Smoke Alarm User Manual

Installation, Operation and Maintenance Manual
Issue 1 Page 5-3
February 2001
5.5 Air Velocity
The air velocity is determined using SNIFF Version 3.0 software. Three settings are available to deal with
all types of sampling systems including return air duct sampling systems. Airflow is measured with a
handheld anemometer. To measure the airflow the meter should be held in close proximity to the
proposed position of the sampling point. The anemometer should then be rotated to obtain the maximum
reading. All related HVAC systems should be operating when the measurements are taken.
Figure 5.1 Anemometer
5.6 Branch Point
This term is used to describe a pipe segment that has been divided into two or more pipe segments by a
tee connector or a junction box.
5.7 Elutriator
The Elutriator is an optional item used if the protected area is expected to have heavy amounts of non-
combustion particulate. If used, it is attached to the inlet of the Detector. This unit is recommended for
use with a Detector using a standard detector head.
5.8 Elbow, Standard 90 Degree
A standard 90-degree elbow is similar to that used in the plumbing industry. However, it should be noted
that each elbow increases the resistance of the system. Bearing this in mind, systems should be
designed to minimise the number of elbows.
5.9 Sweep Elbow
A sweep elbow is the type used in making electrical conduit bends. Sweep elbows have a longer radius
than standard elbows. When included the sweep elbow will minimise the friction loss when making a
90-degree bend resulting in quicker transport times. The sweep elbow is preferred for air sampling
systems (available in electrical conduit fittings).