Bracing on vertical sprinkler drops - 15 ft long

[C***@ch2m.com]

I’ve been hunting the answer to this question and so far have come up short.

I have a case where there are drops off the bottom of 2” branch lines down to sprinklers in a ceiling 15 feet below. They are hard piped to within 2-3 ft of the ceiling with a flex drop from that point to the ceiling.

This is seismic design cat. B, so no EQ bracing required.

I’ve been trying to find rules on bracing of vertical drops but find only info on unsupported armovers, which this is not.

Also the pump rated pressure is 150 psi so the system will see pressures over 100 psi.

Any help on locating that elusive one line or paragraph on bracing requirements for vertical drops would be appreciated.


Craig L. Prahl
Fire Protection Group Lead/SME
CH2M
200 Verdae Blvd.
Greenville, SC 29607
Direct - 864.920.7540
Fax - 864.920.7129
CH2MHILL Extension 77540
***@ch2m.com

[Ed Cyr]

Hi Craig,
NFPA 13, 2013 says:
9.3.6.7 Drops and armovers shall not require restraint.

Post by C***@ch2m.com
I’ve been hunting the answer to this question and so far have come up short.
I have a case where there are drops off the bottom of 2” branch lines down
to sprinklers in a ceiling 15 feet below. They are hard piped to within
2-3 ft of the ceiling with a flex drop from that point to the ceiling.
This is seismic design cat. B, so no EQ bracing required.
I’ve been trying to find rules on bracing of vertical drops but find only
info on unsupported armovers, which this is not.
Also the pump rated pressure is 150 psi so the system will see pressures over 100 psi.
Any help on locating that elusive one line or paragraph on bracing
requirements for vertical drops would be appreciated.
*Craig L. Prahl*
Fire Protection Group Lead/SME
*CH2M*
200 Verdae Blvd.
Greenville, SC 29607
Direct - 864.920.7540
Fax - 864.920.7129
CH2MHILL Extension 77540
_______________________________________________
Sprinklerforum mailing list
http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.
org

[Mike Stossel]

Craig,

I don’t know of any requirement for the length of drops, especially in building that don’t require seismic restraint. Drops to a single sprinkler are excluded. The only requirement I know of is for sprigs and not drops, and in the commentary it specifies that it is not required on drops.
A.9.3.2.3
(5) Within 24 in. (610 mm) of the top of drops exceeding 15 ft (4.6 m) in length to portions of systems supplying more than one sprinkler, regardless of pipe size
Drops to a single sprinkler are not required to be equipped with a flexible coupling because of the concern regarding the difficulty of sprinkler installation and replacement [see 9.3.2.3(6)]. The rotation inherent in a flexible coupling can prevent the development of the torque necessary to properly install the sprinkler.
9.3.6.6* Sprigs 4 ft (1.2 m) or longer shall be restrained against lateral movement.
Sprig-ups are addressed in 9.3.6.6. A vertical sprig, or a sprig-up, is considered the opposite of a pipe drop. A vertical sprig is a pipe rising from the branch line to serve an individual upright sprinkler. They are susceptible to rotation during relatively minor seismic events. The requirement for restraint of sprigs was originally instituted for sprigs more than 8 ft (2.4 m) in length but was changed in the 1996 edition of NFPA 13 to apply to sprigs exceeding 4 ft (1.2 m) in length. The change was based on observations of rotated sprigs following the Northridge, CA, earthquake. The additional stability gained from this requirement results in time and money saved, because sprigs do not have to be manually repositioned after the event. The restraint provisions of 9.3.6.6 do not apply to drops to individual sprinklers, because gravity acts to pull them back to center.

Hope this helps.

