User's Manual

September 2013 A-2 P/N 81-CO2MAN-001
The equation assumes instantaneous mixing of the discharged carbon dioxide with the
enclosure atmosphere.
A-3 DERIVATION OF THE MATERIAL CONVERSION FACTOR (MCF)
Equation A.3
Where:
= material conversion factor
= higher design concentration
= reference design concentration, 0.34
= natural logarithm
A-4 RATE OF CARBON DIOXIDE LOSS THROUGH AN OPENING IN AN ENCLOSURE
The following equation can be used to calculate the rate of carbon dioxide loss through an
opening in an enclosure, assuming the conditions in the previous paragraph are true:
Equation A.4
Where:
= Rate of CO
2
in lbs./min.
Example
Determine the weight of carbon dioxide per unit enclosure volume required to create a 34%
concentration.
From Equation A.2
Equation A.2 represents the idealized situation where the amount of carbon dioxide lost upon discharge
through openings or vents is only the amount necessary to displace the required atmosphere while
maintaining a constant pressure in the enclosure. In general, such a situation exists only in the limit of
very large volumes.
Example
A chemical storage room is known to contain Butadiene. Determine the material conversion factor for
carbon dioxide protection.
The recommended minimum design concentration for Butadiene is 41% (from Table 3-1). Using Equation
A.3:
W
V
-----
1
S
---
ln 1 1 C–
1
9
---
ln 1 1 .34–0.1110.41550.0461 lb./ft.
3
== = =
MCF
1 C2–ln
1 C1–ln
--------------------------
=
MCF
C2
C1
ln
MCF
1 .41–ln
1 C1.34–ln
----------------------------------
0.527–
0.415–
----------------
1.27===
R 60CpA
2gp
1
p
2
h–
p
1
--------------------------------=
R