Area classification 2

[dtoo]

I am involved with a compressor plant that is extracting gas from a landfill, compressing it to 60 psig and delivering it via pipeline to a power plant a mile away. The compressors are driven by electric motors and all the equipment is installed outdoors. Would this be considered a class 1, div. 2 location or, because of the outdoor location, a non classified location?

Thanks,

Dave D.

 

[bigbillnky]

dtoo

Is not gasoline dispensing pumps outdoors also? Seek help from a local engineering firm.

Bigbillnky,C.E.F.....(Chief Electrical Flunky)

 

[Comcokid]

Even your standard residential propane tank is classified as a hazardous location and requiring Class 1, Div 1 for items mounted within 10ft of the valves.

 

[aquila99]

The seals of the compressor as well as other items in the line may be considered sources of emissions. These could include control valves, PSVs, flanges, etc. In the immediate vicinty about these sources would be considered Class 1 Div 1. This distance is dependent on the potential volume released by the source. The size and shape of the classified area would also be affected by whether the gas is heavier than air or lighter than air - the lighter than air gases will disperse much quicker and, as a result, may not need as large an area to be classified. A good reference would be API RP500. NFPA also has a publications covering this topic.

Hope this helps.

 

[charlie10]

Refer to NFPA 497 Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas and then referring to figure 5.9.1a you would have a 10' C1D2 circle around the pump for 18" above grade. The next figure 5.9.1b shows a "leak" point in the air. This has a 3' C1D2 bubble around the leak point and then the same 10' C1D2 bubble that is 18" tall. In both case's anything below grade inside the bubbles goes to a C1D1.

 

[FordF350]

The area should be Class 1 Division 2 because the hazardous material is "normally confined within closed containers or systems". Refer NFPA Code 70 (NEC) 500.5 (B) (2) Class 1 Division 2.

In a Class 1 Division 1 the hazardous material is present "under normal operating conditions". Refer NFPA Code 70 (NEC) 500.5 (B) (1). A good example of this is the inside of an automotive spray booth. If you have this in an open area you probaly have an environmental hazard also.

 

[peebee]

I disagree. Per NFPA 54 National Fuel Gas Code:

7.12.5.2 Electrical Requirements. Where gas-mixing machines are installed in well-ventilated areas, the type of electrical equipment shall be in accordance with NFPA 70, National Electrical Code, for general service conditions unless other hazards in the area prevail. Where gas-mixing machines are installed in small detached buildings or cutoff rooms, the electrical equipment and wiring shall be installed in accordance with NFPA 70 for hazardous locations (Articles 500 and 501, Class I, Division 2).

Based on the above, I don't think your installation would be considered hazardous. Similarly, NFPA does not require XP installations around gas stoves, water heaters, fireplaces, etc., nor around propane refrigerators (like you'd find in campers). I strongly suspect Comcokid is mistaken in his statement regarding propane.

IBC may have differing requirements from NFPA.

Your local engineering firm is probably NOT the right group to ask. The right guy to ask would be your insurance agent, or possibly your local inspector (are you getting a permit for this thing?).

 

[rbalex]

NFPA 54 doesn’t apply to the OP. See Section 1.1 (Scope) in general and Subsection 1.1.1.2 (3) specifically.

This is a Division 2 application per NEC 500.5(B)(2)(1).

The problem is finding an appropriate standard to determine the envelope. When all specific documents are silent, I fall back on NFPA 497. The title may be a bit misleading, but the stated scope is general enough to cover most applications in absence of a specific document.

In any case, the application described will definitely have a fairly small envelope around the compressor and conrol valves. I'd have to be more familiar with the over process to be more specific.