A risk assessment is useful only when its conclusions lead to effective precautions. In Module 3, you identified hazards, people at risk, existing safeguards, and improvements. We now turn those findings into a workable set of controls. The measures must suit the actual space, the work, the workforce, and the ways conditions may change.

The next two modules examine how to prevent harm during work in and around substantially enclosed spaces. Begin with the most powerful option: design the task so that nobody has to enter. Then consider the layers of protection needed if the work cannot reasonably be completed from outside.

You will see how the hierarchy of control guides those decisions. Removing the need to enter should be actively explored, documented, and revisited whenever equipment or methods change.

For necessary entries, this module develops the safe system of work: suitable access and escape, lighting and ventilation, appropriate equipment, and control over anything introduced into the space.

We will also cover competent management and training, dependable communication, atmospheric testing, and the isolation of pipes, moving machinery, electricity, and free-flowing materials. These precautions work together; a good gas reading alone never makes an unsafe entry safe.

We will work through these subjects in a practical order:

• How the hierarchy of control sets priorities
• Methods of avoiding entry altogether
• Building a task-specific safe system of work
• Providing safe access, exit, lighting, and ventilation
• Choosing and maintaining suitable work equipment
• Reducing risks from chemicals and other substances
• Management, supervision, and checks during the job
• Training and competence for each assigned role
• Reliable communication between the space and the outside team
• Atmospheric testing before and while work continues
• Isolation from connected services and mobile materials

Risk assessment follows a sequence, and so does choosing controls. Start with the strongest feasible measure and move downward only when a higher level cannot adequately deal with the hazard. For confined spaces this matters because several hazards can worsen quickly and may leave little time to escape. Explain the choice and check that the combined measures remain effective.

• Eliminate the exposure: avoid putting a person into the space. Use external inspection, remote cleaning, relocation of equipment, or a redesigned process if reasonably practicable. This is the starting point for every task.
• Substitute something safer: change a solvent, process gas, cleaning method, or powered tool so that it introduces less fire, toxicity, oxygen-depletion, or other danger. Confirm the substitute does not bring an unexpected new risk.
• Use engineering measures: physical barriers, positive isolation, mechanical ventilation, extraction at the source, protected access, and intrinsically suitable equipment can separate people from hazards. Verify their performance rather than assuming installation alone is enough.

Continue down the hierarchy:

• Apply administrative controls: plan the sequence, permit, supervision, training, instructions, testing schedule, and communications. These arrangements rely on people following the agreed method and therefore need active checks.
• Supply appropriate PPE where the remaining risk requires it. Helmets, protective clothing, suitable footwear, and respiratory protection have defined roles; breathing apparatus may be essential in a planned rescue. PPE must match the assessed hazard, fit the user, and be supported by training.

Use the hierarchy as a decision tool throughout planning, not as a one-off checklist. Several levels may be necessary at once, but choosing PPE should never replace a reasonably practicable way to remove the need for entry.

The duty to plan a safe task extends beyond the person who climbs inside. Employers, people controlling premises, designers, manufacturers, contractors, and workers all influence whether exposure is created or avoided. Their particular legal duties differ, so assign actions clearly in the project plan.

A designer or builder should first ask whether a vessel, structure, or piece of plant can be arranged without creating an enclosed area that later needs a person inside it. If this is not reasonably practicable, reduce the number and difficulty of foreseeable entries through the design.

• Design new equipment to allow inspection, cleaning, maintenance, and fault finding from a safe external position. Remote cleaning heads, removable sections, sampling ports, and accessible components can prevent routine entry. These decisions are cheaper and more effective when made before construction.
• Plan the full working life of the space. Consider not only its normal operation but also blockages, shutdowns, periodic inspection, and eventual repair. An opening adequate for normal access may be too small for a casualty and rescue equipment.
• Where elimination is impossible, minimise the time spent inside and the hazards brought into the space. Record the remaining entries so the future team understands why entry is necessary and which controls the original design provides.

A space already in service may still be adapted. Review each task separately: cleaning, inspection, sampling, and maintenance do not necessarily require the same access method. Modifications can avoid an entry or reduce the frequency of entry and the number of people exposed.

• Remote clearing tools: use suitable powered heads, air purgers, or vibration from a safe position to dislodge build-up in a silo or hopper. Assess stored energy, material movement, and dust before using a tool; remote operation must not create a new uncontrolled hazard.
• Inspection openings: install correctly positioned sight glasses, portholes, or access panels to view conditions without opening the main entry route. Keep them maintained so a cloudy window does not become a reason for unnecessary entry.
• Better visibility: use properly selected fixed lighting or externally directed light through a protected window. Consider electrical and ignition hazards before introducing lighting to an area that may contain flammable vapour or dust.

