Roll Tissue 1

[mx272]

Existing 32' warehouse with sprinklers and they want to store roll tissue to 20'in half of the building. Insurance company is making them put a false noncombustible ceiling in at 25'. Will provide new system for below. Existing system above the ceiling to be removed due to weight concerns. If the ceiling to roof deck is open on one end would you need to sprinlker above false ceiling? If so, how far? Where is this written?

Thanks

 

[stookeyfpe]

What's the building's construction type?

 

[mx272]

all noncombustible

 

[firepe]

So, if the space above is not enclosed, then it is not a concealed space, and would not qualify for omission of sprinklers.

It is not a matter of providing some sprinklers at the perimeter, such as the "locallizing" provisions for combustible construction in otherwise non-combustible concealed spaces. This would actually NOT be a concealed space.

I recommend they button it up, or leave the existing sprinkler protection above in place.

 

[mx272]

Good answer but what is going to burn?

 

[firepe]

Ok, I'll bite.

Asking what's going to burn is a cop-out. Are you going to comply with the NFPA 13 standard or not? I don't see where you get to pick and choose, unless you plan to make some sort of engineering judgement and an equivalency claim.

NFPA 13, 2007 edition, Section 8.1.1 states "The requirements for spacing, location, and position of sprinklers shall be based on the following principles:

1. Sprinklers shall be installed throughout the premises

4. Sprinklers shall be permitted to be omitted from areas specifically allowed by this standard.

Based on the situation you described, the sprinklers at the original elevation are required, unless you can cite an exception. And since what you have described does not constitute a concealed space, the new lower "false ceiling" is an obstruction to the existing overhead sprinklers requiring additional protection below the obstruction.

By not providing the protection for the area above, you would be allowing for a potential fire at the threshold of the two levels to spread unchecked to the unprotected area above the new lower ceiling, perhaps eventually leading to structural damage and/or collapse due to the increasing heat build-up without sprinkers to hold it in check.

I'd love to entertain any alternate interpretations.

 

[cdafd]

Good answer but what is going to burn?

there is the idea if there is an opening and no protection above it.

the fire and heat can spread up there, by pass the heads below, and possibly not activate the sprinkler heads.

you can look at openings allowed such as air returns, light fixtures, do not have copy of 13 in front of me to site the section

 

[FFP1]

FM Global Data Sheets indicate the following for Rolled Paper Storage (including tissue paper):

"2.2.2 False Ceilings
2.2.2.1 When a false ceiling is constructed ensure that proper clearance is achieved (see Section 2.3.2.7,
Excessive Clearance). Install sprinklers below the false ceiling designed in accordance with the recommendations
in this data sheet. Install additional sprinklers at roof level, within the concealed space, when the
roof or false ceiling consists of combustible construction or there are combustibles within the space. Water demands from sprinklers at roof level, within the concealed space do not need to be available simultaneously
with the water demands from sprinklers below the false ceiling.
2.2.2.2 Construct false ceilings, capable of withstanding temperatures above 1000°F (540°C) for up to
10 minutes and uplift velocity pressures of at least 3 lb/ft2 (0.14 kPa). Materials suitable for such a purpose
include 3?8 in. (0.95 cm) plywood, 3?8 in. (0.95 cm) gypsum board, corrugated or sheet steel, or mineral tile.
Sheets of these materials can be mechanically fastened to the underside of existing framework, or supported
on framework from above or below."

Important Note........this text specifically refers to concealed spaces. Also, remember that Class II steel deck roof systems, which are common at rolled paper storage facilities, are considered combustible construction.


FM Global Data Sheets also indicate the following for the storage of Non-woven material (similar commodity, but not exactly the same fire hazard as tissue paper):

"2.1.3 False Ceilings
2.1.3.1 If necessary to achieve appropriate clearance over the top of the storage, a false ceiling should be
installed over the storage with sprinklers installed below the ceiling. Sprinkler protection should be provided
at roof level if the roof or ceiling is combustible. False ceilings should be of substantial construction, capable
of withstanding temperatures above 1000°F (538°C) for up to 10 minutes and uplift velocity pressures of
at least 3 lb/ft2 (0.14 kPa). Materials suitable for such a purpose include 3?8 in. (9.5 cm) plywood, 3?8 in. (9.5 cm)
gypsum board, corrugated or sheet steel, or mineral tile. Sheets of these materials can be mechanically fastened
to the underside of existing framework or supported on framework from above or below. If the false
ceiling is hung from existing roof framework, it should be verified that the roof framework can support the ceiling
and additional automatic sprinkler piping.
2.1.3.2 If the false ceiling is partial, it should extend at least 10 ft (3 m) beyond any storage and with a row
of sprinklers 2 to 3 ft (0.6 to 1 m) inside the edge (storage side of edge) of the false ceiling."

VERY similar requirements with a little extra detail for instances where the false ceiling does not create a concealed space.

In most instances, you will have sprinkler protection above and below these false ceilings; however, there are some situations which do not warrant sprinkler protection for the space above these false ceilings. One could make a strong case that the sprinkler protection above these ceilings could potentially be detrimental during a severe high hazard fire incident (assuming the space is completely noncombustible or has a very limited amount of combustible loading above the false ceiling). A high heat release fire or a fire incident which lasts for several hours would eventually open the sprinkler heads above the false ceiling.....this would reduce the water volume and pressure available for the sprinklers directly above the burning material and the fire fighters. When dealing with tissue paper and non-woven material, you would typically expect a fast burning fire incident with very intense heat release. If the fire burns for several hours as I stated above, the sprinkler system has probably been overtaxed anyway.

