RAMS for Confined Space Entry: UK Guide to Safe Working

Confined spaces kill people who know what they are doing. That is what makes them so dangerous. The victims are not untrained labourers; they are experienced workers, supervisors, and (most commonly) the rescuers who rush in to help a fallen colleague. A safe atmosphere can become lethal in seconds. The only defence is a properly written RAMS backed by a genuine safe system of work.

This guide covers every critical section your confined space RAMS must include: gas testing protocols, ventilation requirements, permit to work procedures, communication plans, and the rescue plan that will determine whether a bad situation stays recoverable or turns fatal.

What is a Confined Space?

The legal definition comes from the Confined Spaces Regulations 1997. A confined space is any place that is substantially (though not necessarily entirely) enclosed, and where there is a reasonably foreseeable risk of serious injury from hazardous substances or conditions within the space or nearby.

Size is irrelevant. A large storage tank is still a confined space. A football-pitch-sized excavation can be a confined space if heavier-than-air gases accumulate. The defining factors are enclosure and the presence of foreseeable risk, not physical dimensions.

Common confined space examples include:

• Manholes and inspection chambers
• Sewers and drainage systems
• Storage tanks, silos, and vessels
• Excavations deeper than 1.2 metres
• Roof voids, ceiling spaces, and enclosed lofts
• Ducts, pipework, and flues
• Chambers, vaults, and pits

The hazardous conditions that make these spaces dangerous include oxygen depletion (biological or chemical processes consuming O2), toxic gas accumulation (H2S from decomposition, CO from engines or processes), flammable atmospheres (methane, petrol vapour, dust), engulfment by liquids or free-flowing solids, and excessive heat.

The Fatal Statistics

Confined spaces kill between 15 and 20 workers in the UK every year. The number has stayed stubbornly consistent for decades despite improvements in equipment, training, and regulation.

The most alarming statistic: roughly 60% of confined space deaths are rescuers. People who were never meant to enter the space, who saw a colleague collapse, and who entered on instinct without breathing apparatus. They died trying to help. This single fact should shape everything in your RAMS.

Many victims are experienced workers. They have entered the same space dozens of times without incident. The atmosphere was fine last Tuesday. But confined space atmospheres can change in seconds. A pocket of trapped gas shifts. Biological decomposition accelerates. A nearby process releases fumes. The space that was safe at 9am becomes lethal at 9:05am.

These deaths are preventable. Every single one. That is why the Confined Spaces Regulations 1997 place such strict duties on employers and the self-employed.

Confined Spaces Regulations 1997: Key Duties

The Regulations are short (only 6 substantive regulations) but the duties they impose are absolute. Three regulations matter most when writing your RAMS.

Regulation 4: Avoid entry where reasonably practicable. This is the first question your RAMS must answer. Can the work be done from outside? Remote cameras, long-reach tools, mechanical cleaning systems, and robotic inspection equipment mean that many tasks previously requiring entry can now be completed without anyone going inside. Your RAMS must demonstrate that you have considered alternatives and explain why entry is necessary.

Regulation 5: Safe system of work. If entry cannot be avoided, the work must follow a safe system of work. This is the core of your RAMS. It covers everything from pre-entry gas testing to the sequence of operations inside the space. The safe system must be documented, communicated to every person involved, and followed without deviation.

Regulation 6: Emergency arrangements. Suitable and sufficient arrangements for rescue must be in place before anyone enters the confined space. Not after. Not during. Before. This includes trained rescue personnel, pre-positioned equipment, and a tested communication system. If your rescue plan is "call 999", your RAMS is not compliant.

Writing the RAMS: Critical Sections

A confined space RAMS follows the same structure as any RAMS, but certain sections carry far more weight. Get these wrong and people die. There is no middle ground.

Gas Testing and Atmospheric Monitoring

Atmospheric testing is non-negotiable. Your RAMS must specify a minimum 4-gas monitor capable of detecting oxygen (O2), lower explosive limit (LEL), carbon monoxide (CO), and hydrogen sulphide (H2S). These four gases cover the most common confined space hazards. Depending on the specific environment, additional sensors may be needed (for example, SO2 near industrial processes).

Testing must happen at two stages. First, pre-entry testing: the atmosphere must be tested before the permit to work is issued. Test at multiple levels within the space (top, middle, bottom) because gases stratify by density. Second, continuous monitoring: the gas detector must remain active throughout the entire duration of work. It should be worn by the entrant with audible and visual alarms enabled.

Your RAMS must state the acceptable atmospheric levels:

• Oxygen (O2): 19.5% to 23%. Normal air is 20.9%. Below 19.5% indicates oxygen depletion. Above 23% creates a severe fire and explosion risk.
• LEL (Lower Explosive Limit): Below 10% of LEL. Any reading above 10% means immediate evacuation.
• Carbon monoxide (CO): Below 20 ppm. The workplace exposure limit is 20 ppm (8-hour TWA). CO is odourless and colourless, making it impossible to detect without instruments.
• Hydrogen sulphide (H2S): Below 5 ppm. H2S smells like rotten eggs at low concentrations but destroys the sense of smell at higher levels, so workers can stop smelling it just as it becomes lethal.

If any reading falls outside acceptable limits, the RAMS must require immediate evacuation and reassessment. No exceptions, no judgement calls on site.

