Question for the engineers: What kind of pressure and the temperature would the steam be in these pipes? I ask because when I was in high school I worked installing sprinkler, drainage and sewer lines. And I am pretty sure that most lawn contractor folks are not qualified in high pressure/high temperature work. I also note that the maximum recommended temperature for Schedule 40 PVC is 130°F, well below the boiling point, and I doubt that there are many lawn contractor guys who use 6 inch schedule 40 steel pipe for lawn systems.
Speaking as a nationally certified pipefitter. low pressure pipe will use A105 carbon steel piping. High pressure would use A106 (seamless) carbon steel piping. You would not need stainless steel for a short duration system (3 years is short for industrial piping) unless your heat exchanger was exchanging heat with a corrosive chemical. The piping should be welded where possible because steam leaks will quickly cut steel. From what I saw in the deposition, I would assume that it is a low pressure system. Flanged connections should be with a metal gasket. Valves should be flanged gate valves. You could have a ball valve for quick stopping and starting of flow but it needs to be a specialty valve rated for steam usage and should have a gate valve backup. Contrary to what others have said, Home depot would not have any of this material but all of it except for any control valves in the system would readily available at an industrial pipe supply although there might be a couple of month lead time on the 180 degree elbows because they are rarely used and might have to be preordered. Although not exceptionally large, the total order would be two or more 40 foot trailer loads and need a significant staging area. Including prefabrication, the job would take more than a month for a crew of 10 working 40 hours a week*. If I were planning this job, I would have a crew of 1 supervisor, 1 expeditor, 1 laborer, 1 fork lift/crane operator (on this small of a job, frequently the supervisor will also perform this task), 2 pipefitters, 2 helpers, and 2 welders. The exchanger is listed as being encased in a wooden insulated box so you would need to hire 2 carpenters and 2 insulators after the piping is finished. Note that this does not make any sense because that would keep you from losing the heat that you built the exchanger for unless it is a weird design using enclosed forced ventilation. I find it impossible to believe that IH would not notice that kind of duct work and fan system along with the accompanying high velocity air flow. The system is supposed to be computer controlled but Rossi and the other 2 engineers could probably hook up any control systems.
*My estimate is based on minimal piping and does not include supporting because I have no idea what kind of supports are needed. A concrete floor could be supported in a day or two. Wooden flooring that needed extensive bracing could add weeks to the job.
*I believe the exchanger would take at least 2 months from start to finish with the crew described. My more than a month estimate involves everything going perfectly. As a rule of thumb, all jobs take about 50% longer to complete than a planners handbook indicates. Something always goes wrong in the job that slows you down. For example, there might not be enough clear space to get a 10 meter pipe in the space. This would suddenly increase the number of welds in the base exchanger piping by 50%.
*Proper piping outside the actual exchanger would probably add 1 to 2 weeks to the job.
IH Fanboy
Yes, a crew of 3 could probably dismantle the piping in less than a week but it would not be in any condition to reuse afterward. Rossi stated he dismantled the piping for reuse. It takes a lot longer than you think to salvage welded piping for reuse. It also takes a lot longer than you think to field weld 6 inch piping. On average, a pipefitter, helper, and welder is going to get 2 six inch field welds in a 10 hour day, 3 if they are lucky. Even in a fabrication shop setting, you are only going to make 4-5 6 inch welds in a 10 hour day.
