To ensure safety and reliability, it is important that the explosives and other materials used in munitions do not interact adversely either physically or chemically. Data obtained by heat flow calorimetry on nitrocellulose-based propellants have been reviewed with the aim of identifying improved chemical compatibility assessment criteria. It was shown that relative and absolute assessment techniques could give contrary sentencing. It was concluded that basing the assessment on the absolute criteria would have the advantage that alternative test temperatures and durations could be utilised. After 7 days at 85 degrees C the increase in the absolute heat flow of the mixture should be < 15 J g(-1) in order to be assessed as compatible. The assessment of compatibility is complex and improved sentencing results from additional testing at different temperatures to establishing the Arrhenius data and/or chemical analysis to understand the reactions contributing to the heat flow.