Piping insulation

[DIY]

Hi to everyone,
What is the best type,kind,thickness,and impervious etc. insulation, for CPVC or copper piping that will be for a hot water line and run an inch or 2 over 8' in length,and going underground at least 6 to 16"?

Thanks to all

 

[Furd]

Underground the best is Foamglas (do a Google) but I doubt that you could buy it and the cost would probably deter you. Next best would be Armaflex or Rubatex which you might be able to buy from an HVAC supply. I think that Grainger has Rubatex in limited sizes.

The important thing to remember in underground installations is that you MUST keep the insulation dry (fiberglass is a big NO). I would use nothing less than a one-inch thick wall. You might need a sheet metal or plastic covering anywhere that rodents might gnaw on the insulation, I know they will gnaw on any rubber or foam type of insulation.

 

[Sponsor]

 

[NHmaster]

armorflex breaks down underground. It gets brittle and cracks.

 

[DIY]

Peter Griffin thanks for that bit of information about armor(a)rflex breaking down underground.

Regarding if the soil is moist/wet 6 to 16" underground here....I would at that point decide to maybe slip a length of PVC piping over the insulation. My goals are this: keep the water hot/warm in the pipe length from WH ,so at the openoing of the hot side at any of the 3 faucets the water is not cold. Another goal is to shorten the pipe length as much as possible given the parameters to work with,so water delivery time is as quick as possible to faucet.

 

[Jadnashua]

Unless you are running the hot water fairly frequently, the water WILL cool off, regardless of the insulation you choose. If it is in contact with ground water, it will cool off much faster. To maintain the water hot, run a dedicated return line so you can add a recirculation system. Adding that pipe in at the time of construction is cheap. Use it if you decide you need it later. retrifitting it later is quite expensive, given a slab. depending on the layout of the points of use, you may need some branches on the return line and how many cross-over valves you need to keep each hot.

 

[DIY]

jadnashua hi, What is "If it is in contact with ground water" If you mean the pipe...no it will be covered with insulation. If the portion of pipe touches anything it will be the insulation,and the insulation will touch the earth. ( a pretty nifty idea i got from a plumber today..he said since the portion of pipe that needs to go underground is under a step that is @ 1' x 4',he said trench under step and put in the trench small chair rails, then set the insulated pipe on the chair rails and that will raise the piping up off the ground a good 2",and then at that point a backfill or no backfill under the step can be done depending on how fast you lose hot water when the insulated pipe is incontact with earth.) ...Sound crazy?

Regarding the fixture layout: Kitchen sink on one side of wall,directly on the other side of wall tub/shower/toilet,bathroom sink ..boom..1,2,3, all right there within 6 to 12" of each other.