If it operated successfully with the steel pipe, you should see a little better performance with the sch. 40 PVC as it has better water flow performance characteristics. The only thing you may want to upgrade would be changing the 1/2" risers to 3/4". Only because the pipe is more rigid. Good Luck

This is an old house, 100+ years so the walls are actual 2x4 with lath, plaster & drywall. I could possible get away with the 6" round encase in the wall if I am lucky. Would I be better off just with the round all the way up? I can handle a small box in and we have a new furnace so 6" should be good as long as it is sealed really well. Also I should add that I am guessing the pipe size, it is 18.25 inches around, I have not taken it apart to measure the actual width. Thankfully this is the only gravity line that is left in the house. When we first moved in we had a total of one working line running upstairs plus the gravity line. I guess the previous owners didn't think they needed heat up stairs. When the furnace & a/c was added they add one line per room. I wish we had them redo this line at that time.

It is very unlikely to produce an explosion, but the performance can be very poor with excessive carbon monoxide production form the inadequate gas flow to appliances. The 'trick' to gas is that there is not enough oxygen in the lines for combustion to occur. Pulling to much gas from the line will drop the pressure, but it is nearly impossible to get it below the ambient pressure and have air flow back into the line. The flame usually simply goes out and the gas continues to exit at a low rate. The lines should be sized based on the demand of the appliances connected. You may get away the same way electrical wiring does though. If all the appliances are not on at the same time (load diversity) the maximum demand may never occur.

The Georgia Plumbing code is modeled after the UPC (Uniform Plumbing code). Let us begin our discussion by examining your options under the UPC. Pipe Approved by the UPC for domestic potable water "Supply Lines" (Note- Supply lines are defined as the line from the municipal water main or well to the structure). List of approved materials: 1.ASBESTOS CEMENT PIPE-commonly used for municipal water mains but rarely seen in a residential supply. 2.BRASS PIPE- Extremely expensive and labor intensive because it requires cutting and threading in the same manner as iron pipe. Expected service life is 150+yrs. (In my entire career in the plumbing trade I never encountered a brass service line). 3.COPPER PIPE Type K & L (no type L) Both "Hard drawn copper" (rigid 10' or 20' lengths) and "Annealed copper pipe" continuous roll pipe available in 60' & 100' rolls. Annealed copper continuous roll pipe is the preferred material for supply lines because it can be bent to conform to slight changes in direction or elevation and it minimizes the number of joints below grade. Expected service life 60+ yrs. Disadvantage is the high cost of the material. 4. CPVC-both pipe and tubing. CPVC pipe is made to conform to the sched.40 IPS (iron pipe standard). It has the same overall dimension and pipe wall thickness as sched.40 PVC & Iron pipe. Generally only available through a commercial plumbing supply house by special order. This pipe is generally not sold to the public because the pipe dimension is the same as sched.40 PVC and there is a great risk that untrained installers might co-mingle CPVC pipe with PVC fittings. (code prohibits gluing dissimilar plastic pipes and fittings. The CPVC commonly found in the home supply stores is CPVC-CTS (CTS=Copper Tube Standard). While CPVC-CTS is approved for supply piping, in my humble opinion the tubing wall is too thin to hold up to the rigors of direct burial, and being a rigid material it would require numerous joints. Failed joints are the leading cause of problems with a supply line. 5.GALVANIZED IRON PIPE- Expensive, labor intensive to install, highly succeptable to mineral buildup and internal corrosion. Generally not considered a good choice today. 6. PE PIPE (Polyethelene Plastic tubing). Available in 50', 100' & 250' rolls. Uses standard "Bsrb" fittings which are pushed into the pipe and held in place by stainless steel clamps. Advantages: a.Very inexpensive. b. No buried joints. c.Flexible so it will easily conform to an imperfect trench or change in direction or elevation. d.Proven service life 65+ yrs. e.Requires no tools other than a pvc snap cutter or common utility knife to cut the pipe and a common flat tip screwdriver to tighten the clamps. 7.PEX (Cross linked Polyethelene pipe). PEX is a relatively new material in the plumbing industry. It has all the advantages of the PE pipe with the exception that it requires special tools to make the joints and it may not be code approved by your local jurisdiction. NOTE: both PE & PEX pipe can be installed with a minimal invasion of your landscaping by means of a ditch-witch type trenching machine using a 4" or 6" wide cutter bar. Some trenching machines even have a special pipe rack that will hold a roll of PE or PEX and a dispensing system on the cutter bar so that the pipe is laid during the trenching operation. This method only requires digging a small hole at each end of the run to make the final connection or feed the pipe through a footer wall. 8. PVC pipe-available in 20' rigid lengths. Requires couplings to join additional lengths and fittings to make changes in direction or elevation. Advantages: a.PVC is relatively inexpensive b.pvc is impervious to scaling or mineral fouling. Disadvantage; a.Requires numerous joints which are the leading cause of direct burial pipe failure. b. requires good straight line trenches. In my professional opinion my choices in order would be; 1.PE pipe 2.PEX pipe 3.PVC pipe