CSST opens markets for HVAC contractors

Install gas lines faster, easier

By Asa Foss,

contributing writer

The big paydays of the housing boom may be over for now, but that doesn’t mean you can’t continue to thrive. When the market changes, smart contractors change with it.

Don’t want to get left in the dust? Innovate.

Yellow, flexible gas pipe is run from the main with 3/4” line through a manifold, and then to the water heater and fireplace with 1/2” lines. The furnace is fueled almost directly from the manifold with a few inches of fittings.

One way to stay ahead of the competition: switch from conventional steel pipe to corrugated stainless steel tubing (CSST) flex pipe for running gas lines. This will cut installation time in half without compromising quality, allowing a more competitive bid. In addition, the builder or remodeler can accelerate his schedule because your work is done faster.

CSST is a flexible, stainless steel pipe wrapped in pvc. It is lightweight, bends easily, and can be quickly routed around obstacles. Flex pipe requires fewer connections than traditional gas piping. Although it costs about twice as much as steel pipe per linear foot, the faster installation time more than makes up for the additional cost.

Kevin Wagner of Wagner Heating and Cooling in Lititz, Pa., has been in the HVAC industry for 17 years. He has been using CSST flex pipe since 1999, when it first became available in his area.

I interviewed Wagner and the builder, Dave Pusey of Pusey and Raffensberger, after Wagner finished laying flex pipe in the unfinished basements of four two-story townhomes.

Foss: Why do you use CSST?

Wagner: I use CSST exclusively. This project took about two-and-a-half hours to do everything, including the final touch ups and putting the manifold in. I ran about 60 feet of the 3/4" CSST for the main line, and close to 60 feet of 1/2" line for the furnace, fireplace, and water heater lines. If I used black steel pipe, I would have had to thread the pipe, which probably would have taken me four to six hours.

On top of the time savings, I don’t have to purchase a $5,000 threader, which is required for steel pipe.

Foss: What about costs?

Wagner: Materials probably cost about twice as much for the CSST as for the black pipe. For this project, they cost about $350. Flex pipe costs about $1.70 a foot, fittings are $7 to $12 depending on the size, and the manifold costs about $27. But, once you factor the labor in, flex pipe is much cheaper since CSST is so much faster to install in short runs.

Foss: Could you use flex pipe in any project?

Wagner: If you only have straight runs in the basement, it probably wouldn’t be economical, but flex pipe is a real time saver if you’re also roughing gas pipe into the second and higher floors. If you had to get gas piping up to the third floor of an apartment for a washer and dryer, for example, the time savings would be huge. Once you start going up a wall, across a floor, up another wall, and across another floor, with black pipe you would have all those joints that you’re trying to fish hook a pipe through. That’s where you’re saving time with CSST.

Pusey: Another place where it would be a big time saver would be on a remodel job. If somebody wants a gas fireplace over in a certain part of the house, flex pipe is going to be so much easier to install because once you get a hold of the end of it, it’s almost like you’re fishing wire. That makes CSST the least invasive way to install a natural gas line because you don’t have to knock big holes in the wall at each bend in the pipe. Homeowners like it because it’s so economical and clean.

Foss: What installation tricks have you learned over the years?

Wagner: You have to pay attention when you install flex pipe because it has a memory when you uncoil it. If you get a loop in it, you can’t just untwist it to get it straight. It’s not like an electrical wire where if there’s a little twist in it, you can still make it look good.

Using CSST helped Wagner win the bid for this set of luxury townhomes.

CSST is flexible, but it is also sort of thin, so it can kink. You’re not supposed to make a sharp 90-degree turn with it. If you do need to make a short-radius, 90-degree turn, use a fitting.

You have to treat it somewhat like water pipe. You have to protect it wherever it goes through studs and where nails can get to it. But the manufacturer gives you all kinds of stud protective plates.

Pusey: You also have to make all the other tradesmen aware of the flex pipe because it is more vulnerable than steel. It is possible to put a leak in the CSST pipe with a drywall screw or shoot a nail through it if it’s not protected properly, which you don’t have to worry about with conventional cast iron pipe.

Foss: Did you use a manifold?

Wagner: Yes. I put a manifold in the basement down by the hvac unit so the homeowners could add lines if they remodel, but it doesn’t really matter where you put it. You don’t even have to use a manifold. Instead, you can just put in t-fittings. You might save some time, but they’re less handy in the long run than the manifold, which has extra spaces for future retrofits. You can also turn the main gas line off right there.

For more information on CSST flex pipe and to find a list of manufacturers, visit www.toolbase.org, a joint site of the nahb Research Center and the Partnership for Advancing Technology in Housing.

Asa Foss writes about better building practices on behalf of the Partnership for Advancing Technology in Housing  (PATH) (www.pathnet.org). PATH is administered by the U.S. Department of Housing and Urban Development. Learn more at www.pathnet.org.