(1) fasteners into(a) curved or rounded objects, except if the tool is equipped with a protective device designed for such work;
(b) plaster tiles, hollow bricks or slates;
(c) cast iron, marble, granite, glazed linings and other hard and brittle materials;
(d) steel or alloys that are harder than the fastener used;
(e) hard materials in which holes have already been made, except if the tool is equipped with a device that is capable of holding back the fasteners;
(f) corner bricks or vertical mortar joints; and
(g) steel wherei. the steel is less than 4.83 mm thick;
ii. the point of entry of the fasteners is less than 50 mm from a weld;
iii. the point of entry of the fasteners is less than 13 mm from an edge;
(2) fasteners with a shaft diameter equal to or less than 4.83 mm into concrete where(a) the concrete is less than 65 mm thick or equal to 3 times the depth of penetration of the shaft of the fasteners;
(b) the point of entry of the fasteners is less that 50 mm from an unsupported edge; and
(c) the point of entry of the fasteners is less that 75 mm from another fastener that is broken.