As standard practice. The Procter & Gamble Company tested combustion safeguards on a monthly basis. The study summarized in this paper examined the risk impact of varying the safeguard test interval. Among the consequences considered were fuel explosions, flue gas/burning outside a combustor, steam-side overpressurization, water tube/fire tube rupture, and bringing the combustor down for testing when at full utilization. Abnormal situations in lightoff continuous operation, and shutdown modes were modeled using fault tree analysis. Gate-to-gate and common mode calculations were implemented in an Excel spreadsheet for determining the likelihood of each consequence, The overall loss rate. and the effect of changing the test interval, Results of the study indicate, for the particular combustor selected for analysis, increased risk if safeguards are tested either more than once a month or less than once a year. Survey result from 25 Council of Industrial Boiler Operators (CIBO) member companies indicated that annual testing of combustion safeguards is the predominant industry practice. Procter & Gamble is in the process of changing its standard practice worldwide to a three-month or six-month month combustion safeguards test internal, depending on the type of combustor.