Maximum injection pressure. To meet the operating requirements of § 144.28(f)(3)(i) of this chapter, the owner or operator shall use an injection pressure at the well head no greater than the pressure calculated using the following formula:
Pm = (0.733-0.433 Sg)d
where:
Pm = injection pressure at the well head in pounds per square inch
Sg = specific gravity of injected fluid (unitless)
d = injection depth in feet.
40 C.F.R. §147.503