System Sensor Pipe Installation - Manual (Page 6)

User Guide: Aspirating Smoke Detector Pipe Installation
6
Pipe Network Installation
This section provides the basics to installing a pipe network.
Keep in mind that each system will have different characteris-
tics, and will have variations to accommodate. The most
common issues are described in the following sections. To
ensure a pipe network performs as expected, it must be
designed in PipeIQ and installed as specified by the software.
Cutting Pipe
Proper tools must be used when cutting pipe. Pipe shears or a
wheel type plastic tubing cutter can be used for plastic pipe.
Always keep the cutting edge of the tools sharp. Ensure that
cuts are made perpendicular to the pipe length, keeping the
cuts square. Square cuts ensure maximum bonding area and
help provide a good seal when joining the components.
Remove all loose material and any burrs from the end of the
pipe after a cut. Debris and shavings from cuts must be re-
moved in order to keep sampling ports free of obstruction.
Joining Components
The pipe network must be permanently connected once the
system has been installed and tested. The method to
accomplish a permanent connection depends upon the material
of the pipe and fittings.
NOTE: The immediate connections between the inlet pipe
and exhaust pipe and the FAAST detector SHOULD NOT be
permanently connected.
When bonding components together, never apply solvent on the
inside of a pipe or other component. Apply the solvent only to
the outside of the pipe that is being inserted into a coupling or
other component. If a solvent is applied to the inside of a pipe or
other component, the solvent can build up. This build up can
affect the air flow within the pipe network and may cause
abnormal behavior within the pipe network.
Make sure that pipes are inserted completely and butted
against the lip of the coupling or other component. If this is not
done, turbulence can be created due to the gaps, which can
cause problems with system pressures and air flow.
Frequently Asked Question – Is there a specific glue that
must be used when assembling the network piping?
Yes, glue that is listed for the type of pipe used. When applying
the glue be cautious not to leave excess residue inside the pipe.
This can trap dust or dirt particles that can possibly affect the
airflow of the detector over time.
Prior to drilling any sample ports, the pipe network should be
checked for leaks. This can be done by pushing blank
end caps onto pipe ends and/or covering sample ports with
tape and applying low pressure air to the system to check for
pressure decay.
Mounting the Pipe Network
The following recommendations should be taken into
consideration when mounting the pipe network.
• Minimize flexing of the pipes by securing them at proper
intervals with appropriate mounting brackets.
Maximum Support Spacing at Ambient Temperature
Pipe Diameter 60°F (16°C) 100°F (38°C) 140° F (60°C)
1/2 in. (15mm) 4.5 ft. (1.3 m) 4 ft. (1.2 m) 2.5 ft. (0.7 m)
3/4 in. (20 mm) 5 ft. (1.5 m) 4 ft. (1.2 m) 2.5 ft. (0.7 m)
Table 2: Maximum support spacing at ambient temperature.
• Typically, the pipe network should be mounted between
1 and 4 in. (25 – 100 mm), maximum of 12 in. (300 mm),
below the ceiling, subject to local codes and regulations.
• Allow for expansion and contraction of the pipe network in
areas of extreme temperature fluctuations, especially on
long straight pipe runs.
• In areas of extreme temperature fluctuations, never place
mounting brackets adjacent to couplings, unions or tees.
This can lead to interference with expansion or contraction
of the pipe network.
• To minimize the effect of pressure differentials that could
affect the air flow of the system, the sampled air must be
returned to the protected environment via exhaust tubing
wherever possible.
Pipe Bends
Never bend pipes unless absolutely necessary. Use elbows,
tees, or other fittings to change direction of the pipe.
If bending is necessary, determine how much bending the
pipe can tolerate before beginning the process. Always use
bending springs and pipe benders. Bending a pipe without heat
will cause the PVC to shatter. Never heat the pipe or bend it
around sharp objects. If a pipe creases or buckles while
bending, replace it with a new section of pipe. Conform to all
local codes and regulations for bending of pipes.
Figure 7: Pipe bends.