In architectural acoustics, the reverberation time (RT) is widely used to characterize the acoustical behavior of a room. However, in the particular case of production rooms, workshops or any other industrial halls, RT recommendations or clouds of values cannot be easily found in the literature. The overall objective of the work presented here is to provide recommendations in terms of reverberation time for workshops. In France, the regulation for noisy workshops requires that the rate of decay of sound pressure per distance doubling (DL2) must exceed a certain limit value. In practice, the DL2 values are traditionally measured in workshops together with the RT values; hence, a database was created compiling both values. This database has been used to draw up reference limits for RT values with regards to compliance to the regulation. These reference limits have been further validated with respect to the literature and to a new set of data purposely collected for this comparison. Eight limits are proposed, which are divided in three categories: compliant/non-compliant, for furnished/empty workshops, with a 95/99% confidence interval. These limits are proposed to serve as target values for workshops, either at the design stage or for control purposes, to assess the quality of a workshop acoustic treatment with a simple and affordable measurement protocol.