Special Occupancy Enclosure under a stairway.

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jluna1234

Member
Location
San Jose CA
Our instrumentation shop wants to install a appropriate enclosure for instrumentation under a stairway. The enclosure poses no issue for egress. Is this a building or a electrical issue. The cabinet will have 120 volts for power strips for instrument power low voltage transformers.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Our instrumentation shop wants to install a appropriate enclosure for instrumentation under a stairway. The enclosure poses no issue for egress. Is this a building or a electrical issue. The cabinet will have 120 volts for power strips for instrument power low voltage transformers.

I don't know what you mean by the part of the title that says "Special Occupancy Enclosure". What kind of special occupancy is involved? What is a "Special Occupancy Enclosure"?

Generally I do not have an issue with this kind of installation as long as appropriate working space is present if required. If working space is deemed to be required, it might be hard to find it under the stairs.
 
Under Stairs Instrument Shop

Under Stairs Instrument Shop

The actual prognosis by "occupancy" matched to IBC rules can be found by a quick look up reference in chapter 4 of the 2012 edition 'special detailed requirements based on use and occupancy'.

Un-classified areas are generally considered under the F for factory either F1 or F2. Instrument shops normally are close to maintenance shops where the tools and machinery are closely protected by rules in adopted codes in your State and calibration records are kept for any preventive maintenance or process maintenance in the shop offices of maintenance supervisor directive's.

Under stairs may not (possibly) be considered as an obstruction as long as pathway to exists are not impeded and square foot per occupant is maintained depending on how many are in a facility. A word of caution beyond the required is that is the least amount of your question. Additional information is required and should be directed at the where and adjacent passive and active fire protection relating to the materials that may wind up under the stairs. Other's in your organization can advise more concisely on materials of construction allowed.

The idea of having any transformers under an egress path is an exclusive argument to be reviewed by your code authority. Reference to section 311 (S or Storage) and (U Utility and miscellaneous ) may have certain rules in your instance.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
The actual prognosis by "occupancy" matched to IBC rules can be found by a quick look up reference in chapter 4 of the 2012 edition 'special detailed requirements based on use and occupancy'.
I don't see how an area under a stairway is a different occupancy than the area surrounding it.

Un-classified areas are generally considered under the F for factory either F1 or F2. Instrument shops normally are close to maintenance shops where the tools and machinery are closely protected by rules in adopted codes in your State and calibration records are kept for any preventive maintenance or process maintenance in the shop offices of maintenance supervisor directive's.
I don't see how any of this is relevant to the question asked. The stairway could be on the other end of the building from the instrument lab and the answer would not change any.

Under stairs may not (possibly) be considered as an obstruction as long as pathway to exists are not impeded and square foot per occupant is maintained depending on how many are in a facility. A word of caution beyond the required is that is the least amount of your question. Additional information is required and should be directed at the where and adjacent passive and active fire protection relating to the materials that may wind up under the stairs. Other's in your organization can advise more concisely on materials of construction allowed.
You really think there is a square footage requirement under a stairway based on how many occupants are under the stairs?

The idea of having any transformers under an egress path is an exclusive argument to be reviewed by your code authority. Reference to section 311 (S or Storage) and (U Utility and miscellaneous ) may have certain rules in your instance.
I am pretty sure the OP is talking about small instrument type transformers that are likely Class 1 or 2 power supplies, and not power transformers.
.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I would think the nature of the equipment being served might make a difference if the stairwell was fire rated due to restrictions on foreign circuits being installed in a fire rated stairwell.
 
General and passive versus active FP

General and passive versus active FP

Quite naturally "egress" was the notation used in the original post. Egress has three parts,1. exit access, 2. Exit, 3. egress outside the building to a public way.

The likely hood of remote versus local location in concept of where a calibration shop is tied to material when energy is prevalent. Often small heaters are used and electric overloads or heat, products of combustibility, oxygen, chemical reaction may exist. The risk taken is entirely up to a code authority mentioned in my response.

However just for a quaint understanding the vapor phase of liquids or solids have a vapor flash point governs where in an egress path certain occupancy are allowed to exist in a building , certainly does not leave it up to anyone but qualified what I suggest as his code authority. I feel certain his organization will arrive at the top of the stairs and determine the characteristics of "egress" not under it and by the by the square foot area provided is so trampling does not occur in the stairwell, certainly never intended to mention people standing around under a stairwell when the building is on fire, does that make sense to the person asking in red. I have the notion you should chill out.
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Our instrumentation shop wants to install a appropriate enclosure for instrumentation under a stairway. The enclosure poses no issue for egress. Is this a building or a electrical issue. The cabinet will have 120 volts for power strips for instrument power low voltage transformers.

@nec_addicted

If you read the original post anyone can see that the question is about placing an enclosure under a stairway for instrumentation equipment. It poses no issue with egress, it will have 120v power strips for the low voltage transformers. That's it. The whole instrumentation department isn't moving there, no high voltage transformers.

Your response is typical of some engineers who take a simple project and go off on a tangent creating all kinds of problems that don't or won't ever exist.

-Hal
 
Testing Standards for toxic bases released iinegress paths

Testing Standards for toxic bases released iinegress paths

"Under stairs may not (possibly) be considered as an obstruction" original amnswer

You might be correct you do not know the materials of the enclosure to be built. Your jump to is a narrow focused humor that is not considered life safety.

An example for testing of material (ASTM E502) might be in your interest.
 
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