(1) The clearance between a handrail and any surface behind it shall be not less than,
(a) 60 mm, if the surface behind the handrail is rough or abrasive, or
(b) 50 mm, in all other cases.
(2) All handrails shall be constructed so as to be continually graspable along their entire length with no obstruction on or above them to break a handhold.