Over time there have been a number of revisions to Underwriters Laboratory (UL) standards for Intrinsically Safe (IS) equipment. Here are some insights into how the latest standard impacts new intrinsically safe products. This article also addresses how the process of harmonization can affect product development efforts for manufacturers of personal protective equipment (PPE).
Recent Changes to Intrinsically Safe Standards
What are some examples of changes in IS standards that have occurred that are having the greatest impact on customers or manufacturers?
Three of the important things found in the latest edition of IS standards include:
- First, there is a harmonization of CSA and UL standards to the global ATEX directive’s IS requirements. This harmonization became effective on April 20, 2016 for new products.
- The second item to note are the requirements on how batteries are addressed in the standards.
- Finally, the toughest part of these changes for manufacturers in the recent IS standards like IEC 60079 are the new surface conductivity requirements, which make maintaining compliance to the existing conditioning standards a difficult balance of physical product properties.
How Harmonization Works and its Impact
What are the different agencies involved in IS standards and how has this harmonization occurred?
Over time there have been different governing bodies and test agencies that have written slightly different standards and test methods for intrinsic safety. For some examples of the applicable intrinsic safety standards, CSA had C22.2, while UL had UL913 and then there was the ATEX directive ATEX 2014/34/EU as well as the IEC standards. What has happened most recently is that those standards (UL, CSA and ATEX) have worked to harmonize their IS standards around the latest IEC 60079 edition, which had been specifically called out in the ATEX directive.
In short, this means that standards are coming together to be more unified such that if a product meets the latest IEC 60079 Edition, the product would also meet the other various agency standards as well. There may still be some national differences, but the trend is towards harmonization.
There are also standards for batteries like IEC 62133, UL 2054 and UN 38.3 that had to be considered for product design. These battery standards are still applicable, while the harmonization took place for the three main intrinsic safety standards.
How does harmonization impact manufacturers and users of IS products?
Harmonization is a major convenience for multi-national customers. For products certified under the newest IEC standard, it means that those customers can now order one product harmonized to the same intrinsic safety standard, instead of a different product dependent on the country that it was used. This harmonization is also to the latest standards, so it is the most current testing method with the latest technologies involved.
There are of course potential differences in other safety requirements depending on the product type. A couple of examples include differences between CE and NIOSH for respiratory certifications or gas detection equipment needing different markings for different countries or regions.
It’s expected that global manufacturers of personal protective equipment will take all standards into consideration. With global harmonization to the ATEX Directive (2014/34/EU), the process for manufacturers to certify products for intrinsic safety will become much more streamlined. Even though the process is more streamlined, the requirements for testing are much more stringent than was required by previous products. The harmonization is a good move, but it is also more about global compliance.
It’s important to note that IS standards are written such that products that were approved under an older version are grandfathered in as still being approved as long as those products don’t have any substantial change in construction. So, for example, if you have an older IS product approved under an older edition of IEC 60079, that product can still be used, and the manufacturer can still produce and sell that older product as intrinsically safe as long as they do not change anything. However, new products that are produced under the harmonized standards can not only be sold and used in multiple jurisdictions, but they may have features and benefits that older products under the older standards do not.
How PPE is Affected by these Changes
How will the other UL standard modifications cause changes in new versions of IS PPE products that manufacturers introduce?
For example, the current standards impact batteries in a way that causes manufacturers to make a choice: either create a battery that, on its own, is intrinsically safe, which typically sacrifices performance and run-time; or build a battery that requires mechanical attachment and makes it difficult to remove while in use to protect the users of a product in the IS environment.
In the case of the mechanical battery attachment requirement, you may see manufacturers start to use attachment tools to aid in preventing removal of batteries in an IS environment. This appears to be the intent of the standard. This changes battery design slightly but in the end, it helps to ensure that a battery cannot easily be removed in an IS environment, which could possibly cause a fire or explosion.
How might manufacturers address the new surface conductivity requirements while maintaining compliance with the existing conditioning standards?
The older version of UL 913 sixth edition specifically called for surface conductivity requirements. Those requirements were carried over to the current harmonized standards. Finding plastics and other materials that meet this new requirement while maintaining compliance to the existing conditioning standards are not easy to identify and qualify in a new product offering. In short, making new IS products that are capable of meeting the recent standard is just simply harder to do.