Hg. Fisher et Dd. Goetz, DETERMINATION OF SELF-ACCELERATING DECOMPOSITION TEMPERATURES FOR SELF-REACTIVE SUBSTANCES, Journal of loss prevention in the process industries, 6(3), 1993, pp. 183-194
A self-accelerating decomposition temperature (TSADT) is the lowest am
bient air temperature at which a self-reactive substance undergoes an
exothermic reaction in a specified commercial package in a period of s
even days or less. The same substance and package must be able to surv
ive for seven days at a temperature within 6-degrees-C of the temperat
ure at which the reaction occurred. A TSADT is determined for the purp
ose of deciding whether a self-reactive substance should be subject to
temperature control during transport. We have re-examined the establi
shed T(SADT) test methods to clarify their application, affirm their v
alidity and extend them to a wider range of materials. Two of the four
test methods recommended by the United Nations Orange Book1 require c
alculations to determine a T(SADT). Our proposed method, which uses Ac
celerating Rate Calorimeter (ARC) data, requires similar calculations
to determine a T(SADT). To ensure determination of conservative values
when using any of the methods for self-reactive substances, the inves
tigator should 1. consider pressure increases and potential package fa
ilure due to non-condensable gas formation and 2. account for the effe
cts of a non-uniform temperature distribution within a viscous liquid,
paste or solid by using the Frank-Kamenetskii thermal explosion model
. Methodologies are discussed which address both of these areas. Also
discussed is a method to account for the effect of reactant depletion
on predicted T(SADT) values for both the Semenov and Frank-Kamenetskii
thermal explosion models. This correction can be significant and is r
equired to ensure that analytical values agree with experimental value
s.