Self-ignition temperatures of materials from kinetic-reaction data

R esults of experimental determinations of the kinetic constants of the self-heating reaction are presented for wood fiberboard, cotton linters, sugar pine, cork, crepe rubber, GRS rubber, natural, synthetic, and blended foam rubber (with and without additive), various oils (raw linsecd, cottonseed, rapeseed, sperm, olive, castor, and neatsfoot) applied to cotton gauze in a ratio of 1. part of oil to 6 parts of cotton by weight, ammonium perchlorate, and nitrocellnlose plastic. Under the assumption that self-heating follows a first-order r eaction, these constants were used to calculate the critical radii of spherical piles for each of four surface temperatures likely to be experi enccd in long-period storage. Calcuhted self-ignition temperatures of piles of ~~-inch-diameter to 22-inch-diameter spheres of wood fiberboard and JIg-inch-diameter to 2-inch-diameter sph eres of cotton linters were in r casonable agreement with previous mcasurements by N. D. Mitchell (National Fire Protection Association Quarterly <i5 : 162, 1951).