Mike Stossel SET
[400dpiLogoCropped]
36 Barren Road
East Stroudsburg, PA 18302
Office: 973-670-2627
***@knssprinkler.com<mailto:***@knssprinkler.com>

From: Sprinklerforum [mailto:sprinklerforum-***@lists.firesprinkler.org] On Behalf Of ***@ch2m.com
Sent: Monday, November 14, 2016 12:01 PM
To: ***@lists.firesprinkler.org
Subject: Bracing on vertical sprinkler drops - 15 ft long

I’ve been hunting the answer to this question and so far have come up short.

I have a case where there are drops off the bottom of 2” branch lines down to sprinklers in a ceiling 15 feet below. They are hard piped to within 2-3 ft of the ceiling with a flex drop from that point to the ceiling.

This is seismic design cat. B, so no EQ bracing required.

I’ve been trying to find rules on bracing of vertical drops but find only info on unsupported armovers, which this is not.

Also the pump rated pressure is 150 psi so the system will see pressures over 100 psi.

Any help on locating that elusive one line or paragraph on bracing requirements for vertical drops would be appreciated.


Craig L. Prahl
Fire Protection Group Lead/SME
CH2M
200 Verdae Blvd.
Greenville, SC 29607
Direct - 864.920.7540
Fax - 864.920.7129
CH2MHILL Extension 77540
***@ch2m.com<mailto:***@ch2m.com>

[Hinson, Ryan]

16: 9.2.1.3.3 for suspended ceilings and flex hose fittings, 16: 9.3.2.4(3) IF seismic bracing was required, otherwise,
not required IMO.


Ryan L. Hinson, PE*, SET** \ Burns & McDonnell
Senior Fire Protection Engineer
O 952-656-3662 \ M 320-250-5404 \ F 952-229-2923
***@burnsmcd.com \ burnsmcd.com<http://www.burnsmcd.com/>
8201 Norman Center Drive, Suite 300 \ Bloomington, MN 55437
*Registered in: MN, PA, & TX
**NICET IV - Water-Based Systems Layout

From: Sprinklerforum [mailto:sprinklerforum-***@lists.firesprinkler.org] On Behalf Of ***@ch2m.com
Sent: Monday, November 14, 2016 11:01 AM
To: ***@lists.firesprinkler.org
Subject: Bracing on vertical sprinkler drops - 15 ft long

I’ve been hunting the answer to this question and so far have come up short.

I have a case where there are drops off the bottom of 2” branch lines down to sprinklers in a ceiling 15 feet below. They are hard piped to within 2-3 ft of the ceiling with a flex drop from that point to the ceiling.

This is seismic design cat. B, so no EQ bracing required.

I’ve been trying to find rules on bracing of vertical drops but find only info on unsupported armovers, which this is not.

Also the pump rated pressure is 150 psi so the system will see pressures over 100 psi.

Any help on locating that elusive one line or paragraph on bracing requirements for vertical drops would be appreciated.


Craig L. Prahl
Fire Protection Group Lead/SME
CH2M
200 Verdae Blvd.
Greenville, SC 29607
Direct - 864.920.7540
Fax - 864.920.7129
CH2MHILL Extension 77540
***@ch2m.com<mailto:***@ch2m.com>

[C***@ch2m.com]

Thanks everyone.

I have to find out the length of the flex hoses, the designer didn’t include that information in the “shop drawing”.

Other than that, there does not appear any issue with a 15 ft vertical sprinkler drop and no requirement of any type of support or bracing.




Craig L. Prahl
Fire Protection Group Lead/SME
CH2M
200 Verdae Blvd.
Greenville, SC 29607
Direct - 864.920.7540
Fax - 864.920.7129
CH2MHILL Extension 77540
***@ch2m.com


From: Sprinklerforum [mailto:sprinklerforum-***@lists.firesprinkler.org] On Behalf Of Hinson, Ryan
Sent: Monday, November 14, 2016 12:22 PM
To: ***@lists.firesprinkler.org
Subject: RE: Bracing on vertical sprinkler drops - 15 ft long [EXTERNAL]

16: 9.2.1.3.3 for suspended ceilings and flex hose fittings, 16: 9.3.2.4(3) IF seismic bracing was required, otherwise,
not required IMO.


