Page 81 - International safety guide for oil tankers and terminals

HAZARDS OF PETROLEUM

atmospheres will inevitably arise if the tanks are discharged while the inert gas
plant is inoperable.
---ใช้เพื่อการศึกษาเท่านั้น---
However, various factors may inhibit pyrophor formation or a pyrophoric
reaction, consequently reducing the risk of ignition. These factors include:
งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
Lack of sufficiently thick deposits of iron oxide.

Inclusion of elemental sulphur and crude oil in tank deposits.
Venting of tanks with air.

These inhibiting factors are not, however, predictable nor can anyone be
confident that they will always be effective. Therefore, the degree of risk is
judged to be high enough to require that atmosphere control is always
maintained during and after discharge. To ensure that atmosphere control can
be maintained, the following practices should be observed:
Diligent maintenance of inert gas plants.
Spares should be kept on hand for critical parts which cannot be obtained
quickly or which can fail abruptly (e.g. the fans).
In the event of an inert gas plant failure prior to or during discharge of
cargo or ballast from cargo tanks, discharge should not commence or
continue until the inert gas plant operation is restored, or an alternative
source of inert gas is provided.
ึ
There is evidence that any pyrophoric deposit formed during the loaded
passage will not necessarily be deactivated during the subsequent ballast
passage. Therefore, the atmosphere in the cargo tanks should be maintained
in an inert or non-flammable condition both throughout the voyage and during
any discharge of ballast from them. The correct application of inert gas and
gas freeing procedures, as described in Sections 7.1 and 11.4, should ensure
that a flammable atmosphere is avoided.

2.7 The Hazards Associated with the Handling, Storage
and Carriage of Residual Fuel Oils

2.7.1 General
The first part of this Section deals with the flammability hazards associated
with residual fuel oils and provides information on flashpoint and vapour
composition measurement, together with recommended precautionary
procedures to be adopted when handling, storing or carrying residual fuel oils.

It should be noted that this guidance refers only to residual fuel oils and not to
distillate fuels.

Reference should be made to Section 11.8.2 for precautions to be taken when
measuring and sampling in non-inerted tanks when there is any possibility that
a flammable gas/air mixture may be present.

The last part of this Section refers to the hydrogen sulphide hazard associated
with fuel oil (see also Section 2.3.6).

© ICS/OCIMF/IAPH 2006 47