Gas union in attic

[bigb56]

I am re-locating a gas pipe that was originally run exposed in the laundry room, I am putting it in the wall. I will need to use a union to re-connect (The union is presently exposed in the laundry room). It is allowed where I live as long as it in not installed in a concealed location. I will be connecting to the incoming line which is in the accessible attic, in fact it will only be about 3 feet from the scuttle hole. I am also planning on R-38 insulation. The supply pipe is currently on top of the ceiling joists and the new insulation will make it not visible, so I am assuming I will need to make a loop that extends up out of the insulation for my union?

Not using a union is not an option as the line continues on to the fireplace and there is no way to get to all of it in order to build it from the supply end.

 

[Breplum]

I would say if you have a union, because unions have a tendency to leak, that having it above the insulation is the way to go.
Alternatively you could use a right-left union and coupling. That is how to make up a leak proof joint in an inaccessible location.
Another way to go is to use CSST, but I never recommend non-certified diy folks to try that.

 

[Sponsor]

 

[bigb56]

I thought about a right-left but I was reading some old posts where some people weren't too keen on them saying they are tricky to get right. I still may go that route though. I would say my skill level is advanced, I have done quite a bit of threaded pipe over the years. I always pressure check and never had a leak.

 

[Fitter30]

When tighting a union first put a light coat on bevel end of union half. Tighten union with two wrenches then put one on the bottom and smack the union.on the top tighten again. Nat gas before appliance is 7"-8" = 1/4 lb. With a loop will act like a expansion loop. Black pipe has rating of 125 lbs working. Being in AZ 160° summer 35° winter there's going to be both expansion and contraction.

 

[DIYorBust]

I think the left right nipple and coupling is a good way to go, and if you take your time and make sure you've done it right, it is not too tricky. In my area unions are not used except at appliances and meters and maybe a few other special cases. One disadvantage I can think of is that doing work elsewhere on the pipe could disturb this fitting if it is not done properly, as what would normally be a tightening rotation could unscrew this connection.