Edwards LaserSense HSSD-2

Chapter 2: Installation and assembly
LaserSense HSSD-2 Aspirating Smoke Detector Installers Handbook 19
Sampling pipes must have capped ends. The end cap should be drilled with a
sampling hole normally between 4 or 5 mm (0.16 or 0.20 in.) diameter and free
from burrs. Sampling holes should normally be 3 to 4 mm (0.12 or 0.16 in.)
diameter or as calculated by PipeCAD and free from burrs. Each pipe run should
not have more than 25 holes.
Pipe transit time must not exceed 120 seconds and an approved type of pipe
must be used for installations. When drilling holes in the sample pipes, or cutting
off lengths of pipe, ensure that all swarf and debris is removed from the pipe.
This guide holds true for average sampling pipe lengths, but if using long pipes
(typically more than 60 metres (197 ft.) total), performance may be improved by
making the sampling holes near the ends slightly larger than those nearer the
detector.
Use of PipeCAD software
PipeCAD pipe modeling software must be used when designing a pipe network
and verifying its performance. Refer to the PipeCAD System Design and
Installation User Manual for complete instructions on how to design and install an
air sampling pipe network.
Mechanical installation
Before installing the detector the local standards for installation of aspirating
detection systems must be consulted as these standards differ throughout the
world. Specific advice for one country may not be applicable to another.
The detector body is fitted to a wall-mounting bracket which is attached to the
wall via three mounting holes E as shown in Figure 12 on page 20. The detector
is then fitted over the mounting stud D and secured inside the detector body with
the nut provided for the purpose.
For a more discreet layout, it is possible to allow the sampling pipes and cables
to enter the detector from the rear, with the sample pipes and connection cables
channeled into the wall. Figure 11 on page 18 depicts the detector with cables
channeled into the wall and the sampling pipes not channeled into the wall.) In
order to achieve this, sampling holes A and B need to be opened up to a
diameter of. 30 mm (1.25 in) to take the sampling pipes A and the exhaust pipe
B. The holes C need to be opened up to 25 mm (1.0 in.) diameter in order to take
a suitable threaded metal cable gland to provide adequate RF screening for the
connection cables. These modifications are shown in dotted lines in Figure 12.
The wall will also need to be suitably prepared to allow the mounting plate to sit
flush against the wall. The sampling and exhaust pipes must also extend out of
the wall sufficiently to tightly engage in the pipe entry points on the rear of the
detector (as shown in Figure 12). If the detector does not fit flush with the
mounting bracket, the pipe excess should be trimmed back in small increments
until the correct fit is achieved.