Maximum injection pressure. The owner or operator shall limit injection pressure to the lesser of:
(a) A value which will not exceed the operating requirements of § 144.28(f)(3) (i) or (ii) as applicable or;
(b) A value for well head pressure calculated by 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 inject fluid (unitless)
d = injection depth in feet.