Introduction

A machinery risk assessment is the backbone of safe design and legal compliance. It is required for CE marking in the EU and UKCA marking and compliance in Great Britain and, done properly, it prevents accidents, reduces lifecycle costs, and makes audits straightforward. This guide sets out a watertight, practicable method you can adopt across industries and machine types, with a strong emphasis on harmonised EN standards and real-world implementation.

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What “Good” Looks Like

A best-practice risk assessment should:

• Be systematic (traceable from hazard → risk → control → residual risk).
• Follow ISO 12100’s logic (identify hazards, estimate and evaluate risk, reduce risk, verify).
• Apply the hierarchy of controls (inherently safe design → safeguarding → information for use/PPE).
• Cross-reference essential health and safety requirements (EHSRs) from the Machinery Directive (or UK equivalent).
• Reference relevant Type-B / Type-C standards used to control specific hazards.
• End with validation, a clear residual risk statement, and a robust technical file.

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Regulatory Context (CE and UKCA)

Machinery Directive / UK Regulations

• EU: Machinery Directive 2006/42/EC requires a documented risk assessment that drives design decisions to meet EHSRs before CE marking.
• GB: The Supply of Machinery (Safety) Regulations mirror the same principles for UKCA marking (UK “designated standards” align with harmonised ENs).
• Northern Ireland: Follows EU CE rules.
• Practical point: whether CE or UKCA, the process and technical expectations are materially the same. Design to the relevant EN standards and maintain a complete technical file.

Other Directives/Regimes that Often Apply

• Electrical safety: Low Voltage (EU) / Electrical Equipment Safety Regs (UK).
• EMC: Electromagnetic Compatibility (immunity and emissions).
• Pressure: Pressure Equipment/Assemblies where thresholds are exceeded.
• ATEX: Equipment for explosive atmospheres.
• RoHS/REACH, Radio Equipment, Outdoor Noise, Lift, etc., as applicable.
  Tip: Determine applicability early, and make sure your risk assessment covers the specific hazard domains implied by each regime.

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Using Harmonised EN Standards Effectively

Anchor Standard (Type-A)

• EN ISO 12100 (Safety of machinery — General principles — Risk assessment and risk reduction): your process blueprint.

Common Type-B Standards (Examples)

• EN ISO 13849-1/-2: Safety-related parts of control systems (Performance Levels).
• EN 62061 / IEC 62061: Functional safety of safety-related control systems (SIL) — alternative to 13849.
• EN ISO 13857: Safety distances to prevent reach into danger zones.
• EN ISO 14120: General requirements for guards.
• EN ISO 13855: Positioning of safeguards with respect to approach speeds.
• EN 60204-1: Electrical equipment of machines.
• EN ISO 4413 / 4414: Hydraulic / pneumatic systems and components.
• EN ISO 14119: Interlocking devices.
• EN ISO 14118: Prevention of unexpected start-up.
• EN ISO 11202/-4/-7, EN ISO 5349, EN ISO 2631: Noise and vibration measurement/evaluation.

Type-C (Machine-Specific)

Where a Type-C standard exists (e.g., robots, presses, woodworking machinery), it takes precedence for that machine type and often embeds B-standard principles. Applying the right C-standard typically provides state-of-the-art solutions and a strong presumption that the corresponding EHSRs are met.

Practical workflow:

1. Start with ISO 12100.
2. Map hazards → select relevant B standards.
3. Check whether a C standard applies; if yes, follow it.
4. Record every chosen clause you rely on in your risk log and technical file.

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Step-by-Step Risk Assessment (ISO 12100 Approach)

1) Define Machine Limits and Intended Use

Capture, in writing:

• Intended use and reasonably foreseeable misuse.
• Operating modes: normal, set-up, teaching, cleaning, fault-finding, maintenance, decommissioning.
• User profile: skill/competence, physical capabilities.
• Environment: indoor/outdoor, temperature, dust, moisture, explosive atmospheres, co-located equipment.
• Interfaces: power, pneumatics, hydraulics, utilities, material in/out, human-machine interface.
• System boundaries: standalone vs integrated line, upstream/downstream interactions.

Checklist — Machine Limits

• Purpose and throughput defined.
• Operating modes listed.
• Intended users and training level documented.
• Environmental and installation constraints stated.
• Interfaces and boundaries drawn.

2) Identify Hazards (All Lifecycle Stages)

Consider the whole lifecycle: transport, installation, commissioning, operation, cleaning, adjustment, maintenance, fault-finding, decommissioning.

Hazard families to sweep:

• Mechanical: crushing, shearing, entanglement, drawing-in, impact, cutting, ejection, instability, gravity/stored energy.
• Electrical: shock, arcing, fire, ignition sources, inadequate isolation/earthing, EMC upset.
• Thermal: hot/cold surfaces, flames, steam, cryogens.
• Noise/Vibration: exposure limits, startle effects, hand-arm/whole-body.
• Ergonomics: posture, force, repetition, reach/visibility, control labelling and layout.
• Materials/Substances: fumes, dust, mists, coolants, cleaning chemicals, biological agents.
• Radiation: lasers, UV, IR, ionising/non-ionising.
• Control system faults: unexpected start, loss of braking, dangerous failure modes, software errors, single-fault tolerance.
• Energy isolation: LOTO adequacy, stored energy dissipation.
• Environment/Utilities: ventilation, lighting, floor condition, trip/slip, manual handling.
• Combination effects: e.g., awkward posture + vibration + heat.

