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Thread: changing a space classification temporarily

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    changing a space classification temporarily

    Hi all,
    My first post to this forum though I've viewed it for years and appreciate the level of responses provided to questions. Brief background: I'm an engineer who has worked in/with hazardous locations for many years in the chemical industry, primarily for operations and instrumentation. Now I am in an EH&S role and am currently revising a hot work permit process.

    How can I temporarily change the classification of a space for maintenance activities? Sorry if this question is common; I don't know the right word to use (declassify? de-rate? re-classify?) so I've been coming up empty on my searches. For example, I'd like to bring a non-rated scissor lift into a Class 1 Div 2 area. Currently we use a hot work permit for this activity, but it doesn't really fit. It seems like I should be able to take steps to properly address safety concerns (remove hazards, monitor atmosphere), and therefore make the space unrated for a specific time period so that it would be okay to use unrated equipment. Of course for any hot work that falls under hot work definition we would use our hot work permit process (e.g. NFPA 51B).

    Thanks much,
    Kevin

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    I'd say bring in sufficient amount of ventilation to make it no longer a classified area.

    Purging the area with say nitrogen would work, but isn't all that great for workers in the area.
    I live for today, I'm just a day behind.

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    In the plants I have worked in that did that, the hot work permit required a combustible gas monitor set up in the work area. Work would be stopped with any reading .
    Don, Illinois
    (All code citations are 2017 unless otherwise noted)

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    Quote Originally Posted by kschott View Post
    Hi all,
    My first post to this forum though I've viewed it for years and appreciate the level of responses provided to questions. Brief background: I'm an engineer who has worked in/with hazardous locations for many years in the chemical industry, primarily for operations and instrumentation. Now I am in an EH&S role and am currently revising a hot work permit process.

    How can I temporarily change the classification of a space for maintenance activities? Sorry if this question is common; I don't know the right word to use (declassify? de-rate? re-classify?) so I've been coming up empty on my searches. For example, I'd like to bring a non-rated scissor lift into a Class 1 Div 2 area. Currently we use a hot work permit for this activity, but it doesn't really fit. It seems like I should be able to take steps to properly address safety concerns (remove hazards, monitor atmosphere), and therefore make the space unrated for a specific time period so that it would be okay to use unrated equipment. Of course for any hot work that falls under hot work definition we would use our hot work permit process (e.g. NFPA 51B).

    Thanks much,
    Kevin
    Why doesn't a hot work permit work for this situation? No amount of ventilation or monitoring is going to raise the classification from division 2 to no classification. So the only way I see to "remove" the classification is to remove any gasses that may be present during the work. It seems to me that a JSA and then a hot work permit it actually the right way to deal with it.


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    Quote Originally Posted by Strathead View Post
    Why doesn't a hot work permit work for this situation? No amount of ventilation or monitoring is going to raise the classification from division 2 to no classification. So the only way I see to "remove" the classification is to remove any gasses that may be present during the work. It seems to me that a JSA and then a hot work permit it actually the right way to deal with it.
    Wouldn't each situation have it's own circumstances that need to be looked into?

    Simple ventilation may be very effective in some places but maybe not others.

    Some places may have higher chance of gas being present when certain process is running but very little risk when not running.

    Is a paint booth a classified area when not in use, and vapors from the last use have cleared?
    I live for today, I'm just a day behind.

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    Quote Originally Posted by kwired View Post
    Wouldn't each situation have it's own circumstances that need to be looked into?

    Simple ventilation may be very effective in some places but maybe not others.

    Some places may have higher chance of gas being present when certain process is running but very little risk when not running.

    Is a paint booth a classified area when not in use, and vapors from the last use have cleared?
    Agreed, so the area is not currently subject to the gasses, That seems to me the entire intent of a Job safety analysis and a call it work permit, not necessarily a hot work permit to affirm that safe practices are being followed and work can ONLY proceed under specific temporary conditions.


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    Thanks so much for the discussion on this topic!

    My hesitation to continue calling some activities "hot works" is because they don't fall into the definition. As another example, suppose I needed to bring a non-rated laptop into the room to modify parameters in an instrument. Same as the scissor lift example, I'm not doing anything that produces a spark, flame, or heat.

