Mechatronics Canada

July 18, 2022

 

MC IEC 62061 Safety Integrated Level by PILZ 1 400

Functional safety in accordance with IEC 62061

IEC 62061 / EN IEC 62061 represents a sector-specific standard under IEC 61508. It describes the implementation of safety-related control systems on machinery and examines the whole lifecycle from the concept phase through to decommissioning.

The new edition of IEC 62061 was published in 2021. This new edition is not just an update of the existing standard. For a start, the standard is no longer limited to electrical systems but can be used for all types of technology, such as hydraulic or pneumatic systems for example.

IEC 62061:2021 harmonized as EU standard EN IEC 62061:2021!

In April 2022, IEC 62061 was published in the Official Journal of the EU as harmonized standard EN IEC 62061, the content being identical.

MC IEC 62061 Safety Integrated Level by PILZ 2 400

As a result, presumption of conformity has officially come into force within the EU. A manufacturer can assume that he meets the health and safety requirements of the Machinery Directive if he complies with the provisions of the EU standard. In the conformity assessment procedure, he can issue the declaration of conformity and so affix the CE mark to his plant or machinery.

Presumption of conformity for the previous version EN 62061:2005 ends on 11 October 2023 at the latest! After this transition period, new declarations of conformity can only be issued on the basis of EN IEC 62061:2021.

The European Commission announced the newly harmonized standards on the EU website with CID 2022/ 621, dated April 2022. As of May 2022, they have not yet been published by the EU Commission in the informal "Summary List"!

To read about thge procedure for publishing harmonized standards in the EU, click here 

 

MC IEC 62061 Safety Integrated Level by PILZ 5 400

You can also listen to the PILZ podcast "For Your Safety" to hear about the "Updates to the Standard IEC 62061" by clicking here 

Important changes to IEC 62061 / EN IEC 62061:

  • •Changes to the methodology used to define the required SIL level
  • •The need to draft a Safety Requirements Specification
  • •The option to use devices developed in accordance with other standards
  • •More details on safety-related application software

 

 

 

Contents of IEC 62061

MC IEC 62061 Safety Integrated Level by PILZ 3 400

IEC 62061 addresses the issue of how reliable a safety-related control system needs to be. In this case the estimation is based on a hybrid method, a combination of a matrix and a quantitative approach. It also addresses the validation of safety functions based on architectural and statistical methods.

As with EN ISO 13849-1, the objective is to establish the suitability of safety measures to reduce risks. Even with this standard, extensive calculations are required. You can significantly reduce the work involved by using appropriate software such as the Safety Calculator PAScal.

 

How do you determine the required safety integrity in accordance with IEC 62061?

For each risk requiring a safety-related control system, the risk must be estimated, and the risk reduction (SIL) defined, dependent on the control system. The risk associated with the safety function is estimated in accordance with IEC 62061, with consideration given to the following parameters:

  • •Severity of injury (Se)
  • •Frequency and duration of exposure (Fr)
  • •Probability of occurrence of a hazardous event (Pr)
  • •Probability of avoiding or limiting harm (Av)

 

SIL classification in accordance with IEC 62061

Classification of severity (Se)

Consequences

Severity (Se)

Irreversible: death, losing an eye or arm

4

Irreversible: broken limb(s), losing a finger(s)

3

Reversible: requiring attention from a medical practitioner

2

Reversible: requiring first aid

1

 

Classification of the frequency and duration of exposure (Fr)

Frequency of exposure

Duration (Fr) <= 10 min

Duration (Fr) > 10 min

≥ 1 per h

5

5

< 1 per h up to ≥ 1 per day

4

5

< 1 per day up to ≥ 1 every 2 weeks

3

4

< 1 every 2 weeks up to ≥ 1 per year

2

3

< 1 per year

1

2

 

Classification of probability (Pr)

Probability of occurrence

Probability (Pr)

Very high

5

Likely

4

Possible

3

Rarely

2

Negligible

1

 

Classification of probability of avoiding or limiting harm (Av)

Probability of avoiding or limiting

Avoiding and limiting (Av)

Impossible

5

Rarely

3

Probable

1

 

 

What is determination of the required Safety Integrity like in accordance with IEC 62061?

Assignment matrix for determining the required SIL (or Plr) for a safety function

MC IEC 62061 Safety Integrated Level by PILZ 4a 400

EXAMPLE: For a specific hazard where Se = 3, Fr = 4, Pr = 5 and Av = 5, then:
Cl = Fr + Pr + Av = 4 + 5 + 5 = 14
Using this table would lead to a SIL 3 or PL e being assigned to the safety function that is intended to mitigate the specific hazard.

 

How do you design a safety function?

For each safety function it is necessary to identify the critical elements for performing the function, the so-called subsystems. The selection or design of these subsystems must cater for a SIL which is equal to or higher than the required level. The combination of all of these subsystems must also enable you to reach the required SIL.

