Confined Spaces 

Section 4   Safety and Operational Procedures 

n 

the loss of consciousness of any person at work arising from an 

increase in body temperature 

n 

the loss of consciousness or asphyxiation of any person at work 

arising from gas, fume, vapour or the lack of oxygen 

n 

the drowning of any person at work arising from an increase in the 

level of liquid; or 

n 

the asphyxiation of any person at work from a free flowing solid or 

the inability to reach a respirable environment due to entrapment by a 

free flowing solid. 

4.3.3  

Under the Confined Space Regulations 1997, a Confined Space has two 

defining features.  Firstly, it is a place which is substantially (though not 

always entirely) enclosed and, secondly, there will be a reasonably 

foreseeable risk of serious injury from hazardous substances or conditions 

in the space or nearby. 

4.3.4  

Some obvious confined spaces are fairly easy to identify, for example, 

closed tanks, vessels and sewers. 

4.3.5  

Others are less obvious but may be equally dangerous, for example, open 

topped tanks and vats, closed and unventilated or inadequately ventilated 

rooms and silos, or structures that become confined spaces during their 

construction. 

4.3.6  

The expression  confined space  may also refer to the following and other 

similar places: ducts, vessels, culverts, tunnels, boreholes, bored piles, 

manholes, shafts, excavations, sumps, inspection pits, cofferdams, freight 

containers, ship cargo holds / tanks, ballast tanks, double bottoms, ships' 

engine rooms, flues, buildings, building voids, some enclosed rooms 

(particularly plant rooms) and compartments within them, enclosures for 

the purpose of asbestos removal, and interiors of machines, plant or 

vehicles. 

4.3.7  

The expression also includes places that only occasionally become  

confined spaces due to the type of work to be undertaken e.g. a room 

during spray painting. 

4.4   

CONFINED SPACE CLASSIFICATION

4.4.1  

Due to the wide variation and nature of confined spaces that may be 

encountered, each space requires risk assessment and classifying according 

to the assessed risk, i.e. High, Moderate or Low. 

4.4.2  

Authorised Persons must classify each space in the area of their 

responsibility and maintain a register of classification of all confined 

spaces. 

4.4.3  

All manholes on foul and surface water drainage systems shall be deemed 

to be confined spaces.  Where adequate general instructions are given to 

all personnel who may gain access to manholes assessed as low and 

moderate risk confined spaces, warning notices at the entry points may be 

omitted provided access is controlled by suitable covers / locks.  The 

Authorised Person may treat other similar confined spaces in the same 

manner provided adequate instruction is given. 

April 2005 

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