Hello all

Recently my company changed work scope, and all of sudden my department have to design and put supports on the fire fighting line which have 'groove joint' and internal galvanized coating.

I'm using B31.1, and as my part of my job is arranging pipe supports. I might have to use shorter length of span than other line because of the groove joint, but I could not find any certain data or standards.

So I come up with these to review the system.

1. Modelling all the groove joint: It is time consuming, but if there are no rule I need to do this.

2. Ask pipe vendor: Considering the item vendor, would never heard from them. But I'll try.

3. Just use the same span as others: Recently visited site did that. Not noticible damage or sagging of pipe, but not sure it's safe.

Any opinion or experiences would be helpful.

Thank you.

CAESAR III, if you want to "just use the same span as others" please remember also that if NFPA13 is applicable (check with HSE or PM), you should comply with the pipe span shown in that code, and the
Another requirement of NFPA13 is that support should be designed to carry 5 times the weight of fire fighting pipes full of water, + 250 lbs.

Corrado Vannella
www.vannella.com

Sweat the details. Be careful since Victaulic supplies at least two types of basic couplings, an Anchor type and a flexible type. The flexible type allows some rotation and also some axial play that will be affected by pressure. A span requirement is only ONE factor in the design. These types of couplings have a solid reputation and decades of proven application.

Actually I have used these couplings in pairs to act like a ball joint system or universal expansion joint to absorb tank settlement for utility piping and water systems.

I would be a bit concerned about wear in a victaulic coupling in my region used thusly. But we have tanks that rise and lower as part of the filling operation, and not just as a "one time settlement."

Thank you for the opinions.

Victaulic does have reference span & minimum number of support in thier catalogue.
But regardless of suggested span, I'll check each support and isometric drawing to prevent unexpected joint failure due to lack of supports.

Eventhough pipe end will be grooved and joint will be thighten, relatively big concentraed load due to sag or other weight can cause the slip or failure of the joint....

Victaulic has established load limits for some of its couplings. I would use them if they are available.

Few yeas back I wrote the attached paper. It is for joints without grooves. Similar older paper for grooved joints was available as a download from COADE site at the time.

After writing the paper we did actual testing and the results confirmed the modelling method. Paper is free to use.