NEC Related Questions?

[anbm]

I have two questions hope some of you can clear for me:

1. I heard some where in NEC or building code indicates when you have a high rise office building, we have

a. Provide an emeregncy generator

b. Separate egress lighting + fire alarm load on a separate ATS from other load.

Do you what particular section of NEC or building code talk about this rule? And how long (hour) should generator require to serve the emergency load in case of loosing normal utility?


2. I know the TVSS using with switchboard rated at 320kA, 240kA, 180kA, etc. Are these standard number? How do we decide what rate of TVSS should we use?

Thank you!

TX-man

 

[cadpoint]

I have two questions hope some of you can clear for me:

1. I heard some where in NEC or building code indicates when you have a high rise office building, we have

a. Provide an emeregncy generator

b. Separate egress lighting + fire alarm load on a separate ATS from other load.

Do you what particular section of NEC or building code talk about this rule? And how long (hour) should generator require to serve the emergency load in case of loosing normal utility?


2. I know the TVSS using with switchboard rated at 320kA, 240kA, 180kA, etc. Are these standard number? How do we decide what rate of TVSS should we use?

Thank you!

TX-man

Its a building code issue or an AHJ issue, and your miles may vary.

90 minutes is our local code requirement, In respects to egress, which is standard! IBC ...

A TVss is a voltage surge supression not a measurement of protection in respects to backup Genorator it's what the voltage might see and be inhabited to that voltage spike or strike, - 2 different animals ...

 

[anbm]

Cadpoint,

1. what i mean is what is max. hour requirement (i.e. 8, 12, or 24 hours) should generator run before it runs out of gasoline not 90 min. for egress emergency lighting requirement.

Question #2 doesn't relates to question #1.

Thanks!

 

[cadpoint]

Let me say it this way, the NEC-70 tells (in the broad sense of all things) how to wire a generator. What is required per the type of applaction.
It just doesn't state what you asking.

Now once a owner wants to add a generator to an office building, or even a factory building, the total demand load needs to be found of what they want to keep running. Can this sum be infinty in respect to time, well yes.
I'd go with a natural gas generator. The bottom line is it has to be calculated.

With a installation it might cause some of NEC-70 codes Articles to be appplied. Note all the FPN notes under the (and not limited only to these listed when applying a generator)
Article 700 Emergency
Article 701 Legally Required Standby Systems
Article 702 Optional Standby Systems

The question seems to be are you doing it for any of the three articles above ?

All depending on the type, purpose, Class of Structure all Building code Issues, and/or your state or local AHJ.

Take a close look at 701.2 Defination
Legally Required Standby Systems

| Article 705 (all editted for contant((not stated))

| Article 708 Critical Operations Power Systems (all editted for contant).

Two statments my EE friend said was, 90 minutes egress and why the generator?!
BASED on 2008 NEC-70