Seals off required for deisel dispensing
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petersonra
Senior Member
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- Northern illinois
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- engineer
Why would a diesel dispensing area be classified?
- Location
- Mission Viejo, CA
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- Professional Electrical Engineer
You do not know how much I appreciate that you read the Scope. Now read 514.3(A). Find the MSDS for the deisel that will be used and find its flashpoint.
I'm not following you, Bob. For the question, 514.3(A) simply says the area is not required to be classified. 514.9 still requires a seal at each dispenser - classified or unclassified.
Reading the handbook, it looks like the intent may have been to require a seal at each dispenser in a classified area, even if the conduit doesn't leave the classified area (for example, the conduit runs to another dispenser in the same island).
But I don't see any exceptions for a dispenser for unclassified liquids.
Robert,
I appreciate the reference to 514.3, but as Steve pointed out, 514.9(A) does not reference the classification of the area. I understand that deisel is not flammable, but when it comes to wiring methods and seals at the dispenser no reference is made to the classification of the area. In the old days Article 514 applied exclusively to gasoline dispensing facilities. It seems to have lost it's way in the last few code cycles.
I appreciate the reference to 514.3, but as Steve pointed out, 514.9(A) does not reference the classification of the area. I understand that deisel is not flammable, but when it comes to wiring methods and seals at the dispenser no reference is made to the classification of the area. In the old days Article 514 applied exclusively to gasoline dispensing facilities. It seems to have lost it's way in the last few code cycles.
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
Steve,
It does take a close reading and understanding of the principles. Art 514 is largely, although somewhat incompletely, extracted from NFPA 30A.
One problem is the term Class is not used consistently, at least with clarity, in either Art 514 or NFPA 30A. For example, Section 514.3(B) references Class I two different ways. The first instance in the main text refers to Class I Liquids, which is properly defined in NFPA 30 (and consistent with 30A) as:
The Section Title and second reference in the text is to Class I Locations. Liquids and locations aren?t the same thing, but if you aren?t familiar with the distinction it?s easy to get them confused. (It?s one reason why only folks who know what they are doing should be classifying locations.)
Diesel is a Class II Combustible Liquid (Note it doesn't create a Class II Location
) also defined in NFPA 30 as:
4.3.2 Combustible liquids, as defined in 3.3.30.1 and 4.2.2, shall be classified in accordancewith the following:
(1)Class II Liquid ? Any liquid that has a flash point at or above 100?F (37.8?C)and below 140?F (60?C)
(2)Class III Liquid ? Any liquid that has a flash point at or above 140?F (60?C)
RBA Notes:
It does take a close reading and understanding of the principles. Art 514 is largely, although somewhat incompletely, extracted from NFPA 30A.
One problem is the term Class is not used consistently, at least with clarity, in either Art 514 or NFPA 30A. For example, Section 514.3(B) references Class I two different ways. The first instance in the main text refers to Class I Liquids, which is properly defined in NFPA 30 (and consistent with 30A) as:
4.3.1 Flammable liquids, as defined in 3.3.30.2 and 4.2.3 shall be classified as Class Iliquids and shall be further subclassified in accordance with the following:
(1)Class IA Liquid ?Any liquid that has a flash point below 73?F (22.8?C) and aboiling point below 100?F (37.8?C)
(2)Class IB Liquid ?Any liquid that has a flash point below 73?F (22.8?C) and aboiling point at or above 100?F (37.8?C)
(3)Class IC Liquid ? Any liquid that has a flash point at or above 73?F (22.8?C),but below 100?F (37.8?C)
(1)Class IA Liquid ?Any liquid that has a flash point below 73?F (22.8?C) and aboiling point below 100?F (37.8?C)
(2)Class IB Liquid ?Any liquid that has a flash point below 73?F (22.8?C) and aboiling point at or above 100?F (37.8?C)
(3)Class IC Liquid ? Any liquid that has a flash point at or above 73?F (22.8?C),but below 100?F (37.8?C)
The Section Title and second reference in the text is to Class I Locations. Liquids and locations aren?t the same thing, but if you aren?t familiar with the distinction it?s easy to get them confused. (It?s one reason why only folks who know what they are doing should be classifying locations.)
Diesel is a Class II Combustible Liquid (Note it doesn't create a Class II Location
) also defined in NFPA 30 as:4.3.2 Combustible liquids, as defined in 3.3.30.1 and 4.2.2, shall be classified in accordancewith the following:
(1)Class II Liquid ? Any liquid that has a flash point at or above 100?F (37.8?C)and below 140?F (60?C)
(2)Class III Liquid ? Any liquid that has a flash point at or above 140?F (60?C)
(a)Class IIIA Liquid?Any liquid that has a flash point at or above 140?F (60?C),but below 200?F (93?C)
(b)Class IIIB Liquid?Any liquid that has a flash point at or above 200?F (93?C)
Note that 514.3 (B) only applies to Class I Liquids. Effectively, Art 514 doesn?t apply to Class II Liquids where they are the only fuel used and they are handled below their flash-points. Obviously diesel is often dispensed along with other Class I liquids and that may affect the installation.(b)Class IIIB Liquid?Any liquid that has a flash point at or above 200?F (93?C)
RBA Notes:
- IMO The NEC Handbook generally gets a B+; hazardous locations is one of its weakest areas.