Each subsystem must meet the following requirements:


- Architectural constraints for hardware safety integrity
- Probability of dangerous random hardware failures (PFH)
- Systematic safety integrity (requirements for avoiding failures and requirements for controlling systematic faults)

 

Architectural constraints of a subsystem

The SIL value that subsystems achieve is influenced by the architecture of the control system and the "Safe failure fraction" (SFF) or diagnostic level.

Safe failure fraction
(SFF)

Hardware fault tolerance
HFT 0

Hardware fault tolerance
HFT 1

Hardware fault tolerance
HFT 2

< 60 %

Not permitted, unless well-tried components

SIL 1

SIL 2

60 % to < 90 %

SIL 1

SIL 2

SIL 3

90 % to < 99 %

SIL 2

SIL 3

SIL 3

>= 99 %

SIL 3

SIL 3

SIL 3

HFT: Hardware fault tolerance
SFF: Safe failure fraction

 

Requirements for the probability of dangerous random hardware failures

The probability of a dangerous failure of any safety-related control function (SRCF) because of dangerous random hardware failures shall be equal to or less than the failure threshold value defined in the safety requirements specification.

SIL level in accordance with IEC 62061

Probability of a dangerous failure per hour (PFHD) [1/h]

SIL 3

>= 10 E-8 to < 10 E-7

SIL 2

>= 10 E-7 to < 10 E-6

SIL 1

>= 10 E-6 to < 10 E-5

 

Why not try PILZ’s calculation tool (PAScal), which you can use to determine the relevant characteristic values with ease?

 

Further information:

Their experts will be happy to support you with the implementation of IEC 62061, thereby ensuring safe operation of your plant and machinery.

To learn more about PILZ services for automation, plant, and machinery safety, click here 

To use their Safety Calculator PAScal – Calculation tool for verifying functional safety, click here 

PILZ Logo 300x150

 

 

Source

 

Latest Articles

  • Prev
  Derating is a protective measure which allows the use of power supplies at high ...
  The production of tires and the production of wafers seem to have absolutely nothing ...
  As machines become more connected, the need to service equipment remotely is ...
  Ask a Bishop-Wisecarver Engineer: How do I protect my linear guide wheel ...
  POSITAL has compiled some expert troubleshooting tips to get your encoder back up and ...
  The introduction to SEW Eurodrive’s Innovation Lab was a big success. With Ontario ...
  Corks are so light they float, but when shipped in bulk to wineries around the world, ...
  If a product is scratched by a robot but nobody was there to see it, how do you know ...
  IEC 62061 / EN IEC 62061 represents a sector-specific standard under IEC 61508. ...
  Limitations on the electrical power system make it important for the customer to ...

Products

  • Prev
  ABB is expanding its FlexPicker® Delta robot portfolio with the IRB 365. With five ...
  The generic PITreader Keys are now available in six new colours. As a ...
  With ABB Access, you can unlock all aspects of your drives, motors, or PLCs, from one ...
  Less than an hour away from the Detroit-Windsor border in Canada lies Orora Fresh, a ...
  Endress+Hauser announces a new version of its J22 TDLAS gas analyzer, an update to ...
    AutomationDirect has added new pressure sensing accessories from Winters. ...
  Kit (or modular) encoders are designed to be integrated into electric motors or other ...
  Advanced Motion & Controls Ltd. supplies automation solutions by Epson ...
  HyperCyl industrial products are available in Canada through Advanced Motion ...
  The new analysis unit PSEN rd1.x I/O with USB connection is available now for safe ...

Featured Product: 


MC Rittal AX Fiberglass Enclosures Added Durability with Non Metallic WM Enclosures 1 725

 

AX Fibreglass Wallmount Enclosures available now 

Rittal has rounded off its AX range of compact enclosures with its newly developed fibreglass enclosures. The manufacturer now offers the best of two worlds: the advantages of sophisticated technology combined with the benefits of an extremely robust material.

The AX fibreglass enclosure protects the electrical components even in very harsh environments. Its new mounting functions make rapid expansion possible and provide a greater scope for installation using smart technology.

What the new AX Fibreglass Enclosures provide:

  • •Sophisticated technology
  • •Robust material
  • •Simple, fast configuration
  • •High safety standards

 

For more information, click here

 

 

 

Mechatronics Canada

Mechatronics Canada‘s editorial informs and engages a targeted audience of manufacturers, distributors, specifiers and end users delivering an editorial mix of the right content for the right audience.

Subscribe Here

Kerrwil Publications

538 Elizabeth Street, Midland,Ontario, Canada L4R2A3 +1 705 527 7666
©2022 All rights reserved

Use of this Site constitutes acceptance of our Privacy Policy (effective 1.1.2016)
The material on this site may not be reproduced, distributed, transmitted, cached or otherwise used, except with the prior written permission of Kerrwil