Type I-B, E Occupancy Space Above Ceiling Grid (no sprinklers)

[Glennman CBO]

I'm getting from a sprinkler designer that section 8.15.1.2.2 in NFPA 13 that states that "Concealed spaces of noncombustible and limited-combustible construction with limited access and not permitting occupancy or storage of combustibles shall not require sprinkler protection. The space shall be considered a concealed space even with small openings such as those used as return air for a plenum" is referring to the spaces above the ceiling grid where there is 6 to 10 ft above the grid to the ceiling.

I take those spaces to be small areas that are cut off by walls, etc. In this case, the rooms are being divided horizontally by the drop in ceiling.

Am I looking at this correctly? Thanks all in advance.

 

[cda]

In no combustibles up there or no combustible construction

Sprinklers are not required

Does not matter how big the void space is , per nfpa dividing the space is not required

Question answered ?

 

[Glennman CBO]

No combustible construction, and no combustibles up there.

Thanks cda.

 

[Glennman CBO]

In rethinking my post and the reference in NFPA, if it states that even small openings such as with return air ducts, if those "small openings" are what is considered as limited access, then what about the hundreds of square feet of panels that can simply be pushed up?

I suppose a fire would not reach these areas if it will always be started under the ceiling, and subsequently extinguished, where the building combustible contents are going to be contained under the ceiling as well.

 

[cda]

Yea something like that

Hopefully the fire is confined, and another reason I think on limited openings is to keep the heat where the sprinkler heads are, so they will activate without delay

No way to have a solid ceiling

 

[tmurray]

What version NFPA 13? 2007 specifically calls out ceilings suspended from wood joist or trusses do not have to have sprinklers installed in the gaps in the installed insulation when sprinklers are installed within the joists above the insulation. Also, facing, substrate and support of insulation does not exceed 1000 Btu/ft^2 heat content.

 

[tmurray]

In rethinking my post and the reference in NFPA, if it states that even small openings such as with return air ducts, if those "small openings" are what is considered as limited access, then what about the hundreds of square feet of panels that can simply be pushed up?I suppose a fire would not reach these areas if it will always be started under the ceiling, and subsequently extinguished, where the building combustible contents are going to be contained under the ceiling as well.

No, your original feelings are correct. There are specific details in NFPA 13 showing how sprinklers must be installed above finished ceilings. The only exception I know of includes a ceiling that has one set of joists super-imposed over another set (given certain distances are met).

 

[cda]

No, your original feelings are correct. There are specific details in NFPA 13 showing how sprinklers must be installed above finished ceilings. The only exception I know of includes a ceiling that has one set of joists super-imposed over another set (given certain distances are met).

He is dealing with

Non combustible in the void

And

Non combustible construction

So nothing to burn above the ceiling

 

[cda]

8.15.1.2.1* Concealed spaces of noncombustible and limited-combustible construction with minimal combustible loading having no access shall not require sprinkler protection.

A.8.15.1.2.1 Minor quantities of combustible materials such as but not limited to: cabling, nonmetallic plumbing piping, non-structural wood, etc. can be present in concealed spaces constructed of limited or noncombustible materials but should not typically be viewed as requiring sprinklers (see 8.15.1.1). For example, it is not the intent of this section to require sprinklers, which would not otherwise be required, in the interstitial space of a typical office building solely due to the presence of the usual amount of cabling within the space. The threshold value at which sprinklers become necessary in the concealed space is not defined.

8.15.1.2.1.1 The space shall be considered a concealed space even with small openings such as those used as return air for a plenum.

The presence of openings in the ceiling, such as those for return air for a plenum, does not result in a perfunctory requirement for sprinklers in the concealed space. Evaluation of the size and number of openings in relation to the overall area of the ceiling is important.

 

[tmurray]

8.15.1.2.1* Concealed spaces of noncombustible and limited-combustible construction with minimal combustible loading having no access shall not require sprinkler protection.A.8.15.1.2.1 Minor quantities of combustible materials such as but not limited to: cabling, nonmetallic plumbing piping, non-structural wood, etc. can be present in concealed spaces constructed of limited or noncombustible materials but should not typically be viewed as requiring sprinklers (see 8.15.1.1). For example, it is not the intent of this section to require sprinklers, which would not otherwise be required, in the interstitial space of a typical office building solely due to the presence of the usual amount of cabling within the space. The threshold value at which sprinklers become necessary in the concealed space is not defined.

8.15.1.2.1.1 The space shall be considered a concealed space even with small openings such as those used as return air for a plenum.

The presence of openings in the ceiling, such as those for return air for a plenum, does not result in a perfunctory requirement for sprinklers in the concealed space. Evaluation of the size and number of openings in relation to the overall area of the ceiling is important.

I always thought that this section referred to the space contained within the duct, but on reading the appendix it would appear you are correct.

 

[Coug Dad]

The section is attempting to codify those ceilings commonly referred to as "clouds". Where the ceiling is not continuous. The noncombustible space above a continuous ceiling does not require sprinkler protection even if there are minor openings, such as for HVAC. The noncombustible space above a cloud ceiling does require sprinklers.

 

[Glennman CBO]

Is it assumed then that your typical accoustical drop in ceiling is suitable to keep heat down to its level so that the sprinklers will activate?

 

[cda]

Yeppers...