%VL = (VL/(VT + VC)) * 100
where:
%VL = Percent leaking valves as determined through periodic monitoring required in paragraphs (b) through (d) of this section.
VL = Number of valves found leaking excluding nonrepairables as provided in paragraph (e)(3)(i) of this section.
VT = Total valves monitored, in a monitoring period excluding valves monitored as required by (f)(3) of this section.
VC = Optional credit for removed valves = 0.67 * net number (i.e., total removed-total added) of valves in organic HAP service removed from process unit after the date set forth in § 63.100(k) of subpart F for existing process units, and after the date of initial start-up for new sources. If credits are not taken, then VC = 0.
40 C.F.R. §63.168