27.—(1) In carrying out its relevant functions in relation to radioactive substances activities, SEPA must have regard to the following maximum doses which may result from the planned carrying on of a radioactive substances activity, for use at the planning stage in radiation protection—
(a)0.3 millisieverts per year from any source from which radioactive discharges are first made on, or after, 13th May 2000; or
(b)0.5 millisieverts per year from the discharges from any single site.
(2) For the purposes of sub-paragraph (1), the maximum doses do not apply to doses which arise from medical exposures.