The requirements of subpart H of this part shall be strictly observed: Provided, however, That in cases of practical difficulties or unnecessary hardship, the Assistant Secretary in his discretion may grant exemptions or variations from any provision in that subpart.

Except as otherwise noted in this part, all functions required by subpart H of this part shall be carried out by or under the supervision of a person accredited for the purpose or by his authorized representative.

All required unit proof load tests shall be carried out by the use of weights as a dead load. Only where this is not possible may dynamometers or other recording test equipment be used. Any such recording test equipment owned by an accredited person shall have been tested for accuracy within the 6 months next preceding application for accreditation or renewal thereof. Such test shall be performed with calibrating equipment which has been checked in turn so that indications are traceable to the National Bureau of Standards. A copy of test reports shall accompany the accreditation application. Where test equipment is not the property of the accredited person, that person shall not issue any certificate based upon the use of such equipment unless its owner has made available a certificate of accuracy based on the requirements of this paragraph obtained within the year prior to such use, and stating the errors of the equipment. In any event, reasonable standards of accuracy shall be met and proof loads adjusted as necessary.

The qualifications of any person appointed or recognized by any accredited person for the purpose of carrying out certification functions shall meet with the approval of the Assistant Secretary.

Sections 1919.10(e) and (g) and 1919.11 shall govern, to the extent applicable, persons accredited under subpart F of this part.