"Standard dimension ratio (SDR)" means the ratio of pipe diameter to pipe wall thickness.
N.H. Admin. Code § Env-Wq 1002.88
(See Revision Note at chapter heading for Env-Wq 1000) #9086, eff 2-9-08; renumbered by #9904-A (from Env-Wq 1002.85)
The amended version of this section by New Hampshire Register Volume 36, Number 41, eff.10/1/2016 is not yet available.