In brief
Process FMEA, well known to quality teams in the automotive supplier industry, can be used in OHS risk assessment once its columns are redefined. RPN is the product of the severity, occurrence and detection scores; but it can hide high-severity risks behind a low score. That is why measures must be taken on every line with a severity of 9–10, whatever the RPN, and the results must be linked to the risk assessment document in the way the legislation requires.
What is FMEA, and why adapt it to OHS?
FMEA (failure mode and effects analysis) is a method that questions step by step how a product or process can fail, and scores the effect and cause of each failure. In the automotive supply chain, process FMEA (PFMEA) is a routine part of the quality system; in the automotive supplier industry concentrated in and around Bursa, quality teams prepare these tables for new parts and process changes. FMEA risk analysis is therefore not unfamiliar to the OHS team in these businesses: the same team, the same meeting arrangement and the same line flow chart can also be used for occupational safety.
The legislation allows this. The Regulation on Risk Assessment does not make any particular method compulsory; Fine-Kinney, the L-type matrix, FMEA and HAZOP are common in practice. What the regulation requires is that the method used is stated in the document, the pages are initialled and the last page is signed. However, copying a quality FMEA directly into OHS gives misleading results; the meaning of the columns must change.
From process FMEA to OHS FMEA: redefining the columns
In a quality FMEA, a “failure” is the part not meeting the specification; in OHS, it is a deviation that could lead to someone being harmed. In the FMEA occupational safety adaptation, the columns are read as follows:
| PFMEA column | Equivalent in the OHS FMEA | Example |
|---|---|---|
| Process step | Work step or task | Press die change |
| Failure mode | Hazardous deviation or event | Unexpected descent of the ram |
| Effect of failure | Harm: injury, occupational disease | Crushing or amputation of hand and fingers |
| Cause of failure | Cause of the deviation | Energy not isolated, valve failure |
| Current prevention control | Measure that prevents the deviation | Lockout and tagout procedure, safety block |
| Current detection control | Noticing the deviation before harm occurs | Lockout checklist, door lock monitoring |
| Recommended action | Measure according to the hierarchy of controls | Making the mechanical safety block mandatory |
The difference shows most in the detection column. In a quality FMEA, detection is catching the defective part before it reaches the customer. In OHS, detection means noticing the hazardous situation before anyone is harmed. A deviation noticed at the moment of crushing does not count as “detected”.
Scoring: severity, occurrence and detection
Each line is given three scores from 1 to 10. The team must define the scale in writing before starting; otherwise, different people give the same risk different scores. An example of a shortened scale adapted to OHS:
| Score | Severity (S) | Occurrence (O) | Detection (D) |
|---|---|---|---|
| 1–2 | Effect not requiring first aid | Almost never expected | The deviation is always detected automatically before harm occurs |
| 3–4 | Injury requiring first aid | Rarely, once over several years | The deviation is usually noticed |
| 5–6 | Injury causing lost work days | Occasionally, a few times a year | Noticing it depends on the person’s attention |
| 7–8 | Permanent disability, occupational disease | Frequently, a few times a month | Hard to notice |
| 9–10 | Death or loss of a limb | Almost every shift | The deviation is not noticed until harm occurs |
When giving the occurrence score, use your workplace’s near miss records and accident statistics; scores based on guesswork drift towards the view of the most optimistic person in the team.
RPN calculation: an example on a supplier line
RPN calculation is simple: RPN = S × O × D. The result is between 1 and 1000. Below are four lines from a line in an automotive supplier plant where pressing, spot welding and shipment preparation are carried out:
| Work step | Hazardous deviation | Harm | S | O | D | RPN |
|---|---|---|---|---|---|---|
| Press die change | Unexpected descent of the ram | Amputation of a finger or hand | 10 | 2 | 6 | 120 |
| Press part feeding | Light curtain being disabled | Crushed hand | 9 | 2 | 4 | 72 |
| Spot welding | Sparks and spatter | Eye and skin burns | 4 | 6 | 3 | 72 |
| Carrying shipping crates | Lifting a heavy crate by hand | Back strain | 4 | 8 | 5 | 160 |
A team looking only at RPN gives priority to back strain (160). Yet disabling the light curtain, although it has the same RPN (72) as spot welding spatter, is a risk whose outcome could be permanent loss of a limb. This example shows why RPN cannot be the sole decision criterion.
The limits of RPN and how to compensate for them
RPN is a practical ranking tool, but it has known limits:
- It hides severity: A fatal risk with S=10 and O=1 can receive a low RPN because it is unlikely.
