CHAPTER 4 RESPONDING TO GAS EMERGENCIES
What You Smell o Remember, civilians often think any “nasty” odor is natural gas.
What You Hear—Audible Identification Clues
o Transmission Releases—Very loud; painfully loud even at distances of a few hundred feet or more; people compare the release to the noise of a jet engine.
o Distribution Releases—Loud even from several hundred feet.
o Service Release—noisy; the sound will allow you to know some- thing’s venting. The noise will resemble a home compressor hose.
o Appliances—perceptible hissing to virtually non-perceptible noise. In many cases with appliances it is the odor that may have precipi- tated the emergency call.
Early identification and verification of a natural gas emergency is crucial
for the Incident Commander who must determine the strategic goals and identify specific tactics for achieving the ultimate outcome, protecting the public, and restoring service to the community. We also looked at many of the methods of identifying natural gas in Chapter 2. On occasion fire ground operations are well under way before the presence
of natural gas is detected. In these instances, efforts must be directed toward establishing an effective site management policy and then following appro- priate emergency procedures for natural gas. Safety issues must always be assessed on the hazards and risks involved.
Step 3: hazard and Risk Evaluation
Once the hazardous material, natural gas, is specifically identified, you must evaluate the hazards and risks associated with the chemical. “Hazards” refer to the physical and chemical properties of natural gas. Hazard assessment is essential in determining the harm that the chemical presents. It also aids in estimating dispersion patterns, hazards zones, evacuation areas, and selecting protective clothing. It also factors into selecting strategic and tactical issues which are:
• How long has the gas been leaking? • Is the leak inside or outside? • Where is it in the flammable range? • What are the ignition temperature and ignition sources? • What is the source of the release?
There are primary and secondary sources of hazard information available
to responders in this evaluation. Primary reference sources generally include those that are readily available at the scene.
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