Checklist — Hazard ID

• Lifecycle walk-through performed.
• Cross-functional input (design, EHS, maintenance, operators).
• Use of standard annexes/checklists to avoid blind spots.
• All hazards logged with unique IDs and locations.

3) Risk Estimation (Before Additional Measures)

For each hazard, record:

• Severity (e.g., slight injury → fatality).
• Exposure (frequency/duration).
• Occurrence (probability of hazardous event).
• Avoidance (possibility of escaping harm).
  Use a defined risk matrix/graph (document your scale and thresholds). Be realistic; treat high-severity outcomes conservatively.

Checklist — Estimation

• Method and scales defined.
• Inputs/evidence noted (calculations, test data, field history).
• Initial risk rating assigned for each hazard.

4) Risk Evaluation (Acceptability & Priorities)

• Decide whether each initial risk is acceptable against your policy (often ALARP).
• Prioritise by risk level and severity.
• Determine which hazards require risk reduction.

Checklist — Evaluation

• Acceptance criteria documented.
• Prioritised action list produced.
• Rationale written for any risks deemed acceptable as-is.

5) Risk Reduction (Hierarchy of Controls)

(a) Inherently Safe Design
Eliminate or reduce hazards via geometry, kinematics, limits, materials, automation. Examples:

• Increase reach distances; remove nip points by design.
• Limit forces/pressures/speeds; add compliant mechanisms.
• Replace manual in-feed with automatic/robotic handling.
• Choose non-flammable coolants; design for stability.

(b) Safeguarding / Protective Measures
If residual hazards remain, apply guards and safety functions:

• Fixed / interlocked guards, interlock logic per EN ISO 14119.
• Electro-sensitive protective equipment (light curtains, scanners) with placement per EN ISO 13855 and distances per EN ISO 13857.
• Two-hand controls, enabling devices, safe speed/limited torque.
• Emergency stops (complementary), hold-to-run in set-up mode.
• Functional safety design using EN ISO 13849-1 (PLr) or EN 62061 (SIL).

(c) Information for Use / Administrative Controls / PPE
For remaining residual risks:

• On-machine warnings and pictograms.
• User manual: residual risks, safe working procedures, inspection/maintenance, LOTO, replacement parts, training.
• PPE requirements (e.g., eye, hearing, gloves).
  Note: Do not rely on warnings/PPE to control serious hazards that can reasonably be engineered out.

Checklist — Risk Reduction

• Controls applied in the correct order (design → safeguarding → info/PPE).
• Relevant standards and performance levels specified.
• Justification recorded where further reduction is not reasonably practicable.
• User interaction considered (avoid creating incentives to defeat guards).

6) Verification, Validation, and Residual Risk Statement

• Verify: Does each control exist and meet the stated requirement/standard?
• Validate: Does it actually reduce the risk? Examples:
  • Stopping-time tests vs. protective device distances.
  • Proof of PL/SIL via calculations and component data.
  • Electrical tests to EN 60204-1; earthing, insulation.
  • Noise/vibration measurements vs. declared values.
• Residual risk: Re-estimate risk with controls in place; confirm acceptability.
• Record any user obligations required to maintain safety (e.g., anchor to floor, periodic interlock checks, filter changes, guarding inspections).

Checklist — V&V

• Test records and calculations filed.
• Residual risk ratings updated and signed off.
• Manual and labelling reflect residual risks and safe methods.
• Commissioning checklist complete.

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Practical Examples

Example 1 — Conveyor Nip Hazard

• Hazard: Drawing-in at driven roller.
• Initial risk: Severe injury; frequent exposure.
• Controls:
  • Design: Smaller nip gap; auto-feed guides.
  • Safeguarding: Fixed nip guards; emergency-stop pullcord along length; interlocked access doors.
  • Information: “Keep hands clear” symbol; training on jam-clear procedure; LOTO instructions.
• Validation: Stopping distance vs cord switch spacing; guard gap check per EN ISO 13857; interlock fault-exclusion tested.
• Residual risk: Low (acceptable).

Example 2 — Robot Cell

• Hazard: Collision/crushing during auto mode and teaching.
• Initial risk: High severity; potential exposure during set-up.
• Controls:
  • Design: Paths kept away from access routes; speed/force limits in manual mode.
  • Safeguarding: Perimeter fencing with interlocks; safety laser scanner with warning and stop zones; enabling device for teaching; safety PLC to PL d/e or SIL 2/3.
  • Information: Teach procedure; PPE; floor markings; maintenance isolation steps.
• Validation: Safety function PL/SIL achieved; scanner coverage and response time; door interlock diagnostics; reduced speed measured.
• Residual risk: Low (acceptable).

