Page 64 - Safety and health in construction

Safety and health in construction

9.3.4.6. If welding or flame cutting is done underground:
(a) timber supports and other combustible structures or materials should be protected
by a fireproof screen;
(b) suitable fire extinguishers should be kept readily available;
(c) a constant watch should be kept for outbreaks of fire;
(d) welding fumes should be removed by exhaust ventilation.

9.3.5. Electricity

9.3.5.1. Electrical installations in shafts and tunnels should comply with the
relevant national laws or regulations.
9.3.5.2. Main switchgear for cutting off the supply of electricity from all
underground installations should:
(a) be installed on the surface;
(b) be accessible only to authorised persons;
(c) be attended by a competent person authorised to operate it.

9.3.5.3. Where necessary suitable lightning arresters should be installed on the
surface to protect the installation below ground from abnormal voltage due to
atmospheric electricity.

9.3.5.4. The main cables supplying current to electric motors installed in the
vicinity of shafts (such as those for underground fans or drainage pumps) should be
duplicated if the stopping of these motors would cause danger.
9.3.5.5. All switches should be of the enclosed safety type.

9.3.5.6. Fixed lamps underground should be provided with a strong protective
cover of glass or other transparent material or with a guard.
9.3.5.7. Whenever required by local conditions, lamp fittings should be proof
against dust, gases and water.
9.3.5.8. The voltage of hand lamps (portable lamps) used underground should
not exceed extra-low safety voltage.

9.3.6. Underground lighting

9.3.6.1. All places where workers have to work or pass should be adequately lit.

9.3.6.2. In addition to the main lighting, there should be emergency lighting that
functions long enough to enable the workers to reach the surface safely.

9.4. Drilling

9.4.1. When drilling is done in rock, loose rock should be scaled down to protect
drillers against falls of ground; where this is not practicable, a protective canopy or
overhead screen should be provided.

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