Introduction to Health and Safety at Work

Introduction to Health and Safety at Work
324
17.7 Confi
 ned Spaces Regulations 1997

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2. Other than in an emergency, no person shall enter, 
carry out work or leave a confi ned space otherwise 
than in accordance with a safe system of work, 
relevant to the specifi ed risks.
17.7.5 Risk 
assessment
Risk assessment is an essential part of complying 
with these Regulations and must be done (under the 
Management of Health and Safety at Work Regulations 
1999) to determine a safe system of work. The risk 
assessment needs to follow a hierarchy of controls to 
comply. This should start with the measures – both in 
design and procedures – that can be adopted to enable 
any work to be carried out outside the confi ned space.
The assessment must be done by a competent 
person and will form the basis of a safe system of work. 
This will normally be formalized into a specifi c permit to 
work, applicable to a particular task. The assessment 
will involve:
(a) The general conditions to assess what may or may 
not be present. Consider:
➤
what has been the previous contents of the space
➤
residues that have been left in the space, for 
example, sludge, rust, scale and what may be 
given off if they are disturbed
➤
contamination which may arise from adjacent 
plant, processes, services, pipes or surrounding 
land, soil or strata
➤
oxygen defi ciency and enrichment. There are 
very high risks if the oxygen content differs sig-
nifi cantly from the normal level of 20.8%; if it is 
above this level increased fl ammability exists, if 
it is below then impaired mental ability occurs, 
with loss of consciousness under 16%
➤
physical dimensions and layout of the space can 
affect air quality.
(b) Hazards arising directly from the work being under-
taken, consider:
➤
the use of cleaning chemicals and their direct ef-
fect or interaction with other substance
➤
sources of ignition for fl ammable dusts, gases, 
vapours, plastics and the like.
(c) The need to isolate the confi ned space from outside 
services or from substances held inside such as 
liquids, gases, steam, water, fi re extinguishing media, 
exhaust gases, raw materials and energy sources.
(d) The requirement for emergency rescue arrange-
ments including trained people and equipment.