User's Manual

Table 3-2A. Volume Factors - Surface Fires (For 34% CO
2
Concentration), US Units
Enclosure Volume (ft.
3
)
Volume Factor
Calculated Quantity
f
1
f
2
(ft.
3
/lb.) (lb./ft.
3
)
Not Less Than (lb.)
Up to 140 14 0.072 --
141 - 500 15 0.067 10
501 - 1,600 16 0.063 35
1,601 - 4,500 18 0.056 100
4,501 - 50,000 20 0.050 250
Over 50,000 22 0.046 2,500
Ducts and Covered Trenches
(S
ee Section 3-5.2.2.1)
8 0.125 --
Design
September 2013 3-6 P/N 81-CO2MAN-001
3-5.2.2 BASIC TOTAL FLOODING QUANTITY
The discharge of carbon dioxide into an enclosure will displace a portion of the atmosphere in
the enclosure. The displaced atmosphere is exhausted freely from the enclosure through
openings or vents as the carbon dioxide is discharged. Since some suppression agent is lost
with the vented atmosphere, the volume of carbon dioxide required to develop a given
concentration will be greater than the volume that actually remains in the enclosure. This
method of application is called "free efflux" flooding.
A small volume has proportionally more surface (or boundary) area per unit of enclosed volume
than a larger volume, and has a proportionally greater leakage rate. Accordingly, larger
quantities of carbon dioxide per unit of enclosed volume are injected into smaller volumes to
account for the higher leakage rates anticipated upon discharge. The quantity of carbon dioxide
per unit volume is called the Volume Factor and is shown in Table 3-2. Also note that the
minimum quantity of CO
2
is specified for the smallest volume in each group to avoid a possible
overlap of CO
2
requirements.
(Equation 1)
or
Where:
= Basic quantity of agent, lb.(kg)
= Enclosure volume,
ft.
3
(m
3
)
= Volume factor from Table 3-2,
ft.
3
/lb.(m
3
/kg)
= Volume factor from Table 3-2, lb./
ft.
3
(kg
3
/m
3
)
W
B
Vf
1
=
W
B
Vf
2
=
W
B
V
f
1
f
2