Fastening of permanent protectors with a padlock

by Apr 24, 2019Machine Safety

One of the most frequently asked questions concerning the fastening of permanent protectors is the possibility of using a padlock as a means of fastening (conformity of fastening with a padlock).

It is a question that appears simple, but quickly becomes ambiguous when we try to rely solely on regulatory articles and applicable standards. This is a gray area where no clear answer can decide as to the conformity of this action. For this reason, deeper understanding and interpretations are needed to line up our actions with the true goals of these texts.

The article of the regulation dealing with the conformity of permanent protectors is article 174. This article states that a permanent protector is one that can only be removed with the assistance of a tool or is set in place permanently, for instance, by being welded.

We note that according to this requirement/definition, details about the tool and the purpose of its requirement are not provided. This does not allow for one to rely on the article to assess the level of safety associated with the practice of fastening of permanent protectors by padlock.

The other available source is the use of standards, namely ISO 12100 and ISO 14120.

The ISO 12100 standard, which is a Type A standard, adds more precision and gives an idea of ​​the main function desired by the installation of a permanent protector. In article of this standard, it is stipulated that permanent protectors must be kept in place in a safe or permanent manner or by means of fasteners (screws, nuts) making their removal and opening impossible without the use of tools. Permanent protectors should not remain in the closed position without their fastening elements.

In this article, ISO 14120 has been cited as a reference. This standard clearly states the aims of putting a permanent protector, other than providing isolation from a hazardous phenomenon. The concept of easy dismantling was mentioned in article 5.3.6 which requires that the removable parts of a permanent protector must only allow for disassembly with the aid of a tool.

—Permanent protectors must be designed to prevent easy disassembly.

This is because operators may prefer to use a removable guard rather than an interlocking protector.

Based on these requirements, one can analyze the situation of permanent protectors fastened by padlocks. In this case the padlock key would be considered the tool and it would be impossible to remove the protector without the use of the key. At this point, the situation remains in conformity, but what distinguishes the padlock key from other tools is the possibility to leave it in the padlock. In this case, we would find ourselves in a situation where it is a manually openable protector and the fastener is easily opened. In addition, it assumes that the permanent protector will be fastened at a single point of attachment. For this reason, it is preferable that padlocks not be used as means of fastening, because by analyzing the true aim behind protection by permanent protectors, we can conclude that this practice is more a bypass than a proper means of fastening for permanent protectors.


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Intervention Prévention concentrates its operations in the field of work safety, offering specialized services following Standards CSA Z462 – Workplace Electrical Safety, CSA Z460 – Control of Hazardous Energy: Lock-out and Other Methods, and CSA Z432 – Safeguarding of Machinery.


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