
of the emitter tube, providing rapid warm-up
without any need for preheating. The burner operates
in a totally enclosed combustion chamber
with the safety controls housed separately to protect
them from dust and contamination. If it is
required to exhaust the products of combustion to
the atmosphere, the individual heaters can be
linked into a manifold system with one exhaust
fan. Typical capital costs are about half those of
an equivalent central boiler system and about the
same as a ducted warm air system. The heaters
can either be wall mounted and inclined, or suspended
at heights from 3 to 12 metres. The units
are able to cope with high air exchanges and they
can also reduce the spread of airborne dust and
fumes.
Ceramic plaque heaters are silent in operation
and are marketed as being ideal for spot heating
and for the heating of lofty uninsulated buildings
which suffer high air movement. They incorporate
a totally enclosed burner with a skirt to protect the
ceramic plaque from cold air washing over the hot
surface.