4. A safeguard shall –
(a)in the case of a safeguard which is designed to be attached, be securely attached to all the required anchors, and the anchors and the means of attachment thereto shall be suitable and of sufficient strength and stability for the purpose of safely supporting the foreseeable loading in arresting any fall and during any subsequent rescue;
(b)in the case of an airbag, landing mat or similar safeguard, be stable; and
(c)in the case of a safeguard which distorts in arresting a fall, afford sufficient clearance.