SummaryStandards for measuring room acoustic parameters, such as ISO 3382, in manyc ases do not, or only partially, specify the requirements that ameasured impulse response should meet to allowcalculation of acertain parameter.A mong other things, it is often left to the user of the standard to findapractical interpretation of the time infinity that appears in the theoretical formulas defining the parameters. Hence, the parameter value may depend on the decay range and measurement time. Under the most adverse conditions this may lead to variations in the calculated parameter values larger than the Just Noticeable Difference (JND).U sing the suggested ISO 3382 'infinite' integration time limits for some parameters and otherwise the crosspoint of decay line and noise level as the 'infinite' integration time limit for the other parameters, the influence of the decay range on the calculated parameter values is investigated. This is done for all ISO 3382-1 parameters: