Long PVC Runs

[iwire]

If we need reducing washers, must they be made of PVC, too? :grin:

For what it's worth the bell end on 3/4" PVC fits over the bell end of 1/2" PVC very nicely.

 

[paul]

Arlington Pipe Hangers

Arlington Pipe Hangers

Arlington makes a perfect product for this. I've used them for years with great success.

http://www.arlcatalog.com/Rigid/Pipe Hangers.htm

 

[Energy-Miser]

Arlington makes a perfect product for this. I've used them for years with great success.

http://www.arlcatalog.com/Rigid/Pipe Hangers.htm

Thanks Paul. I just ordered a few of those from the catalog page you referenced, to try them out. Thanks again. E/M

 

[Energy-Miser]

Don't drive the screws in so tight ..... seriously.

I am just afraid of possibility of a leaking roof. But I guess the clear silicone we use will do a good job? I always thought the product used to prevent leaks on roof was a substance like black tar, but we are using this silicone that is as clear as water.

 

[hardworkingstiff]

I am just afraid of possibility of a leaking roof. But I guess the clear silicone we use will do a good job? I always thought the product used to prevent leaks on roof was a substance like black tar, but we are using this silicone that is as clear as water.

If silcone is not enough, use 3M 5200. That stuff is TUFF!

 

[Cow]

Dragging up an older thread for some ideas. Does anyone have a good method for dealing with expansion when running pvc on strut?

I'm running some 3/4" pvc right now and I'm tempted to cut some 2" long chunks of 1.25" pvc, strut strap those pieces in, then slide my 3/4" through it. I could even use 1.25" sch. 80 if need be to make the fit a little tighter around the 3/4" pvc. From what I can tell it only has to secured at the ends near the terminations, but just supported in the middle. So what do you guys think? Too hokey?

 

[LarryFine]

Yes, too hokey. Use 2-hole PVC straps.

 

[ty]

I am just afraid of possibility of a leaking roof. But I guess the clear silicone we use will do a good job? I always thought the product used to prevent leaks on roof was a substance like black tar, but we are using this silicone that is as clear as water.

You must be doing Solar.

Can you not attach most of your runs to the rails?
I am picturing alot of holes in that roof. The more holes, the more chance of an eventual leak.

There are some flashing mounts that have a stud that you can mount a minnerallac strap to.
Also, maybe mount a short (couple inches) piece of strut with a lag and a mastic under. I would trust that more than silicone around the screw holes on a roof.

If I ever get time, I'll upload some pics of different mounts on the roof.

 

[Cow]

Yes, too hokey. Use 2-hole PVC straps.

2 hole straps aren't strong enough, plus they don't mount to strut. What I have is an existing strut rack holding a group of conduits about 7-8' off the ground in the free air. This is in a barn where high humidity and vibration are a problem on this strut rack. The existing conduit is emt, but I'm trying to get away from that due to rust. Using strut straps with small chunks of pvc means I know I'll never have a strap failure like the weak pvc straps. I guess I'll just go ahead with it. I thought maybe somebody else might have done it this way before...

Personally, it may look a little funny but I know it'll hold and function as it should. That means more than asthetics in this particular situation.

 

[kwired]

2 hole straps aren't strong enough, plus they don't mount to strut. What I have is an existing strut rack holding a group of conduits about 7-8' off the ground in the free air. This is in a barn where high humidity and vibration are a problem on this strut rack. The existing conduit is emt, but I'm trying to get away from that due to rust. Using strut straps with small chunks of pvc means I know I'll never have a strap failure like the weak pvc straps. I guess I'll just go ahead with it. I thought maybe somebody else might have done it this way before...

Personally, it may look a little funny but I know it'll hold and function as it should. That means more than asthetics in this particular situation.

It won't look funny if you have your method installed next to PVC straps that have broken. your method is achieving the equivelant of running the conduit through bored holes in framing members which is allowed as support method.

 

[ty]

What about using a spring nut and minnerallac strap?

 

[winnie]

Cow,

I've seen clamps for mounting pipe on strut that have a plastic insert, for vibration isolation. Essentially a pre-made part that does what you want to do with the oversized pipe holding your conduit. I've never used them.

See www.mcmaster.com and search for Vibration-Damping Strut-Mount Clamps on page 1518 and 1519 of their current catalog to get the idea.

kwired's comment about bored holes also rings a bell; I've seen wood lined clamps specifically made to mount free air conductors to strut, again I've only seen these in catalogs, never used them. See for example http://www.stanleyfastners.com/catalog/ch36/ch36-11.html

-Jon

 

[Cow]

Great link Winnie. Thank you.

 

[Cow]

Here's what I found out:

Thomas and Betts Superstrut P-716 series cushioned strut straps WORK AWESOME for pvc on strut. I used some of their 1 1/8" OD straps on some 3/4" pvc, the pipe was just barely loose enough that it could slide back and forth.

I found them in Grainger first but they wanted around $9 a strap for regular zinc.:roll: Called our local electrical supply house and got them for around $5 and it only took 3-4 days to get them. They offer them in stainless, galvanize and regular zinc I believe.