floor ceiling exceptions NFPA 13 1

[viperman]

construction is weeks from completion on a three story group I assisted living building being constructed under NFPA 13. The architectural plan called for the truss cavity to be filled with insulation, thus allowing an exception for the space to be sprinklered. Aparently there was also a note and cut diagram showing that the insulation was to be filled to a level which allowed a maximum 6" space between the top of insulation and the botttom of the floor. After recently being questioned about this, the GC did several tests and confirmed that an average of aproxomately 3-4" air space was left between the insulation and the bottom of floor. So, the question is now what? A fix could be hundreds of thousnad of dollars and this just doesnt seem practical ofr filling a 3-4" gap. this building is weeks from oopening and the inspector is looking for the owner to provide a reason or explanation as to how this is NFPA approved. The architect apparently had the detail on the plan, because this was allowed on another similar building he designed. Perhaps he felt the intent was to reduce the air gap to less than 160cubic sq ft, because I think there is some exceptions for that. I am also wondering if there would be something to do with the spread rate being reduced with that minimum of a gap, perhaps theres something in the code with that? my buddy is on a witch hunt right now, because he is the PM for the GC and thinks he could lose his job over this if theres not a good resolution. not my area so Im not sure what to tell him. any suggests on a reasonable "economical" solution?

 

[cdafd]

Do not have 13 nearby

Not clear on the problem

Architect designed so it met 13???

Somebody bid the job off the design so it met 13??

If the answer to the two questions is yes,

Then whoever bid the job needs to correct it to meet 13

 

[SprinklerDesigner2]

If I read the question correctly what a mess.

I assume the joists are open web and not composite joists.

If the insulation is blown in you'll never entirely fill the void and just because the architects drawings show it so doesn't mean the insulation won't settle over time.

From 2002

8.14.1.2.7 Concealed spaces entirely filled with noncombustible insulation shall not require sprinkler protection.

I guess it depends on what the word "entirely" means. Is to within 1/2" of the floor above considered "entirely"?

Unless it was a dry system I bet they spent more money on insulation getting away from sprinklers than if they just bit the bullet spending the few thousand to put them in.

What if you can get someone competent (as in FPE) to certify the space is under certain flame spreads or whatever. Probably won't find one but I don't know what else but grasp at straws at this point.

 

[cdafd]

Some bid the insulation to meet 13, so install as bid

 

[SprinklerDesigner2]

cdafd,

The longer I sit here thinking of the problem the madder I am getting.

Whose fault? It's the architect's and it sounds like he's the one that is most apt to skate away. Did the architect define "fill" or require some sort of compaction test? If it is blown insulation there's little doubt the experts from the blown in insulation industry couldn't be called to testify (this is going to end up in court) that voids were filled by their industry standards which is use the machine to blow in as much insulation as you can until no more goes in.

Being nearly finished I take it the insulation was blown in three, four or even six months ago and now everyone is surprised there's settling? Of course it is going to settle and every one of us who has ever blown insulation into our attic to cut heating costs can tell the architect that.

The more I think about it the space probably was completely full the day they blew the insulation in.

Someone (architect) thought he was going to be smarty pants using a "trick" to avoid sprinklers and now everyone but the architect is going to get burned.

But the architect didn't dream this up himself some so called layout technician passed this makings of a nightmare on to the architect who bought it hook, line and sinker.

Tell you what, take a 2'x2'x2' cardboard box, fill it to the top with blown in insulation then came back next month and see how many inches it settled.

If the architect really wanted to be sure why didn't he use fire treated lumber?

When you think about it someone used the standard on how to install sprinklers get get out of having to install sprinklers. In my opinion this was not the intent.

//RANT OFF (sorry)

 

[cdafd]

Codes/ standards have always been used to get out of code requirements

That is why you find a building one sq ft less then the size required fir sprinklers

 

[viperman]

The bottom line after looking into this more today, there is plenty of blame to go around. First the architect put a diagram and notation on the plan that does not meet code. that diagram calls for a minimum of 18" of insulation within a 24" open web wood floor truss, thus leaving the potential of a 6" gap. The architect also had a diagram showing no insulation on another sheet, and a UL assembly that also conflicted with both of his diagrams. So, my buddy figured lets be safe and have the insulator use the most stingent diagram "18" of blown" and lets be safe and blow it 20". Obviously there are some areas with 20", some with 22", some with 18" as it is impossible to blow perfectly to one height, since blowing from the bottom. this could have been caught durning the bidding process, the review process, the plan review, caught by the local inspectors during construction, etc, etc, etc. The problem now is that the building is done and it doesn't meet code.... In terms of settling, I was told that it was blown in blanket insulation which apparently has zero settlement qualities. Had they used typical loose attic insulation, there definately would have been settlement. i'm thinking that 20" of non settlment material should meet the same intent as 24" loose material that will settle 4"..... Thoughts?