    So that I (hopefully) don't sound like I'm just being pedantic, here are two other factors that I did not mention: 1) our permit through our town requires us to contact the fire department whenever we have an active hot work, and 2) our procedures dictated a one hour fire watch at the completion of hot work activities. I'd like to not involve the FD if these situations aren't really hot work, and I have a hard time keeping people focused on our hot work process when a fire watch has to maintained for an hour after the scissor lift has left the room.

    I was hoping to hear that industry best practice is to use another form of permitting process (like a work permit) where we go through a lot of the same steps (atmosphere testing, moving flammables, etc.) that does essentially the same but isn't a "hot work permit" and therefore isn't subject to FD contact and fire watch.

    All that said, maybe I don't understand 51B quite right? I confess I am confused by 51B 5.6.1 that says I (the PAI) shall require a fire watch "...where other than a minor fire might develop" yet 5.6.1.1. says "a fire watch shall be maintained for 1 hour after completion of hot work operations...". If the standard actually says I (the PAI) have an option to require a fire watch, I would probably be okay continuing to use a hot work permit.

    Thanks again! I really appreciate the input. Again, no actual safety procedures will change, I just want to call things what they are and try to do things as they are done across the industry.

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    Quote Originally Posted by kschott View Post
    Thanks so much for the discussion on this topic!

    My hesitation to continue calling some activities "hot works" is because they don't fall into the definition. As another example, suppose I needed to bring a non-rated laptop into the room to modify parameters in an instrument. Same as the scissor lift example, I'm not doing anything that produces a spark, flame, or heat.

    So that I (hopefully) don't sound like I'm just being pedantic, here are two other factors that I did not mention: 1) our permit through our town requires us to contact the fire department whenever we have an active hot work, and 2) our procedures dictated a one hour fire watch at the completion of hot work activities. I'd like to not involve the FD if these situations aren't really hot work, and I have a hard time keeping people focused on our hot work process when a fire watch has to maintained for an hour after the scissor lift has left the room.

    I was hoping to hear that industry best practice is to use another form of permitting process (like a work permit) where we go through a lot of the same steps (atmosphere testing, moving flammables, etc.) that does essentially the same but isn't a "hot work permit" and therefore isn't subject to FD contact and fire watch.

    All that said, maybe I don't understand 51B quite right? I confess I am confused by 51B 5.6.1 that says I (the PAI) shall require a fire watch "...where other than a minor fire might develop" yet 5.6.1.1. says "a fire watch shall be maintained for 1 hour after completion of hot work operations...". If the standard actually says I (the PAI) have an option to require a fire watch, I would probably be okay continuing to use a hot work permit.

    Thanks again! I really appreciate the input. Again, no actual safety procedures will change, I just want to call things what they are and try to do things as they are done across the industry.
    The scissor lift has switches, relays, power contactors, motors...that all have arcing when contacts make/break or even just a possibility of increased surface temps being an issue. Laptop computer - each key on a keyboard is connected to a switch. Very low current passes through them, and they are probably sealed but not necessarily verified to any intrinsically safe standards, but chance of an issue in a division 2 location when there has been no incidents releasing gas into the space is probably a low risk. Also said computer may not seem to get very warm, but there can be more heat concentrated at the processor then one may realize, cooling fan blows out warm air, but if you opened things up and touched the right spot it may be hot enough to burn you.
    I live for today, I'm just a day behind.

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    The "root" issue is described in Section 500.4(A):

    500.4 General.
    (A) Documentation.
    All areas designated as hazardous
    (classified) locations shall be properly documented. This
    documentation shall be available to those authorized to design,
    install, inspect maintain, or operate electrical equipment
    at the location.
    (NOTE: It appears 500.4(A) and (B) will be absorbed into a single Section in the 2020 NEC.)

    In addition, see the definition of Unclassified Locations. (Depending on the edition, this may be in Article 100 or Section 500.2)

    Unclassified Locations. Locations determined to be neither
    Class I, Division I; Class I, Division 2; Class 1, Zone 0;
    Class I, Zone 1; Class 1, Zone 2; Class II, Division I; Class
    II, Division 2; Class III, Division I; Class III, Division 2;
    Zone 20; Zone 21; Zone 22; or any combination thereof.
    What we conclude is a hot work permit must be a "proper document" issued/created by a person competent to "determine" a location's classification is unclassified​ under specified temporary conditions.
    "Bob"
    Robert B. Alexander, P.E.
    Answers based on 2017 NEC unless otherwise noted.

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