No structural alteration, addition or renewal shall be made in or to any boiler registered under this Act unless such alteration, addition or renewal has been authorised in writing by the Chief Inspector: Provided that no such authorisation is required where the structural alteration, addition or renewal is made under the supervision of a competent person.

No structural alteration, addition or renewal shall be made in or to any boiler registered under this Act unless such alteration, addition or renewal has been authorised in writing by the Chief Inspector: Provided that no such authorisation is required where the structural alteration, addition or renewal is made under the supervision of a competent person.