Other options include:

• Remote imaging: a camera, crawler, or probe can inspect tank walls, joints, and equipment that cannot be seen from an access point. Check that the device is suitable for the atmosphere and can be retrieved without sending someone inside.
• Sampling from outside: use long-reach probes and suitable gas-testing equipment from a protected position. Test at the relevant levels and locations; a reading at the opening may not reflect pockets deeper within the enclosure.

If a job genuinely requires entry, the decision must be supported by a suitable assessment and a written, task-specific method. Reconsider the alternative of remote work whenever the scope changes; a previously approved entry is not a permanent licence to enter.

The safe system translates each identified risk into a precaution, a person responsible, and a check before or during work. It also describes how the team will respond if conditions deteriorate or somebody needs help.

Safe place: make the approach, access opening, work area, exit route, lighting, and ventilation fit for the task and for a possible emergency. Guard open edges and keep the route clear of tools and hoses.

• Suitable equipment: select tools, platforms, meters, lighting, communications, and retrieval equipment for the environment. For example, an engine-driven generator can introduce exhaust gases and should be located outside the space.
• Safer substances: avoid or replace solvents, chemicals, fuels, and process gases that could create an atmosphere hazard. Where use remains necessary, control storage, quantities, release, and monitoring.
• Competent direction: managers allocate sufficient people and time; supervisors verify the precautions; an attendant can monitor entry and raise the alarm. Confirm who has authority to stop the job.

A safe system also needs:

• Prepared entrants: workers need role-specific instruction, practical competence, equipment checks, and a clear understanding of the emergency arrangements. A rescue plan is arranged before entry; improvised rescue puts others at risk.
• Write down the method and brief everyone who will apply it. A permit can authorise a defined hazardous task, but it does not replace the assessment or the physical measures described above.

The following slides develop each part of the safe system so you can connect a control with the hazard it is intended to manage.

A safe work area includes the approach to the opening, the space itself, and a route a worker could use to leave or be rescued. Restricted manholes and awkward hatches deserve special attention because PPE, breathing equipment, or a rescue harness may reduce usable clearance.

• Access and approach Remove unnecessary obstructions, secure covers, guard open edges, and provide a stable platform or ladder where needed. Plan how people will pass pipes, low plant, and changes in level without losing balance.
• Escape and recovery Keep the route clear throughout the job. Check that a person wearing the required PPE can turn, reach the opening, and be recovered by the planned method. Test the proposed method before entry where practicable.
• Lighting matched to the hazard Illuminate the whole work area, including changes of level and the route out. Where a flammable atmosphere could occur, select equipment appropriate to the assessed explosive-atmosphere risk and seek competent advice.
• Ventilation that works Provide an adequate fresh-air supply and remove airborne contaminants at source where possible. Position ducts so air reaches the actual work area, avoid recirculating exhaust, and verify effectiveness by monitoring.

A tool that is safe in a normal workshop may be unsafe in a wet, oxygen-poor, or potentially flammable enclosure. Match every item to the task and environment, taking the six listed hazards and other hazards into account. Inspect and maintain equipment according to the manufacturer’s instructions.

Examples of choices that may reduce risk:

• Appropriate electrical tools Use a correctly specified battery or reduced-voltage system where it lowers electrical risk. Protect cables and connections from water and damage, and confirm the chosen equipment is suitable for any explosive atmosphere.
• Guarded hand and powered tools Select low-noise equipment where useful, keep moving parts guarded, and control dust or fumes created by cutting and grinding. Avoid bringing a combustion engine or uncontrolled exhaust inside.
• Secure access platforms Provide a stable, properly assembled working platform with appropriate edge protection. A loose board across an opening is not a safe platform or escape route.
• Clearly identified machinery Check lifting gear and other equipment for the applicable conformity marking, capacity, inspection status, and suitability. A marking does not replace a task-specific inspection or competent installation. Before entry, check what each tool adds to the atmosphere, the available space, and the rescue route. Remove unused items to keep access and movement clear.

The assessment must cover chemicals already inside and materials introduced by the job. Small amounts can become dangerous quickly in a poorly ventilated enclosure, and some substances react with residues or displace oxygen.

Ask about all of the following:

• Physical and chemical behaviour: toxicity, flammability, oxygen displacement, reactivity, and possible by-products of mixing or heating.
• Existing contents and residue: deposits on a tank wall, flammable vapour left after drainage, chemical contamination, or grain and dust retained in a silo.
• Materials introduced for work: cleaning products, paints, adhesives, solvents, welding gases, and liquids pumped in for a process or a repair.

Natural or biological sources matter too. Sewage, slurry, rotting material, and stored crops can release harmful gases or create a combustible dust cloud even when no manufactured chemical was deliberately added.

