protecting under open stairs 1

[sac32079]

There is a job that I worked on back in 2011, the engineer is saying that we are required to protect under the open stair on each level. we have sprinkler protection around the floor opening. the stair case is off to the far side of the opening. the heads around the opening are not obstructed. where in 13 does it say this is required? would this be the 4' rule? I am having issues with this, it doesn't seem feasible to install sprinklers under 5 levels of stairs. any insight on this would be appreciated.

 

[cdafd]

What do you mean by open stairs as like in an apartment building where you stand at the bottom and can see all the bottoms of all the treads,

Or open as in the steps have holes in them?

How wide are they???[pre][/pre]

 

[cdafd]

are they combustible? or Non Com??

gues you have checked 8.15.3 NFPA 13 2010 edition???

and yes four foot rule applies

 

[skdesigner]

13-2013 8.10.6.5.3.3 Sprinklers shall be installed under all fixed obstructions over 4ft wide.

The allowance to omit sprinklers everywhere but top and bottom is in 8.15.3.2.1, which specifically calls out non-combustible stair shafts (i.e enclosed). If you've got an open staircase that exceeds 4 ft in width, then you would be required to install sprinklers beneath it.

R M Arsenault Engineering Inc.

http://www.rmae.ca

 

[sac32079]

please see the attached stair detail. the stairs have open risers, how would it collect heat? I have coverage on the landings adjacent to each level.

 

[cdafd]

Sac


No attachment


8.15.3.2.4
Sprinklers shall be permitted to be omitted from exterior stair towers when the exterior walls of the stair tower are at least 50 percent open and when the stair tower is entirely of noncombustible construction.

Do you have 50%

 

[sac32079]

revised. please see the attachment

 

[sac32079]

The project is at Duke University. The floor opening goes from level 0 to level 5M. the stair is only on the left hand side of the opening. there is no riser on the steps, there is about a 6" gap in between. I don't see how it would even collect heat to activate a sprinkler.

 

[cdafd]

with out seeing it in person,

I am thinking at the top, each landing, and for sure complete protection under the 1st floor set of stairs going up.

 

[chicopee]

Get hold of the fire marshal for his input. What is the spacing of the sprinkler heads on each end of the stairway footprint which could satisfy the sprinkler head spacing.

 

[rmae]

The presupposition that a sprinkler or sprinklers installed under fixed obstructions exceeding 4' in width require that heat be collected to activate the sprinkler is not the intent of the requirement. Think of a sprinkler under a duct over 4' wide. Heat may not collect too well here either. The intent of such sprinklers is so that combustible material that may be on fire below the obstruction would be blocked from getting water from the ceiling sprinklers. Likely there would be a delay in the activation of obstruction sprinklers but they may end up saving the building in the end. The is rule has been in NFPA 13 for a long time.

R M Arsenault Engineering Inc.

http://www.rmae.ca

 

[rmae]

Note you would be required to install sprinklers below the stair treads as well, not just the landings if the stair is over 4' wide.

R M Arsenault Engineering Inc.

http://www.rmae.ca

 

[chicopee]

Are there any exceptions for sprinkler protection under open stairs over 4' wide in the NFPA 13?

 

[cdafd]

8.15.3 Stairways.

8.15.3.1 Combustible Construction. Sprinklers shall be installed beneath all stairways of combustible construction.


8.15.3.1.1 Sprinklers shall be installed at the top of combustible stair shafts.


8.15.3.1.2* Sprinklers shall be installed under the landings at each floor level.


A.8.15.3.1.2 Sprinklers at each floor level landing should be positioned to protect both the floor level landing and any intermediate landing.


8.15.3.1.3 Sprinklers shall be installed beneath the lowest intermediate landing.

The requirement for sprinklers to be installed under “all stairways” needs to be clarified. In stairs with both floor landings and intermediate floor landings, the interpretation has been that the sprinklers need to be installed under both, but that would be overkill. The committee believes the original intent of this section was to provide protection at the floor landings.
Finally, clarification was needed in protecting exterior combustible stairs, so additional language was added for requirements on the location of sprinklers at the floor landings. Combustible stair shafts must be entirely protected irrespective of storage capability or exterior location.





8.15.3.2 Noncombustible Construction.

8.15.3.2.1 In noncombustible stair shafts having noncombustible stairs with noncombustible or limited-combustible finishes, sprinklers shall be installed at the top of the shaft and under the first accessible landing above the bottom of the shaft.

FAQ Why are sprinklers required in noncombustible stair shafts at the top of the shaft and under the first landing above the bottom of the shaft?
The storage of materials in stairwells obstructs the egress route and is prohibited by NFPA 101. However, if there is an open space under the first landing or a large landing at the top of the stairs it is often an irresistible location for transient storage. As a result, 8.15.3.2.1 requires sprinklers at these locations.




8.15.3.2.2 Where noncombustible stair shafts are divided by walls or doors, sprinklers shall be provided on each side of the separation.


8.15.3.2.3 Sprinklers shall be installed beneath landings or stairways where the area beneath is used for storage.


8.15.3.2.3.1 Sprinklers shall be permitted to be omitted from the bottom of the stairwell when the space under the stairs at the bottom is blocked off so that storage cannot occur.

The concept of eliminating the sprinkler at the bottom of the stairs has always been implied by NFPA 13, but the statement was never made explicitly in the text. Where the egress path is the only available space in the stairwell, sprinklers should not be necessary. This makes it very clear that when the area beneath the bottom landing is blocked off, sprinklers are not required in the bottom of the stairwell. In the past, many authorities having jurisdiction still required sprinklers to be provided under the 2nd floor main landing even when the space at the bottom was blocked off.





8.15.3.2.4 Sprinklers shall be permitted to be omitted from exterior stair towers when the exterior walls of the stair tower are at least 50 percent open and when the stair tower is entirely of noncombustible construction.

 

[cdafd]

FAQ Why are sprinklers required in noncombustible stair shafts at the top of the shaft and under the first landing above the bottom of the shaft?
The storage of materials in stairwells obstructs the egress route and is prohibited by NFPA 101. However, if there is an open space under the first landing or a large landing at the top of the stairs it is often an irresistible location for transient storage. As a result, 8.15.3.2.1 requires sprinklers at these locations.

 

[fireguy519345]

And if heads are installed 7' 6" or less from the floor, head guards are required. Right?

 

[MatthewJWillis]

I love a number attached to the head guard requirement.
There is NO number. Please stop propagating it. Where the sprinkler is subject to mechanical damage, one is required.
The stairs requirements have been further clarified in the 2013 edition. The handbook is invaluable.

R/
Matt