Monitoring
The following monitoring methods must be conducted during initial site entry when the site evaluation produces information which shows the potential for ionizing radiation or IDLH conditions, or when the site information is not sufficient to reasonably eliminate these possible conditions:
- Monitor the air with appropriate direct reading test equipment for (i.e., combustible gas meters, detector tubes) for IDLH and other conditions that may cause death or serious harm (combustible or explosive atmospheres, oxygen deficiency, toxic substances.)
- Monitor with direct reading instruments for hazardous levels of ionizing radiation. Survey for gamma and beta radiation with a Geiger-Mueller detection tube or a gamma scintillation tube. However, if alpha radiation is expected, use a proportional counter.
- Look for signs of actual or potential IDLH or other dangerous conditions.
Any indication of IDLH hazards or other dangerous conditions should be regarded as a sign to proceed with care and deliberation. Extreme caution should be exercised in continuing the site survey when such hazards are indicated. The table below provides some basic guidelines for decision-making.
| Guidelines for Some Atmospheric Hazardsa | |||
|---|---|---|---|
| Hazardb | Monitoring Equipment c | Measured Level | Action |
| Explosive Atmosphere | Combustible gas indicator | <10% LELd 10% - 25% LEL >25% LEL |
Continue Investigation Continue on-site monitoring with extreme caution as higher levels are encountered. Explosive hazard. Withdraw from area immediately. |
| Oxygen | Oxygen concentration meter | <19.5% 19.5% - 25% >25% |
Monitor wearing self-contained breathing apparatus. NOTE: Combustible gas
readings are not valid in atmospheres with <19.5% oxygen. Deviation from normal level may be due to the presence of other substances. Fire hazard potential. Discontinue investigation. Consult a fire safety specialist. |
| Radiation | Radiation survey equipment | <2mrem/hre,f >2 mrem/hr |
Radiation above background levels (normally 0.01-0.02 mrem/hr)g
signifies the possible presence of radiation sources. Continue investigation with caution. Perform
thorough monitoring. Consult with health physicist. Potential radiation hazard. Evacuate site. Continue investigation only upon the advice of a health physicist. |
| Inorganic and organic gases and vapors | Colorimetric tubes. Chemical-specific instruments, including halide meter, hydrogen sulfide detector, carbon monoxide monitor, and mercury meter. |
Depends on Chemical | Consult standard reference manuals for air concentration/toxicity data. Action level depends on PEL/REL/TLV.h |
| Organic gases and vapors | Portable photoionizer Organic vapor analyzer (1) Operated in gas chromatography (GC) mode (2) Operated in survey mode |
Depends on chemical | Consult standard reference manuals for air concentration/toxicity data. Action level depends on PEL/REL/TLV.h |
aBased on Standard Operating Guides. U.S. EPA. December, 1984.
bThese are general classes of hazards. Not all components of these classes can be measured.
cConsult manufacturers' literature for use limitations associated with the specific equipment and for
the specific substances the equipment can detect.
dLEL = lower explosive limit
emrem/hr = milliroentgen equivalent in man per hour
fSource: U.S. Nuclear Regulatory Commission Rules and Regulations, 10 CFR Chapter 1, Part 20.105
gSource: Sax, I.N. 1979. Dangerous Properties of Industrial Materials. Fifth Edition. p. 167. Van
Nostrand Reinhold Company, New York
hPEL = OSHA permissible exposure limit. REL = NIOSH recommended exposure limit. TLV = threshold limit
value
Knowledge Check Choose the best answer for the question.
8-2. When monitoring the atmosphere during initial site entry, if explosive levels of the atmosphere are measured at >25% LEL, what should the entry team do?
You forgot to answer the question!