First seek to eliminate or substitute the hazardous material. Where use is unavoidable, limit quantities, control the release point, ventilate, protect the worker, and test the atmosphere as the assessment requires. Record how substances are stored outside, transferred, used, and removed. Include foreseeable spills, hose failures, and the effect on people waiting outside the opening.

Choosing a chemical is only one decision. Plan how it reaches the space, what happens to vapour or dust during use, and how remaining material is removed. Review the hierarchy of control whenever a method or product changes.

• Avoid hazardous chemicals if a safe mechanical method works. If a chemical is needed, seek a less hazardous product and verify its suitability for the surface, existing residue, and ventilation arrangement. A safer product may still require gloves, extraction, or monitoring.
• Keep compressed-gas cylinders outside the space where practicable. Protect hoses from abrasion and crushing, inspect connections, and isolate supplies when not in use. Check whether a leaking gas could displace oxygen or contribute to fire.

The final module returns to the specific risks arising from cylinders, hoses, and hot work; consider those interactions before allowing any such equipment into the work area.

• Where exposure or atmospheric deterioration is foreseeable, arrange competent testing before entry and appropriate periodic or continuous monitoring during work. Keep the readings with the work record and define the action required at each alarm level.

The applicable chemicals framework in Ireland requires suppliers to provide safety information for hazardous substances. Obtain the current Safety Data Sheet, or SDS, for each product that may be used or encountered; check the exact formulation rather than relying on a generic product name.

In Ireland, EU REACH and CLP provide the framework for chemical information and classification. The route by which a product is supplied can affect which regulatory regime applies. Site managers should confirm current supplier information and the local rules relevant to their location.

An SDS helps the work planner:

• Identify the product and its main hazardous properties
• Understand exposure routes and the effects of accidental contact
• Choose compatible storage, handling, and emergency measures

The SDS is evidence to feed into a site-specific assessment. It cannot tell you by itself whether a residue in a tank, a nearby process, or inadequate ventilation makes this particular entry unsafe.

Look especially for:

• Product identity and recommended uses
• Hazard classification, warnings, and limits
• Composition and ingredients of concern
• First-aid instructions and symptoms that need urgent action
• Safe handling, storage, and transport information
• Spill, fire, and accidental-release response instructions

A safe method needs people to organise it, supervise it, and verify that it still works as the job progresses. Assign these responsibilities before the entry briefing rather than leaving them to be inferred by the crew.

Management ownership

A responsible manager ensures the project has enough time, competent people, equipment, and emergency capability. Check the arrangement again when the timetable, contractor team, or work scope changes.

Supervision appropriate to the risk

Choose a supervisor with sufficient knowledge of the hazards and controls. The assessment determines whether continuous attendance is needed; do not assume that a brief periodic visit is suitable simply because an earlier job appeared straightforward.

Checks during work

Monitor whether entry conditions, ventilation, isolation, access, communication, and worker behaviour match the plan. Record significant checks and actions, pause if a control is lost, and do not resume until the hazard has been reassessed. The supervisor and attendant should know how to raise the alarm and when to stop entry. Monitoring also includes checking the atmosphere where the assessment identifies that need.

Anyone planning, supervising, attending, entering, testing the atmosphere, or undertaking rescue needs instruction and practical competence for their assigned role. Generic awareness does not by itself qualify a person for a particular vessel or rescue method.

Understand the rules Explain The Safety, Health and Welfare at Work (Confined Spaces) Regulations 2001 and the requirement to avoid entry where reasonably practicable. Workers should know who authorises work and how the site applies its written safe system.

Understand the site hazards Brief the exact space, connected plant, work activities, likely atmospheric changes, controls, alarm triggers, and restrictions on tools or substances. Verify understanding, especially when several employers work together.

Follow the entry method Practise the permit procedure where one is required, pre-use inspections, entry and exit records, gas-monitor response, communications, and the stop-work rule. Training must reflect the actual equipment provided.

Respond without improvised rescue Explain alarms, withdrawal, casualty recovery, and who will contact emergency services. Nobody should enter to rescue a colleague unless specifically trained, equipped, authorised, and working to the planned rescue method.

Before entering, check: Can you describe the controls assigned to you in the current assessment? Have you been shown the equipment and the correct method of use?

If either answer is no, stop and tell the supervisor before work begins.

Instruction must cover the work to be done, the conditions in the space, the individual’s role, and the action expected if a safeguard fails. Record competence and refresher needs rather than treating attendance at a classroom session as the only test.

Examples of role-specific preparation:

Supervisors A supervisor must be able to check that the written method, isolation, monitoring, and permit conditions are applied throughout the job, not only when the permit is first signed.

Rescue personnel People assigned to rescue need practical training with the retrieval route, equipment, communications, casualty handling, and any breathing apparatus identified by the rescue assessment.

New starters Give a new worker the necessary site briefing and practical training before exposure. Direct supervision should continue until the person in control has confirmed competence for the assigned activities.

