Smoke Alarm User Manual

Installation, Operation and Maintenance Manual
Page 5-8 Issue 1
February 2001
5.18.1 Telephone Central Offices
In this application it is recommended that distributed pipe network sampling combined with return air grill
sampling. Within this type of installation it is often desirable to provide two levels of sampling. One set of
sampling points would be at ceiling level and the second set below the cable trays just above the
equipment racks. This can be accomplished either, by running the main pipe above the ceiling and using
an extended sampling point. The second method would be to install a second level of piping below the
cable trays. In either case a second detector is usually not required unless the square footage of the
protected area exceeds 2000 square meters (20,000 square feet).
5.18.2 Computer Rooms
Two methods are commonly used in computer room applications. Distributed pipe networks can
sometimes be installed above the dropped ceiling with extended sampling points penetrating the ceiling
into the protected area. Another method is to monitor the return air usually at the top of the air handling
units. Both of these methods are effective however, monitoring the Liebert units has a disadvantage in
that shut down or cycling of the units will affect the overall smoke detection. A combination of both
methods will give the quickest response.
If sub-floor detection is required, a distributed pipe network is used with the sampling points facing down.
5.18.3 Clean Rooms
Place sampling points inside the return air plenum or use return air grill sampling. The exact method will
depend on the air handling equipment and location of the filters. In most clean room applications, the
“SNIFF” Version 3.0 software can be used to design a sampling network located inside the return air
plenum.
5.18.4 Atriums
Use the distributed pipe network method. In many applications of this type multiple level sampling will be
required. Also, monitoring the return air may significantly reduce the response time.
5.18.5 Office Areas
Use the distributed pipe network method. In many applications of this type the main pipes can be run
above a dropped ceiling with extended sampling points dropped through the ceiling into the protected
area. Special attention should be given to the type of pipe used for the installation to ensure compliance
with local requirements. Most office areas use the volume above the ceiling tiles as an air return plenum.
5.18.6 Warehouse Storage
Distributed pipe sampling networks are recommended for use in warehouse applications. In many
instances two or more levels of sampling are required due to the effects of stratification. Freezer
warehouses can be accommodated although it may be necessary to condition the air before it enters the
Detector. Also the Detector must be mounted outside of the low temperature area. Refer to Chapter 2
for the Detector environmental specifications.