IBC Table 503 (again)

[SprinklerDesigner2]

Seems to me we've beat this horse to death several times already but I'm bidding this project and I am curious to know if I am correct.

http://img25.imageshack.us/img25/3465/13or13r.jpg

Based on Table 503 am I correct in believing the entire building must be sprinkled in accordance with NFPA #13 and not 13R as called for?

It is not my responsibility to make this determination. I am not an architect or professional engineer I am a layout technician and as such I strongly believe making this sort of determination is outside of my responsibility or pay scale.

Accordingly I will bid per 13R and if it changes along the line there will be a change order.

But am I right?

 

[TravisMack]

R2 and IIIB gives you 4 stories and 14k sq ft per floor. Did they do anything with the frontage allowance to increase the floor area? If it is being increased solely on the sprinkler allowance, then, you appear to be correct and it should be a 13 system.

I usually send the architect a request on this to clarify the issue.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[TravisMack]

I re-read the scanned image a bit better. It looks like he is specifically taking the area increase due to sprinklers. It is my understanding that if you do that, you need a full 13 system.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[SprinklerDesigner2]

" It is my understanding that if you do that, you need a full 13 system."

Mine as well. It appears you can take the height allowance with a 13R system but not the area increase.

 

[SprinklerDesigner2]

While we are beating this dead horse again....

506.3 points to 903.3.1.1 "Where the provisions of this code require that a building or portion....sprinklers shall be installed throughout in accordance with NFPA 13 except as provided in Section."

Following is 903.3.1.1.1 which lists exempt locations and then we come to 903.3.1.2 "NFPA 13R sprinkler systems. Where allowed in buildings of Group R, up to and including four stories in height, automatic sprinkler systems shall be installed throughout in accordance with NFPA 13R."

This is where I have problems understanding.

It appears to me that if the area increase for sprinklers is taken you may install the system per 13 but only where allowed, Group R, in buildings four stories or less.

506.3 is very clear 13 systems must be used "except as provided in Section." and isn't 903.3.1.2 in the section and therefore an exception to a 13 system?

 

[stookeyfpe]

The architect has applied IBC Section 506.3 and taken the 300% area increase provision. The automatic sprinkler system must comply with Section 903.3.1.1, including NFPA 13.

Since we're hammering the proverbial dead pony, let me clarify the proper application of IBC Section 506.3 and 903.3.1.2.

IBC Section 506.3 allow the area of most occupancies to be increased by 300% when the building is protected by a NFPA 13 compliant sprinkler system. What 903.3.1.2 is saying is that when a NFPA 13R system is installed, only the increases and reductions specifically allowed for by the IBC can be applied with a life safety sprinkler system is installed. Travis is correct in that you can use a NFPA 13R system for a height increase of one-story. However, area increases are not allowed by the IBC for NFPA 13R designs. In such cases your sprinkler system must comply with NFPA 13.

Note that nothing in the IBC or IFC prevents the design professional from using the residential design provisions in NFPA 13. So if you want to design the system using a 4 sprinkler calculation, its permitted so long as the system complies with all of the other NFPA 13 requirements.

Horse tar-tar anyone?

 

[SprinklerDesigner2]

Thank you, Stookey.

I'll take a double heaping helping.

 

[pipesnpumps]

Excuse me for hi-jacking your thread SD2, but what cost differences would there be if the apartments consists of all dwelling units? Residential heads vs QR light hazard heads is one I can think of..

What other design or cost impacts are there in going with 13 vs 13R? I suppose I could do a rigorous search, but I'm not familiar with the differences, and thought you could quickly sum it up.. I may run into this issue some.

 

[SprinklerDesigner2]

No problem with the hijacking I think I am done beating this horse until next year.

On a typical building I am looking at, with dry system in the attic etc, the dollar difference can easily be $50,000 for 13R and $140,000 for 13.

Attic sprinklers (dry system in most locations in the country).

Upright sprinklers in interstitial space between floors if open web wood joists are used.

Sprinklers at bottom of elevator shaft W/possible shunt trip in certain locations.

Sprinklers in portico-cosheres (I can never spell that right without looking it up) if combustible construction and attached.

55 static, 50 residual flowing 890 gpm will give a decent 13R system about anywhere but if the attic is any size at all you're gonna have a huge problem with the dry system that's on the third or fourth floor.

 

[TravisMack]

You can use residential sprinklers in the dwelling units and adjoining corridors and do a 4 head calc provided that you meet the requirements in 13 to allow it - nothing driving you to a 3000 sq ft design area.

In an apt building, you will need to protect the closets, where it can be excluded in 13R provided they meet the size requirements.

As SD2 stated, the biggest cost will be in the attic and possible interstitial space. Also, I believe if you protect the spaces between floors, you will likely have to use the specially listed concealed space sprinklers. These are about 2x the cost of SSU sprinklers.

I am sure there are many other things as well. Just too tired to think of all of them

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[stookeyfpe]

The reverse side of SD2 and Travis's information is the amount of money it saves the building developer. If the building is provided with automatic sprinkler protection complying with NFPA 13 (rather than 13R), the design professional can:

-- Create an unlimited area building, regardless of construction type
-- Receive a reduction for interior finish
-- Increase the common path of travel for means of egress to 125 feet (this equals longer corridors and increased egress path travel distances)
-- Increased travel distances for dead end exits
-- A single means of egress door in any apartment or hotel sleeping unit
-- Increased length of FD apparatus access roads
-- Increase fire hydrant spacing
-- Elimination of incidental accessory use rooms fire resistive separation (e.g., elevator machine rooms, trash rooms)
-- Area of any openings in fire walls
-- Elimination of fire dampers in sheet metal ducts of HVAC systems
-- Draft stops are completely eliminated.
-- Elimination of handicapped accessible elevators

The list is very extensive and the costs cited by SD2 and Travis more than offset all of the concessions I cited to the building owner. An owner makes money faster in a Group R-1 or R-2 occupancy with a properly protected building.

I sincerely hope these systems are maintained because if a fire occurs and the sprinklers fail, it could be a bad day for the occupants.

Conversely, the fire loss history in sprinklered buildings substantiates these credits. I support these credits provided the fire protection systems are adequately maintained.

It all goes back to SD2s original question: 13 or 13R? I'm glad SD2 asked. It's a very important question when one is interpreting the International Building Code and considering the design of the automatic sprinkler system.