Page 244 - International safety guide for oil tankers and terminals

INTERNATIONAL SAFETY GUIDE FOR OIL TANKERS AND TERMINALS

Lowering of equipment
Cargo tank operation when
hazard can occur with ropes or tapes of Loading clean oils Tank washing
synthetic material
Electrostatic hazard Rubbing together of Flow of static Water mist droplets
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
[Chapter 3] synthetic polymers accumulator liquids [Section 3.3.4 & 11.8.2.5]
[Sections 11.8.2.2] [Sections 11.1.7 &
11.8.2.3]
Precautions necessary 30 minutes thereafter่านั้น---
For dipping, ullaging and [Sections 11.8.2.3 & [Section 11.8.2.3] [Sections 11.3.5.2 g) &
sampling with: 11.3.5.2 g)] 11.8.2.5]
(i) metallic equipment Do not use ropes or tapes Not permitted at any time Not permitted during
not earthed or made of synthetic washing and for 5 hours
bonded: materials for lowering into thereafter
---ใช้เพื่อการศึกษาเท
cargo tanks at any time
(ii) metallic equipment " Not permitted during No restrictions
which is earthed and loading and for
bonded from before
introduction until after
removal:
(iii) non-conducting " No restrictions No restrictions
equipment with no
metallic parts:

Exceptions permitted if: " Sounding pipe is used a) Sounding pipe is used
or
b) Tank is continuously
mechanically
ึ 5 hours can be
ventilated, when
reduced to 1 hour

Table 11.2 – Summary of precautions against electrostatic hazards when
ullaging and sampling non-inerted tanks

bonding cable is bolted. The stud should have electrical continuity
through the frame to the metal measuring tape. The other end of
the bonding cable should terminate in a spring-loaded clamp
suitable for attachment to the rim of an ullage opening.

Those responsible for the supply of non-conductive and
intermediate conductive equipment to ships must be satisfied that
the equipment will not act as spark promoters. It is essential that
non-conducting components do not lead to the insulation of any
metal components from earth. For example, if a plastic sample
bottle holder includes a metallic weight, the weight must be
bonded as described above or fully encapsulated in a minimum of
10 mm thick plastic.

Measures to Avoid Introducing Charged Objects
The suitability of equipment made wholly of non-metallic
components depends upon the volume and surface resistance of
the materials employed and their manner of use. Non-conducting
and intermediate conducting materials may be acceptable in
some circumstances, for example plastic sample bottle holders
can be lowered safely with natural fibre (intermediate conductivity)
rope. Natural fibre rope should be used because synthetic rope
generates significant static charge when sliding rapidly through an
operator’s gloved hand. This type of apparatus needs no special
bonding or earthing.

210 © ICS/OCIMF/IAPH 2006