Where:
RM = Annual percentage of process unit uptime during which control device is down for routine control device maintenance;
PUp = Process unit uptime for the previous semiannual compliance period;
PUc = Process unit uptime for the current semiannual compliance period;
DTp = Control device downtime claimed under the routine control device maintenance exemption for the previous semiannual compliance period;
DTc = Control device downtime claimed under the routine control device maintenance exemption for the current semiannual compliance period.
40 C.F.R. §63.2281