There are a few, basic principles you can follow to ensure your employees practise the correct caution when working in a confined space. If entry to a confined space is unavoidable, you need to develop a safe system for working inside the space.
Step #1: Appoint a competent person
- carry out a risk assessment of the conditions, and the work and activities that will be conducted in the confined space
- identify the necessary safety precautions to be taken according to the findings to avoid posing hazards to workers
- make recommendations on safety precautions to be taken (regarding the nature of the confined space, the associated risk and the work involved).
Step #2: Make sure the safe system of work (including the precautions you’ve identified) is developed and put into practice
Everyone involved will need to be properly trained and instructed to make sure they know what to do and how to do it safely.
Step #3: The 9 essential elements to include when preparing your safe system of work
- Appoint suitable persons for the work
Suitable workers should meet the following requirements:
- They should have received training to become ‘certified workers’
- They should have sufficient experience in the type of work to be carried out
- They should have a suitable build for the work if the risk assessment highlights exceptional constraints as a result of the physical layout
- They should be fit to wear breathing apparatus if the work requires the use of such apparatus, and there is no medical advice against an individual’s suitability to work in a confined space.
- Disconnect and properly lock off the power supply of all the machinery and equipment that could cause hazards in a confined space
- Blank off pipelines and service pipes with contents that could cause hazards
- Take effective steps to prevent an ingress or in-rush to the confined space of hazardous gas, vapour, dust, fume or free-flowing solid and liquid
- Cleaning and cooling before entry
A confined space should be adequately purged before the entry of workers to ensure that no sludge or other deposits will give off hazardous gas, vapour, dust or fume during the course of work. If steam cleaning is used, sufficient time should be allowed for cooling to ensure that it is safe to work in the confined space.
- Check the size of the entrance
Is the entrance big enough to allow workers wearing all the necessary equipment to get in and out easily, and provide safe access and egress in an emergency? For example, if the entrance is narrow, air-line breathing apparatus should be used instead of self-contained breathing apparatus, which is more bulky and therefore restricts passage.
- Provision of ventilation
You may increase the number of openings and therefore improve ventilation. Mechanical ventilation may be necessary to ensure an adequate supply of fresh air. Do not use oxygen to freshen the air inside the confined space as this will greatly increase the risk of fire or explosion. An adequate supply of fresh air is of particular importance if compressed gas or burning equipment is used inside the confined space (because of the dangers from build-up of engine exhaust).
Warning! Exhaust from fuelled engines contains carbon monoxide, which is so dangerous that use of such equipment in confined spaces should never be allowed.
- Testing the air
This is necessary in order to check that the air is free from both toxic and flammable gases, and that there is no deficiency in oxygen and the air is fit to breathe. Testing should be carried out by a competent person using a suitable gas detector, which is correctly calibrated. Where the risk assessment indicates that conditions may change in the course of work, or as a further precaution, continuous air monitoring as advised by the competent person is required.
- Provision of special tools and lighting
Non-sparking tools and specially-protected lighting are essential where flammable or potentially explosive atmospheres are likely. In certain confined spaces (e.g. inside metal tanks), suitable precautions to prevent electric shock include the use of extra low voltage equipment and, where necessary, residual current devices.
- Provision of personal protective equipment
Where the use of ‘approved breathing apparatus’ is recommended in a risk assessment report, or entry into a confined space for underground pipework is required, this is to ensure that any person entering or remaining in the confined space:
- is properly wearing an approved breathing apparatus of a type that gives appropriate protection given the nature of the confined space
- is wearing a suitable safety harness connected to a lifeline that is strong enough to enable him to be pulled out, and that the free end is held by a person staying outside the confined space who has sufficient physical strength to be capable of pulling the worker out of the confined space in an emergency. That person must remain in situ throughout the course of work.
- Issuance of safety certificate
You must issue a safety certificate, which ensures that all the safety precautions are in place and a formal check has been undertaken before workers are allowed to enter or work in the confined space. The certificate specifies the period during which workers may remain safely in the confined space. It is also a means of communication between site management, supervisors, and those carrying out the hazardous work. Essential features of a safety certificate are:
- location of the confined space
- names of workers who are going to enter the confined space
- names of persons who may authorise particular jobs and any limits to their authority
- risk control measures
- the name of the person responsible for specifying the necessary precautions (e.g. isolation, air testing, emergency arrangements, etc.)
- the name of the person staying outside the confined space
- the period during which workers may remain safely in the confined space.