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Documentation & Technical File (What to Keep)

Minimum contents to be watertight:

• Machine description, intended use, limits, and system boundary.
• Team, dates, competency evidence.
• Hazard register with unique IDs.
• Risk estimation/evaluation method, criteria, and initial ratings.
• Risk reduction actions with standards/clauses referenced and performance targets (PLr/SIL).
• Verification/validation records (tests, calculations, certificates).
• Residual risk statement and required user controls.
• Drawings, schematics, bill of safety-relevant components.
• User instructions (as supplied), labels/artwork.
• EC/EU Declaration of Conformity (or UK Declaration of Conformity) and applied standards list.
• For assemblies: integration risk assessment and interface hazards.

Retention: Keep the technical file for at least 10 years after the machine is placed on the market.

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When to Involve a Notified/Approved Body

• Annex IV / high-risk machinery (or UK equivalent), where conformity assessment may require a third party unless fully covered by harmonised standards and self-assessment route is permissible.
• Where novel technology or complex functional safety means you need independent review.
• If your internal competence/resources cannot demonstrate the claimed PL/SIL or other specialised safety performance.
  Good practice: Engage early to align on scope, standards, and evidence expectations.

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CE vs UKCA Marking – Practical Notes

• Design once, document for both: Same standards and evidence typically satisfy both regimes.
• Marking plates: Apply the correct mark (CE or UKCA), manufacturer details, year, model/type, serial, and essential ratings.
• Declarations: Use the right template (EU or UK), list directives/regulations and standards, and name the responsible person.
• NI and exports: Be mindful of Northern Ireland rules and any non-EU/UK markets’ additional requirements.

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Common Pitfalls (and How to Avoid Them)

• Late risk assessment → Build safety into the design from the start.
• Checklist tunnel vision → Use checklists to prompt thinking, not replace it.
• Over-reliance on signage/PPE → Engineer out serious hazards first.
• Defeatable guards → Design so normal work can be done with guards closed; use interlocks and diagnostics.
• Underspecified safety functions → Define PLr/SIL targets from the risk and prove achievement with calculations and component data.
• No operator/maintainer input → Involve them; they expose blind spots and improve buy-in.
• Weak verification → Measure, test, and document (stopping times, distances, noise, electrical tests).
• Stale documentation → Update the risk assessment when design or use changes, and after incidents/near-misses.

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Quick Hazard Sweep

• Mechanical: crushing, shearing, cutting, entanglement, drawing-in, impact, ejection, instability, stored energy.
• Electrical: shock, burn, arcing, fire, inadequate isolation, EMC upset.
• Thermal: hot/cold surfaces, steam, cryogens, ignition.
• Noise/Vibration: exposure limits, startle, HAV/WBV.
• Ergonomics/HMI: posture, force, reach/visibility, labelling, confusion.
• Substances: fumes, dust, mists, coolants, cleaning chemicals.
• Radiation: laser, UV/IR, RF.
• Control faults: unexpected start, loss of stop/brake, software error, diagnostics.
• Energy isolation: LOTO points, stored energy release.
• Environment: slips/trips, lighting, weather, ATEX, manual handling.
• Interfaces: upstream/downstream conflicts, robot paths, AGVs.
• Lifecycle: transport, install, commission, operate, clean, adjust, maintain, decommission.

Risk Log Columns

• Hazard ID
• Location / Scenario
• Hazard Description
• Severity
• Exposure / Occurrence / Avoidance
• Initial Risk Rating
• Control Measure(s) — Design
• Control Measure(s) — Safeguarding / SRP/CS (PL/SIL)
• Control Measure(s) — Information / PPE
• Standards/Clauses Applied
• Verification/Validation Evidence
• Residual Risk Rating
• Notes / User Obligations

Verification Snippets

• Stopping-time test performed; distances compliant with EN ISO 13855/13857.
• Interlocks to EN ISO 14119; fault-exclusion justified where used.
• SRP/CS achieves PLr per EN ISO 13849-1 (or SIL per EN 62061); calculations on file.
• Electrical tests per EN 60204-1 (insulation, protective bonding, functional).
• Noise/vibration measured; declarations consistent; controls implemented where necessary.
• LOTO procedure verified; stored energy dissipation proven.
• Manual and labelling reflect residual risks and maintenance schedules.

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PUWER and the End-User

Manufacturers design and document; employers must also ensure equipment is safe in use (e.g., PUWER in the UK). Help them succeed by:

• Stating any installation/anchoring conditions.
• Providing inspection and test intervals for guards/interlocks.
• Declaring residual risks and mandatory PPE.
• Supplying clear lock-out/tag-out instructions and training requirements.

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Conclusion

A watertight machinery risk assessment is practical engineering, not bureaucracy. Use ISO 12100 to structure your approach, apply the right EN standards, prioritise inherent safety, and prove performance with verification. Capture everything crisply in your risk log and technical file. Do this, and CE/UKCA conformity ceases to be a hurdle: it becomes a natural outcome of sound design, safer operation, and professional diligence.

For an in-depth, official guide to assist in the correct application of the Machinery Directive, see the official EU guidance.

PDE can help you with your compliance objectives, get in touch today.