A space may appear lower risk after assessment, yet unforeseen change remains possible. In such cases:

Confirm that a worker who may operate without continuous direct supervision understands the full method, limits, and means of calling for help.

Record that decision and provide proportionate supervision and checks. Do not equate lower risk with an absence of monitoring or emergency arrangements. Where site conditions differ from the training example, pause and brief the new hazard rather than expecting the worker to improvise.

The person inside must be able to stay in contact with the attendant and receive clear instructions when conditions change. Spoken communication can be enough for some simple arrangements, but walls, machinery, PPE, distance, or noise may make it unreliable.

The method should connect:

• Entrants working in separate parts of the enclosure
• Entrants with the attendant stationed outside
• The entrant or attendant with the prearranged emergency response contact

During planning, check:

• Is the space underground or shielded in a way that blocks radio signals?
• What processes, products, tools, and machinery operate inside or nearby?
• Do internal baffles, walls, or changes in level obstruct sight or sound?
• How far will a worker move from the access point?
• Can the attendant see the entrant continuously, or only at some stages?
• Will noise or hearing protection interfere with verbal warnings?
• How fast must a warning reach the worker to allow safe withdrawal?

Decide which method works throughout the route and in foreseeable abnormal conditions. Test it at the furthest work location before entry, then establish a schedule of contact and an action if contact is missed.

Direct speech may work for a short, unobstructed entry where both people can reliably hear and see each other. Visibility alone does not remove the need for an attendant or a planned emergency response.

Two-way radio can support a more complex job, but check signal strength, battery life, and equipment suitability inside the space. A system that works only at the opening is inadequate for an entrant deeper inside.

A wired intercom can provide a dependable alternative where radio waves are blocked. Route and protect the cable so it does not snag the entrant, damage equipment, or obstruct escape.

Simple agreed rope signals may be a supplementary option in a suitable arrangement. Define each signal, test comprehension, and check that it cannot be confused with accidental movement.

Choose more than one means where a single failure could prevent a prompt warning or alarm. The assessment should explain how the attendant calls rescuers without abandoning the entry point. Include a clear loss-of-contact rule: the entrant stops work, withdraws if safe, and the attendant starts the planned emergency response if a contact check fails.

Where low oxygen or harmful substances could arise, sample the atmosphere before allowing entry and as needed during the job. Gas concentration can differ between the top, middle, and bottom of a vessel and can change once cleaning, welding, or nearby operations begin.

• Potential oxygen deficiency
• Potential toxic, asphyxiating, or flammable gases, vapours, and dust

If the atmosphere may deteriorate, use an appropriate continuous or repeated testing method. Forced ventilation often requires verification during operation, including checks after the fan stops or ducting is moved.

Monitoring supports a decision; it does not remove the need for isolation, ventilation, supervision, and a rescue plan. Set clear safe limits and alarm actions before the first reading.

A trained and competent person should choose the measurement points, use suitable calibrated equipment, interpret the readings, and record results. Check the meter before use and follow its operating instructions.

Where reasonably practicable, take the initial readings from outside the space. Do not send a worker into an untested enclosure simply to find a convenient place to sample.

A safe atmosphere at the start of a shift can become unsafe when a connected pipe is opened or a machine unexpectedly starts. Identify every source of material and energy that could enter or operate while people are inside.

• Prevent the release of gas, vapour, liquid, or free-flowing solid into the space. Trace connected services, drains, tanks, conveyors, and shared systems, and choose an isolation method that provides reliable separation for the duration of the job.
• Secure electrical, mechanical, hydraulic, pneumatic, and gravity-driven equipment. Lock off and prove disconnection, restrain moving parts, and prevent stored energy from being released. A stop button alone is not a verified isolation.

Use a method suited to the connected plant and foreseeable failure modes. Where one barrier would allow dangerous material to enter on failure, consider a positive separation or an additional verified safeguard.

• Physically disconnect a line or install a suitable blank when a pipe could deliver hazardous material. Identify and control both sides of the break so residual contents cannot spill unexpectedly.
• Where valves form part of the arrangement, secure them in the correct position and verify the line is depressurised and drained. Assess leakage paths and avoid assuming that a closed valve is always a complete isolation.
• Check that walls, partitions, covers, and other barriers genuinely separate the worker from material or energy under the expected pressure and loading.
• Isolate and secure machinery that is not needed during entry, but identify essential lighting, ventilation, and communications before disconnecting a supply. A control must not disable another safeguard.
• Test each isolation and confirm it stays effective through shift changes and handovers. Include the isolation points and any reinstatement conditions in the task record.

Where a lock-and-tag system is used, workers must understand its rules, personal lock allocation, verification steps, and the procedure for removing locks. Review the system as the work changes.