Specifications

Introduction
The control of volume, pressure
and cleanliness of the air entering a
spray gun are of critical importance
to the performance of the system.
Following some key installation
principles will help decrease the
risk of contaminants. For example,
it’s important to use the right size
air compressor for your application.
An overworked air compressor can
produce a significant amount of dirt
and oil. Additionally, proper piping
is very important to help prevent
condensation from forming within
the line and contaminating the air
supply.
This chapter examines the various
types of equipment available to
perform these control functions.
1. What is air control equipment?
Any piece of equipment installed
between the air source and the
point of use that modifies the
nature of the air.
2. Why is air control equipment
necessary?
Raw air, piped directly from an air
source to a spray gun, is of little
use in spray finishing. Raw air
contains small, but harmful,
quantities of water, oil, dirt and
other contaminants that will alter
the quality of the sprayed finish.
Raw air will likely vary in pressure
and volume during the job.
There will probably be a need for
multiple compressed air outlets to
run various pieces of equipment.
Any device, installed in the air line,
which performs one or more of
these functions, is considered to
be air control equipment.
3. What are the types of air
control equipment?
Air control equipment comes in a
wide variety of types, but it
basically all performs one or more
of the following functions; air
filtering/cleaning, air pressure
regulation/indication and air
distribution through multiple
outlets.
4. How does an air filter work?
It filters out water, oil, dust and dirt
before they get on your paint job.
Air entering the filter is swirled to
remove moisture that collects in
the baffled quiet zone.
Smaller impurities are filtered out
by a filter. Accumulated liquid is
carried away through either a
manual or automatic drain.
Figure 1 - Air Filter
5. What is an air regulator?
This is a device for reducing the
main line air pressure as it comes
from the compressor. Once set, it
maintains the required air pressure
with minimum fluctuations.
Regulators are used in lines already
equipped with an air filtration
device.
Air regulators are available in a
wide range of cfm and psi
capacities, with and without
pressure gauges and in different
degrees of sensitivity and accuracy.
They have main line air inlets and
regulated or non-regulated air
outlets.
6. How is an air filter/regulator
installed?
Bolt the air filter/regulator A
securely to the spray booth wall
near the operator. (see Figure 2)
This location makes it convenient
to read the gauges and operate the
valves. Install the filter/regulator at
least 25 feet from the B
compressed air source. Install the
C takeoff elbow on top of the D
main air supply line.
Piping should slope back toward
the compressor, and a E drain leg
should be installed at the end of
each branch, to drain moisture
from the main air line.
Use piping of sufficient I.D. for the
volume of air being passed, and
the length of pipe being used.
Table 1
5. Air Control Equipment
20
Minimum Pipe Size Recommendations*
Compressor Main Air Line
HP CFM LENGTH SIZE
1 1/2-2 6-9 Over 50' 3/4"
3-5 12-20 Up to 200' 3/4"
Over 200' 1"
5-10 20-40 Up to 100' 3/4"
100' - 200' 1"
Over 200' 1 1/4"
10-15 40-60 Up to 100' 1"
100' - 200' 1 1/4"
Over 200' 1 1/2"