4-2.2.2.1 Adjusting For Altitude Or Pressure; Atmospheric Correction Factors - Kidde Fire Systems ECS Manual

4-2.2.2.1 Adjusting for Altitude or Pressure

The procedure for determination of the agent quantity assumes that the protected enclosure
is at sea level or has an internal pressure of 14.7 psia (101.4 kPa). The design agent quantity
must be adjusted where the protected enclosure is at an altitude or pressure that differs by
more than 11% from sea level values. Table 4-2 lists "Atmospheric Corrections Factors" as a
function of altitude or pressure. Calculate the adjusted (altitude-corrected) agent quantity as
follows:
Adjusted quantity = (Sea-level quantity) x (Atmospheric Correction Factor)
Note: Use the value of Atmospheric Correction Factor corresponding to the highest possible
enclosure pressure where the pressure can be varied, by design, from the prevailing
barometric pressure at the altitude of the installation. This procedure assures that the
agent concentration will not be less than the design concentration at the highest achiev-
able enclosure pressure.
06-236115-001
Table 4-2. Atmospheric Correction Factors
Altitude
Enclosure
Above Sea
Pressure
Level
ft. m psia
-3000 -920 16.25
-2000 -610 15.71
-1000 -300 15.23
0 0 14.70
1000 300 14.18
2000 610 13.64
3000 920 13.12
4000 1,210 12.58
5000 1,520 12.04
6000 1,830 11.53
7000 2,130 11.03
8000 2,440 10.64
9000 2,740 10.22
10000 3,050 9.77
4-3
Atmospheric
Correction
Factor
kPa
112.1 1.11
108.3 1.07
105 1.04
101.4 1.00
97.8 0.96
94.1 0.93
90.5 0.89
86.8 0.86
83 0.82
79.5 0.78
76.1 0.75
73.4 0.72
70.5 0.69
67.4 0.66
Design and Installation
October 2014