How long can I run black pipe (LP gas) run?

Old 01-24-08, 11:05 AM
Thread Starter
Join Date: Feb 2006
Location: MI
Posts: 131
Upvotes: 0
Received 0 Upvotes on 0 Posts
How long can I run black pipe (LP gas) run?


I would like to install a vent free fireplace in an upstairs living room. In order to do this I would need to run about 40 total feet of black pipe from a T off of my water heater in the basement. I was thinking of running 1/2 inch black pipe up and parallel to the ceiling joists in my basement- the out through an exterior wall to an area under my deck. The long lengths of pipe would be next to a cold air return duct, and fastened to the inside studs of a soffit that contains the cold air return. When the black pipe leaves the house for the outside I would like to use flexible yellow gas line to enter the house and hook up to the fireplace.

My question is- is there a max length run for black pipe? Also- does it hurt it to be outside at all? I am in Michigan, and it gets real cold, but my LP tank is outside to begin with so I figure the LP should not freeze.

Also- is it OK to use flex Yellow line for the last tricky run into the house from the outside? Or should I run rigid black pipe the whole way.

I am fine with fitting black pipe, and have done it for several jobs. Just never one with this long of a run.

Opinions would be appreciated.

Old 01-24-08, 12:59 PM
Join Date: May 2007
Posts: 107
Upvotes: 0
Received 0 Upvotes on 0 Posts
IMO, vent free fireplaces have no place in a home. They put too much water vapor into the home and the CO/CO2 issues aren't worth the risk.

To properly size the gas piping, need to know your LP supply pressure, length of pipe to the water heater, BTUH of water heater, total length of pipe to the fireplace, and BTUH of fireplace.

I would only run the corrugated stainless steel tubing where it will remain protected; I wouldn't run it exposed outside.
Old 01-24-08, 02:06 PM
Ed Imeduc's Avatar
Join Date: Aug 2002
Location: Mountain Williams Missouri
Posts: 17,505
Upvotes: 0
Received 1 Upvote on 1 Post

Like said DONT DO it. In most states now you cant sell the vent free gas units.The shut offs are for oxygen depletion only Its the CO2 that can kill you.
You dont say what BTU it is are what else you have there on the LP. What size your tank is and can it burn off lp so you have gas to it..
I am in Michigan, and it gets real cold, but my LP tank is outside to begin with so I figure the LP should not freeze.
HA HA Yes it can, not freeze but go back to a liquid in the line on that inside and outside this can shut off the gas to the unit like.
Old 01-24-08, 02:35 PM
Banned. Rule And/Or Policy Violation
Join Date: Dec 2007
Location: Chicago
Posts: 904
Upvotes: 0
Received 0 Upvotes on 0 Posts

Many people in the fireplace maintenance industry are uncomfortable with the basic concept of vent-free log sets period, and frequently refer to them as “lung-vented” logs, see for example:

To which, the vent-free log industry says “hogwash”:

(We report, you decide....)

You can get a rough idea of the piping requirements here, but you must follow local codes as regards materials and sizing.
Old 01-24-08, 03:06 PM
Join Date: Oct 2006
Location: Wilmington
Posts: 3,994
Upvotes: 0
Received 0 Upvotes on 0 Posts
Michael's last line "YOU MUST FOLLOW LOCAL CODE". And usually, the homeowner cannot makes changes to gas lines, it must be a licensed contractor rated for such installations.
Old 01-24-08, 04:01 PM
Join Date: Aug 2005
Posts: 2,128
Upvotes: 0
Received 2 Upvotes on 2 Posts
Just Bill beat me to it.... Unfortunately, I've never lived in a region that allowed, by code, a homeowner to do his own piping for gas work.......

As far a unvented gas fireplaces..... I fear that many fireplace maintenance companies are negative about them because now there are no chimney's to install/clean, flues to adjust/repair. Major manufacturers build them, numerous regions allow them by code, and safety factors (according to the government and manufacturers, to be sure) are built in. I say, if they're allowed in your area - jump on in. Check the safety features - if they're only for O2 or include CO...You can always buy a CO alarm for the room in question. Keep in mind, I grew up with propane space heaters (unvented) in every room of the house - and somehow me and my 6 siblings lived through it.
Old 01-24-08, 04:14 PM
Thread Starter
Join Date: Feb 2006
Location: MI
Posts: 131
Upvotes: 0
Received 0 Upvotes on 0 Posts
Hi guys, thanks for the responses. I appreciate the concern too, but I have to say that I am going to go ahead with the project. I am a licensed builder, not a plumber pipefitter, but I do appreciate codes. However, I am sure most of us here have done several things without being licensed. In any case, I was hoping for some specifics from someone who knew about this in general- so here is the rest of the data I have gathered.

LP supply pressure - 250 psi max- 215 max allowable at 100degrees
Length of pipe to H2O heater is 15' (all pipe in home is 1/2 " currently)
BTU of H2O heater is 40,000
Length of pipe to Fireplace #1 would be 50', to Fireplace #2 is 25'
BTU of vent free fire logs is 30,000 - 40,000 btu/hour

Point taken about the rigid pipe being safest outside.
Does anyone have a reccommendation on the sizing of black pipe. Will 1/2 " be OK since the rest is already 1/2 inch?

Also, I don't intend this to be a primary heat source- mostly a rarely used but still functional decoration.

Thanks for the help

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: