Page 347 - Drilling Technology in Nontechnical Language

338 Drilling Technology in Nontechnical Language, Second Edition

Permit to Work Systems

A permit to work (PTW) system ensures that nonroutine work is carried

out safely and without conflicting with other work going on around the
rig. A permit is signed by the OIM or toolpusher; sometimes the drilling
supervisor will countersign the permit.

The permit will contain the conditions under which the work must take
place, any safety precautions required, how long the permit is valid for,
and any other relevant information. Once the work is complete, the permit
is returned to the OIM and closed.
Permits are generally issued for hot work, tank entry, overwater work,
and electrical work.
Hot work. Hot work refers to any welding, cutting, or grinding that
will be done in an area that could potentially experience an explosive
atmosphere. Typically this will be anywhere outside of the welder’s
workshop or accommodation. The hot work permit will call for gas
detection tests to be done before the job and perhaps at intervals during

the job, along with any special firefighting precautions (such as keeping an
extinguisher or hose ready at the job site).
Tank entry. If somebody has to enter a tank or enclosed space, the
permit will call for the atmosphere to be tested to ensure it is breathable.
It is likely that the person entering an enclosed space must wear breathing
apparatus. A safety monitor will stay outside the tank, probably with a
radio transmitter, and if the person in the tank requires assistance, this
monitor will call for help first and then take appropriate action to help.

Over water work. If somebody has to work over the water except
on properly constructed walkways, several precautions will be taken. A
safety harness with a line attached to the rig structure will be required,

as will a flotation vest. A safety monitor will stand by with a radio. The
standby boat will be called and will stay down current of the rig for as long
as the work continues.

Electrical work. Where electrical equipment will be worked on
outside of the electrician’s workshop, a work permit is needed. This permit
will show how the equipment is to be electrically isolated from the supply
plus any other precautions that may be required.

_Devereux_Book.indb 338 1/16/12 2:13 PM