(a) the entrance to the pit must be covered and be at least 1 metre deep and 900 mm wide;
(b) the neck of the pit must be at least 900 mm wide;
(c) there must be a clearance of at least 150 mm on each side of a lever in the neck of the pit;
(d) there must be free access to every part of the underwork and—
(i) if free access is available from above to every part of the underwork, there must be a clearance of at least 150 mm below all parts of the underwork; or
(ii) in any other case there must be a clearance of at least 400 mm below the lowest lever; and
(e) the pit must be free-draining or be provided with automatic mechanical drainage and be kept free from any accumulation of water, mud and debris.