22. Every employer shall take appropriate measures to ensure that work equipment is so constructed or adapted that, so far as it is reasonably practicable, maintenance operations which involve a risk to health or safety can be carried out while the work equipment is shut down, or in other cases—
(a)maintenance operations can be carried out without exposing the person carrying them out to a risk to his health or safety; or
(b)appropriate measures can be taken for the protection of any person carrying out maintenance operations which involve a risk to his health or safety.