Water Curtain for fire separation of open kitchen and dining area

[bragase]

We have a small restaurant project where we are designing a water curtain for fire separation of open kitchen and dining area. The building is not required to be fully sprinklered.

Regarding the hydraulic calculations for the water curtain, I will mention the applicable code sections:

NFPA13-2007: 11.2.3 Water Demand Requirements - Hydraulic Calculation Methods.
11.2.3.1.1 The water supply for sprinklers shall be determined only from one of the following:
(1) Density/area curves of Figure 11.2.3.1.1 in accordance with the method of 11.2.3.2
(2) On the basis of the room design method in accordance with 11.2.3.3
(3) Special design areas in accordance with 11.2.3.4, at the discretion of the designer

NFPA13-2007: 11.3 Special Design Approaches.
NFPA13-2007: 11.3.3 Water Curtains.
11.3.3.1 Sprinklers in a water curtain such as described in 8.15.4 or 8.15.16.2 shall be hydraulically designed to provide a discharge of 3 gpm per lineal foot (37 L/min per lineal meter) of water curtain, with no sprinklers discharging less than 15 gpm (56.8 L/min) .
11.3.3.2 For water curtains employing automatic sprinklers, the number of sprinklers calculated in this water curtain shall be the number in the length corresponding to the length parallel to the branch lines in the area determined by 22.4.4.1.1.
11.3.3.3 If a single fire can be expected to operate sprinklers within the water curtain and within the design area of a hydraulically calculated system, the water supply to the water curtain shall be added to the water demand of the hydraulic calculations and shall be balanced to the calculated area demand.
11.3.3.4 Hydraulic design calculations shall include a design area selected to include ceiling sprinklers adjacent to the water curtain.

If I perform the hydraulic calculation per density/area method the existing water supply system will not be capable of meeting the demand. However, I believe I am going to the wrong direction since this is only a water curtain system, and I think the density and area of sprinkler operation from FIGURE 11.2.3.1.1 is not applicable.

What do you guys think?

Thank you.

 

[cdafd]

Is this in the USA??

Has the ahj approved the use of a water curtain?

 

[bragase]

This project is in New York City.

The NYC DOB has approved the use of water curtain for this project based on the 1968 NYC Building Code section §27-339 Fire segregation of occupancies.

Nonresidential kitchens need not be separated by fire separations from adjoining dining spaces, provided:
[ol 1]
[li]The cooking equipment is vented directly to the outdoors, and[/li]
[li]Draft curtain of noncombustible material, at least twenty-four inches down from the ceiling, is provided to separate the cooking facilities from dining spaces, and[/li]
[li]Sprinkler heads constructed in accordance with the provisions of subchapter seventeen of this chapter, are provided on the cooking facilities side of the curtain, or any opening between the kitchen and dining space, located within twenty-four inches of the curtain or opening, and spaced not more than forty-eight inches on centers if the opening is more than sixty inches wide. When fire separations are provided double-action doors may be permitted.[/li]
[/ol]

Edit: I mentioned the 2014 NYC BC section in my previews answer. However, the applicable BC for this specific project is the 1968 NYC BC, which is quoted above.

 

[cdafd]

OK when I think of water curtain, I think deluge.

this sounds like more like similar to large opening protection for say an escalator.

""""" located within twenty-four inches of the curtain or opening, and spaced not more than forty-eight inches on centers if the opening is more than sixty inches wide""""

""provisions of subchapter seventeen of this chapter""" does not seem to say much???


Does the city this is in have a fire sprinkler plan reviewer or FPE you can ask the question to??

 

[bragase]

subchapter seventeen of this building code doesn't say anything applicable to water curtains, it just redirects me to NFPA 13.

So basically, I will design this water curtain based on the requirements of the NFPA 13.

I am trying to make my case before I submit this project for plan examiner review.

 

[cdafd]

Sorry not near the books

Read this to see if it helps any.

You are using closed heads??

https://www.meyerfire.com/daily/water-curtain-in-addition-to-remote-area

 

[cdafd]

One more

https://www.eng-tips.com/viewthread.cfm?qid=455518

 

[cdafd]

Not a designer or engineer

Appears you have the correct hydraulics, to use, in your original post

 

[UFT12]

What your building code says does not look like a typical open-head deluge system as meant by 11.3.3 of NFPA 13-2007. Like cdafd said, it seems like you need to provide sprinklers with a shorter spacing near the curtain. So double check if you really need to design a deluge system or not because it will seriously have complications on water hydraulics and adequacy of supply as well as increased chances of water damage.

 

[cdafd]

Sounds like closed sprinklers spaced per NY.

Just have not heard something like referred to as a “”” Water curtain. “”””

 

[TravisMack]

This is very commonly called a water curtain in many areas. I would choose the calculated area such that it includes the water curtain sprinklers. You will need to calc them at 18 gpm (3 gpm per lineal foot).

Many use this idea for the wrong application. It was only meant for atriums and large floor openings like escalators and such. But, many use it for occupancy separation.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, a Ferguson Enterprise

http://www.mfpdesign.com