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Thread: What defines the boundaries of a Class I div. II location?

  1. #1
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    What defines the boundaries of a Class I div. II location?

    Imagine if you will a 12'x12' raised slab that houses a vertical propane tank and dispensing pump. This is outdoors. The slab sits approximately 10-12 ft from the building. The customer has previously installed 3/4" PVC Sched. 80 running in a trench from building to slab. I am trying to determine if this is acceptable. Obviously we have to change to rigid but I am unsure of any portion of this can be in PVC. I guess more specifically I am trying to find out what defines the boundary of the hazardous area? I have been pouring through Art. 500 and can't seem to find it. Open for guidance. Thank you.

  2. #2
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    Quote Originally Posted by blugrs77 View Post
    Imagine if you will a 12'x12' raised slab that houses a vertical propane tank and dispensing pump. This is outdoors. The slab sits approximately 10-12 ft from the building. The customer has previously installed 3/4" PVC Sched. 80 running in a trench from building to slab. I am trying to determine if this is acceptable. Obviously we have to change to rigid but I am unsure of any portion of this can be in PVC. I guess more specifically I am trying to find out what defines the boundary of the hazardous area? I have been pouring through Art. 500 and can't seem to find it. Open for guidance. Thank you.
    You should probably be looking in Article 515 or, possibly 514, depending on the actual purpose of the installation. Read their Scopes [51X.1] carefully.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

  3. #3
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    Quote Originally Posted by blugrs77 View Post
    Imagine if you will a 12'x12' raised slab that houses a vertical propane tank and dispensing pump. This is outdoors. The slab sits approximately 10-12 ft from the building. The customer has previously installed 3/4" PVC Sched. 80 running in a trench from building to slab. I am trying to determine if this is acceptable. Obviously we have to change to rigid but I am unsure of any portion of this can be in PVC. I guess more specifically I am trying to find out what defines the boundary of the hazardous area? I have been pouring through Art. 500 and can't seem to find it. Open for guidance. Thank you.
    In addition to Bob's commentary , take a look at API 500. There are numerous details contained therein to help determine you're particular scenario - I've attached a couple of examples. Depending upon tank configuration, you may have a 5' radius of CID1 near the source, followed by another layer of Division 2 at 10' from the source. Your building is so close to the tank, there may be some 'overlap' into the Division 2 area which could become problematic if the building is not vapor tight or pressurized.
    Concrete encased PVC duct banks are very common - sometimes a simple 2" red-concrete 'cap' is placed above a PVC conduit for protection. You may be better off simply running a single, rigid galvanized steel conduit from stub-up to stub-up since you're only going 10 feet or so.
    Attached Images Attached Images

  4. #4
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    Quote Originally Posted by rbalex View Post
    You should probably be looking in Article 515 or, possibly 514, depending on the actual purpose of the installation. Read their Scopes [51X.1] carefully.

    Which I can't see anything that requires the underground portion to be classified. Only open area below the tank radius.


    I know what I don't know, and I know where to go to find it!

  5. #5
    Join Date
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    What defines the boundaries of a Class I div. II location?

    Quote Originally Posted by Strathead View Post
    Which I can't see anything that requires the underground portion to be classified. Only open area below the tank radius.
    See 514.8 and 515.8 - underground itself is unclassified


    Sent from my iPhone using Tapatalk
    Last edited by Dale001289; 07-03-18 at 08:07 AM.

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