Licensing limit, LA
LA is the licensing limit [reference below, page 96] for daily handling. The values for the licensing limits are derived from the inhalation dose coefficient einh since inhalation is the main risk when radionuclides are handled in the laboratory. The inhalation of an activity LA on a single occasion yields a committed effective dose of 5 mSv. In some cases, the value derived for LA is lower than the value for LE, which is not consistent. In such cases, the LA value has been replaced by the LE value.
For inert gases, the licensing limit corresponds to the activity in an enclosed space of 1000 m3 and a concentration CA.
See also Exemption limit, LE
It follows that the quantity LA is absolute activity which gives rise to a dose of 5 mSv following inhalation, i.e.
LA = 5 mSv / einh(Sv/Bq)
Using the relation, the value of LA for a number of radionuclides is given in the table.