SACOR BUSINESS GROUP-2019 COMPANY CATALOGUE SACOR BUSINESS GROUP 2019 COMPANY CATALOGUE | Page 107

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lIBrary
Each day, Industrial Scientific Corporation receives
hundreds of phone calls requesting information on every-
thing from exposure limits to the definition of intrinsic
safety. Remember, anytime you have a question involving
monitoring or safety, simply call 1-412-788-4353, or visit
our Web site at www.indsci.com.
Our customer service representatives helped us pull
together a library of the questions we’re asked most
often. Use this section as a quick reference when you
have a question. And, if you don’t find your answer here,
give us a call. There’s never a charge for a question.
GlOssary Of OccuPatIONal safety aNd HealtH terms
dB: decibel – A unit used to measure the relative
power of sound. A 3 dB increase in sound output power
represents a doubling of the perceptible volume. ppm: Part Per million – A common unit of measurement
for toxic gases. This term literally means one part out of
one million possible parts.
eV: electron Volt – A measurement of energy equal
to the amount of energy it takes to move 1 electron
through 1 volt of potential. tlV-stel: short term exposure limit – The average
amount of gas (in ppm) a worker can be exposed to
in a 15 minute period with no long term health effects.
This may occur 4 times a shift with one hour between
15 minute exposures.
IdlH: Immediately dangerous to life and Health –
The maximum concentration of gas (in ppm) from which
a worker could escape within 30 minutes with-out
experiencing any escape-impairing or irreversible health
effects.
lel/lfl: lower explosive limit/lower flammable
limit – The minimum concentration at which a gas will
explode. A common unit of measurement is a percent
of the LEL.
tlV-tWa: time Weighted average – The average
amount of gas (in ppm) a worker can be exposed to over
a certain time period. This time is defined as 8 hours to
represent a normal work day.
tlV: threshold limit Value – A term used to signify
limits in gas exposure. TLV is used as a prefix for TWA
and STEL.
ma: milliamp – A unit of electric current expressed in
amperes. 4-20 mA signals are commonly used analog
signals in industrial electronics, where 4 represents the
lowest value, for instance 0 ppm, and 20 represents the
maximum, for instance, 999 ppm. uel/ufl: upper explosive limit/upper flammable
limit – The maximum concentration at which a gas
will explode.
Pel: Permissible exposure limit – Level of gas (in
ppm) a worker can be exposed to 8 hours a day/40 hours
a week for the rest of their life with no long term health
effects. Vdc: Volts direct current – An electric current of
constant direction.
PId: PhotoIonization detector – An instrument that
utilizes ultra-violet light energy to ionize and detect the
presence of an unknown gas or vapor.
Vac: Volts alternating current – An electric current
that reverses direction at regular intervals.
VOc: Volatile Organic compound – Any compound
containing carbon, except methane, that can be
readily vaporized.
lOWer eXPlOsIVe lImIts Of cOmBustIBle Gases
The following are the lower explosive limits of selected gases which should be useful:
Acetone
Acetylene
Benzene
Butane
Butyl Alcohol (Butanol)
Diethyl Ether
Ethane
Ethyl Alcohol (Ethanol)
Ethylene
Ethylene Oxide
Hexane
2.5%
2.5%
1.2%
1.9%
1.4%
1.9%
3.0%
3.3%
2.7%
2.7%
1.1%
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Hydrogen
Isopropyl Alcohol (Isopropanol)
Methane
Methyl Alcohol (Methanol)
Methyl Ethyl Ketone
n-Pentane
Propane
Propylene
Styrene
Toluene
Xylene
4.0%
2.0%
5.0%
6.0%
1.4%
1.4%
2.1%
2.0%
0.9%
1.1%
1.1%
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