ProVent’s single stack system is a cost-saving solution in multi-story plumbing jobs in three stories or more. “It saves money spent on skilled labor and additional piping,” said Ken Cornwall, who spent 20 years as a mechanical contractor before developing the PVC single stack system in 2009. “It provides a much better method for contractors to stay ahead of the modern fast track job requirements.”

The system sounds very straightforward, and Cornwall, not surprisingly, believes it’s way overdue in gaining the proper plumbing code approval the system deserves. A specially designed PVC stack fitting is used at each floor level and receives the discharge from groups of bathroom fixtures at each floor. The fitting has interior separations that control the velocity flow from the wastewater in the stack. The branch waste piping is designed so the wastewater will not fill more than 40 percent of its diameter; this eliminates any possible water plugging that would require additional venting.

While the PVC aspect makes it somewhat new, the same type of system has been used for more than 50 years, starting with copper and then cast iron. The approval for using this type of system has been a problem area with some in the plumbing industry and some local plumbing codes. A test Standard ASSE 1043 for cast-iron systems was developed in 1993 to prove that this type of stack fitting would work as well as conventional DWV two-pipe systems.

“Some local plumbing contractors and inspectors are still a little leery of accepting a single stack system,” Cornwall added. “Where they allow it, they require the professional plumbing engineer to be licensed in each area to design the system.”

That means the plumbing engineer must take full responsibility for the entire operation of the system. Despite this condition, the single stack system is increasingly becoming accepted in the same manner as code-approved convention two-stack systems.

Some municipalities, however, haven't come to the same conclusions. Wisconsin has been an exception.

“They have recognized that the single stack plumbing system is the same as conventional plumbing,” said James J. Lagina, who runs Lagina Agency, Greenfield, Wisconsin, a manufacturers rep agency he started in 2012. “A master plumber or an engineer is allowed to professionally design and layout the system. The city or state examiner reviews and approves the single stack design, then submits it to the inspection department for issuing of the plumbing permit.”

Thanks to Lagina’s legwork, he says as many as 40 contractors prefer using ProVent throughout the Badger State.

“Everything that is three stories or more,” Lagina added, “it’s almost a given that the plumbing and mechanical contractor will use ProVent.”

Cornwall certainly has the type of rep he needs to educate the market on its single stack system. Lagina was in the plumbing trades for 35 years, ultimately running his own contracting business for a decade, before starting his agency. He started installing copper single stack systems when he was an apprentice and saw the system make the transition to cast iron.

Code approval

Burgess McMillian, plumbing plan examiner for the City of Milwaukee, broke down the approval process from the inspection and designer viewpoint. From an inspection viewpoint, McMillian initially questioned whether such a system would effectively drain properly.

“That’s the good thing about being an inspector,” McMillian said. “You’re there from when the shovel hits the ground until the running of the sinks. Initially, I would make the guys fill the sinks and just watch the drain performance. I was impressed that it did take the water fast.”

From a design criteria, since the single stack system requires less piping, the installation is much more efficient.

“Of course, it tends to be much more of a greater deal when it's a high-rise building,” he added. “That's when it seems to really kick in what a good idea this is.”

Added together, Burgess believes the planning process with a single stack moves along faster.

“Somebody, of course, whether it’s a master plumbers or engineer has to sign the plan,” Burgess explained. “But it gets permitted the same, it goes through the same inspections. I’m used to it now. It’s easier because it is less systems within the system, so to speak, because the conventional methods can have four or five different venting systems.”

Clearly, it’s a technical system that requires proper installation.

“For us to make sure the system works, we need to come alongside the plan reviewers and make sure they have the most current information and resources,” Lagina said. “We then, along with contractor, help to design the system properly so that it takes the strain away from the inspectors.”
Lagina and the ProVent team also came up with a certified installer program.

“We train the plumber before he touches a piece of pipe,” he added. “We have a program that makes sure they understand the design manual, the history of the system that is used all over the world. And they can use us as a resource.”

Labor-saver

Greg Jones, CEO and president, and Greg Stutz, vice president of commercial construction, for Dave Jones Inc., Madison, Wisconsin, gave the installation perspective. Greg’s father, Dave Jones, started the company from his garage in Mt. Horeb, Wisconsin, in 1977, along with his wife, Jill, as business partner and bookkeeper. In 1992, the relocated to Madison, Wisconsin, acquired a few local companies, and eventually grew to become a full-service plumbing, heating and cooling, and fire protection company with 300 employees. Last June, Greg and his sister, Holly, took over the business.

“It's definitely a time saver,” Jones said of the ProVent system. “That's the whole reason we looked at it in the first place about five years ago. We had a couple of six- or eight-story buildings that we were considering doing, and we looked at what the cost comparison was between the conventional system that we were installing and the ProVent system. The elimination of all those vents and piping, and being able to not have to coordinate much of what we used to have to do with the other contractors is a big advantage.”

Time-saver, is one thing, but judging from the tough building schedules imposed by the general contractors, we’ll have to say, the ProVent systems sounds like a really skin-saver, too.

“We get a schedule,” Stutz added, “and barring any adverse weather conditions, we have to be prepared to find the most effective way to get our things in and get it done. The ProVent system gives us the advantage to get ahead of some of the other guys on the job site. We can progress through the job quicker, which allows us to set the pace for the other mechanical trades.”

Ultimately, what the single stack system saves the most is labor.

“Plumbing jobs, whether union or non-union, have to contend with the same problem,” Lagina added. “The industry can’t find enough people. And it appears that’s going to be the case. Plus, things are getting busy again – the quantity of work is back to probably what the level was five years ago. So all of a sudden you have this backlog, but everybody is starting the work at the same time.”

Simply put, contractors need to do more work with less people.

“I constantly remind contractors that instead of looking for a toilet that’s two bucks less than the white one they’re buying now,” Lagina said, “to look at how they could install an entire system in a way that will put more of their people to work and do that work more productively.”

According to Jones, the fast-track nature is best for everyone.

“The projects that drag out are the ones that end up less profitable,” Jones added. “It’s a huge advantage for us to be able to meet that schedule because of the installation methods and products we’ve decided to move to.”

That attitude is good for everybody.

“We’re very much in a business that’s built on relationships,” Stutz said. “We have a lot of customers who hire us because they don’t have to worry about us. We do what we’re supposed to do. We get the job done. We’re not holding up anyone else’s schedule."