# Rules for Windows By Stairs in IRC 2018 NJ



## nickedemus (Mar 9, 2021)

I know there are limitations concerning the placement of windows by stairs in the IBC. But I'm not seeing them in IRC. What section are they in? Or, does IRC not address this?


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## fatboy (Mar 9, 2021)

Looking for something like this?




R308.4.6 Glazing adjacent to stairs and ramps. Glazing
where the bottom exposed edge of the glazing is less
than 36 inches (914 mm) above the plane of the adjacent
walking surface of stairways, landings between flights of
stairs and ramps shall be considered to be a hazardous
location.
Exceptions:
1. Where glazing is adjacent to a walking surface
and a horizontal rail is installed at 34 to 38 inches
(864 to 965 mm) above the walking surface. The
rail shall be capable of withstanding a horizontal
load of 50 pounds per linear foot (730 N/m) without
contacting the glass and have a cross-sectional
height of not less than 11/2 inches (38 mm).
2. Glazing 36 inches (914 mm) or more measured
horizontally from the walking surface.
R308.4.7 Glazing adjacent to the bottom stair landing.
Glazing adjacent to the landing at the bottom of a stairway
where the glazing is less than 36 inches (914 mm) above
the landing and within a 60-inch (1524 mm) horizontal arc
less than 180 degrees (3.14 rad) from the bottom tread
nosing shall be considered to be a hazardous location. (See
Figure R308.4.7.)
Exception: Where the glazing is protected by a guard
complying with Section R312 and the plane of the glass
is more than 18 inches (457 mm) from the guard.


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## nickedemus (Mar 9, 2021)

Yes! Thank you very much.


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## Inspector Gift (Mar 9, 2021)

Can someone PLEASE tell me why the IRC height for hazardous windows near landings and stairs was lowered from less than 60 inches to less than 36 inches?   

And yet the IBC height for windows adjacent stairs and landings is less than 60 inches.

It makes no sense to me.


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## nickedemus (Mar 9, 2021)

Inspector Gift said:


> And yet the IBC height for windows adjacent stairs and landings is less than 60 inches.



I saw that. I'm not sure why. But I notice that the IBC tends to be more restrictive than IRC. Take, for example, stair risers. IBC limits the rise to 7". IRC allows 8.25" Maybe it's because in a residence, you basically have the same people using the building every day, whereas with IBC, it could be many different users using the building in a limited way. For example, a doctor's office.


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## tbz (Mar 9, 2021)

NJ modifies the Model IRC riser height from 7-3/4" to 8-1/4", that is a local change.

The same for tread depth, from 10" to 9"

-

I/G -  The theory I have heard is that residentially the difference is numbers.  The odds of just a few being near the glass in the 1 and 2 family compared to the entrance of a building with larger crowds.    Simply the larger occupancy load.  Again, I have been told.


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## Paul Sweet (Mar 10, 2021)

The hazard of tripping and falling into glass between 36" & 60" above the floor is greater than the hazard of tripping into glass more than 60" above the floor, so the IRC is tougher.


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## nickedemus (Mar 16, 2021)

tbz said:


> NJ modifies the Model IRC riser height from 7-3/4" to 8-1/4", that is a local change.
> 
> The same for tread depth, from 10" to 9"


Ture, but the unammended IBC still requires lower heights and deeper treads than the unammended IRC. IBC also has a minimum riser height of 4". I haven't been able to locate a minimum riser height in IRC. 

There's just a wider range of options in the IRC, probably because there are a limited number of people using the building.


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## nickedemus (Mar 16, 2021)

Paul Sweet said:


> The hazard of tripping and falling into glass between 36" & 60" above the floor is greater than the hazard of tripping into glass more than 60" above the floor, so the IRC is tougher.


 Don't you mean that the IRC is more _permissive_, since it allows the greater hazard?


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## Paul Sweet (Mar 16, 2021)

You're right.  I got the verbiage twisted around (which isn't hard to do the way codes are often written!)


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