CSA Z432: Safeguarding of Machinery

Safeguarding of Machinery

Last edit: 25/07/2023

On October 25, 2016, the third edition of Canadian Standard Z432 on safeguarding of machinery was published.

It is the reference Standard for the Assessment and Reduction of Risk due to hazards of mechanical nature. Inside this Standard there is also a set of regulations inspired by EN ISO technical Standards.  

For the first time, the use of EN ISO13849 for the functional safety of control systems is made official.

Moreover, additional Annex material has been added to provide a technical guidance for users and allowable minimum (safe) distances have been changed to allow for the use of CAN/CSA-ISO 13857.


References to standars ISO and IEC

CSA Z432-16, for example, explicitly refers to ISO Standards 13855 and ISO 13857 for determining openings and safe distances from hazardous movements.

6.3.3 Requirements for design of guards and protective devices, General requirements
[…] Guards and protective devices shall
a) be of robust construction,
b) not give rise to any additional hazard,
c) not be easy to bypass or render non-operational,
d) be located at an adequate distance from the danger zone (see ISO 13855 and ISO 13857), […]
For openings in the guards, see ISO 13857.

As for the sizing of fixed guards, however, it refers to ISO Standards 12100 and ISO 14120.

9.2 Guards, fixed
All guards shall meet the applicable requirements of ISO 12100 and ISO 14120. […]

For machinery safety and safety-related parts of control systems, the Canadian Standard refers to the two “sovereign” Standards, ISO 13849-1 and IEC 62061.

in fact you can read:

6.2.11 Applying inherently safe design measures to control systems, General
The design measures of the control system shall be chosen so that their safety-related performance provides a sufficient amount of risk reduction (see ISO 13849-1 or IEC 62061). […]
These principles and methods shall be applied singly or in combination as appropriate to the circumstances (see ISO 13849-1, IEC 60204-1 and IEC 62061).

Finally, one of the most important passages in CSA Z432-16 on Canadian machinery safety says:

8.2 Safety control system performance criteria, 8.2.1 General
Safety-related parts of control systems (mechanical, electrical, electronic, fluidic etc.) for newly manufactured machinery shall provide functional safety performance as determined by ISO 13849-1 or IEC 62061. Existing, or rebuilt or redeployed machinery, should meet ISO 13849-1 or IEC 62061.

Responsibilities for the end user

While in the world of CE marking it is the manufacturer who is the first guarantor of the safety of a machine and therefore also the first responsible party, in North America, on the other hand, the responsibility for that safety is shared and distributed between end user and manufacturer. It might seem paradoxical to us, but a piece of machinery could be delivered to Canada without fixed guards and the implementation of those guards would then be the responsibility of the end user.
Here are a few excerpts in which there is evidence of this: the end user must provide missing or additional safeties; in short, he must fill in the gaps, a practice different (and unusual!) from what is prescribed within the Machinery Directive.

7 Machine design and controls
7.1.1 Designers shall follow the general principles in Clause 5 of this Standard and shall take into account the relevant standards for specific type(s) of machinery. When appropriate, the end user shall ensure provisions are made to facilitate the fitting of alternative types of safeguarding where variations in the tasks reduce the effectiveness of the existing safeguarding. The risk assessment documentation shall be changed to reflect the change in safeguarding methodology.
7.1.2 Where specific applications require guards or safety devices not provided by the manufacturer, the user shall ensure that appropriate safeguarding is installed. The user shall ensure written instruction is provided for the inspection of these additional safeguards.

10 Application (integration and use) requirements of guards and protective devices, 10.1 General
[…] Where specific applications require safeguarding that was not provided by the manufacturer, the user shall ensure that appropriate safeguarding is selected, integrated, installed, and validated in accordance with the risk assessment.

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