This paper presents accelerated lifetime tests on a polypropylene film capacitor. Experimental parameters (20% droop, 5 Hz repetition rate) simulate anticipated operating conditions encountered in the SLAC P2 Marx. Elevated film electric field stress is utilized as the acceleration parameter. Results indicate that, for the particular film of interest, a film stress of ~290 V/m corresponds to a 10^5 hour lifetime. In addition, the voltage scaling exponent for this film is 13.1.