Confined space: Any area which is generally not designed for human occupancy, Limited means of entry and exit is called Confined space.
Standby man (Manhole watcher) is responsible person of Confined space.
Check points:
1. Entry into any confined space is potentially dangerous due to the possibility of oxygen deficiency, presence of flammable gas, hydrogen sulphide, or other toxic substances
2. Never enter a confined space / vessel until an Entry Permit has been authorized by the concerned asset owner in consultation with Occupational Hygienist / certified gas tester.
3. A confined space / vessel includes tanks, drums, large piping, manhole, pits, or any enclosure that may contain flammable & / or toxic substances or oxygen deficient environment.
4. Any trench deeper than 1.5 meters (e.g. excavation, pit, and sump) should be considered as a confined space.
5. All confined spaces must be ventilated and have a constant flow of air to be maintained. Air blowers can be installed necessary.
6. Gas tests are mandatory before authorizing an entry permit. The gas tests must include the following
- Flammable (combustible gas
- Oxygen content
- Toxic substances, which may be present, such as carbon monoxide, or hydrogen supplied.
7. Gas test limits for a normal vessel entry are: oxygen content more than 19.5%, combustible gas at 0% LEL, and hydrogen sulphide at 0 parts per million.
8. If gas test results are out of the normal range, then special equipment such as respirators, protective clothing and forced air ventilation will be required
9. The results of gas tests and any special precautions must be recorded on the entry permit
10. The frequency of gas test in confined space shall be indicated on the entry permit by authorized gas tester / Occupational Hygienist.
11. Communication methods: Face to face, Hand signal, Verbal communication, Radio communication, Distress meter use is appreciable.
O.A.T.H Method
- O for Ok
- A for advance give me rope
- T for take me up
- H for help