- Interlocking Devices: The Good, The Bad and the Ugly
- Presence Sensing Devices – Reaching over sensing fields
- Trapped Key Interlocking
- Canada Adopts ISO 13857 – Safety Distances
- How to Apply a Safety Edge to a Machine Guard – Part 1: Pressure-sensitive devices
- How to Apply a Safety Edge to a Machine Guard – Part 2: Design Considerations
- How to Apply a Safety Edge to a Machine Guard – Part 3: Stopping Performance
As part of the work on the 3rd Edition of CSA Z432, Canada has decided to adopt ISO 13857 as CAN/CSA-ISO 13857. The standard was adopted in 2015 without technical deviations.
Why ISO 13857?
CSA Z432 has long had portions of the information in ISO 13857 in its annexes – Annex C has tables for reaching through openings and reaching over structures, much like the one above, that users have found useful over the years. Unfortunately, these tables have also proved a bit confusing, as they are somewhat different than CSA Z432-04 Table 3. While neither set of safe-distance values is less safe, the values in Table 3 are very similar to those used in the USA, which was the original source for that information. The tables in CSA Z432-04 Annex C are informative, meaning they are provided as a helpful guide to applying the standard, but they are NOT a mandatory part of the standard.
When Z432 was first being developed in the late 1980’s, most machinery products were coming to Canada from the US, so harmonisation with US OSHA guidelines was more important than harmonising internationally. Today, import of machinery from the EU is common, and Canadian export of machinery around the world is part of doing business. CSA’s Safety of Machinery Technical Committee decided to help manufacturers and importers by harmonising Canada’s standards with the International Standards by adopting ISO 13857 as a Canadian Standard.
Fixing the Problem
While the CSA Z432 committee was working on revising the standard in 2014/15 it was recognized that Annex C had caused a lot of confusion. The committee also recognized that there was no evidence that Table 3 or ISO 13857’s tables lead to “less safe” or “safer” machine designs. Since Table 3 didn’t deal with anything except openings in guarding, there was a big gap if Annex C was completely discarded. Users needed information on reaching over guarding, and on reaching through guarding where the opening was big enough to get an arm through up to the shoulder, but there were other obstructions inside that might limit access to hazards. This information was available in ISO 13857. The decision was taken by the committee to adopt ISO 13857:2008 as a Canadian standard, and so it became CA/CSA-ISO 13857 – 2015.
When CSA Z432-16 was issued in October of 2016, the normative text included both standards. The old Table 3 has been corrected (the SI conversions in the 2004 edition were…off) and incorporated as Table 10.1, and the text allows that CAN/CSA-ISO 13857 can be used instead.
The Bottom Line
Canadian machine builders can now use EITHER CSA Z432-16, Table 10.1, OR ISO 13857’s tables. They both result in safe designs. The big difference is that Table 10.1 will often result in a somewhat more compact machine, BUT, ISO 13857 has finer gradations in the reach-through tables, and also allows for users older than 14 or younger than 14, so may be more advantageous depending on the end-use environment and the specific design issues you are required to consider.
One final point: ISO 13857 is under review, with a new edition expected in 2017. Pro Tip: The basic tables remain unchanged, and there is lots of new information in the coming update.
If you are interested in reviewing and commenting on this adoption, please visit the CSA Public Review Page for the standard. Comments close 13/07/2015.
Title: Safety of machinery — Safety distances to prevent hazard zones being reached by upper and lower limbs (Adoption without deviations) (New Standard) Expiry date: 13/07/2015
This International Standard establishes values for safety distances in both industrial and non-industrial environments to prevent machinery hazard zones being reached. The safety distances are appropriate for protective structures. It also gives information about distances to impede free access by the lower limbs (see 4.3).
ed. note: This post was corrected and updated 28-Aug-2017.