Reasonably Practicable in Health and Safety

The phrase "so far as is reasonably practicable" (SFAIRP) appears throughout UK health and safety law. But what does it actually mean? And how do you prove you've done enough?

What does reasonably practicable mean?

"Reasonably practicable" is a legal standard that sits between two extremes:

• It's more than what is convenient or affordable
• It's less than what is technically possible regardless of cost

The test balances the level of risk against the cost, time, and effort needed to control it.

The legal definition

The authoritative definition comes from Edwards v National Coal Board [1949]:

"'Reasonably practicable' is a narrower term than 'physically possible' and seems to me to imply that a computation must be made by the owner, in which the quantum of risk is placed on one scale and the sacrifice involved in the measures necessary for averting the risk (whether in money, time or trouble) is placed in the other; and that if it be shown that there is a gross disproportion between them - the risk being insignificant in relation to the sacrifice - the defendants discharge the onus on them."

This 1949 case involved a coal mine accident. It established that:

1. You must identify and assess the risk
2. You must consider what measures could reduce or eliminate it
3. You must weigh the risk against the cost/effort of controls
4. Only if the sacrifice would be grossly disproportionate to the risk can you justify not taking action

How reasonably practicable differs from absolute duties

UK health and safety law contains two types of duties:

Examples in legislation

Reasonably practicable duties (SFAIRP):

• Section 2(1) HSWA 1974: "ensure, so far as is reasonably practicable, the health, safety and welfare at work of all employees"
• Regulation 3 Management Regulations: "make a suitable and sufficient assessment of the risks, so far as is reasonably practicable"
• Regulation 4(1) Work at Height Regulations: "ensure that work is not carried out at height where it is reasonably practicable to carry out the work safely otherwise than at height"

Absolute duties (no SFAIRP qualification):

• Regulation 5 Electricity at Work Regulations: "every work activity shall be carried out in such a manner as not to give rise, so far as is reasonably practicable, to danger" - BUT many specific requirements in this regulation are absolute
• Regulation 6(1) Lifting Operations Regulations: "lifting equipment must be of adequate strength and stability" - absolute requirement
• RIDDOR: duty to report specified injuries and dangerous occurrences - absolute duty, no balancing test

The reasonably practicable test

To determine if a control measure is reasonably practicable, you must:

1. Identify the risk

• What is the hazard?
• Who might be harmed and how?
• What is the likelihood of harm occurring?
• What would be the severity if it did occur?

2. Identify possible control measures

• What could you do to eliminate the risk entirely?
• What could you do to reduce the likelihood?
• What could you do to reduce the severity?
• What is considered good practice in your industry?

3. Assess each control measure

For each potential measure, consider:

The risk side of the scales:

• How much would this measure reduce the risk?
• How significant is the risk it addresses?

The sacrifice side of the scales:

• What would it cost (money, time, effort)?
• How difficult is it to implement?
• What disruption would it cause?
• Is the technology mature and available?

4. Apply the gross disproportion test

The key question: Is the sacrifice grossly disproportionate to the risk?

• If the risk is significant and the measure is standard practice → you must implement it
• If the risk is minor and the sacrifice is enormous → you may not need to
• Most cases fall in between → exercise judgment and document your reasoning

The ALARP principle

ALARP stands for "As Low As Reasonably Practicable" - essentially the same concept as SFAIRP, expressed differently.

ALARP is often visualized as a triangle:

        ┌─────────────────────────────┐
        │   UNACCEPTABLE REGION       │
        │   Risk cannot be justified  │
        ├─────────────────────────────┤
        │   TOLERABLE REGION          │
        │   (ALARP/SFAIRP applies)    │
        │   Risk reduced to a level   │
        │   that is ALARP             │
        ├─────────────────────────────┤
        │   BROADLY ACCEPTABLE        │
        │   No need for detailed      │
        │   working                   │
        └─────────────────────────────┘

