ASTM International

Standard Practice for Calculation of Hazard Potential Figures of Merit for Thermally Unstable Materials
 N E1231

Annotation

This practice covers the calculation of hazard potential figures of merit for exothermic reactions, including:

(1) Time-to-thermal-runaway,

(2) Time-to-maximum-rate,

(3) Critical half thickness,

(4) Critical temperature,

(5) Adiabatic decomposition temperature rise,

(6) Explosion potential,

(7) Shock sensitivity,

(8) Instantaneous power density, and

(9) NFPA instability rating.

The kinetic parameters needed in this calculation may be obtained from differential scanning calorimetry (DSC) curves by methods described in other documents.

This technique is the best applicable to simple, single reactions whose behavior can be described by the Arrhenius equation and the general rate law. For reactions which do not meet these conditions, this technique may, with caution, serve as an approximation.

The calculations and results of this practice might be used to estimate the relative degree of hazard for experimental and research quantities of thermally unstable materials for which little experience and few data are available. Comparable calculations and results performed with data developed for well characterized materials in identical equipment, environment, and geometry are key to the ability to estimate relative hazard.