Smoke Alarm User Manual
Installation, Operation and Maintenance Manual
Page 5-4 Issue 1
February 2001
5.9.1 Equivalent Feet
A method used to determine relative efficiencies of different types of plumbing. 3.05 meters (1 foot) of
straight pipe equals 3.05 equivalent meters (1 equivalent foot). The following table gives the equivalent
measurement for different size and types of elbows. This data becomes critical when the maximum
allowed pipe lengths are being approached.
Table 5.1 Elbow Equivalent Measurements
Elbow ID 32 mm (1 in.) 25 mm (0.75 in.) 20 mm (0.5 in.)
Standard 90
o
Elbow 1.83 meters (6 ft) 1.22 meters (4 ft) 0.92 meters (3 ft)
Sweep Elbow 1.22 meters (4 ft) 0.92 meters (3 ft) 0.61 meters (2 ft)
5.9.2 Extended Sampling Point (ESP)
Extended sampling points are extensions of pipe from the pipe segment to the area being protected.
A typical use of an extended sampling point would be to drop a sampling point down from the main pipe
segment into the protected area.
5.9.3 Sampling Point (SP)
Sampling points extend from rigid pipe segments into the area being protected via a length of 9.5 mm
(3/8 inch) capillary tubing. A Sample Point Kit provides all the hardware necessary to make twenty-five of
these connections. A typical application would be to drop a sampling point down from a main pipe
segment, through a dropped ceiling into the protected area.
5.10 Pipe Segment
A length of pipe with or without sampling holes with nominal Internal Diameters of 32, 25, 20 millimetres
(1, ¾, ½ inch). A pipe segment is defined as the total length of pipe in any of the following:
(1) From Detector to pipe end.
(2) From Detector to branch point.
(3) From branch point to branch point.
(4) From branch point to pipe end.
5.11 Sampling Hole
Sampling holes are strategically located penetrations into a pipe segment. The sampling holes are
specifically designed to draw air into the sampling system. The requirements of BS 5839 (Part 1) or other
local requirements should be considered when spacing sampling points. By the use of SNIFF version 3
software the sampling point hole size will be determined.