Hazardous Classification Boundary at Landfill

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jbt260

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What is the hazardous locaction boundary at an active solid waste landfill? For example, 'x' feet above grade, 'x' feet from actual dumping area, 'x' feet from leachate pipe venting. Where can I find this info?

Thanks!
 
jbt260 said:
What is the hazardous locaction boundary at an active solid waste landfill? For example, 'x' feet above grade, 'x' feet from actual dumping area, 'x' feet from leachate pipe venting. Where can I find this info?

Thanks!
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You have to get that information from the design engineer.
 
I was looking for info similar to Articles 511-516, except for landfills. I am designing power feeds to leachate pumps. Maybe the amount of methane is not enough to warrant a hazardous location classification?!?
 
don_resqcapt19 said:
You have to get that information from the design engineer.
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It would appear that Jeff is the design engineer. I am unaware of any reference document that directly addresses his question. I'd have had some initial "lack of experience" issues myself. However, I believe I can suggest a reasonable approach.

Even though a gas monitoring system would not be a recognized Section 500.7(K) protection technique in this case, tell me about it anyway; if there isn't any, then I wouldn't be too concerned about classifying the location. If there is one, someone thinks there is a possibility of gas being present, so I would assume 24? above grade to be Class I, Division 2, Group C&D, T2B anywhere encompassed by the monitors and not look back. I would also classify a 3' radius around each vent, Division 1 and an additional 2' beyond that Division 2. I would drop the Division 2 classification to grade from the resulting vent envelope.

The problem with landfill gas is it is only 60% or so methane with a fair portion of hydrogen sulfide; hence the Group C and moderately low temperature class rating. Methane is very light and disperses very quickly. Hydrogen sulfide has a vapor density that is fairly close to air (1.2) and, as such, also disperses quickly but it will ?fog? and hug the ground while it does especially, with air movement less than 3 mph. Even with continuous emissions, I would not anticipate either of them being released in any significant quantities except possibly near the vent, so the 24? above grade should be sufficient to allow them to be effectively dispersed beyond the monitors.
 
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