Deluge system couplings

[JBENGR]

Is there a difference in 300# rolled grooves and what I know as Victaulic couplings? Has anyone done comparison test on performance in overpressure situations. No doubt, screw couplings are problematic; you have to go one schedule higher to ensure adequate wall thickness after the threads are cut and the threads are notorious as start points for significant corrosion over time.

If grooved is stronger than threaded, perhaps I should consider changing to grooved where we currently allow threaded, I won’t budge off butt welded flange for larger than 2” unless some really good data is available.

Any information is appreciated.

 

[MatthewJWillis]

Roll Grooves are indeed stronger.
The piping for Fire Suppression has higher testing standards as well. ASTM 795.

I can understand then flange requirement somewhat. But I think you will again find great comparison when using roll grooved.
I used to have a copy of the groove testing standard. I believe UL 213..?

Victaulic if the Father, so we generally just say "Vic" coupling when speaking about them even thought they may be made by someone else.
Most of the grooved stuff we use is rated to #300, but they may be some stragglers out there. The UL and or FM mark will tell the tale.

R/
Matt

 

[rconner]

While both are good organizations/standards (and while I'm not familiar specifically with rolled groove FM and UL testing protocols), with regard to comparative "over-pressurization" strength evaluation or preference, I do know some FM protocols for some other products actually require a 4X list pressure rating strength test, whereas UL may be 2X listed pressure rating.

 

[Duwe6]

One caveat on 'Vic' roll-grooved pipe vs. buttwelded; Supports. Big bore welded piping can have some pretty long minimum support intervals, i.e. greater than 20-ft. Vic needs a support for every 'stick' of pipe and on both sides of every fitting; the Vic joints are for pressure, not bending stress.

 

[MatthewJWillis]

If it is a Deluge system, the support lengths are set by the standard. Normally every 15'-0" for piping larger than 1½" Also there are other bracing requirements that may be more strict. Unless certain items are met, all pipes in a Water Based Fire Suppression system must have a support "per pipe" regardless of connection method.

R/
Matt

 

[TravisMack]

Correct, Matt. There is nothing in Chapter 9 that I am currently aware of that lets you exceed the minimum hanging requirements. There are some areas that place more stringent requirements than just 15'. I would be interested to learn where having a butt-weld pipe would allow some greater distance between hanger supports.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

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[rconner]

You may be interested in the comments regarding cut and rolled grooves on e.g. page 34 at

http://www.standard-club.com/media/24158/AMastersGuidetoShipsPiping2ndedition.pdf​.