Grooved Piping Systems in HVAC applications | Eng-Tips

I believe that most of the problems people have suffered using grooved piping in systems like this, is due to faulty design and or installation. If the people at Victaulic or GruvLok (there could be others) are consulted about what kind of couplings & gaskets should be used, and how to lay out the system, there should be no problems. The systems that I've seen with problems, were pretty much due to expansion issues that weren't dealt with properly. If the job is being done by the "low bidder", somebody needs to be paying attention that the system is being installed correctly. Grooved joints are expensive, and every one that the contractor can eliminate, is money in his pocket. I operate a Victaulic system designed to operate at 230 deg. F. This system was installed in ,and has been in continuous use since. When I came here in the system had to be operated at above 160 deg. F at all times to stop leaks from happenning. By we had to operate at 180 deg. F to stop leaks and had to replace a complete secondary heating loop to stop leaks. This was because if you disturbed the lines to fix a leak it created several more leaks in jionts near bye.

In we replaced nearly gaskets ranging from 10 inch to 2.5 inches. This was done in consultation with Victaulic as to the best method to redo the gaskets. Since then we have had a policy of not exceeding 223 deg F because Victaulic has stated that even a short time of use over 230 deg. F (this is also the tempurature that they will warranty their gaskets to) will cause rapid deterioration of the gaskets. For three years we had no problems but then we started getting leaks in and as of this year we once again have to either drain the lines or leave them hot at about 120 deg. F to prevent leaks.
In fact we are now looking at welding all the jionts as it is very expensive when we have a leak and it destroys our clients product.
My question is has anyone designed and operated a Hot Water Heating system that operates at 220 deg. F to 230deg. F and if so how long has it operated trouble free.
A couple of quick facts: gaskets are Victaulic recommmended EPDM and only victaulic grease was used & our water treatment is by GE with a compatible product.

All,

My experience in fire protection has been limited to the contractor side, and I was always taught to use grooved fittings whenever possible. The benefits as explained to me always made sense, prefabrication, less labor for installation, lower overall cost, etc.

I continually see project specifications that require threaded fittings on all piping 2" or smaller. I have never heard a pro threaded argument, just grumblings from my coworkers and supervisors that the design engineer is old fashioned and driving the project cost up.

I have tried googling the topic, but only seem to find sales literature from grooved fitting suppliers singing the praises of their products. Can anyone here offer any insight on this? Or is it really just a matter of "We have done it this way for the past XX years and we aren't going to change it now."?

The only benefit I could think of would be the ability to reduce branch line sizes at every head with the proper size reducing tee. My current employer does not keep an extensive stock of threaded reducing tees, and they may be on back order. In addition we like to use a single size pipe for branch lines to reduce the variety of sizes that need to be handled during prefabrication in the shop. K.I.S.S. These two points make the idea a non-starter before I get into the cost-benefit analysis of using one size of SCH10 pipe vs more optimized sizes of SCH40 pipe.

When I was fresh out of school and working on boilers in power gen I thought all of the "Old Farts" were out of touch and I was going to change the world. Over time I learned that most of the decisions made by senior engineers were based on good reasons, and that those reasons held true through the years more than I originally thought. Looking back on it, I can really only think of one person I would put in the "Out of Touch Old Fart" category at this point, and my attitude has been tempered with time and a little bit of embarrassment.

Considering my limited view as a contractor, and only having been in this trade for a few years, I was wondering if this board could enlighten me on anything I may be overlooking. I am on my way to obtaining a PE license, and some day I may be writing specifications myself. With that in mind I really want to expand my product knowledge.

Huey For me it depends on a lot of factors. Generally speaking if it's a tree system I'm designing with varying size of branchlines then I'll go threaded. If it's a larger system with all the branchlines being the same size all the way down then I go grooved. Sometimes ugly jobs that aren't all that accurate like retrofits I'll go threaded because they're going to be doing a lot of cut to fit anyways and they use the same machine for the cutting and threading. If I'm up in the air about it I'll see what the foreman or project manager wants - let them chew on it a bit and get back to me.

Of course different companies have their own way of doing things. I like to get the guys in and out even if that means going a little heavy on the material costs but to each his own.