System Sensor Pipe Installation - Manual (Page 5)

User Guide: Aspirating Smoke Detector Pipe Installation
5
End Caps
The end of the pipe should be terminated with an end cap. The
end cap may have a sampling port depending on the system
design. The size of the port in the end cap is determined by the
PipeIQ software. An end cap is shown in figure 4.
ASP-79
Figure 4: End caps.
Capillary Tubes and Sampling Ports
A capillary tube is a length of flexible tubing that is connected
to the main sampling pipe with a sampling port at the end.
The purpose of these tubes is to extend the placement of the
area being sampled away from the main pipe network. This may
be necessary to reach in to an enclosed space, such as a
cabinet, or for aesthetic or security reasons. This allows the core
pipe network to be hidden while only a small sampling port is
located in the main space. Figure 5 shows the capillary tube ex-
tending down from the main sampling pipe with a sampling port
at the end. PipeIQ allows for capillary tubes and sampling ports
to be added to the pipe network design and will calculate the
appropriate air flow through the system.
The maximum length for capillary flexible tubing is 26 ft. (8 m).
When multiple capillary tubes are used in a network, the length
of each capillary tube should be approximately equal.
ASP-83
Figure 5: Capillary tubes and sampling ports.
Mounting Brackets
The pipe network is mounted to the ceiling, or other appropriate
location, using mounting brackets. A large variety of brackets
are available from a standard pipe supplier. Typical brackets
include clips, saddle clamps, or tie wraps, as shown in Figure 6.
The mounting choice will depend on the material being mounted
to, environmental temperature, and local codes and regula-
tions. Mounting brackets are usually centered 5 ft. (1.5 m) apart
when using 3/4" schedule 40 pipe at 70°F (21°C). At 140°F this
spacing reduces to 2.5 ft. between support brackets. Open
style mounting clips should not be used in an inverted position
with the open section facing downward, because the pipe could
drop from the clip.
ASP-81
Figure 6: Mounting brackets.
Labels
Labels are available to identify the pipe network as a fire
detection system, both at the sampling ports and along the pipe
itself. NFPA 72 ® states that the pipe should be labeled:
1. At changes in direction or branches of piping
2. At each side of penetrations of walls, floors, or
other barriers
3. At intervals on piping that provide visibility, but no
greater than 20 ft. (6.1 m)