Use Window or Standard Sprinkler for Lot Line?

8/3/2020

Lot line window sprinkler protection: In the design drawings I have lot line window protected with standard concealed sprinklers. This same sprinkler is used to protect the whole room on the inside. Distances to all walls are less than 7'-6". The room is light hazard, and this only occurs in a single room.

Is this acceptable or should the window be protected by one sprinkler and a separate sprinkler for the room protection?

Also, is a standard pendent acceptable or would you rather have a Tyco Window Sprinkler (special application) for the window?

Thanks in advance.

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9 Comments

Wayne Ammons

8/3/2020 07:36:35 am

I am not entirely sure what a “lot line window” is but window (glazing) protection is its own beast and must be protected with sprinklers specifically listed for that application. You will need to design and install them in accordance with NFPA 13 as well as the very specific criteria outlined in the sprinkler data sheets. Collaboration with the architect may also be required to confirm the construction of the windows.

Wayne Ammons

8/3/2020 07:43:25 am

I will also add that Tyco has a new concealed style window sprinkler that may be helpful when it comes to the aesthetics of the project.

https://www.tyco-fire.com/index.php?P=detailprod&S=6210

Franck

8/3/2020 10:21:38 am

I don't know what the AHJ would require in your area.

Normally, when the room is protected by sprinklers, you don't need to provide an additional window protection (otherwise it would be a nightmare in all offices, industrial buildings....).

The window protection is required when you need a specific fire rating fro the window (1 h) and the window is not rated. I don't know if you have a requirement for this 1 h fire rating for your windows.
Another application for windows protection is protection from exposures. In that case, the sprinkler rpotection is provided on the outside of the building to protect the windows openings from potential outside exposures (adjacent non sprinklerd building, outside storage...). It don't have the feeling that this is your case.

Casey

8/3/2020 11:25:49 am

There is a LOT to this topic and it gets very complicated, very quickly. make sure you know what edition of codes are driving this. I believe IBC/IFC states that you can use standard spray sprinklers when allowable per NFPA 13. Double check that, but there is mention in there about standard spray. It does not sound like you are trying to maintain a wall rating, but more of exposure protection from an adjacent building that is too close.

Wayne Cordiner link

8/3/2020 11:52:11 am

I'm assuming based on the term "Lot Line" that you are in the NYC area as that is the only place I've heard that term used before - please correct me if my assumption is wrong.

With that specific location in mind, the NYC BC addresses this through "BUILDINGS BULLETIN 2015-017" (see link below) but will generally refer you to NFPA 13 as modified by Appendix Q. Keep in mind, there are some variables such as building class, height, and location that come into play causing variations. In short, yes a standard pendent is permitted as the goal of this code/bulletin is to create a water curtain (provide a 1hr rating) similar to what you would with an atrium opening. It is common in NYC, for these to be fed from the end of a branchline, however note the requirements for the calculation procedures in 11.3.3 of NFPA 13. The lot line head should not be used to protect the space and a baffle will be needed if you can't achieve the 6'-0 of separation.

https://www1.nyc.gov/assets/buildings/bldgs_bulletins/bb_2015-017.pdf

Aaron

8/3/2020 01:51:19 pm

You must know you'r stuff to deduce that!

You wrote that standard spray is good and referenced the Bulletin.
However the bulletin states "protected by an approved water curtain using automatic sprinklers a͟p͟p͟r͟o͟v͟e͟d͟
f͟o͟r͟ ͟t͟h͟a͟t͟ ͟u͟s͟e͟ and installed in accordance with NFPA 13 as modified in Appendix Q" does this mean that it must be specially listed for windows?

Please help me out with this and let us know where we can look more to clarify this.
Thanks

Wayne Cordiner link

8/3/2020 02:07:42 pm

Aaron,

Because these are not considered exposure protection systems they do not have to be specifically listed for window protection. Note in VI.A.4 of that bulletin where it references "openings" rather than windows. This will be handled much the same as a glass partition between a tenant space and lobby area. Again, this is specific to NYC and only the lot line protection locally mandated there so please do not take this as a blanket statement for all jurisdictions.

Artur

8/3/2020 03:42:02 pm

Thank you!
I didn't know tho it's NYC thing only.
The thing is we often use standard sprinklers to protect lot line window separate heads for the rest of the room (and we use bafles if needed).

On this one project engineer of record says lot line sprinkler can protect the whole room.
Just wanted to know your opinion on this.

Brian Gerdwagen FPE

8/3/2020 01:47:57 pm

You also need to look at Table 705.8 of the IBC, assuming it is codified, that allows what percentage of opening in a wall allowed as determined by distance to the FSD/Property Line. Less than 3', you are not allowed openings. Meaning that windows need to be rated like a wall, not a protected opening.

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