Page 107 - International safety guide for oil tankers and terminals

GENERAL HAZARDS FOR SHIP AND TERMINAL

It is also permissible to restore voltage to apparatus for testing during a
period of repair or alteration, subject to the same conditions.
---ใช้เพื่อการศึกษาเท่านั้น---
Before undertaking any Hot Work, reference should be made to Section 9.4.

งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี

4.5 Use of Tools

4.5.1 Grit Blasting and Mechanically Powered Tools

It should be noted that grit blasting and the use of mechanically powered tools
are not normally considered as falling within the definition of Hot Work in the
shipping industry. However, these activities have a significant potential for
producing sparks and should be carried out under the control of a Permit to
Work system, or under the control of the ship’s Safety Management System.

The following precautions should be observed:
The work area should not be subject to vapour release, or a concentration
of combustible vapours, and should be free of combustible material.
The area should be gas free and tests with a combustible gas indicator
should give a reading of not more than 1% LFL.
Mechanical tools should not be used when the ship is alongside a terminal,
unless the express permission of the Terminal Representative has been
granted. ึ
There must be no cargo, bunkering, ballasting, tank cleaning, gas freeing,
purging or inerting operations in progress.

Adequate fire-fighting equipment must be laid out and ready for immediate
use.

The hopper and hose nozzle of a grit blasting machine should be electrically
bonded and earthed to the deck or fitting being worked on.

There is a risk of perforation of pipelines when grit blasting or chipping, and
great care must be taken when planning such work. Before commencing work
on cargo lines on deck, they should be flushed. Drop line valves should be
closed and bottom lines filled with water. The atmosphere inside the section to
be worked on should be confirmed as either inerted to less than 8% oxygen by
volume or gas free to not more than 1% LFL. Similar precautions should be
adopted for inert gas and crude oil washing lines, as appropriate.

4.5.2 Hand Tools

The use of hand tools such as chipping hammers and scrapers for steel
preparation and maintenance may be permitted without a Hot Work Permit.
Their use must, however, be restricted to deck areas and fittings not connected
to the cargo system.

The work area should be gas free and clear of combustible materials. The ship
must not be engaged in any cargo, bunker, ballasting, tank cleaning, gas
freeing, purging or inerting operations.

Non-ferrous, so called non-sparking, tools are only marginally less likely to give
rise to an incendive spark and, because of their comparative softness, are not
as efficient as their ferrous equivalents. Particles of concrete, sand or other
rock-like substances are likely to become embedded in the working face or

© ICS/OCIMF/IAPH 2006 73