Swing Joint or Flex Drop Required for Cloud?

2/28/2023

I'm working on a performing arts theater in California. There are floating clouds with pendents in them.

I seem to remember an inspector bringing up an NFPA requirement for either a swing joint or a flexible drop to connect to the pendent sprinkler. I can't find anything in the 2016 Edition of NFPA 13.

Is there a requirement for a swing joint or flexible drop for a cloud?

Could anyone provide a code reference?

Thanks in advance.

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9 Comments

Glenn Berger

2/28/2023 08:06:02 am

Recommend approved flexible hoses to be used to pipe to sprinklers in the floating (suspended) clouds.

Depending on where you are located in California, this requirement may come from the seismic section.

Anthony

2/28/2023 08:19:43 am

First off get the code excerpt whenever someone says there is a requirement you've never heard of. 9/10 times they mean "old Jimmy Fitterwise always said" the other 1/10 times you learn something.

I think they might be referring to the hanging requirements of pendants (see below). There is not requirement for sprinkler drops to be on any swing joint (back to back 90° fittings) and there is not a "must use flex drop" anywhere in code that I'm aware of. Also clouds have a habit of not being installed with extreme laser precision so the inspector might just mean its best practice not to design Stright drops to a cloud. I'd agree with that line of thinking; always build in flexibility when you can.

9.2.3.4.4* Unsupported Length with Maximum Pressure Exceeding 100 psi (6.9 bar) and Branch Line Above Ceiling Supplying Sprinklers in Pendent Position Below ceiling.

9.2.3.4.4.1 Where the maximum static or flowing pressure, whichever is greater at the sprinkler, applied other than through the fire department connection, exceeds 100 psi (6.9 bar) and a branch line above a ceiling supplies sprinklers in a pendent position below the ceiling, the hanger assembly supporting the pipe supplying an end sprinkler in a pendent position shall be of a type that prevents upward movement of the pipe.

9.2.3.4.4.2 The unsupported length between the end sprinkler in a pendent position or drop nipple and the last hanger on the branch line shall not be greater than 12 in. (300 mm)for steel pipe or 6 in. (150 mm) for copper pipe.

The person might be referring to a return bend and erroneously calling that a swing joint. Those are only required when 'raw' water is used. i.e. non potable water from a pond, river or otherwise.

Anthony

2/28/2023 08:51:45 am

Per some of the comments here I think perhaps the fitter is referring to 9.3.2.4

the Annex material goes on to say:

The horizontal relative displacement should be determined using the least value from one of the following formulas and be taken as the height of the top point of attachment to the storage rack above its base or the highest point of potential contact between the rack structure and the piping above its base, whichever is higher. The design should account for the differential movement value as determined from one of the two formulas, not both, and the lesser of the two values is acceptable. It should be determined how to account for the differential movement using flexible couplings or other ap-proved means.

Jess Lutz

2/28/2023 11:16:20 am

Hey, that "old Jimmy Fitterwise" has had some good information! LOL.
However, you are 100% correct...

QUESTION EVERYTHING!

Anthony

2/28/2023 12:42:58 pm

Today was a learning day :)

Glenn Warga

2/28/2023 08:29:09 am

This is most likely coming from the seismic section where you either have to have an oversize hole or on flex drop. The oversize hole may not be practical when dealing with concealed heads or some other type of decorative environment.

Ken Thackery

2/28/2023 10:44:06 am

Glenn,

The oversize hole is not required when using flex drops, only hard pipe and only in certain states. This is where you would use an "expansion plate/kydex ring". Ceiling code not sprinkler code.

If Berc clips are used on the grid edge no expansion plate/ring required.

ASCE7-05 Section 13.5.6.2.2
e. Except where rigid braces are used to limit lateral deﬂec-tions, sprinkler heads and other penetrations shall have a 2 in.(50 mm) oversize ring, sleeve, or adapter through the ceiling tile to allow for free movement of at least 1 in. (25 mm) inall horizontal directions. Alternatively, a swing joint that canaccommodate 1 in. (25 mm) of ceiling movement in all hori-zontal directions is permitted to be provided at the top of the sprinkler head extension.

NWCB Tech Doc 401
ASTM E580
ASCE 7-05

Ken Thackery

2/28/2023 10:59:33 am

© NORTHWEST WALL AND CEILING BUREAU
HEADQUARTERS
2825 Eastlake Ave E Ste 350 | Seattle, WA 98102
tel 206-524-4243 | email info@nwcb.org

This is what is accepted in Oregon and Washington, CA may be different.

Sprinklers
• For ceilings without rigid bracing, sprinkler head
penetrations shall have a 2 inch oversize ring, sleeve or
adapter through the ceiling tile to allow free movement of
at least 1 inch in all horizontal directions. Flexible head
design that can accommodate 1 inch free movement shall
be permitted as an alternate. Source: ASTM E580 Section 5.2.8.5

This document provides the IBC-2012 referenced standards for the installation of suspension systems for acoustical lay-in
ceilings. Incorporation of this document will provide a more uniform standard for installation and inspection. This document is
designed to accomplish the intent of the International Building Code (IBC) with regard to the requirements for seismic design
category D, E and F for suspended ceilings and related items. Unless supported by engineering, the suspension system shall be
installed per these requirements and those of the referenced documents. Manufacturers’ recommendations should be followed
where applicable.

Dan Wilder

2/28/2023 09:24:20 am

Nothing within NFPA specifically, this falls over to the IBC/ICC for requirements which transition back into Chapter 9, however there may be local amendments concerning different parts of the building moving independently of each other that would require some sort of separation/movement via flex hoses (seems a little too specific of a requirement). Flex hoses are not listed for a seismic separation application (think Metraflex), only to remove the oversized hole requirement for the penetration within the ceiling to avoid damage to the sprinkler from impact to the ceiling.

Flexhead Submittal Page 4 - https://www.cmdgroup.com/documents/FS/catalogs/Flexhead_CA_Commercial%20Fire%20Sprinkler%20Connections%20%20Submittal%20Package.pdf

Flexible hoses are not required, they are just an alternate means to additional restraint and oversize holes.

https://www.pmengineer.com/articles/85192-new-seismic-fire-sprinkler-regulations

Swing Joint or Flex Drop Required for Cloud?

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