gas pipe sizing

[sulconst2]

hello all.
new to the site. hope to get a question answered quickly as i'm in the middle of an addition.

installing a 90,000 btu furnace into an addition. calls for 82 cubic feet per hour. have a 50' branch run from meter. according to chart it should be 3/4"

my question is can i run 30' horizontal of 3/4" ips then reduce to 1/2" for my vertical run of 20' to the unit? or do i need to run 3/4" the whole way?

thanks in advance

[master plumber mark]

honestly, if you are running black pipe,

its usually best to do the max go 3/4 all the way

......because if you or the next owner might want to add a gas
water heater or other outlets someday it would
not be a big problem...

I myself would run it out of 1 inch black pipe

and reduce it down to half inch once you have gotten
into the mechanical room. putting a tee and a cap
in the line for future needs if any would arise.

it might sound like overkill,
but it dont really cost that much more

at least do the 3/4

[Dunbar Plumbing]

This is floating around the web forums alot try this one.


http://www.uscarb.com/natural-gas-chart.htm