If your operating plan includes more than 100 hours per year of curtailment, peak shaving, or any other type of operation during times when normal power is available, then a T4-certified solution and associated engine label is required by US Federal Law. Compliant solutions may address local requirements supplementing the Federal Law for stationary emergency use but any application operating beyond the 100 hour limit must have a certifiedT4 solution, and must be documented. Compliant solutions are not legally allowed for generator set operation beyond the 100 hour limit. The law addresses operational use of the generator within the 100 hour limit for conditions termed “Demand Response” in the January 30, 2013 Federal Register. The Federal Register document can be found here. See pages 6679-6681.