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Fan Discharge of a Class 1 DIV2 Rated Area

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    Fan Discharge of a Class 1 DIV2 Rated Area

    We are an HVAC company - but don't let that scare you. We have a building that is Class 1 DIV 2 rated - it's a Headworks Building for a Waste Water Treatment plant. The fans they installed on the building are just a ODP or TEFC motor and are not explosionproof in design.

    I know - somewhere - there is a code that states "Anything within a 10 radius from the "Discharge" of said fan has to be rated for the environment on which it is exhausting. So that would mean any motor, disconnect, outlets, lights etc... has to be rated for a Class 1 DIV 2 space.

    What code reference is this??? I've looked in NFPA 70 and NFPA 91 with no luck.

    Any help appreciated!

    Thanks,
    D

    #2
    take a look at article 501.125.

    ODP is potentially an issue.
    Bob

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      #3
      Originally posted by petersonra View Post
      take a look at article 501.125.

      ODP is potentially an issue.
      What makes an Open Drip Proof motor a possible issue?
      Don, Illinois
      (All code citations are 2017 unless otherwise noted)

      Comment


        #4
        Two issues here:
        1. ODP and TEFC would be equally suspect per NEC (2017) Section 501.125(B)(3). The problem is FedOSHA. Some (note some, not all) motors suitable for Class I, Division 2 are listed as such. Motors identified [Section 501.125(B)(1)] under Section 501.125(B)(3) may or may not be listed even if they are suitable. At the moment, no NEMA manufacturer lists an ODP motor for Class I, Division 2, but FedOSHA requires that a listable product must be listed.
        2. "Discharge" from a Class I, Division 2 location fan has no specified hazard radius.
        "Bob"
        Robert B. Alexander, P.E.
        Answers based on 2017 NEC unless otherwise noted.

        Comment


          #5
          Interesting

          Originally posted by rbalex View Post
          Two issues here:
          1. ODP and TEFC would be equally suspect per NEC (2017) Section 501.125(B)(3). The problem is FedOSHA. Some (note some, not all) motors suitable for Class I, Division 2 are listed as such. Motors identified [Section 501.125(B)(1)] under Section 501.125(B)(3) may or may not be listed even if they are suitable. At the moment, no NEMA manufacturer lists an ODP motor for Class I, Division 2, but FedOSHA requires that a listable product must be listed.
          2. "Discharge" from a Class I, Division 2 location fan has no specified hazard radius.
          I work in and was involved in buliding out a Class 1, Div.2 Distillery. Aside from what was required on the interior and 100% OA makeup, there was nothing special about the exhaust fan specified in this case. I can tell you from experience that this process if not wise to leave unattended, which is exactly what people in this trade are inclined to do, many of them.....
          What goes on with regards to this industry and the growth of smaller operations would seem to be quite a bit more varied than what may happen in hydrocarbon settings etc. There are also regular exlposion stories in the news which are usually related to people doing very stupid things in those settings. I toured a place in Colorado in the recent past that was a Mechanical Systems Nightmare, and the distillation capacity was MASSIVE.

          Star
          Microwave Radiation Dangers should be openly discussed

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