Smoke Alarm User Manual

Installation, Operation and Maintenance Manual
Issue 1 Page 5-9
February 2001
5.19 Computer Balanced System Design using “SNIFF“ Version 3.0 Software
A distributed pipe network sampling system is designed using the “SNIFF“ Version 3.0 software. The
sampling system may have only one pipe segment or as many as 40 segments. The terminating pipe
segments can be capped or open-ended. The pipe and hole size diameters are calculated and optimised
by the “SNIFF“ Version 3.0 software. “SNIFF“ Version 3.0 software can also optimise hole diameters with
fixed pipe diameters. The “SNIFF“ Version 3.0 software dynamically balances the piping network to
provide equal amounts of air from each sampling hole while maintaining a minimum transport time of the
air sample. This allows each system to meet the needs of a specific installation, where optimal coverage
may call for unequal pipe lengths or an uneven number of sampling holes per sampling pipe. Since each
sampling hole samples an equal amount of air, the sensitivity of each sampling hole remain equal.
5.19.1 Parameters for Computer Balanced Systems
The following parameters must be considered when laying out the pipe network:
(1) The maximum number of sampling points is 100.
(2) The maximum number of pipe segments is 40.
(3) The maximum hole spacing is 9 meters (30 feet) 6 meters (20 foot) spacing
recommended in high value areas).
(4) All pipe segments should be capped at a maximum of 150 mm (6 inches) from the final
sampling hole. Exception with a hole in the end cap on larger systems.
(5) Extended sampling point (ESP) drops using 25 or 20 mm (¾” or ½”) up to 7 meters
(25 feet).
(6) Sampling points (SP) should be constructed of a 25 or 20 mm (¾” x ½”) or 20 or 20 mm
(½” x ½”) tee. The drop is always 9.5 mm (3/8”) tubing. The maximum (SP) length is
3.5 meters (12 feet).
5.20 Using the “SNIFF“ Version 3.0 Software
The “SNIFF” Version 3.0 software is a windows based computer program compatible with Windows 95,
98 or NT. Data input is accomplished graphically, with pop-up windows showing options to select the
following:
(1) Pipe Type
(1) Main and Branch Pipe Diameters
(2) Maximum Transport Time
(3) Average Ambient Temperature
(4) Static Pressure Differential
(5) Air Velocity
(6) Elevation Above Sea Level