 

[cdafd]

Who caught this???

 

[pipesnpumps]

I would have caught it during the plans review. In fact I have caught alot of these type issues including combustible overhands left unsprinklered, etc.. And the fire code I use requires a multi-disciplined FPE to be a part of the design team.

This kind of thing happens all the time.. Bottom line either the Arch or the Mechanical Engineer (who did the sprinkler plans) will have to pay up against their Errors and Omissions insurance...

Unless you can somehow go back and separate out into fireblocked areas (with a solid composite joist being able to count as fireblocking) then it needs to be sprinklered. But you said "truss" which sounds like open truss..

Going to be really really hard to fireblock that. Lots and lots of gyp board and spackle where fireblocking is perpendicular to the trusses. Only solution is to reinstall the insulation somehow. $$. Are sprinklers even possible/viable in the space?





Real world knowledge doesn't fall out of the sky on a parachute, but rather is gained in small increments during moments of panic or curiosity.

 

[MaInspector]

If I understand your problem right, it’s that the space was overfilled with insulation. If that is the case, I wouldn’t be too alarmed by it, it sounds like the Arc. tried to spec. a 6” gap to use the exception for concealed spaces less than 6” not to be protected by sprinkler coverage. A 4” air gap should be plenty for air flow, and the insulation will settle over time. You should speak to the manufacture about this.

 

[viperman]

MaInspector, do you know of a sprinkler exception that falls in concealed areas less then 6"? if so, do you know what part of the NFPA code book i could find it?

 

[SprinklerDesigner2]

If it is open wood truss construction I don't think it will help.

8.14 Special Situations.
8.14.1 Concealed Spaces.
8.14.1.1 Concealed Spaces Requiring Sprinkler Protection. All concealed spaces enclosed wholly or partly by exposed combustible construction shall be protected by sprinklers except in concealed spaces where sprinklers are not required to be installed by 8.14.1.2.1 through 8.14.1.2.15.
8.14.1.2* Concealed Spaces Not Requiring Sprinkler Protection.
8.14.1.2.1 Noncombustible and limited combustible concealed spaces with no combustible loading having no access 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.
8.14.1.2.2 Noncombustible and limited combustible concealed spaces 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.
8.14.1.2.3 Concealed spaces formed by studs or joists with less than 6 in. (152 mm) between the inside or near edges of the studs or joists shall not require sprinkler protection. (See Figure 8.6.4.1.5.1.)
8.14.1.2.4 Concealed spaces formed by bar joists with less than 6 in. (152 mm) between the roof or floor deck and ceiling shall not require sprinkler protection.
8.14.1.2.5 Concealed spaces formed by ceilings attached directly to or within 6 in. (152 mm) of wood joist construction shall not require sprinkler protection.
8.14.1.2.6* Concealed spaces formed by ceilings attached to composite wood joist construction either directly or onto metal channels not exceeding 1 in. in depth, provided the joist channels are firestopped into volumes each not exceeding 160 ft3 (4.53 m3) using materials equivalent to the web construction and at least 3½ in. of batt insulation is installed at the bottom of the joist channels when the ceiling is attached utilizing metal channels, shall not require sprinkler protection.
8.14.1.2.7 Concealed spaces entirely filled with noncombustible insulation shall not require sprinkler protection.
8.14.1.2.8 Concealed spaces within wood joist construction and composite wood joist construction having noncombustible insulation filling the space from the ceiling up to the bottom edge of the joist of the roof or floor deck, provided that in composite wood joist construction the joist channels are firestopped into volumes each not exceeding 160 ft3 (4.53 m3) to the full depth of the joist with material equivalent to the web construction, shall not require sprinkler protection.

 

[MaInspector]

Are you picking up on the 6” theme?
8.14.1.2.3 Concealed spaces formed by studs or joists with less than 6 in. (152 mm) between the inside or near edges of the studs or joists shall not require sprinkler protection. (See Figure 8.6.4.1.5.1.)
8.14.1.2.4 Concealed spaces formed by bar joists with less than 6 in. (152 mm) between the roof or floor deck and ceiling shall not require sprinkler protection.
8.14.1.2.5 Concealed spaces formed by ceilings attached directly to or within 6 in. (152 mm) of wood joist construction shall not require sprinkler protection.