The three regions

1. Unacceptable region (top):

• Risk is so high it cannot be justified
• Activity should not proceed, or immediate action required
• Examples: unguarded dangerous machinery in use, work in immediately dangerous atmosphere without controls

2. Tolerable/ALARP region (middle):

• Risk has been reduced but cannot be eliminated entirely
• Further reduction is required if reasonably practicable
• This is where most workplace risks sit
• You must demonstrate that further reduction would be grossly disproportionate

3. Broadly acceptable region (bottom):

• Risk is negligible or trivial
• No further action required beyond maintaining current controls
• Examples: risk of meteor strike, risk of earthquake in UK (generally)

Demonstrating compliance - proving reasonably practicable

If prosecuted or challenged, you need to show that you made informed, reasonable decisions about risk control. Here's how:

1. Conduct and record proper risk assessments

• Identify hazards systematically
• Evaluate risks (likelihood × severity)
• Consider all reasonably foreseeable scenarios
• Document your findings

Evidence needed:

• Written risk assessments
• Records of who conducted them and when
• Evidence of review when circumstances change

2. Identify and evaluate control measures

• Research industry good practice
• Consult HSE guidance and standards
• Consider the hierarchy of control
• Evaluate multiple options

Evidence needed:

• Notes on options considered
• Reasons for accepting or rejecting each option
• Reference to guidance followed
• Professional advice obtained

3. Implement controls that are reasonably practicable

• Prioritize controls based on risk reduction
• Implement standard industry measures as a minimum
• Only reject a control if you can justify it's grossly disproportionate

Evidence needed:

• Records of controls implemented
• Dates of implementation
• Evidence of maintenance and monitoring
• Training records

4. Document your reasoning

• Explain why you did what you did
• Explain why you didn't do certain things
• Show your working - don't just state conclusions

Evidence needed:

• Decision logs
• Cost-benefit analyses for major decisions
• Meeting minutes discussing risk controls
• Professional advice received

5. Review and update regularly

• Reassess when circumstances change
• Monitor the effectiveness of controls
• Update when better methods become available
• Keep pace with industry standards

Evidence needed:

• Review schedules and records
• Records of changes made
• Evidence of staying informed about developments

Cost-benefit analysis in health and safety

"Reasonably practicable" involves weighing costs, but this is often misunderstood.

What cost-benefit analysis means

You CAN consider:

• Financial cost of the control measure
• Time to implement
• Disruption to operations
• Technical feasibility
• Availability of the technology or solution

You CANNOT simply decide:

• "We can't afford it" (unless truly grossly disproportionate)
• "It's too much hassle"
• "We don't want to spend that much"

The gross disproportion requirement

The courts have made clear that:

• The greater the risk, the less weight you can give to cost
• For serious risks (death or serious injury), the cost would need to be grossly disproportionate to justify not acting
• A factor of 3-10 times is sometimes used as a rule of thumb for "gross disproportion", though this is not fixed in law

Worked examples

Example 1: Working at height

Risk: Workers accessing roof for maintenance, risk of fall from 5 meters, likely to cause death or serious injury.

Control measure: Edge protection and guard rails (cost: £3,000)

Analysis:

• Risk is high (death/serious injury likely if fall occurs)
• Control measure is standard practice
• Cost is modest compared to risk
• No technical barriers to implementation

Conclusion: Reasonably practicable - must be implemented. Cannot argue cost is grossly disproportionate.

Example 2: Vehicle barriers in car park

Risk: Vehicle could mount pavement and strike building, very low likelihood, low severity (slow-moving vehicles, no pedestrians in impact zone)

Control measure: Concrete bollards around entire building (cost: £50,000)

Analysis:

• Risk is low (unlikely scenario, low severity)
• Not standard practice for this type of site
• Cost is very high
• Existing controls (speed limits, parking layout) already mitigate risk

Conclusion: May not be reasonably practicable. Cost could be grossly disproportionate to the low residual risk. But you must document this reasoning.

