TM 5-6640-212-14
tor to sample gas until meter reading stabilizes. If
then following from the point on the diagonal to the vertial
desired, standard propane gas cylinders (1 percent gas
scale at left indicates a percent LEL meter reading of
by volume in air, Part No. 0023-4009, 46 per-cent LEL)
approximately 58 percent for ethylene oxide. For gases
may be used to calibrate gas detection systems for
that are not represented on the chart, figure 4-5, the
correct response to gases other than propane as follows:
multiplying (K) factors in table 4-1 may be used to
calibrate with propane for gases other than propane. Or
1. On conversion chart (fig. 4-5) horizontal scale
the multiplying factors may be used as a preferred
for "% LEL GAS", find point representing 46 percent (the
alternate method to use of the chart. For example, to
correct percent LEL reading if a standard propane by
use pro-pane gas to calibrate for ethylene oxide, multiply
volume in air is used).
the propane standard (1 percent by volume) sample
2. Follow up 46 percent line vertically to diagonal
percent LEL value of 46 percent by the ethylene oxide
line representing gas for which calibration is wanted.
multiplying (K) factor of 1.265 as shown in the table, and
3. From point found on diagonal line, follow
get 58.190 percent as calculated per-cent LEL meter
horizontally to left and read percent LEL meter reading
reading.
on vertical "% LEL METER READING" scale. For
(c) While continuing exposure of detector to
example: Following up from the 46 percent point of the
sample gas, adjust GAIN potentiometer R10 on control
horizontal scale to the diagonal line representing
module printed circuit board so that meter reading
ethylene oxide, and
matches percent LEL concentration of sample gas or
percent equivalent for another gas.
Table 4-1. Multiplying (K) Factors for Conversion of Propane Gas
Percent LEL to Percent LEL Readings for Other Gases
Acetone
1.33
0.71
Acetylene
1.36
Hydrogen Sulfide
8.42
Acrylonitrile
0.99
Isopropyl Alcohol
1.48
Butadiene
1.52
Methyl Alcohol
1.46
Butane
1.04
Methyl Acrylate
1.47
Butyl Acetate
2.35
Methyl Chloride
0.72
Carbon Disulfide
8.88
Methyl Ethyl Ketone
Carbon Monoxide
0.78
(MEK)
1.74
Cyclohexane
1.51
O-Xylene
2.86
Ethane
0.78
Pentane
1.67
Ethyl Acetate
1.62
Propylene
1.22
Ethyl Alcohol
1.11
Propylene Oxide
1.24
Ethylene
0.91
Styrene Monomer
4.00
Ethyl Ether
1.31
Tetrahydrofuran
1.33
Ethyl Oxide
1.51
Toluena
1.69
Heptane
1.90
Trichloroethylene
1.00
Hexane
1.70
Vinyl Acetate
2.54
Vinyl Chloride
1.18
4-5
