Page 290 - IGC BOOK

Factors to be assessed when assessing the risk in the Confined space

General conditions of the confined space must be assessed to identify the hazards that could be

present in the confined space.

Previous content - Information about previously stored contents for example cements or flammable

liquid storage facility gives indication of potential hazards.

Residues - Left over in the confined space including residual chemicals, sludge or wall scale can be

highly reactive.

Contamination - If the valves not closed correctly there could be leaks which could contaminate

adjacent areas.

Oxygen deficiency and oxygen enrichment - A lack of oxygen in the atmosphere may

also lead to asphyxia or unconsciousness, oxygen enrichment increase the risk of fire.

Physical dimensions - The physical dimensions, structure and layout of the confined space can result
in air quality differences within the space, which are unaffected by ventilation.

Hazards arising directly from confined space work

The hazards arising from work undertaken in confined space must be assessed. Conditions may
become hazardous when work is done in conjunction with residues, contamination etc.

Hazards that can be introduced into a space includes:

Operation of internal combustion engines

The operation of internal combustion engines, e.g. portable electrical generators or pumps, whose
exhausts contain carbon monoxide, carbon dioxide and nitrogen dioxide likely to seriously

contaminate the atmosphere.

ENSIGN | General Workplace Issues 23