Pendent sprinklers on return bends on a pre-action system

Discussion:

Sean Lockyer

2015-03-17 03:03:47 UTC

Even though (non-dry) pendent sprinklers must be installed on return bends on dry systems what about pendent sprinklers in a heated/conditioned space that is protected by a double-interlock, pre-action system (such as a video production room, etc.) ?

Does the fact that it is above a conditioned ceiling space matter ? To my knowledge there is nothing in NFPA codes or the manufacturers listing that give you an allowance for special situations like this but I was wondering if anyone else has any experience with this sort of issue ?

I would like to hear everybody's thoughts..

              Sean Lockyer
              Project Designer                               4617 Parkbreeze Court
              Cell    386-279-1197                              Orlando, Florida 32808
              ***@AITLifeSafety.com            Phone:      407-816-9101
              www.AITLifeSafety.com                       Fax:         407-816-9104

Travis Mack

2015-03-17 03:13:54 UTC

Permalink

My understanding is pipe must still be pitched and return bends required.

Travis Mack, SET
MFP Design, LLC
"Follow" us on Facebook: https://www.facebook.com/pages/MFP-Design-LLC/92218417692
Send large files to MFP Design via:
https://www.hightail.com/u/MFPDesign

Sent from my iPhone

Post by Sean Lockyer
Even though (non-dry) pendent sprinklers must be installed on return bends on dry systems what about pendent sprinklers in a heated/conditioned space that is protected by a double-interlock, pre-action system (such as a video production room, etc.) ?
Does the fact that it is above a conditioned ceiling space matter ? To my knowledge there is nothing in NFPA codes or the manufacturers listing that give you an allowance for special situations like this but I was wondering if anyone else has any experience with this sort of issue ?
I would like to hear everybody's thoughts..
Sean Lockyer
Project Designer 4617 Parkbreeze Court
Cell 386-279-1197 Orlando, Florida 32808
www.AITLifeSafety.com Fax: 407-816-9104
_______________________________________________
Sprinklerforum mailing list
http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org

Duane Johnson

2015-03-17 12:03:04 UTC

Permalink

See (5) below for pendent conditions without return bends on preaction systems otherwise see (3).

2013 ED.
7.3.2 Preaction Systems.
7.3.2.5 Sprinklers. The following sprinkler orientations and arrangements shall be permitted for preaction systems:
(1) Upright sprinklers
(2) Listed dry sprinklers
(3) Pendent sprinklers and sidewall sprinklers installed on return bends, where the sprinklers, return bend, and branchline piping are in an area maintained at or above 40°F (4°C)
(4) Horizontal sidewall sprinklers, installed so that water is not trapped
(5) Pendent sprinklers and sidewall sprinklers, where the sprinklers and branch line piping are in an area maintained at or above 40°F (4°C), the water supply is potable, and the piping for the preaction system is copper or CPVC specifically listed for dry pipe applications

Duane Johnson
Strickland Fire Protection

-----Original Message-----
From: Sprinklerforum [mailto:sprinklerforum-***@lists.firesprinkler.org] On Behalf Of Travis Mack
Sent: Monday, March 16, 2015 11:14 PM
To: ***@lists.firesprinkler.org
Subject: Re: Pendent sprinklers on return bends on a pre-action system

My understanding is pipe must still be pitched and return bends required.

Travis Mack, SET
MFP Design, LLC
"Follow" us on Facebook: https://www.facebook.com/pages/MFP-Design-LLC/92218417692
Send large files to MFP Design via:
https://www.hightail.com/u/MFPDesign

Sent from my iPhone

Lamar Vaughn

2015-03-17 12:42:06 UTC

Permalink

Sean, this may not be so much a code issue but an equipment protection
issue. The reasoning for the pre-action system is to protect what is in the
room from a potential leak of water. I have always been required to use the
dry pendent drops in these applications for this reason. Nothing to do with
freezing. My opinion.

Lamar Vaughn, SET

Post by Sean Lockyer
Even though (non-dry) pendent sprinklers must be installed on return bends
on dry systems what about pendent sprinklers in a heated/conditioned space
that is protected by a double-interlock, pre-action system (such as a video
production room, etc.) ?
Does the fact that it is above a conditioned ceiling space matter ? To my
knowledge there is nothing in NFPA codes or the manufacturers listing that
give you an allowance for special situations like this but I was wondering
if anyone else has any experience with this sort of issue ?
I would like to hear everybody's thoughts..
Sean Lockyer
Project Designer 4617
Parkbreeze Court
Cell 386-279-1197 Orlando,
Florida 32808
407-816-9101
407-816-9104
_______________________________________________
Sprinklerforum mailing list
http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org

Matt Grise

2015-03-17 12:48:26 UTC

Permalink

You could also face corrosion issues if you have drops that are filled with water.

Matt Grisé PE*, LEED AP, NICET II
Sales Engineer
Alliance Fire Protection
130 w 9th Ave.
North Kansas City, MO 64116

*Licensed in KS & MO

913.888.0647 ph
913.888.0618 f
913.927.0222 cell
www. AFPsprink.com

-----Original Message-----
From: Sprinklerforum [mailto:sprinklerforum-***@lists.firesprinkler.org] On Behalf Of Lamar Vaughn
Sent: Tuesday, March 17, 2015 7:42 AM
To: Sprinkler Forum
Subject: Re: Pendent sprinklers on return bends on a pre-action system

Sean, this may not be so much a code issue but an equipment protection issue. The reasoning for the pre-action system is to protect what is in the room from a potential leak of water. I have always been required to use the dry pendent drops in these applications for this reason. Nothing to do with freezing. My opinion.

