Confined Space Entry Permits, Gas Testing and Rescue Plans Explained

Why Confined Spaces Catch Experienced Workers Out

Electricians end up in confined spaces more often than you might think. Cable chambers, service ducts, ceiling and floor voids, plant rooms, tanks, sewers and below-ground substations can all count as confined spaces. The danger is that most of them look harmless. You can’t see, smell or taste an oxygen-deficient atmosphere, and a build-up of toxic gas can overcome you before you notice anything is wrong.

In the UK, the Confined Spaces Regulations 1997 apply alongside the Health and Safety at Work etc. Act 1974 (HASAWA) and the Management of Health and Safety at Work Regulations 1999. Together they require employers to avoid confined space entry wherever reasonably practicable. When entry can’t be avoided, they require a safe system of work and suitable emergency arrangements to be in place before anyone goes in.

This guide works through the key points from a confined space safety training video by HSE Professionals: permits, gas testing, respiratory protection and rescue planning. It also covers what you need to know for the Special Site Hazards section of the ECS HS&E test.

The Confined Space Entry Permit

The video makes the first rule plain:

“No one should enter or work in a confined space without a valid entry permit.”

A permit to work is more than paperwork. It shows that someone has thought through the hazards and that the controls have been checked. A valid confined space permit should clearly show:

• Identification and location of the confined space
• Purpose of entry: what work is being done
• Date, time and validity period of the permit
• Hazards identified and the control measures in place
• The named confined space attendant
• Ventilation and lighting arrangements
• Results of atmospheric testing

Who Signs It Off?

The permit process has more than one person checking it:

1. The supervisor applies for the permit and fills in the details.
2. A safety assessor goes with the supervisor to inspect the space and carry out a gas test. The results are recorded.
3. The authorised manager reviews the results. Once satisfied that the space is safe and the controls are in place, they approve and issue the permit.
4. A copy of the endorsed permit is displayed at the entrance of the confined space before work starts.

If any of these steps hasn’t happened, don’t go in. Treat an unsigned or out-of-date permit as no permit at all.

Gas Testing: Checking the Atmosphere

The video gives the reason for testing:

“Most toxic or flammable gases and oxygen deficiency cannot be easily detected, so it’s important to test the atmosphere of a confined space.”

All gas test results must be recorded and attached to the permit. A typical test follows a set order.

1. Oxygen First

Test oxygen levels before anything else. The video gives an acceptable range of 19.5% to 23.5% for safe entry. Normal air is about 20.9%.

• Below the range: oxygen deficiency, which can cause collapse and asphyxiation
• Above the range: oxygen enrichment, where materials ignite far more easily and burn far more fiercely

2. Flammable Gases and Vapours

Next, test for flammable gases. Concentrations should not exceed 10% of the Lower Explosive Limit (LEL). For an electrician this matters a great deal. A single spark from a tool, a light or a termination could ignite a flammable atmosphere.

3. Toxic Gases and VOCs

Finally, test for toxic gases, vapours and volatile organic compounds. Make sure they’re below their exposure limits. In the UK these are the Workplace Exposure Limits (WELs) published in HSE guidance EH40, which supports the COSHH Regulations 2002.

Getting Gas Testing Right

• Choose the right detector for the hazards that are likely to be present
• Calibrate it and make sure you know how to use it
• Test at different depths. Gases collect at different levels: some are heavier than air and sink, while others rise.
• Monitor continuously. At least one person in each group working nearby should carry a portable gas detector.
• Retest at intervals. Conditions can change during the work, especially if you disturb sediment, use solvents or run equipment.

Respiratory Protective Equipment (RPE)

The aim is always a space that is safe to breathe in without extra equipment. Sometimes that can’t be achieved, or entry is needed for a rescue. In those cases suitable RPE must be provided. Under the Personal Protective Equipment at Work Regulations 1992, PPE is the last line of defence, after other controls such as ventilation and isolation. For more on this, see our guide to PPE basics for electricians.

There are two main types of RPE.

Supplied-Air Respirators

These are used when there is too little oxygen or a high level of contaminants. Examples include:

• Self-contained breathing apparatus (SCBA)
• Airline respirators

Air-Purifying Respirators

These filter the air you breathe in. They’re lighter and easier to use, but they must not be used in:

• Oxygen-deficient atmospheres
• Poorly ventilated confined spaces
• Areas where the levels of toxic contaminants are unknown
• Atmospheres immediately dangerous to life or health (IDLH)
• Areas where contaminant levels are above the maximum permissible concentration or the capacity of the filter class

This often comes up in exams: a filter mask doesn’t give you oxygen. If the air is low on oxygen, a filter respirator gives you no protection.

Other PPE

Depending on the task, you may also need protective clothing, a safety helmet, eye protection, hearing protection, gloves, safety boots and a safety harness. The harness lets you be pulled out without someone else having to come in after you.

The Confined Space Attendant

Every confined space job needs an appointed attendant, sometimes called a top person or standby person. Their role is to:

• Stay outside the confined space at all times
• Monitor everyone who goes in and works inside
• Keep in contact with the people inside
• Start the emergency rescue plan if something goes wrong

The attendant must not go in to attempt a rescue. Many confined space deaths involve would-be rescuers who were overcome by the same atmosphere that caught the first casualty.

Emergency Rescue Plans

Regulation 5 of the Confined Spaces Regulations 1997 says nobody may enter a confined space unless suitable emergency arrangements are in place. The video lists what an effective rescue plan should include:

• Names of the designated rescue personnel
• Methods of rescue
• Type and availability of rescue equipment
• A reliable way to call the rescue team
• Regular rescue drills

The video ends with a warning worth remembering:

“Rushing into a confined space without proper preparation or equipment can endanger your life. Remember, an unplanned rescue will probably be your last.”

Any incident in a confined space that causes a death, a specified injury or a dangerous occurrence must also be reported under RIDDOR 2013.

What This Means for Your ECS HS&E Test

Confined spaces sit within the Special Site Hazards topic, along with asbestos, buried services and working near water. Make sure you’re confident on:

• When a permit to work is needed and what it contains
• The order of gas testing: oxygen, then flammable gases, then toxic gases
• Why filter respirators must never be used in oxygen-deficient atmospheres
• The attendant’s role, and why they must never enter
• The need for a planned rescue before work begins

For more on this topic, read our earlier article on confined space hazards, gas testing and safe entry. Asbestos is another hazard covered in the same section of the test, so our guide to asbestos in construction is worth reading too.

How Sparky Safety Can Help

Confined spaces show up regularly in the ECS HS&E test, and the details matter: gas testing order, oxygen ranges, RPE limits and who does what. The Sparky Safety app includes:

• 300+ ECS HS&E practice questions across all 11 topic areas, including Special Site Hazards
• Mock tests that work like the real exam, so you can check you’re ready before test day
• Study guides that explain why each answer is right, not just what it is
• Reference guides for quick revision of the key regulations and procedures
• 10 BS 7671 calculators for the electrical side of your day-to-day work

Download Sparky Safety today and go into your ECS HS&E test confident, ready to pass first time.