Flammability limits of ammonia-air mixtures

Document Type

Conference Proceeding

Publication Date



Mechanical Engineering


In an attempt to increase the level of understanding of ammonia combustion, this paper presents the results of a recent study of the flammability limits of ammonia-air mixtures. In the past, these studies have been conducted using a flame tube to determine the flammability limits of the gas. The study reported here used the ASTM E 681-85 (ASTM 1985) standard method. Even though the flammability limits of ammonia have been established in the past, it was necessary to determine the limits using this relatively new method, since it is drastically different from any previously used method. A brief but complete literature review is provided, followed by a discussion of the flammability testing apparatus and experimental results. The measured upper and lower flammability limits in dry air were 27.35% and 15.15%, respectively. In air with a relative humidity of 100%, the upper and lower flammability limits narrowed to 15.95% and 26.55%, respectively.

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Last Page


Publication Title

ASHRAE Transactions


At the time of publication, Randy D. Kelley was affiliated with Kansas State University.

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