lights in residential

[cdafd]

So in NFPA 13R
There is mention of distance of a Pendent head from a light

6.4.6.3.4.1 Pendent sprinklers shall be located at least 3 ft (914 mm) from obstructions such as ceiling fans and light fixtures unless the requirements of 6.4.6.3.6 are met.

But it is not in the residential section of NFPA 13 8.10 2013 edition, But it does have the same wording for fans as in 13 R.


any thoughts, or just go with the obtsruction rules in the residential section?

 

[SprinklerDesigner2]

Stay far away from any and all lights.

Pretty restrictive.

 

[TravisMack]

NFPA 13 does not have the same wording about fans. It says you don't need to consider the fan blades if more than 50% open. But, it doesn't give that 3' dimension text.

If the surface mounted light were protected down, it would be a column. So, you could in theory use the 3x rule for surface mounted lights. You either get 4x the distance away, or 36". I try to comply with the beam rule for surface mounted lights, but can easily make an argument for being 3' away from the near side of the surface mounted light.

Similar goes for the fan motor, which is your obstruction to deal with. You need to be 4x away from the edge of the motor, or 3' maximum. Basically, get 3' from the edge of the fan motor housing and you are good.

If you happen to be using standard spray sprinklers, then the fan motor housing does not need to be considered, as it is not a structural member, and you only consider structural members in light and ordinary hazard spaces when using standard spray sprinklers and applying the 3x rule.

Travis Mack
MFP Design, LLC

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[chicopee]

I am not sure if your concern is with the temperature rating of the sprinkler heads near lights or with the obstruction presented by the lights. I believe that the NFPA 13 is concerned with obstruction. If the issue presented by NFPA 13 is with temperature and NFPA13R is moot on this point then consult with the fire marshal or the local fire department. If "Stay far away from any and all lights" is impractical and temperature is the issue, then, you think about higher temperature rated sprinkler heads, nonetheless, consultation with the fire department is a must.

 

[cdafd]

Sorry

Obstruction is the question

In Nfpa 13 R it is addressed specifically

6.4.6.3.4.1 Pendent sprinklers shall be located at least 3 ft (914 mm) from obstructions such as ceiling fans and light fixtures unless the requirements of 6.4.6.3.6 are met.

In NFPA 13 in the residential section there is no wording about lights.

I threw in the fan wording because the exact wording is in both 13 and 13 R, and was just wording that was but in, but not the three feet for the lights???[pre][tt][/tt][/pre]

 

[MatthewJWillis]

Running this thru my little brain..., I am wondering if the difference is due to the expectations of the system. 13R- Get out. 13- Protect life, then building. 13 has many differences relating to obstructions, amount of water..., etc. Considerations of what blocks or affect distribution and testing is different. I think the obstruction rules are they to address the lights in 13. 13R just spells out lights and fans because the spacing usually places all 3 (lights, sprinklers, and fans) in the center of the living room. Many throw out the "Structural Only" consideration, but I would be very careful with that. As the "soon to be" FPE stated, the beam rule should be applied as well. Remember, 13 has that pretty "Performance Objective" picture firmly placed in the beginning of chapter 8.

 

[TravisMack]

Yeah. I think the beam rule is practical. That is what I try to comply with initially. However, if it is a large apt complex and going to be a difference in several hundred sprinklers, then I start to think: "How is a light different than a column in a projection view?" If there was a 12" diameter column, you would just be 36" away from the side. So, why is the requirement more stringent for a surface mounted light?

Again, apply the beam rule if possible, but if it gets to be quite onerous, we may be able to use something else.

Also, that "structural members only" exception is in the section for SSU/SSP only. It does not apply to Ex Cov or Residential sprinklers. I have seen that applied incorrectly on more than a handful of jobs.

Travis Mack
MFP Design, LLC

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[cdafd]

Thanks all

Just do not know why they just did not copy the three foot rule over to 13 from 13R and make life a little easier [pre][/pre]

 

[TravisMack]

I think it as Matt pointed out. There are much different intents for 13 and 13R. If everyone gets out of the building and it burns down, the 13R system was a success. If everyone gets out and the building burns in a 13 system, it is still a failure.

Travis Mack
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[chicopee]

"...success. If everyone gets out and the building burns in a 13 system, it is still a failure." I would say partial failure,after all what's more important?

 

[TravisMack]

Not quite what I meant, but I see your point.

I was implying that NFPA 13 is about property protection in addition to life safety. I was just trying to point out that many people get the systems confused and think that NFPA 13R is about property protection, when it is not.

Travis Mack
MFP Design, LLC

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