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The revised ISO standard for safety of machinery regarding safety distances

2019-11-07
• 14 min read

Standards are supposed to make everything easier, but sometimes it doesn’t feel like that. And unfortunately, some people often misinterpret the former documents. In  working group 6,  the goal has been to turn it into a more comprehensive version, and the result was: 

"ISO 13857:2019 Safety of Machinery – Safety distances to prevent hazard zones from being reached by upper and lower limbs."

Foot under mesh panel.

The history of ISO 13857

The old standard from 2008 replaced two standards and was a combination of EN 294, which was about safety distances to prevent hazard zones from being reached by upper limbs; and EN 811, which described the hazard zones with regards to lower limbs. Due to a lot of questions and misunderstanding caused by the mixed standard ISO 13857, it was time for a revision.

 

What should the safety distance be?

The anthropology of the human body is different depending on the person. Therefore, it is crucial that the machine guarding covers all global requirements. But the minimum gap isn’t the same all over the world. In Canada and some states of the USA, the minimum gap is 6 inches (152 mm), and in the rest of the states, it’s 7 inches (177 mm). 

Gap, whole body access illustration.

In the revised standard, the minimum size of the gap is 180 mm. Anything greater than 180 mm is defined with the term – Whole Body Access, where a human can access the safeguarded area: 

"4.4 Consideration of whole body access. What does it help with a Safeguarded space ? If it’s possible to defeat the safeguarding through opening greater than 180 mm; whole body access."

Troax machine guarding lives up to the global standards of whole body access by having a minimum gap of 150 mm.

Kim Dahl, Safety Specialist at Troax.

You should measure from the reference plane

Sweden, lead by me, initiated the work in 2015 with a new proposal to revise the standard. First, some phrases and words were updated to reduce the risk of misunderstanding. Secondly, we added references to other standards as supporting evidence material e.g.  

“NOTE 2 This document is not intended to provide measures against reaching a hazard zone by climbing over (see ISO 14120:2015, 5.18)”. 

Furthermore, we made it clearer how the height of the safeguarding can be measured by adding a new term – Reference Plane. Hopefully this means there will be no confusion about what applies, but clear guidelines to follow:"

3.2 Reference plane. Level at which persons would normally stand during the use of the machine or access to the hazard zone
Note 1 to entry: The reference plane is not necessarily the ground or the floor (for example a working platform can be the reference plane)."

The way it’s written now states that all reasonably foreseeable access shall be taken into account. This is a potent reminder to help you think about how it might be possible to defeat or misuse the safeguarding. Some of the well-known figures in the standard were also updated to include reaching over the safeguarding.

If there is a risk, it should be safeguarded

The headlines of Table 1 and Table 2 were confusing when determining low and high risks. Now it’s clearer. Table 1 has been changed from Low risk to Only minor injuries along with a low probability of occurrence; and the term high risk has been deleted from table 2 (according to ISO 12100 Safety of machinery — General principles for design — Risk assessment and risk reduction). 

Remember, ISO13857 is one of thirteen
ISO B1 and B2 Standards Safety of Machinery

SIS logo and the brochure Your guide to better safe guarding.

Find all the directives and standards you need

With Troax Machine Guarding, the safety distances according to ISO 13857 will be easy to follow as our products are developed according to ISO Standards. We have summarized all relevant directives and standards in Your guide to better safe guarding to guide you.

I represent Troax in the work of drafting standards, and have been active in SIS, Svenska Institutet för Standarder (Swedish Institute of Standards) for twelve years. If you have any questions, please don’t hesitate to contact me.

 

In one way or another it’s a standard you need to create your safe machine guarding solutions
 

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Kim Dahl, Machine Safety Specialist
Kim Dahl
Machine Safety Specialist