Certificates of compliance are valid for the following periods:

(a) for an ionising radiation apparatus used for medical diagnosis, other than a mammography unit, bone densitometry unit or ionising radiation apparatus used for dentistry, 2 years;

(b) for a mammography unit, one year;

(c) for a bone densitometry unit, 4 years;

(d) for an ionising radiation apparatus used for dentistry, 4 years;

(e) for an ionising radiation apparatus used for medical therapy, 2 years;

(f) for an ionising radiation apparatus used for a purpose other than medical diagnosis, medical therapy or industrial radiography, 4 years;

(g) for an ionising radiation apparatus used for industrial radiography, 2 years;

(h) for a radiation source that is a sealed source, one year;

(i) for a non-ionising radiation apparatus, 4 years.