MASTER`S GUIDE TO: ENCLOSED SPACE ENTRY
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<strong>MASTER`S</strong> <strong>GUIDE</strong> <strong>TO</strong>:<br />
<strong>ENCLOSED</strong> <strong>SPACE</strong> <strong>ENTRY</strong><br />
PAGE : 35 of 60<br />
DATE : 01.07.14<br />
PREPARED: MAR<br />
EDITION : 1.0<br />
09 Testing the atmosphere<br />
Do not enter an enclosed space without completing an entry permit.<br />
No enclosed space is to be entered until the atmosphere in the space has been found safe following<br />
thorough testing with approved and calibrated instruments. Tests should confirm that all areas of the space<br />
(bottom in particular) are safe for entry, that is, testing for:<br />
• oxygen deficiency<br />
• flammable gases and vapours<br />
• toxic gases and vapours<br />
At any time an atmosphere-related limit is exceeded, no matter what the reason, all personnel should<br />
immediately exit the space, and no-one should enter until atmospheric conditions are returned to safe<br />
levels. The entry permit should be revoked and re-entry suspended until authorised by a senior officer.<br />
Flammable atmosphere<br />
A combustible gas meter indicates flammability in percentage terms, within a safety range of 0–10% of the<br />
Lower Explosive Limit (LEL). It should ideally read 0%. A space with an atmosphere with more than 1% of<br />
the Lower Flammable Limit (LFL) or Lower Explosive Limit (LEL), on a combustible gas indicator should not<br />
be entered.<br />
Toxic atmosphere<br />
Toxins are measured in parts per million (ppm). An enclosed space shall be considered not fit for entry if<br />
the alarm concentrations are exceeded. If it is suspected the space contains toxins then a competent shore<br />
chemist should determine whether it is safe for entry.<br />
MARISCON GROUP 01.07.2014
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