What type copper to use for Hotel job.

i think that is a perfectly legit question....

you can use M or L. as Mark said it depends on the designe M is a little bit "quicker" and allows a dab more flow.

appendix A-4.of UPC gives values for water at 60 F . our potable water entering is signifigantly cooler.. most heating is above that temp. the propress fittings you use and the air eliminators reduce the air in the pipe and that in turn reduces the internal wear and tear of the pipe. i am thinking that Siggy's program does the pencil and button pushing for Pex Al pex,M and at the temp of your choise...plus it has a little orange warning

this has exceeded elebenteen GPM

or that pump no likey mojo

or the return temp is currently -34F and ya just might need a wee bit larger boiler:)

...chapter 6 of his book has some salient advise on pipe size to pump to $ type perspective.

my buddy Dave would never use L copper (unless it was speced) he is just frugal

one thing though L can take a few more freeze ups and dosent wowee the pipe and fittings like M, it has its strong suits. with all radiant the slab in the mech room is going to hold heat though for over a day and as long as the circs are rolling maybe even weeks:) might not say that in the books buh it is a consideration.. i wonder if Tom Boddet ,s light would work in 75 below:)

our underground water latterals are 80 K. because we have a supply and return latteral you can select the next meter and pipe size larger as the return latteral will become a "supply" as the main will see the pressure differential drop and water being lazy and wanting to get out of that main seeks the path of least resistance. there is a definite increase in F.U.(volume) that the larger meter and larger house sized pipe can carry.

there are locations that have used Wirsbo from underground storage tanks....they are buried Deep and insulated...