Hazard Class 1 Div 2 Group B

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WorkerBee

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Hello! On a data sheet we specified a pump manufacturer and model number. In addition, the data sheet has other process information, ie. specific gravity, viscosity, design flow rate, power supply, etc. We also specified the Area Class to be Class 1 Div 2 Group B.

When we look up the pump information on the manufacturers website it says it's, "Class 1, Group C&D". I assume they mean Class 1 Div 1 or Div 2 Groups C&D.

1) Does "Class 1, Group C&D" envelope both Div 1 and Div 2?

2) Will a Class 1, Group C&D rated pump/motor be code compliant when a Class 1, Div 2 Group B was specified?

I have read Article 500 and 501 (2008 edition) and it sounds like if it's Div 2 then even though Group B was specified, a Group C or D could be used. I'm just not sure I'm interpreting the Code correctly. What section of the Code has the answer?


I really appreciate the help! Thanks in advance!
 

rbalex

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Location
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Professional Electrical Engineer
Read Section 500.8(C)(2) and its FPN/IN carefully.

With regard to the pump motor only, in Division 2, the Group is irrelevant. [See Section 501.125(B)] For other ancillary pump equipment, the Group may still be a consideration.

BTW, "Class 1" would usually refer to something in Article 725. For hazardous location applications, Class is capitalized and identified with Roman numerals (I, II or III). Divisions are identified with Arabic numerals (1 or 2).
 

WorkerBee

Member
Location
US
Read Section 500.8(C)(2) and its FPN/IN carefully.

With regard to the pump motor only, in Division 2, the Group is irrelevant. [See Section 501.125(B)] For other ancillary pump equipment, the Group may still be a consideration.

BTW, "Class 1" would usually refer to something in Article 725. For hazardous location applications, Class is capitalized and identified with Roman numerals (I, II or III). Divisions are identified with Arabic numerals (1 or 2).

Thanks for the response! I'm new to the NFPA codes so please forgive my ignorance :ashamed1:

-We specified a Weil pump model #1621. Section 501.125(B) is confusing. Our pump has thermal overload protection so the first part of 501.125(B) indicates the motor shall be identified for Class I, Div 1 locations. However, our pump is hermetically sealed so according to 501.125(B)(1), our pump can be identified as Class I, Div 2, correct? If so then a Group C or D will work in a group B location since the grouping for Class I, Div 2 is irrelevant, right?

-Hypothetically, if you have a Class I, Div 2, Group B location but the pump must be identified as a Class I, Div 1 per 501.125(B), does the grouping become relevant since the pump is identified as a Class I Div 1 or is the group still irrelevant since the location is Class I, Div 2?

Thanks again! :thumbsup:
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Thanks for the response! I'm new to the NFPA codes so please forgive my ignorance :ashamed1:

-We specified a Weil pump model #1621. Section 501.125(B) is confusing. Our pump has thermal overload protection so the first part of 501.125(B) indicates the motor shall be identified for Class I, Div 1 locations. However, our pump is hermetically sealed so according to 501.125(B)(1), our pump can be identified as Class I, Div 2, correct? If so then a Group C or D will work in a group B location since the grouping for Class I, Div 2 is irrelevant, right?

-Hypothetically, if you have a Class I, Div 2, Group B location but the pump must be identified as a Class I, Div 1 per 501.125(B), does the grouping become relevant since the pump is identified as a Class I Div 1 or is the group still irrelevant since the location is Class I, Div 2?

Thanks again! :thumbsup:
I never heard of a hermetically sealed pump.
 

stgga

Member
Location
GA
author of confusion

author of confusion

workerbee...I feel your pain. This is one reason I joined this forum....between what a vendor says is "code", an OSHA inspector, insurance guy or an engineer of some sort....its tough to get straight answers some times.

rbalex---its great to get book, chapter and verse. I'm sure I'll be asking a similar question!
 

WorkerBee

Member
Location
US
With regard to the pump motor only, in Division 2, the Group is irrelevant. [See Section 501.125(B)].

I do not see in Section 501.125(B) where it tells us if we have a Class I, Div 2 location...the group identification of the motor is ingermane. Can you be more specific where it tells us if Class I, Div 2, the group doesn't matter???

Thanks again! :D
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I do not see in Section 501.125(B) where it tells us if we have a Class I, Div 2 location...the group identification of the motor is ingermane. Can you be more specific where it tells us if Class I, Div 2, the group doesn't matter???

Thanks again! :D

The last sentence of the cited paragraph says this.
In Class I, Division
2 locations, the installation of open or nonexplosionproof
enclosed motors, such as squirrel-cage induction motors
without brushes, switching mechanisms, or similar arc producing
devices that are not identified for use in a Class
I, Division 2 location, shall be permitted.
Nothing is said about group in this sentence.

Although I never noticed it said you could install open motors. I thought they had to be enclosed. Maybe Bob A. can comment on that.
 

WorkerBee

Member
Location
US
The last sentence of the cited paragraph says this.

Nothing is said about group in this sentence.

Although I never noticed it said you could install open motors. I thought they had to be enclosed. Maybe Bob A. can comment on that.

Thanks for the fast reply.

I saw the last sentence but to me it is saying, the installation of those motors (open, non xprf, etc,) that are not identified for use in a Class I, Div 2 location is permitted in a Class I, Div 2 location. Our pump/motor is identified as Class I, Div 2 so of course it's permitted in a Class I, Div 2 location, but it doesn't say a Group C or D motor is permitted in a Group B location as long as it's Class I, Div 2...or maybe it is saying that and I'm just not interpreting it correctly (likely the case :lol:).

Thoughts?
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
You have a rather arcane application and I confess, I was inclined to say "Trust me and don't worry about it." However, after reviewing the cut-sheet link I am concerned about how the Division 2 classification was arrived at in the first place. If the installation is remotely similar to the diagram, the lack of ventilation would indicate a Division 1 classification.

That said, assuming the location is correctly classified Division 2, all UL listed "Class I" motors (explosionproof) are "totally enclosed".

I believe I mislead you. Essentially, most three-phase induction motors are acceptable in Class I, Division 2, "totally enclosed" or not AND Group is not relevant. Most single-phase motors or three-phase motors with auxiliary arcing components need some additional form of protection technique, explosionproof being the most common. [See Section 500.7 for other various alternatives]

NOW we need to deal with Group B if the Division 2 installation requires an explosionproof protection technique.

I would also note identified does not necessarily mean listed or labeled. See the definition in Article 100. Also see suitable in Section 500.8(A).
 
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