natfuelbill
Senior Member
Please discuss NFPA 30 where adequate ventilation must be continuous.
Natual gas enclosed building using NEC 500.5 for D1 to D2
Natual gas enclosed building using NEC 500.5 for D1 to D2
NFPA 30 Ventialtion
- Thread starter natfuelbill
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Are you referring to Chapter 17 in NFPA 30 Processing Facilities? 17.11 does not say ventilation has to be continuous.
Futhermore, NFPA 30 is the Flammable and Combustible Liquids Code. Your post says you are in a Natural Gas service. You would be better served using API RP500 or NFPA 497 as a basis.
NEC 500.5(B)(2)(2) does not require continuous ventilation.
BobG
Futhermore, NFPA 30 is the Flammable and Combustible Liquids Code. Your post says you are in a Natural Gas service. You would be better served using API RP500 or NFPA 497 as a basis.
NEC 500.5(B)(2)(2) does not require continuous ventilation.
BobG
natfuelbill
Senior Member
I don't have NFPA 30.
natfuelbill
Senior Member
So NFPA 30 does not apply to gas?
I believe API 500 does not require continuous ventilation. Am I mistaken?
I believe API 500 does not require continuous ventilation. Am I mistaken?
I would say NFPA 30 does not apply to natural gas (maybe for natural gas liquid condensate tanks). NFPA54 would cover Fuel Gas, but I would say it stops short of your facility unless you are a boiler or other appliance. I'm trying to recall from previsou posts what your facility is.
You really need to have adequate ventilation that maintains less than 25% LEL. There are various ways of doing so. Review API RP500.
Has an inspector told you to comply with NFPA30?
You really need to have adequate ventilation that maintains less than 25% LEL. There are various ways of doing so. Review API RP500.
Has an inspector told you to comply with NFPA30?
natfuelbill
Senior Member
Compressor station.
Adequate ventilation is present.
Must the adequate ventilation be running when gas detections show <25%? Ie: continuous ventialtion.
Does any Code permit ventilation to be OFF during low gas (0% to say 20%)?
Adequate ventilation is present.
Must the adequate ventilation be running when gas detections show <25%? Ie: continuous ventialtion.
Does any Code permit ventilation to be OFF during low gas (0% to say 20%)?
RICK NAPIER
Senior Member
- Location
- New Jersey
Here is a link to read only NFPA codes it maybe helpful. They only require an email address.
http://www.nfpa.org/aboutthecodes/list_of_codes_and_standards.asp
http://www.nfpa.org/aboutthecodes/list_of_codes_and_standards.asp
If the code don't say you HAVE TO, then you don't HAVE TO. There is no statement that says SHALL be continuous. Intermittent ventilation could still achieve 6 AC and be adequate. Engineering or sound judgment should decide how you achieve adequate ventilation.
NFPA 497 3.3 General Definitions.
API RP500 3.2.47
API RP500Section 6.3.2.
API RP500 6.3.2.4.2 .
In practice, 6AC/hr is more than enough ventilation for a well-maintained compressor building. In cold weather climates it is common to have ventilation that is inadequate as defined above, where the ventilation is only suitable to meet human occupancy requirements, and gas deteciton is used to start fans at a predetermined % LEL, alarm @ 20% LEL and s/d the station @ 40% LEL. API RP500 6.5 can give you a sound basis in using gas detection if you have a well-maintained facility.
Consider the fact that Div. 2 approved compressor ignition coils are usually "spark protected" and generally the only approval agency you will find on them is a CSA International approval. How then can we design a Div. 1 installation if our engines controls are Div. 2?
Side note, also take a look @ NFPA 37, 4.4
Have fun with it!!
BobG
NFPA 497 3.3 General Definitions.
API RP500 3.2.47
API RP500Section 6.3.2.
API RP500 6.3.2.4.2 .
In practice, 6AC/hr is more than enough ventilation for a well-maintained compressor building. In cold weather climates it is common to have ventilation that is inadequate as defined above, where the ventilation is only suitable to meet human occupancy requirements, and gas deteciton is used to start fans at a predetermined % LEL, alarm @ 20% LEL and s/d the station @ 40% LEL. API RP500 6.5 can give you a sound basis in using gas detection if you have a well-maintained facility.
Consider the fact that Div. 2 approved compressor ignition coils are usually "spark protected" and generally the only approval agency you will find on them is a CSA International approval. How then can we design a Div. 1 installation if our engines controls are Div. 2?
Side note, also take a look @ NFPA 37, 4.4
Have fun with it!!
BobG
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
Fundamentally, ?adequate ventilation? is described in terms of the flow rate of diluting air necessary to keep flammable concentrations below 25% LEL.
Within the common standards, such as NFPA 30, ?flow rates? are ultimately described in terms of (air volume) per (unit time), such as 6 air changes per hour or 1 cfm per sqft of floor space. In theory, one could have a 6 air change ?blast? once an hour and meet the first criteria, but at best, the second implies a ?blast a minute? - at least during operation. The first isn?t practical and the second is pretty close to continuous. In my opinion, the term rate pretty much implies continuous for all practical purposes.
The common standard for the natural gas industry is AGA XF0277, Appendix B, Ventilation. It contains recommendations that are consistent with the more common standards and has some good explanatory material as well.
Oddly enough, if API RP 500 Section 6.5 (Gas Detection) were applicable as a protection technique, you could ignore ventilation altogether from an area classification standpoint. However, see NEC Section 500.7(K) for appropriate applications - there aren?t many.
Within the common standards, such as NFPA 30, ?flow rates? are ultimately described in terms of (air volume) per (unit time), such as 6 air changes per hour or 1 cfm per sqft of floor space. In theory, one could have a 6 air change ?blast? once an hour and meet the first criteria, but at best, the second implies a ?blast a minute? - at least during operation. The first isn?t practical and the second is pretty close to continuous. In my opinion, the term rate pretty much implies continuous for all practical purposes.
The common standard for the natural gas industry is AGA XF0277, Appendix B, Ventilation. It contains recommendations that are consistent with the more common standards and has some good explanatory material as well.
Oddly enough, if API RP 500 Section 6.5 (Gas Detection) were applicable as a protection technique, you could ignore ventilation altogether from an area classification standpoint. However, see NEC Section 500.7(K) for appropriate applications - there aren?t many.
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