- The scores are ordinal, not measurements: A severity of 8 is not “twice” a severity of 4; the product is therefore mathematically misleading.
- Same RPN, different risk: 72 can represent both permanent loss of a limb and a temporary burn.
- The detection score is overly influential: A checklist added to lower the detection score can lower the RPN without reducing the risk at all.
These limits have long been debated in the automotive sector; the AIAG-VDA FMEA handbook published in 2019 recommends action priority tables (high, medium, low) that put severity first instead of RPN. In the OHS adaptation, you can apply a similar approach with simple rules:
- Severity rule: On every line with a severity of 9 or 10, measures are taken whatever the RPN.
- Severity first, then occurrence: When setting the priority of measures, look first at severity, then at occurrence; the detection score is considered last.
- Hierarchy of controls: In choosing measures, eliminating the hazard and engineering measures come before instructions and personal protective equipment. For details, see our article on the hierarchy of controls.
- Rescoring: After the measure has been implemented, the line is rescored; severity usually falls only with measures that eliminate the hazard or limit energy.
In our example, the recommended action for the die change line is to physically prevent entry into the die area without the mechanical safety block; for the part feeding line, it is a safety circuit that makes bypassing the light curtain difficult and monitors it, together with periodic verification. For other press safety measures, see our article on press safety.
How is an OHS FMEA workshop run?
A line’s FMEA is not a table filled in by one person at a desk but a team effort that starts on the floor. A workable flow is:
- Define the scope. Which line, which work steps, which shifts? The quality team’s process flow chart is a good starting point; but add work that does not appear on the flow chart, such as maintenance, die changes and cleaning.
- Walk the line. The team observes each work step on the floor and talks to the operators. The difference between what is written in the instructions and what is done on the floor is among the most important findings.
- Collect deviations. For each step, the question “how could someone be injured here?” is asked; near miss records and past accidents are added to the list.
- Score and discuss. Scores are given after discussion within the team; where there is disagreement, the higher severity score is used.
- Assign ownership of actions. The owner and target date of each action are written down; when the action is complete, the line is rescored.
For one line, this work is usually spread over several sessions. Keeping sessions short and completing a few work steps in each one preserves the team’s attention.
Linking FMEA to the risk assessment document
The quality FMEA and the OHS FMEA can be prepared in the same meeting, but the OHS document must meet the requirements of the Regulation on Risk Assessment:
- Team: The employer or their representative, the OHS specialist, the workplace physician, the employee representative, support staff and knowledgeable employees representing the departments. Having the quality engineer on the team is useful but does not replace the people above.
- Method statement: The document states that FMEA was used and gives the scoring scale.
- Format: The pages are initialled and the last page is signed.
- Renewal: Manufacture of parts and accessories for motor vehicles is in the hazardous class in the 2025 list; in the hazardous class, the assessment is renewed at least every 4 years. In situations such as a new line, new equipment, a workplace accident or a near miss, the period is not waited for.
This last point fits the habit on the quality side of FMEA: if a new part or process change requires the PFMEA to be updated, the same change updates the OHS lines too. We explained how the OHS side is questioned in customer audits in our article on preparing for a supplier OHS audit. For the general process, see our article on how to carry out a risk assessment.
In our risk assessment service, we use your quality team’s line flow chart and PFMEA as a starting point and prepare the OHS lines in the same structure. For risks specific to the automotive supplier industry, see our automotive supplier industry page, and for tracking renewal dates, our OHS calendar tool.
Frequently Asked Questions
What is FMEA, and can it be used in an OHS risk assessment?
FMEA is a method that scores what can go wrong at each step of a process, its effect and its cause. Since the Regulation on Risk Assessment does not make any particular method compulsory, it can be used; it is enough for the method to be stated in the document.
Above what RPN must measures be taken?
There is no RPN threshold in the legislation. The business sets the threshold; but whatever the threshold, measures must be taken on lines with a severity of 9–10 without looking at the RPN.
Can we submit our quality PFMEA instead of an OHS risk assessment?
Not directly. A quality FMEA focuses on product defects; for OHS, the harm that deviations cause to employees must be analysed separately, the team must be set up in line with the regulation and the document must be initialled and signed.
How is the detection score given in OHS?
Detection is the likelihood that the hazardous situation is noticed before anyone is harmed. A system that automatically detects the deviation and stops the machine receives a low score; situations whose detection depends only on the employee’s attention receive a high score.
A risk assessment that identifies and scores hazards on site, links each measure to an owner and a date, and has a clear renewal schedule.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.