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4250 Flow Meter
Appendix C General Safety Procedures
Chemical
Common
Gas
Formula
Properties
Hydro-
H
S
Irritant and poi-
2
gen Sul-
sonous volatile
fide
compound. Rot-
ten egg odor in
small concentra-
tions. Exposure
for 2 to 15 min. at
0.01% impairs
sense of smell.
Odor not evident
at high concen-
trations. Color-
less. Flammable.
Methane
CH
Simple asphyxi-
4
ant.
Colorless, odor-
less, tasteless,
flammable.
Nitrogen
N
Simple asphyxi-
2
ant. Colorless,
tasteless.
Non-flammable.
Principal constit-
uent of air. (about
79%).
Nitrogen
NO
Colorless
Oxides
N
O
Colorless,
2
sweet odor.
NO
Reddish-brown.
2
Irritating odor.
Deadly poison
Oxygen
O
Colorless, odor-
2
less, tasteless.
Supports com-
bustion.
Ozone
O
Irritant and poi-
3
sonous. Strong
electrical odor.
Strong oxidizer.
Colorless. At 1
ppm, strong sul-
fur-like odor.
Sludge
—***
Mostly a simple
Gas
asphyxiant. May
be practically
odorless, taste-
less.
C-8
Table C-1 Hazardous Gases (Continued)
Specific
Max
Gravity
Physiological
Safe 60
or Vapor
Effect
Min. Exposure
Density
ppm
Air =1
1.19
Impairs sense
200
of smell, rap-
to
idly as concen-
300
tration
increases.
Death in few
minutes at
0.2%. Exposure
to 0.07 to 0.1%
rapidly causes
acute poison-
ing. Paralyzes
respiratory
center.
0.55
Acts mechani-
Probably no limit,
cally to deprive
provided oxygen
tissues of oxy-
percent-age is suf-
gen. Does not
ficient for life.
support life.
0.97
Physiologically
—
inert.
1.04
60 to 150 ppm
50
cause irritation
and coughing.
1.53
Asphyxiant.
1.58
100 ppm dan-
gerous.
200 ppm fatal.
1.11
Normal air con-
—
tains 20.8% of
O
. Man can tol-
2
erate down to
12%. Minimum
safe 8 hour
exposure, 14 to
16%. Below 10%,
dangerous to
life. Below 5 to
7% probably
fatal.
1.66
Max. naturally
0.08
occurring level
is 0.04 ppm.
0.05 ppm
causes irrita-
tion of eyes and
nose. 1 to 10
ppm causes
headache, nau-
sea; can cause
coma. Symp-
toms similar to
radiation dam-
age.
Variable
Will not support
No data. Would
life.
vary widely with composition.
Explosive
Likely
Max. Safe
Range (% by
Location
8 Hour
vol. in air)
of
Exposure
Limits
Highest
ppm
lower/upper
Concentration
20
4.3
Near bottom,
but may be
45.0
above bottom if
air is heated and
highly humid.
—
5.0 15.0
At top, increas-
ing to certain
depth.
—
—
—
Near top, but
may be found
near bottom.
10
—
—
Near bottom.
—
—
—
Variable at dif-
ferent levels.
0.04
—
—
Near bottom.
5.3
19.3
Near top of
structure.
Simplest and
Most
Cheapest
Common
Safe Method
Sources
of Testing
Coal gas,
1. H
S
2
petro-
Ampoule.
leum,
sewer gas.
2. 5% by weight
Fumes
lead acetate
from blast-
solution.
ing under
some con-
ditions.
Sludge gas.
Natural
1. Combustible
gas, sludge
gas indicator
gas, manu-
factured
2. Oxygen defi-
gas, sewer
ciency indica-
gas. Strata
tor.
of sedi-
mentary
origin. In
swamps or
marshes.
Sewer gas.
Oxygen
sludge gas.
deficiency
Also issues
indicator.
from some
rock strata.
Industrial
NO
detector
2
wastes.
tube.
Common
air pollut-
ant.
Oxygen
Oxygen defi-
depletion
ciency indica-
from poor
tor.
ventila-
tion and
absorp-
tion, or
chemical
consump-
tion of
oxygen.
Where
Detectable
ozone is
odor
used for
at 0.015 ppm.
disinfec-
tion.
From
See compo-
digestion
nents.
of sludge.
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