What supports the pipe?

[begreen]

I've been wondering about cathedral ceiling installations where there's 20 feet of pipe hanging off the ceiling box. How is this securely anchored? Our Duravent, latches into the ceiling box with a quarter turn I think. But with a super long run of heavy pipe, this doesn't inspire great confidence, especially in an earthquake region. I added long screws for additional peace of mind. Is this overkill or is it recommended to secure the pipe with more than just the box collar lock?

 

[Michael6268]

Maybe I'm not understanding the situation, but the 20 feet of pipe isn't hanging from the support box. It resting in/on the stove collar. I put screws through my support collar just because I didn't like relying on just the twist lock to hold it together when cleaning etc. I would think three screws on the support collar and each connection below is more than enough.

 

[begreen]

That was my thought, though the support collar isn't exactly designed to accept screws. As to support, my concern was for the case where it is attached to a rear exit stove. I wouldn't trust the elbow to support the weight.

 

[Michael6268]

Yeah, I just drilled three pilot holes in the support collar and used 1/2" stainless screws in them. Seemed to work out ok. I can see your point on the weight being on the elbow, especially how crappy some of those elbows are made. But if you securely screw each section of pipe from the top down, I don't think anything is going to happen. The support box should more than hold the weight. They also make wall brackets to mount to non combustible surface which could be used unless the stove is not near a wall.

 

[begreen]

My run is short, to a 9' ceiling. I'm comfortable now that I have it secured at the box and each joint has 3 screws as well. But it was SH's installation that started me wondering about how one does this securely with 20+ feet of DVL under the support box.

 

[BrotherBart]

Since the fellow posted this pic a while back I decided that pipe is held up by magic.

 

[begreen]

I remember that shot. I couldn't sleep at night with the stove burning connected like that. I'd be up on a ladder putting a safety strap or two on it, even if it was baling wire.

 

[Gooserider]

I agree from the "belt and suspenders" point of view, but IMHO if the pipe setup is properly designed and installed it shouldn't NEED added supports, and poorly done supports might even increase the strain on the system. As long as the component parts are properly locked / screwed together then there shouldn't be any unusually high level of stress on the pipe even though it looks scary. I will admit that I'd be a bit more nervous when sweeping it than in normal operation, but again, it shouldn't go anywhere if things are put together properly.

Yes there is some down load, and a bit of side load, but each end acts to support it and counter the pressure on the other. A support bracket would need to be flexible enough to deal with any dimensional changes resulting from the pipe heating up, which might be tricky.

I remember years back talking to a guy that did auto exhaust systems. He claimed that if properly done, an exhaust system should fit perfectly into place when secured only at the engine manifold, with the support brackets just filling in the spaces, but not "pulling" the pipe into place. He said anything else led to failure of the supports in fairly short order. I have found that it works that way pretty much on bikes...

Gooserider

 

[mayhem]

Mine is a roughly 20' run of double wall inside the house resting on top of the top exit collar on the stove. Its just using the twist lock to hold it on the stove collar and the pipe has virtually no deflection at the seams where the 3' sections come together...even when pressed pretty hard. Total weight being carried by the stove is maybe 40lb or so...the interior pipe weighs nothng and the silver metalbestos stuff is supported by the roof.

The elbow on the stove is probably supporting significantly less mass than you think. But being in a quake prone region it certainly makes sense to me to want to add a brace.

 

[Highbeam]

I was dinking around on Selkirk's site which I think is much better than Simpson's for homeowners trying to get a clue about this stuff. They actually list the load ratings of the various support hanger contraptions that they sell. As in the ceiling support box can support 50 feet of pipe with no mare than 20 of that hanging below. I will try and assemble the pipe such that the stove itself is supporting little to no weight of the pipe.

Much excitement is made about our earthquakes. It's a bunch of BS if you ask me. I've only lived here a few decades but there has been no wind to fill the sails of these fanatical earthquake people. Now if you live down on the gulf, you should be prepared for hurricanes. THe only reason you hear so much about earthquakes in our region is because there is nothing else to talk about. We don't have much for natural disasters, be more afraid of the goofball neighbor running his tractor into your house.

That's a great picture of the single wall crazy pipe BB. Would you actually brush that without total disassembly?

 

[begreen]

You're right Highbeam, I found in the DuraVent catalog they say the support box can support 60' of chimney. Now that sounds like a draft issue!

Re:earthquakes. Friends that were working in building in downtown Seattle might disagree with the earthquake perspective. Watching a building open up while you're on the 5th floor is no fun. Our chimney rotated 45 degrees in the last earthquake and that wasn't a big one. The neighbor's collapsed as did many others. Thankfully, neither of us were burning at the time. The earthquake did a fair amount of damage in Seattle and Olympia. The funny thing with quakes is that depending on the soil you sit on and the node of vibration that your location may or may not be on, the effect can be radically different only 5 miles apart. We don't get them than frequently, but when they happen, they can be powerful. However, one is much less likely to have catastrophic damage in a rural area as compared to an urban one.

 

[Metal]

I added long screws for additional peace of mind. Is this overkill or is it recommended to secure the pipe with more than just the box collar lock?

Be sure that the screws you use are short enough that they do not penetrate the inner flue.