Page 146 - International safety guide for oil tankers and terminals

INTERNATIONAL SAFETY GUIDE FOR OIL TANKERS AND TERMINALS

8.2.2 Summary of Gas Testing Tasks
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8.2.2.1 Atmosphere Monitoring

The external atmosphere should be monitored for:
taken to detect the presence of hydrocarbon gas, to confirm normalิชย์นาวี
Hydrocarbon vapour when undertaking Hot Work. This is achieved by
using a flammable gas indicator, capable of measuring gas to the
Lower Flammable Limit (LFL) and with the scale graduated as a
percentage of this limit (see Section 2.4.2).
Toxic vapours when loading cargoes containing toxic components and
when undertaking gas freeing operations following the carriage of
such cargoes. This is achieved by using an instrument capable of
measuring concentrations of toxic gases in the human toxicity range,
usually calibrated in parts per million (see Section 2.4.7).
in air of 21% by volume is present.ย์ฝกพาณ
8.2.2.2 Enclosed Space Monitoring

Prior to permitting entry into an enclosed space, measurements must be

oxygen levels and, if applicable, to detect the presence of any toxic
vapours. (For a full description of the tests required prior to entering an
enclosed space, reference should be made to Section 10.3.)

ึ
Measurement to ensure that the atmosphere is free of harmful
hydrocarbon vapour is undertaken using a flammable gas indicator
capable of measuring gas to the Lower Flammable Limit (LFL) and with
the scale graduated as a percentage of this limit (% LFL).
งานห้องสมุด ศูน
An oxygen analyser is used to determine that the normal level of oxygen

Where toxic vapour may be present in the space to be entered, the
atmosphere should also be tested with an instrument capable of
measuring concentrations of toxic gases in the human toxicity range,
usually calibrated in parts per million.

8.2.2.3 Inert Gas Atmosphere Management
To ensure compliance with statutory requirements, ships fitted with an
inert gas system must be equipped with an oxygen analyser for
determining the quality of the inert gas and for measuring the levels of
oxygen in the cargo tanks.

A gas indicator capable of measuring the percentage of hydrocarbon gas
by volume (% Vol) in an inerted atmosphere is also required for safe
management of operations that include the purging and gas freeing of
cargo tanks (see Section 2.4.4).

8.2.3 The Provision of Gas Measuring Instruments
SOLAS requires that a ship carrying cargoes that are likely to emit a toxic or
flammable gas, or to cause oxygen depletion in a cargo space, be provided
with an appropriate instrument for measuring the concentration of gas or
oxygen in the air, together with detailed instructions for its use.

Implicit in the above provision is the requirement that the ship operator
provides the correct instrument for each gas test required. It should be noted

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