After 90, then what?

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charlie b

charlie b

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First let me ask, please do not, I say again DO NOT, postany suggested solutions to resolve or address the scenario I am about todescribe. All I want now is your opinionas to whether this scenario would create "a problem that is in need of asolution." I will deal with possible solutions in a separate thread.

The Setup: A newbuilding will have a small generator and emergency distribution system thatmeets all the requirements in Article 700. The only loads connected to this system will be egress lights. Under this load, the emergency generator’sfuel tank will have capacity to run the generator for the minimum requirementof 90 minutes.

There will be a second generator and distribution systemdesigned under Article 702 (optional standby). The loads connected to thissystem will enable a certain number of employees to continue working. These employees would work in shifts aroundthe clock, performing services to assist other people in an off-site location,during the time that that off-site location experiences an emergencysituation. Take for granted that theemployees in this building need to be working, and that the off-site emergencycould last for several days. The optionalstandby generator’s fuel tank will have capacity to run for 48 hours at fullload, and there will be arrangements for a fuel truck to visit the facility asoften as is needed.

The Scenario: Startwith the occurrence of the off-site emergency. Suppose we are 8 hours into the emergency situation when, as nighttimehas just arrived, the utility company has a transformer failure that knocks outpower to the building. Within the next90 minutes, all non-essential people will have left the building. The people dealing with the off-site emergencykeep working. At the end of 90 minutes,the emergency generator stops, due to lack of fuel. However, if the optional standby generatorfails for any reason, the people remaining in the building will be directed togo to a backup facility to continue dealing with the off-site emergency. However, they will not have any egresslighting to lead them to the exits.

The Question: I thinkwe will all agree that this would not be a healthy situation. But is it a code violation? The code requires us to provide 90 minutes ofegress lighting. We did that. But what happens if the people choose not toegress? Fundamentally, is there aproblem that is in need of a solution?
 
I'm looking at an older Code so things may have changed but I see the 90 min requirement for individual (unit equipment) and for storage battery as backup but I don't see a time limit for generators other than "type of service to be rendered, long or short duration.
 
charlie b said:
First let me ask, please do not, I say again DO NOT, post any suggested solutions to resolve or address the scenario I am about to describe. All I want now is your opinion as to whether this scenario would create "a problem that is in need of a solution." I will deal with possible solutions in a separate thread.

The Setup: A new building will have a small generator and emergency distribution system that meets all the requirements in Article 700. The only loads connected to this system will be egress lights. Under this load, the emergency generator’s fuel tank will have capacity to run the generator for the minimum requirement of 90 minutes.

There will be a second generator and distribution system designed under Article 702 (optional standby). The loads connected to this system will enable a certain number of employees to continue working. These employees would work in shifts around the clock, performing services to assist other people in an off-site location,during the time that that off-site location experiences an emergency situation. Take for granted that the employees in this building need to be working, and that the off-site emergency could last for several days. The optional standby generator’s fuel tank will have capacity to run for 48 hours at full load, and there will be arrangements for a fuel truck to visit the facility as often as is needed.

The Scenario: Start with the occurrence of the off-site emergency. Suppose we are 8 hours into the emergency situation when, as nighttime has just arrived, the utility company has a transformer failure that knocks out power to the building. Within the next 90 minutes, all non-essential people will have left the building. The people dealing with the off-site emergency keep working. At the end of 90 minutes,the emergency generator stops, due to lack of fuel. However, if the optional standby generator fails for any reason, the people remaining in the building will be directed to go to a backup facility to continue dealing with the off-site emergency. However, they will not have any egress lighting to lead them to the exits.

The Question: I think we will all agree that this would not be a healthy situation. But is it a code violation? The code requires us to provide 90 minutes of egress lighting. We did that. But what happens if the people choose not to egress? Fundamentally, is there a problem that is in need of a solution?
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Yes it is a code violation.
In Florida any building which lacks a means of egress (including means of egress illumination) is by definition an Unsafe Structure and may not be occupied. I'm sure it's the same for every state.