- Art 514 will never be corrected until NFPA 30A is clarified.
Robert,
I have no difficulty understanding the requirements of NFPA 30A. I also have no difficulty understanding the structure of NFPA 70. During the development of the 2008 Code a proposal was submitted to add the following sentence to the scope of Article 514:
"The requirements of this article do not apply to dispensing facilities used exclusivley for diesel motor fuel." CMP 14 rejected the proposal with a statement that included the following:
"The scope of the article does not preclude the application of requirements that are in addition to the area classification rules. Some of the requirements apply to all motor fuel dispensing facilities."
Although we know the intent of 514.9(A), the requirement is stated without regard to the classification of the area. How can you positively state that the seal is not required?
I have no difficulty understanding the requirements of NFPA 30A. I also have no difficulty understanding the structure of NFPA 70. During the development of the 2008 Code a proposal was submitted to add the following sentence to the scope of Article 514:
"The requirements of this article do not apply to dispensing facilities used exclusivley for diesel motor fuel." CMP 14 rejected the proposal with a statement that included the following:
"The scope of the article does not preclude the application of requirements that are in addition to the area classification rules. Some of the requirements apply to all motor fuel dispensing facilities."
Although we know the intent of 514.9(A), the requirement is stated without regard to the classification of the area. How can you positively state that the seal is not required?
Bob:
Thanks for the detailed explanation.
In my opinion, there aren't nearly enough of these people around. As long at that is the case, the job is often going to fall on the slightly less qualified people to design and inspect these locations. (At least for the very common areas we find most often - with motor fuel dispensing probably being the most common classified locations in the world). The MH forum is very fortunate to have the benefit of your knowledge.
That's what I kept expecting to find, but couldn't. I guess its the issue you mentioned with correlating the NEC with NFPA 30A. But it seems like a pretty important piece of info. to leave out.
If they clarified that 514 doesn't apply to diesel only dispensing, at least we would know when we don't need a classified location expert A lot of farm's and highway maintenace dept's have diesel only dispensing.
Thanks for the detailed explanation.
In my opinion, there aren't nearly enough of these people around. As long at that is the case, the job is often going to fall on the slightly less qualified people to design and inspect these locations. (At least for the very common areas we find most often - with motor fuel dispensing probably being the most common classified locations in the world). The MH forum is very fortunate to have the benefit of your knowledge.
That's what I kept expecting to find, but couldn't. I guess its the issue you mentioned with correlating the NEC with NFPA 30A. But it seems like a pretty important piece of info. to leave out.
If they clarified that 514 doesn't apply to diesel only dispensing, at least we would know when we don't need a classified location expert
A lot of farm's and highway maintenace dept's have diesel only dispensing.
The CMP response was:
Panel Statement: The assessment of whether diesel fuel should fall within the
requirement of Article 514 is dependent on ambient temperature, how the fuel
is stored, and the range of diesel fuels that are available. There are some diesel
fuels that have flashpoints below 100 degrees F. The scope of the article does
not preclude the application of requirements that are in addition to the area
classification rules. Some of the requirements apply to all motor fuel
dispensing facilities.
They raise some valid points.
Panel Statement: The assessment of whether diesel fuel should fall within the
requirement of Article 514 is dependent on ambient temperature, how the fuel
is stored, and the range of diesel fuels that are available. There are some diesel
fuels that have flashpoints below 100 degrees F. The scope of the article does
not preclude the application of requirements that are in addition to the area
classification rules. Some of the requirements apply to all motor fuel
dispensing facilities.
They raise some valid points.
- Location
- Mission Viejo, CA
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- Professional Electrical Engineer
I know this may come across as condescending; certainly defensive. I truly apologize.
Despite its express statement to the contrary [Section 90.1(C)], the NEC is still often used as a design specification and an instruction manual for untrained persons. It is the most frustrating part of my job attempting to explain the underlying physics and chemistry of a design to those who only know “the Code” and often misinterpret it as well.
I was no longer on CMP14 during the 2008 Cycle. I don’t know how I would have responded to the referenced Proposal. In all honesty, I probably would have voted for the Panel Statement. It would have been acted upon on the last day of a five day Panel meeting when just about everyone was tired and wanted to go home.
