3.1 Upon satisfactory results of both the audit
of the company referred to in 2.2 and the demonstration tests referred
to in 2.3, the Administration or organization recognized by the Administration
should issue a certificate of approval as well as a notice to the
effect that the thickness measurement operation system of the company
has been certified.
3.2 Renewal/endorsement of the certificate should
be carried out at intervals not exceeding three years by verification
that original conditions are maintained.