PS: I just banged my spacebar about 99 times on quoting your post. I suggest your turn your keyboard over and knock all the crumbs out of it! :lol:
On a more serious note, I think it's the spacebar which goes first on every keyboard I've thrown in the trash.
 
mgookin said:
PS: I just banged my spacebar about 99 times on quoting your post. I suggest your turn your keyboard over and knock all the crumbs out of it! :lol:
On a more serious note, I think it's the spacebar which goes first on every keyboard I've thrown in the trash.
Click to expand...


I've seen the spacing problem before. I've found it happens when you "copy & paste" the words from elsewhere. I suspect the OP typed it up in a Word document (or similar) copied, then pasted it in this thread.
Also happens to me when I copy something from a PDF (read NEC) and paste it.
 
Little Bill said:
I've seen the spacing problem before. I've found it happens when you "copy & paste" the words from elsewhere. I suspect the OP typed it up in a Word document (or similar) copied, then pasted it in this thread.
Also happens to me when I copy something from a PDF (read NEC) and paste it.
Click to expand...

Thanks Little Bill. I too have seen the problems from pasting from pdf's. I've also had spacebars die on me; must be my fat thumbs!
 
Having been "essential personnel" (EP) as a WW Plant Operator, not having lights is a minor inconvenience. You stated if the 700 genset failed all NEP's leave and EP's stay. If the 702 genset failed the essential personnel would continue at another facility; this 702 backup generator would be supplying the egress lights too, yes? Are there no battery backups in the egress lighting to 'continue the clock' 90 minutes past the point of the standby genset's hypothetical failure?

Without getting into solutions, I'll just say this is one reason to carry flashlights.

I'm not sure codewise about mgookin's claim. If FL gets hit by a hurricane, are they going to evacuate everyone in a hotel without power past the 90minute mark?
 
It sounds like the facility would fall under Article 708, which has specific requirements.
 
I don't see this being any different than a building with 90 minute battery back up egress lighting. Many data centers, 911 centers, etc. have generator backup for critical systems but not the entire building. I don't see a code violation.
 
NEC 700 violation--No

Needs a solution--Maybe--NEP are already out and EP should be prepared for this
 
Just my opinion.

The emergency lighting is there so people can safely exit, or have the time to take whatever other precautions they might need to take to continue working safely.

I think as long as there is 90 minutes of light, you have met the minimum code requirements.
 
I think the situation just got murkier, probably because (silly me!) I just went back and actually read the code. Here is a quote from 700.12:
In selecting an emergency source of power, consideration shall be given to the occupancy and the type of service to be rendered, whether of minimum duration, as for evacuation of a theater, or longer duration, as for supplying emergency power and lighting due to an indefinite period of current failure from trouble either inside or outside the building.
Click to expand...
That last part, in bold text, has me a big concerned. Is that saying that if I know that some employees will need to remain at work for an indefinite length of time, then I need to be able to keep the emergency generator operating indefinitely?
 
charlie b said:
I think the situation just got murkier, probably because (silly me!) I just went back and actually read the code. Here is a quote from 700.12: That last part, in bold text, has me a big concerned. Is that saying that if I know that some employees will need to remain at work for an indefinite length of time, then I need to be able to keep the emergency generator operating indefinitely?
Click to expand...

I suspect this refers to places that cannot evacuate like a hospital or a nursing home.
 
charlie b said:
I think the situation just got murkier, probably because (silly me!) I just went back and actually read the code. Here is a quote from 700.12: That last part, in bold text, has me a big concerned. Is that saying that if I know that some employees will need to remain at work for an indefinite length of time, then I need to be able to keep the emergency generator operating indefinitely?
Click to expand...

And along that line of thought and just thinking out loud, I'm not sure what would prevent you from having your optional 702 ATS picking both the optional loads and the 700 loads. The 700 emergency load ATS could be down stream from the 702 ATS and would transfer to the 700 emergency generator if and when both the POCO and the 702 generator fails. Off the top of my head I think this would be compliant and allow you to keep the building fully occupied until the 702 system failed. The 700 system would then kick in and an orderly evacuation could occur.
 
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