# Risk estimation with the risk graph
The risk estimation is performed using the risk graph shown below. The structure of the risk graph is based on the requirements of EN ISO 12100 Para. 5.5 and the model for calculating risk figures according to Reudenbach.
Risk
Combination of the probability of occurrence of harm and the severity of that harm (Definition according to EN ISO 12100 para. 3.12)
# Risk graph to determine the risk figure
<< Bild Risikograph einfügen >>
# Definition of risk parameters
The risk figure (R) is calculated as the product of Severity of harm (S) and the probability of occurrence, which results from the time spent in the hazard zone (F), the probability of occurrence (O) and the possibility of avoiding the harm (A).
| RISK ESTIMATION (R) | |
|---|---|
| R0 | No Risk |
| R1 – R6 | Low risk |
| R7 – R11 | Moderate risk |
| R12 – R16 | High risk |
Calculation
- R = S x W
- R = S x (F + O + A)
Risk parameters
| SEVERITY OF INJURIES OR DAMAGE TO HEALTH (S) | |
|---|---|
| S1 | Slight reversible injury (e.g. scratch, pressure mark, wound, 1st degree burn) |
| S2 | Severe reversible injury (e.g. fracture, illness, 2nd degree burns) |
| S3 | Severe irreversible injury (e.g. loss of limbs, blindness, illness with consequential damage, 3rd and 4th degree burns) |
| S4 | Death |
| EXPOSURE OF PERSONS TO THE HAZARD (F) | |
|---|---|
| F1 | seldom (daily to weekly) |
| F2 | frequently (more than once per hour/shift) to permanently |
| PROBABILITY OF OCCURRENCE OF HARM (O) | |
|---|---|
| O1 | Almost impossible, only under extreme circumstances |
| O2 | Unlikely to maybe, conceivable and can happen (even for work carried out by skilled workers) |
| O3 | Very likely, not surprising and to be expected (will happen frequently) |
| POSSIBILITY OF AVOIDING OR LIMITING HARM (A) | |
|---|---|
| A1 | Possible by reflex, mobility or danger getting closer slowly |
| A2 | Not possible due to speed or spatial restriction |
The risk assessment is based on subjective considerations. It is not generally specified from when risk reduction measures must be taken or which residual risk can be considered acceptable. The responsibility for this is at the judgement of the respective creator of the risk assessment.
# Risk graph to determine the performance level (PLr)
For risk reduction using the principle of "control", the required performance level (PLr) for the measure is determined according to EN ISO 13849-1. This is done on base of the estimation of the initial risk, which takes into account the possibly already existing risk reduction by other protective measures.
<< Bild Risikograph EN ISO 13849-1 einfügen >>
Risk parameters
| SEVERITY OF INJURY (S) | |
|---|---|
| S1 | Slight injuries (normally reversible) |
| S2 | Serious injuries (normally irreversible, and death are considered) |
| FREQUENCY AND/OR EXPOSURE TIMES TO HAZARD (F) | |
|---|---|
| F1 | Seldom to less frequently and/or the time of exposure to the hazard is short |
| F2 | Frequent to continuously and/or the time of hazard exposure is long |
| POSSIBILITY OF AVOIDING THE HAZARD (P) | |
|---|---|
| P1 | A realistic chance of avoiding an accident or of significantly reducing its effect |
| P2 | There is almost no chance of avoiding the hazard |
| PROBABILITY OF OCCURRENCE OF HARM (O) | |
|---|---|
| O1 | Low probability (can be estimated based on reliable data or accident histories on comparable machines - see EN ISO 13849-1 A.2.3: Where the probability of occurrence of a hazardous event can be justified as low, the PLr may be reduced by one level, see A.2.3.2). |
| O2 | Unknown or high probability |