lpg debate

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jimalone

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in a lpg dispensing area 18" up 20' from edge around is
i say CLASS 1 DIVISION 1

friend says CLASS 1 DIVISION 2
UNLESS THERE IS A PIT OR DEPTESSION.
WHO IS CORRECT?
 
Re: lpg debate

Don is right (other than the "two" in Division 2 is "Arabic" rather than ?Roman? :D ) and I see how I confused the issue in your previous post .

I know what Table 514.3(B)(2) means and I still have trouble reading it. It may be easier to read it this way:

For LPG fuel dispensers, Class I, Division 1 is the:
1. entire space within the dispenser enclosure [and]
2. 18 in. from the exterior surface of the dispenser enclosure to an elevation of 4 ft. above the base of the dispenser [and]
3. the entire pit or open space beneath the dispenser and within 20 ft. horizontally from any edge of the dispenser when the pit or trench is not mechanically ventilated.

Class I, Division 2 is [from grade] up to 18 in. aboveground and within 20 ft. horizontally from any edge of the dispenser enclosure, including pits or trenches within this area when provided with adequate mechanical ventilation
The cautions I noted about trenches is still valid. Both the NFPA 496 and API RP500 technical committees have yet to determine a "width to depth" ratio where a pit, depression or trench may be reasonably considered "adequately ventilated" naturally. Ignitible concentrations of butane can remain in a trench for a long time.

edit Put "two" in parenthesis and isolated the quote.

[ February 14, 2005, 12:51 PM: Message edited by: rbalex ]
 
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