The Proposal should have been submitted to the NFPA 30A Technical Committee. As I said, CMP14 really has very little control over Art 514. Second, if CMP14 had dealt with it properly, 514.3(B)(1) should have been reworded to something like “Table 514.3(B)(1) shall be applied where Class I and Class II liquids handled above their flashpoints …” As far as the “valid points” made in the Panel Statement, I covered them all in the last paragraph before my “Notes.” Personally I've never seen a diesel MSDS indicating a flashpoint below 100?F (37.8?C).
That said, seal it if you want to – it won’t do any good, but it’s only money and it's not unsafe.
Despite its express statement to the contrary [Section 90.1(C)], the NEC is still often used as a design specification and an instruction manual for untrained persons. It is the most frustrating part of my job attempting to explain the underlying physics and chemistry of a design to those who only know “the Code” and often misinterpret it as well.
I was no longer on CMP14 during the 2008 Cycle. I don’t know how I would have responded to the referenced Proposal. In all honesty, I probably would have voted for the Panel Statement. It would have been acted upon on the last day of a five day Panel meeting when just about everyone was tired and wanted to go home.
The Proposal should have been submitted to the NFPA 30A Technical Committee. As I said, CMP14 really has very little control over Art 514. Second, if CMP14 had dealt with it properly, 514.3(B)(1) should have been reworded to something like “Table 514.3(B)(1) shall be applied where Class I and Class II liquids handled above their flashpoints …” As far as the “valid points” made in the Panel Statement, I covered them all in the last paragraph before my “Notes.” Personally I've never seen a diesel MSDS indicating a flashpoint below 100?F (37.8?C).
That said, seal it if you want to – it won’t do any good, but it’s only money and it's not unsafe.
I aked the question to point out an error in the Code. Prior to the development of the 2005 NEC the scope of Article 514 was limited to facilities that dispensed flammable fuels. When the scope was changed to apply to all motor fuel dispensing facilities, there should have been corresponding changes to rules that are intended to apply to classified areas but do not include a reference to the classification of the area.
I had never considered this until I got a question from a young Engineer the other day. I thought it was understood that seals were required only where flammable liquids, or combustible liquids handled above their flashpoint, are dispensed. Then I realized the trap I was falling into. My understanding of the code is based on my experience with prior editions. If you evaluate the rule as it exist today it applies regardless of the properties of the fuel. If water could be used to fuel a vehicle, a seal is required at the dispenser. This same mindset, or trap, can be seen in the reponses that include detailed information on the classification of the area. Remember Charlie's rule: "the code doesn't say what you think it says".
I had never considered this until I got a question from a young Engineer the other day. I thought it was understood that seals were required only where flammable liquids, or combustible liquids handled above their flashpoint, are dispensed. Then I realized the trap I was falling into. My understanding of the code is based on my experience with prior editions. If you evaluate the rule as it exist today it applies regardless of the properties of the fuel. If water could be used to fuel a vehicle, a seal is required at the dispenser. This same mindset, or trap, can be seen in the reponses that include detailed information on the classification of the area. Remember Charlie's rule: "the code doesn't say what you think it says".
davidaengelhart
Member
IMHO
Diesel is not a classified material per NEC 500, simply because it is not there. However, if the dispenser is in a classified location per NEC 500, then seal-offs are required per NEC 501. Simply put, if diesel is the only material being dispensed, then seal-offs are not required, but if the dispensers are grouped with dispensers of gasoline (typically), then the seal-offs are required, as well as all the other requirements of NEC 514, including the disconnecting means.
Diesel is not a classified material per NEC 500, simply because it is not there. However, if the dispenser is in a classified location per NEC 500, then seal-offs are required per NEC 501. Simply put, if diesel is the only material being dispensed, then seal-offs are not required, but if the dispensers are grouped with dispensers of gasoline (typically), then the seal-offs are required, as well as all the other requirements of NEC 514, including the disconnecting means.
Robert and David,
You are missing my point (probaly my fault). The physics and chemistry are simple enough. Is 125F greater than 99F? My point is that this code section was clear and unequivical in the 2002 Code and now it is not; period. When the scope statement and fundamental definitions were changed the entire article should have been re-evaluated to correlate with those changes.
Please without the elementary physics, and your personal beliefs; where is 514.9(A) conditional to the type of material being dispensed?
You are missing my point (probaly my fault). The physics and chemistry are simple enough. Is 125F greater than 99F? My point is that this code section was clear and unequivical in the 2002 Code and now it is not; period. When the scope statement and fundamental definitions were changed the entire article should have been re-evaluated to correlate with those changes.
Please without the elementary physics, and your personal beliefs; where is 514.9(A) conditional to the type of material being dispensed?