Ventilation

Forced mechanical ventilation must be specified in your RAMS. Natural ventilation is almost never sufficient for confined spaces. A powered fan or blower should supply fresh air continuously throughout the work, positioned to create a flow pattern that pushes contaminated air out of the space.

Your RAMS must include a critical prohibition: never use oxygen to ventilate a confined space. Enriching the atmosphere with pure oxygen creates an extreme fire and explosion hazard. Clothing, hair, and materials become highly flammable in oxygen-enriched atmospheres. This has caused multiple fatalities and must be explicitly prohibited in the method statement.

Permit to Work

A permit to work (PTW) is mandatory for confined space entry. The permit is a formal document that authorises specific people to carry out specific work in a specific confined space during a specific time period. It is not a one-off form filed away; it is a live control document.

Your RAMS should specify the permit to work process: who issues it (a competent, authorised person, not the entrant themselves), what pre-entry checks must be completed before issue (atmospheric test results recorded, rescue equipment confirmed in position, top person in place), the time limit (permits should be limited to one shift maximum and re-issued for each new entry), and formal cancellation on completion of work or if conditions change.

Communication

The RAMS must require a trained top person (attendant) stationed at the entry point at all times while anyone is inside the confined space. This person must never enter the space, regardless of what happens inside. Their role is to maintain communication, monitor conditions, summon rescue, and control access.

Continuous visual or radio contact must be maintained between the entrant and the top person. Where line of sight is not possible (bends in pipework, deep shafts), intrinsically safe radios or wired communication systems are required. Your RAMS should define agreed alarm signals: a specific signal to evacuate immediately, a check-in frequency (for example, verbal confirmation every 5 minutes), and a procedure for loss of communication (treat as an emergency).

Rescue Plan

The rescue plan is the most critical section of any confined space RAMS. It is also the section most commonly left vague. Phrases like "rescue will be carried out by emergency services" or "dial 999 in an emergency" are not compliant with Regulation 6. The fire service may take 15 to 30 minutes to arrive. A person exposed to an oxygen-depleted atmosphere will suffer brain damage within 4 minutes and death shortly after.

Your rescue plan must include: a trained rescue team on standby at the site (not on call elsewhere), self-contained breathing apparatus (SCBA) available and ready to use, a winch and tripod system for vertical entry spaces, trained first aiders with oxygen resuscitation equipment, and a clear procedure that prohibits entry without breathing apparatus, even in an emergency.

The rescue team must be briefed before work starts. They must know the layout of the space, the hazards present, the number of people inside, and the extraction route. Equipment must be pre-positioned and checked, not stored in a van 200 metres away.

PPE Requirements

PPE for confined space entry goes beyond standard site requirements. Your RAMS should specify a full-body harness with an attached lifeline connected to a retrieval system (tripod and winch for vertical spaces, horizontal lifeline for horizontal spaces). This allows the rescue team to extract a casualty without entering the space.

Respiratory protective equipment (RPE) depends on the hazard assessment. For spaces where the atmosphere is known to be safe and continuously monitored, an emergency escape breathing device (EEBD) may be sufficient as a backup. For spaces where the atmosphere is or may become hazardous, self-contained breathing apparatus (SCBA) is required for entry. Never rely on filter-type respirators in confined spaces, as they do not protect against oxygen depletion.

The Rescue Plan: Why 60% of Deaths Are Rescuers

This section deserves its own heading because it is the single most important factor in confined space fatalities. The pattern is always the same. A worker collapses inside a confined space. A colleague at the entrance sees it happen. Instinct takes over. They climb in to help. Within seconds, they are unconscious too. Sometimes a third person follows. Sometimes a fourth.

The HSE has documented cases where more rescuers died than original entrants. The toxic atmosphere that incapacitated the first person is still there. It does not care about good intentions. Carbon monoxide does not distinguish between the worker and the hero.

Your RAMS must address this directly. It must state, in unambiguous language, that entry without breathing apparatus is prohibited at all times, including during an emergency rescue. This instruction must be reinforced during the pre-entry briefing. Every person on site must understand it. The top person must be trained to prevent spontaneous rescue attempts and to activate the planned rescue procedure instead.

Pre-positioned rescue equipment makes the difference. When the tripod is already in place, the winch is attached, and the harness lifeline is connected, extraction can begin immediately without anyone else entering the space. When the equipment is in a storage box somewhere on site, people die while others search for it.

The rescue team must be briefed before work starts, not after an incident. They need to know the space dimensions, the access and egress points, the hazards identified, and the exact steps to follow. A rescue plan that only exists on paper is not a rescue plan.

Generate Your Confined Space RAMS

Writing a confined space RAMS from scratch takes hours. Getting the gas monitoring thresholds, rescue plan structure, and permit to work requirements right requires deep knowledge of the Confined Spaces Regulations 1997 and the HSE Approved Code of Practice (L101).

SwiftRMS generates confined space RAMS documents that include pre-built gas monitoring requirements with the correct threshold values, a rescue plan template covering personnel, equipment, and procedures, permit to work integration, and method statement sequences specific to confined space entry. You describe the work, and the system produces a document you can review, edit, and issue.

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Related Guides

For more on the topics covered in this guide, see our related resources:

• Permit to Work Guide
• Construction Phase Plan Guide
• What is a RAMS?
• Safe System of Work Guide