Ryan L. Hinson, PE*, SET** \ Burns & McDonnell
Senior Fire Protection Engineer
O 952-656-3662 \ M 320-250-5404 \ F 952-229-2923
***@burnsmcd.com<mailto:***@burnsmcd.com> \ burnsmcd.com<http://www.burnsmcd.com/>
8201 Norman Center Drive, Suite 300 \ Bloomington, MN 55437
*Registered in: MN, PA, & TX
**NICET IV - Water-Based Systems Layout

From: Sprinklerforum [mailto:sprinklerforum-***@lists.firesprinkler.org] On Behalf Of ***@ch2m.com<mailto:***@ch2m.com>
Sent: Monday, November 14, 2016 11:01 AM
To: ***@lists.firesprinkler.org<mailto:***@lists.firesprinkler.org>
Subject: Bracing on vertical sprinkler drops - 15 ft long

I’ve been hunting the answer to this question and so far have come up short.

I have a case where there are drops off the bottom of 2” branch lines down to sprinklers in a ceiling 15 feet below. They are hard piped to within 2-3 ft of the ceiling with a flex drop from that point to the ceiling.

This is seismic design cat. B, so no EQ bracing required.

I’ve been trying to find rules on bracing of vertical drops but find only info on unsupported armovers, which this is not.

Also the pump rated pressure is 150 psi so the system will see pressures over 100 psi.

Any help on locating that elusive one line or paragraph on bracing requirements for vertical drops would be appreciated.


Craig L. Prahl
Fire Protection Group Lead/SME
CH2M
200 Verdae Blvd.
Greenville, SC 29607
Direct - 864.920.7540
Fax - 864.920.7129
CH2MHILL Extension 77540
***@ch2m.com<mailto:***@ch2m.com>

[Roland Huggins]

the limit of 6 ft without a hanger is not really a concern since UL listed products stop at 6 ft (unless that has recently changed). Has anyone seen a longer one?

Roland


Roland Huggins, PE - VP Engineering
American Fire Sprinkler Assn. --- Fire Sprinklers Saves Lives
Dallas, TX
http://www.firesprinkler.org <http://www.firesprinkler.org/>

Post by C***@ch2m.com
I have to find out the length of the flex hoses, the designer didn’t include that information in the “shop drawing”.
Other than that, there does not appear any issue with a 15 ft vertical sprinkler drop and no requirement of any type of support or bracing.

[Bruce Verhei]

I was the person who did all the follow ups to spk problems in a town with 60m sf of distribution center type buildings, all but tiny fraction sprinklered, built on lousy soils, after the Nisqually earthquake.

I had always been skeptical of the very long drops to single head in foreman's office/restroom type build out. I admit I was surprised that this was not on the list meets code, but still flowed water breaks. And this was just standard 1" pipe usually. Some minor breaks to drop in ceiling tiles. Most the owner never bothered repairing.

There were a number of repeated, meets codes, breaks. Water damage to goods. But none would have prevented system from controlling fire.

Repeated armovers, roll groove, not requiring a hanger, is another story.

Best

Bruce Verhei

Post by Roland Huggins
the limit of 6 ft without a hanger is not really a concern since UL listed products stop at 6 ft (unless that has recently changed). Has anyone seen a longer one?
Roland
Roland Huggins, PE - VP Engineering
American Fire Sprinkler Assn. --- Fire Sprinklers Saves Lives
Dallas, TX
http://www.firesprinkler.org

Post by C***@ch2m.com
I have to find out the length of the flex hoses, the designer didn’t include that information in the “shop drawing”.
Other than that, there does not appear any issue with a 15 ft vertical sprinkler drop and no requirement of any type of support or bracing.

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Sprinklerforum mailing list
http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org