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
I had already "said my piece," so I was going to drop it; however, since your response was specifically directed to me
I don?t believe I?ve missed your point ? you still want to treat the NEC as a design specification [90.1(C)] rather than using the sound engineering judgment of someone who actually knows what they are doing. See Section 500.8(A)(3).
The NEC is full of unintended consequences. Some get corrected, most don?t for a long time - if ever. Code Making Panels (CMP) and external NFPA Technical Committees (TC) routinely step into each other?s Scopes and meddle with them. Occasionally, the NEC Technical Correlating Committee (TCC) will catch it the first time through; usually though, it takes a couple of Code cycles and everyone forgets what the problem was in the first place because rationality eventually works it out in the field. When the problem is between two TCs, it takes running it all the way to Standard Counsel. That is almost never successful. This is why I said 514 will never be corrected unless the NFPA TC for Automotive and Marine Service Stations (Scope: NFPA 30A) ?corrects? it.
Fact is though, read closely and properly, both Subsections 514.3(A) and (B)(1) effectively limit the Article?s application to Class I flammable liquids. If you do happen to find a Class I flammable diesel, by all means treat it like one. BTW NFPA 30A doesn't discuss diesel except as a Class II combustible fuel.
I don?t believe I?ve missed your point ? you still want to treat the NEC as a design specification [90.1(C)] rather than using the sound engineering judgment of someone who actually knows what they are doing. See Section 500.8(A)(3).
The NEC is full of unintended consequences. Some get corrected, most don?t for a long time - if ever. Code Making Panels (CMP) and external NFPA Technical Committees (TC) routinely step into each other?s Scopes and meddle with them. Occasionally, the NEC Technical Correlating Committee (TCC) will catch it the first time through; usually though, it takes a couple of Code cycles and everyone forgets what the problem was in the first place because rationality eventually works it out in the field. When the problem is between two TCs, it takes running it all the way to Standard Counsel. That is almost never successful. This is why I said 514 will never be corrected unless the NFPA TC for Automotive and Marine Service Stations (Scope: NFPA 30A) ?corrects? it.
Fact is though, read closely and properly, both Subsections 514.3(A) and (B)(1) effectively limit the Article?s application to Class I flammable liquids. If you do happen to find a Class I flammable diesel, by all means treat it like one. BTW NFPA 30A doesn't discuss diesel except as a Class II combustible fuel.
Robert,
Actually I have never have required a sealing fitting at a diesel dispenser (we are currently enforcing the 2002 Code) and will not in the future. The code panel itself stated that there are portions of the article that apply to ALL motor fuel dispensing facilities. Because that statement was in response to a proposal to specifically exclude diesel dispensing; how can you conclude that 514.3(A) and (B)(1) limit the applicability of the entire article to hazardous locations?
I am impressed with your ability to quickly evaluate other peoples qualifications.
Actually I have never have required a sealing fitting at a diesel dispenser (we are currently enforcing the 2002 Code) and will not in the future. The code panel itself stated that there are portions of the article that apply to ALL motor fuel dispensing facilities. Because that statement was in response to a proposal to specifically exclude diesel dispensing; how can you conclude that 514.3(A) and (B)(1) limit the applicability of the entire article to hazardous locations?
I am impressed with your ability to quickly evaluate other peoples qualifications.
- Location
- Mission Viejo, CA
- Occupation
- Professional Electrical Engineer
Adding a Scope statement in 2005, didn’t change the context. It wasn't even a consideration when you read the Proposal that introduced it (14-134). While it “says what it says,” what it says in 514.3(B) (1) is that the Article applies to Class I (flammable) liquids.
Rejecting a proposal to specifically exempt diesel doesn’t change the context either. Class II fuels still aren’t included. The “error” in the Panel Statement, such as it was, is that it didn’t include Class II liquids handled above their flash point.
How would you conclude Art 514 ever exempted Class II combustible fuels prior to 2005, other than I have already asserted through 514-3(B)(1) and it predecessors? They weren’t even mentioned or exempted specifically or indirectly anywhere in the Article before 2005. They still aren’t. The text and context of 514-3(B)(1) and 514-9, except for renumbering, was the same before 2005. So either diesel was included before or is still isn’t now.
Rejecting a proposal to specifically exempt diesel doesn’t change the context either. Class II fuels still aren’t included. The “error” in the Panel Statement, such as it was, is that it didn’t include Class II liquids handled above their flash point.
How would you conclude Art 514 ever exempted Class II combustible fuels prior to 2005, other than I have already asserted through 514-3(B)(1) and it predecessors? They weren’t even mentioned or exempted specifically or indirectly anywhere in the Article before 2005. They still aren’t. The text and context of 514-3(B)(1) and 514-9, except for renumbering, was the same before 2005. So either diesel was included before or is still isn’t now.
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