Lamar Vaughn, SET

Post by Sean Lockyer
Even though (non-dry) pendent sprinklers must be installed on return
bends on dry systems what about pendent sprinklers in a
heated/conditioned space that is protected by a double-interlock,
pre-action system (such as a video production room, etc.) ?
Does the fact that it is above a conditioned ceiling space matter ? To
my knowledge there is nothing in NFPA codes or the manufacturers
listing that give you an allowance for special situations like this
but I was wondering if anyone else has any experience with this sort of issue ?
I would like to hear everybody's thoughts..
Sean Lockyer
Project Designer 4617
Parkbreeze Court
Cell 386-279-1197 Orlando,
Florida 32808
407-816-9101
407-816-9104
_______________________________________________
Sprinklerforum mailing list
http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkl
er.org

Mark A. Sornsin, P.E.

2015-03-17 17:59:23 UTC

Permalink

Corrosion is a real possibility. We have seen drops corroded shut on ferrous pipe due to water that was left within after testing (or a trip or whatever). A 'rust plug' had formed across the entire cross section of the drop.

Mark A. Sornsin, P.E. | Karges-Faulconbridge, Inc. | Fire Protection Engineer | Fargo, ND | direct: 701.552.9905 | mobile: 701.371.5759 | http://www.kfiengineers.com

-----Original Message-----
From: Sprinklerforum [mailto:sprinklerforum-***@lists.firesprinkler.org] On Behalf Of Matt Grise
Sent: Tuesday, March 17, 2015 7:48 AM
To: ***@lists.firesprinkler.org
Subject: RE: Pendent sprinklers on return bends on a pre-action system

You could also face corrosion issues if you have drops that are filled with water.

Matt Grisé PE*, LEED AP, NICET II
Sales Engineer
Alliance Fire Protection
130 w 9th Ave.
North Kansas City, MO 64116

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please visit http://www.symanteccloud.com
______________________________________________________________________

Tom Duross

2015-03-17 17:21:27 UTC

Permalink

Been lurking for a while...
We have the 911 room for Boston Police at their headquarters and after
draining each and every return-bend head off their 2 preaction systems last
year, we installed a shut-off.
The client was very nervous about having ANY water in the drops, even under
30 PSI of air. You have to trip these valves so everything will get wet
(inside).
Not a direct answer to the original post but even if I could, I wouldn't use
return bends where main frames, media, etc., are located.
TD

-----Original Message-----
From: Sprinklerforum [mailto:sprinklerforum-***@lists.firesprinkler.org]
On Behalf Of Lamar Vaughn
Sent: Tuesday, March 17, 2015 8:42 AM
To: Sprinkler Forum
Subject: Re: Pendent sprinklers on return bends on a pre-action system

Sean, this may not be so much a code issue but an equipment protection
issue. The reasoning for the pre-action system is to protect what is in the
room from a potential leak of water. I have always been required to use the
dry pendent drops in these applications for this reason. Nothing to do with
freezing. My opinion.

Lamar Vaughn, SET

issue ?

Post by Sean Lockyer
I would like to hear everybody's thoughts..
Sean Lockyer
Project Designer 4617
Parkbreeze Court
Cell 386-279-1197 Orlando,
Florida 32808
407-816-9101
407-816-9104
_______________________________________________
Sprinklerforum mailing list
http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkl
er.org

Roland Huggins

2015-03-17 17:26:14 UTC

Permalink

It is addressed by NFPA 13 - see section 7.3.2.5(5)

It is not a freeze issue since even with a return bend, it has to be in a heated area. It’s a build-up of stuff issue (either silt from non potable water or scale). All these items are covered by the #5 allowance added in the 2007 edition that was posted and referenced above.

Roland

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

Duane Johnson

2015-03-17 17:49:08 UTC

Permalink

This has not been brought up yet, but worth noting:

8.16.2.5.3 Auxiliary Drains for Dry Pipe Systems and Preaction Systems.
8.16.2.5.3.4 Auxiliary drains are not for pipe drops supplying dry pendent sprinklers installed in accordance with 7.2.2.

8.16.2.5.3.4 should also reference 7.3.2.5 in my opinion. The committee needs to amend this since 7.2.2 only covers dry pipe while 7.3.2 covers preaction.

Duane Johnson
Strickland Fire Protection

-----Original Message-----
From: Sprinklerforum [mailto:sprinklerforum-***@lists.firesprinkler.org] On Behalf Of Roland Huggins
Sent: Tuesday, March 17, 2015 1:26 PM
To: ***@lists.firesprinkler.org
Subject: Re: Pendent sprinklers on return bends on a pre-action system

It is addressed by NFPA 13 - see section 7.3.2.5(5)

It is not a freeze issue since even with a return bend, it has to be in a heated area. It's a build-up of stuff issue (either silt from non potable water or scale). All these items are covered by the #5 allowance added in the 2007 edition that was posted and referenced above.

Roland

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