Example 3: Manual handling aid

Risk: Staff regularly lift boxes weighing 15-20kg, risk of musculoskeletal injury over time

Control measure: Trolleys and mechanical handling aids (cost: £500)

Analysis:

• Risk is moderate (not immediately life-threatening but significant over time)
• Good practice and recommended in HSE guidance
• Cost is low
• Easy to implement

Conclusion: Reasonably practicable - must be implemented. Standard, affordable risk reduction.

Common mistakes

1. Treating "reasonably practicable" as optional

Mistake: "It says 'reasonably practicable' so we have some discretion."

Reality: SFAIRP is not a get-out clause. You still have to do it unless you can prove it would be grossly disproportionate. The burden is on YOU to justify why you didn't act.

2. Using cost as the primary justification

Mistake: "We didn't implement that control because it was too expensive."

Reality: Cost alone is rarely sufficient justification. You must show the cost is grossly disproportionate to the risk - and for serious risks, that's a very high bar.

3. Ignoring industry standards

Mistake: "We did our own risk assessment and decided we didn't need that."

Reality: If a control is standard in your industry or recommended in HSE guidance, you'll struggle to argue it's not reasonably practicable. Industry norms set a baseline expectation.

4. Not documenting the decision-making process

Mistake: Making decisions informally without recording the reasoning.

Reality: If you can't show what you considered and why you made certain choices, you'll have no defence if challenged. Document everything.

5. Confusing "practicable" with "practical"

Mistake: "It's not practical for us to do that because of how we work."

Reality: "Practicable" means feasible or possible, not convenient or easy. If it CAN be done and would significantly reduce risk, it's probably reasonably practicable - even if it requires changing how you work.

6. Failing to review when circumstances change

Mistake: "We decided 5 years ago it wasn't reasonably practicable."

Reality: What was grossly disproportionate in the past may not be now. Technology improves, costs fall, standards evolve. You must review regularly.

UK regulatory context - HSWA 1974 and reasonably practicable

The Health and Safety at Work etc. Act 1974 is built on the concept of reasonably practicable:

Key sections using SFAIRP:

Section 2(1) - Employer duties to employees:

"It shall be the duty of every employer to ensure, so far as is reasonably practicable, the health, safety and welfare at work of all his employees."

Section 3(1) - Duties to non-employees:

"It shall be the duty of every employer to conduct his undertaking in such a way as to ensure, so far as is reasonably practicable, that persons not in his employment who may be affected thereby are not thereby exposed to risks to their health or safety."

Section 4(2) - Duties of controllers of premises:

"It shall be the duty of each person who has, to any extent, control of premises... to take such measures as it is reasonable for a person in his position to take to ensure, so far as is reasonably practicable, that the premises... are safe and without risks to health."

Why SFAIRP is fundamental to UK law

The Robens Report (1972), which led to the HSWA 1974, deliberately chose a goal-setting, risk-based approach rather than prescriptive rules. This required a flexible standard:

• Goal-setting: Tell duty holders what to achieve (safe workplaces) not exactly how to achieve it
• Risk-based: Focus resources on significant risks, not trivial ones
• Flexible: Adapt to different industries, technologies, and circumstances
• Proportionate: Balance protection with practicality

"Reasonably practicable" was the mechanism that made this work. It allows the law to apply to every workplace from offices to nuclear power stations, while maintaining proportionality.

Practical application - how to apply the test

Here's a step-by-step approach to applying the reasonably practicable test in your workplace:

Step 1: Assess the risk thoroughly

Use a structured risk assessment method:

1. Identify the hazard
2. Identify who might be harmed
3. Evaluate the likelihood (consider how often exposure occurs)
4. Evaluate the severity (consider worst credible outcome)
5. Calculate the risk level (low/medium/high)

Step 2: Research control options

• Check HSE guidance for your hazard/industry
• Look at industry standards (BS standards, codes of practice)
• Consult competent health and safety advisors
• Look at what similar organizations do
• Use the hierarchy of control (eliminate, substitute, engineer, admin, PPE)

Step 3: Evaluate each control option

For each option, document:

Risk reduction:

• How much does this reduce the risk?
• Does it eliminate the hazard or just reduce exposure?

