Chapter 3 Risk Assessment And Safety Level; Risk Assessment - Mitsubishi Electric MELSEC-QS Series Safety Application Manual

3
RISK ASSESSMENT AND SAFETY LEVEL

CHAPTER 3 RISK ASSESSMENT AND SAFETY LEVEL

Conforming to EN954-1, ISO13849-1, and IEC61508, select the risk assessment, safety
category, PL, and SIL to reduce the risk.
This chapter briefly describes the risk assessment, risk reduction and safety category, PL,
and SIL.
For details, refer to each standard.
3.1

Risk Assessment

The risk assessment is to clarify hazards in a machine and assess the degree of the
hazards.
The risk assessment procedure is shown in Figure 3.1. This procedure is standardized in
ISO12100 and 14121.
5) Risk reduction
(
3
- 1 3.1 Risk Assessment
1) Determination of the limits of
machinery
2) Hazard identification
3) Risk estimation
4) Risk evaluation
Safety category (
PL (
SIL (
No
Section 3.1.1
)
Figure 3.1 Risk assessment procedure
Start
Section 3.2
Section 3.3
)
Section 3.4
)
Is the machine safe?
Yes
End
Risk assessment
)
(Referred to ISO12100.)