The best approach is to make sure the false ceiling is a totally eclosed concealed space (if possible) and install sprinklers below the false ceiling which provide adequate fire protection of the storage below the false ceiling. Then protect the concealed space if required based on NFPA while using the FM Global guidelines listed above as a solid "additional reference". If you cannot create a concealed space, I would suggest solid noncoumbustible draft curtains along the exterior edges of the false ceiling.

It requires a lot of thought/research, but one can make a solid case that NFPA 13 does not require sprinkler protection in areas which benefit from noncombustible construction, have no combustible loading and no chance of combustible storage and/or accumulation of dust/other combustible materials. FM Global standards also in my opinion.

This feels like I am giving free FPE consulting with no liability issues.......I hope this information (along with my personal OPINIONS are viewed by everyone as helpful).

 

[firepe]

cdafd, FFP1,

Good information, but sorry, not trying to split hairs, or pick nits, NFPA 13 is very clear, this particular example as described, is NOT a concealed space if it is open on one side. Since it is not a concealed space that would qualify for omission of sprinklers, then the sprinklers at the original deck must stay.

I would also liken this described scenario to that of a mezzanine, since it is open on one side. Do we omit sprinklers at the ceiling/deck above mezzanines??

But since I did not bring my standard home with me for bedtime reading I will have to limit myself to these analogies, and standard excerpts that I have already quoted.

 

[stookeyfpe]

Coming to the defense of Firepe:

He deferred to NFPA 13. InspLCRep backed up his concerns.

Poop paper is pretty light weight material and I can see it being suspended in air and landing in some area where no one cleans it out, it ignites and you have a localized structural failure. I could see that occurring over the life of such a plant. Gyp board is cheap and I would seal the soffit - however, the original poster's client is playing double digit value engineering. Been their and done it.

I think FirePE has a valid concern. I also enjoy how I am again providing fire protection engineering to a mechanical engineer. Am I correct MX272?

We again are not provided enough information and are grabbing our respective design straws to be little design helpers. Sorry - pay to play or go away.

This is not an arena to solve these issues.

I'll probably get electronically yelled at.

 

[mx272]

All very good points and I do agree that per the code this space is not concealed and should be protected. Without it being closed off there are alot of "what ifs" that can be played out here. This is a forum where these types of situations are and should be discussed. That is why I wrote this and added alittle fuel to the fire by the "whats going to burn" comment. Hopefully everybody that reads this forum are more prepared for these types of situations. Thanks, I appreciate the response.

 

[cdafd]

sorry late night post above, NO agree either close it off in approved manner or leave sprinklers above.

Was trying to say that 13 does take into account light fixtures and air registers that created small openings in the ceiling.

If they are going to the trouble of taking out the old system appears a few more dollars would get them a complete ceiling

 

[FFP1]

I need to appoligize.......I read my post and realized I failed to include some very important comments. Due to my inclusion of the second to the last paragraph, the intent of my post was totally altered. I have edited several paragraphs for clarity...........

I included the following text "2.1.3.2 If the false ceiling is partial, it should extend at least 10 ft (3 m) beyond any storage and with a row of sprinklers 2 to 3 ft (0.6 to 1 m) inside the edge (storage side of edge) of the false ceiling.", but I failed to mention this instance would still require sprinkler protection above the partial false ceiling regardless of construction materials.

I also ammended the following paragraphs for clarity:

The BEST APPROACH is to make sure the false ceiling is a totally eclosed concealed space (if possible) and install sprinklers below the false ceiling which provide adequate fire protection of the storage below the false ceiling. Then protect the concealed space if required based on NFPA while using the FM Global guidelines listed above as a solid "additional reference". If you cannot create a concealed space, I would suggest solid noncombustible draft curtains along the exterior edges of the false ceiling AND protect the space above. The draft curtains would trap the heat and delay the activation of sprinklers above the false ceiling (resulting in more water for a longer duration applied dircectly to the storage area fire). The only acceptable instance where sprinkler protection is allowed to be omitted above the false ceiling is if the false ceiling is properly separated from the storage area as outlined above or by a minumum 1 hour fire rated wall as outlined in NFPA 13. If the required fire separation is provided (creating a concealed space) and the space is completely noncombustible, sprinkler protection could be omitted.

It requires a lot of thought/research, but one can make a solid case that NFPA 13 does not require sprinkler protection in areas which benefit from noncombustible construction, have no combustible loading and no chance of combustible storage and/or accumulation of flammable liquids, combustible dust or other combustible materials (as long as the area in question is separated by adequately designed fire rated walls/ceilings). FM Global standards also in my opinion. This is topic which would require a significant amount of thought and discussion prior to the omission of sprinklers......I truly wish I had not included this paragraph in my previous post.


My original intent was to provide the FM Global excerpts and chime in with my draft curtain approach to improve the overall effectiveness of the sprinkler system below the false ceiling. I sincerely apoligize for any confusion or misleading statements.

 

[cdafd]

FFP1

I sure wish we had paypal set up to ket our 2 cents back for some of the ideas we come up with


Taking your approach, they could

1. where the ceiling ends, go straight up from that point to the deck, with some type of material approved by ahj that would seal off the space above the ceiling, and you would still need and have sprinkler protection from where the ceiling ends through the rest of the building.

this would shut off the spread of fire and smoke, and still have ceiling to activate the heads.