Cost:

• Capital cost
• Installation cost
• Ongoing maintenance/running costs
• Lost production/disruption

Feasibility:

• Is the technology mature and available?
• Can it be implemented with current skills/resources?
• How long would it take?

Other factors:

• Is this standard practice?
• Is it recommended in HSE guidance?
• What do similar organizations do?

Step 4: Make and document your decision

For controls you implement:

• Record what you're doing and when
• Assign responsibility
• Set review dates

For controls you reject:

• Document why you considered and rejected them
• Explain the gross disproportion
• Be specific about costs and risks
• Reference any guidance or advice received

Step 5: Implement and monitor

• Carry out the planned controls
• Check they're effective
• Maintain and inspect regularly
• Train staff

Step 6: Review and update

• Set review dates (annually as a minimum, sooner if circumstances change)
• Monitor for accidents, near misses, or control failures
• Stay informed about new guidance or technology
• Update when better controls become available or more affordable

Examples in practice across different risks

Fire safety

Risk: Fire in office building, potential for serious injury or death

Reasonably practicable controls:

• Fire detection and alarm system - YES (standard, proportionate cost)
• Adequate escape routes and signage - YES (legal requirement, absolute duty in most cases)
• Fire extinguishers and training - YES (low cost, high benefit)
• Sprinkler system in 3-story office - MAYBE (depends on building size, occupancy, other controls; expensive but very effective)
• Individual escape respirators for every employee - PROBABLY NOT (very expensive, not standard practice, other controls adequate)

Electrical safety

Risk: Electric shock from faulty equipment

Reasonably practicable controls:

• PAT testing on a risk-based schedule - YES (standard practice, affordable)
• RCD protection on sockets - YES (required in many cases, very effective, affordable)
• Fixed wire testing every 5 years - YES (standard practice for commercial premises)
• Isolating transformer for every piece of equipment - NO (excessive cost, RCD protection already adequate)

Manual handling

Risk: Musculoskeletal injury from repeated lifting

Reasonably practicable controls:

• Eliminate manual handling where possible (e.g., suppliers deliver directly to point of use) - YES (often achievable with little cost)
• Mechanical aids (trolleys, sack trucks, hoists) - YES (affordable, effective)
• Training in safe techniques - YES (low cost, always required)
• Limiting weights to below 25kg - YES (generally reasonably practicable to reorganize)
• Full automation of all lifting tasks - MAYBE (depends on scale and cost; may be grossly disproportionate for small operations)

Working at height

Risk: Falls from height, potentially fatal

Reasonably practicable controls:

• Avoid working at height if possible - YES (legal requirement, first consideration)
• Collective fall protection (edge protection, guard rails) - YES (always preferred, standard)
• Work platforms/scaffolding for extended work - YES (standard practice)
• Fall arrest equipment (harness, anchor points) - YES (when collective protection not practicable)
• Air bags or safety nets below work area - MAYBE (depends on height, duration, other controls available)

Frequently asked questions

Key takeaways

Understanding "reasonably practicable" is essential for anyone with health and safety duties:

Remember:

1. It's a balancing test - weigh the risk against the sacrifice, not an excuse to do nothing
2. The burden is on you - you must prove you've done enough, not wait to be told
3. Document everything - record your risk assessments, decisions, and reasoning
4. Higher risk = higher expectation - for serious risks, the bar is very high
5. Industry standards matter - if it's standard practice, you probably must do it
6. Keep reviewing - what wasn't reasonably practicable before may become so as circumstances change
7. Get advice - for complex decisions, professional input strengthens your position

Next steps

To apply the reasonably practicable test effectively:

Complete your risk assessments →

Understand your duties under HSWA 1974 →

Check your compliance →

Related articles:

• Health and Safety at Work Act 1974
• Risk Assessment: A Complete Guide
• What is a Competent Person?

Useful tools:

• Risk Assessment Tool
• Compliance Audit Tool