Wednesday, November 7, 2018

Why Can’t I Get An Arc Resistant or Arc Tested Certificate For An IR Window?

If I had a dollar for every time I got asked to provide a blanket statement or certificate that IR windows are Arc Resistant or Arc Tested, I would have been able to retire already. Seriously.

Unfortunately, I end up having to make a long explanation about how this is impossible to do. Why? Simply put, there is no standard test protocol that has been developed, neither in North America (UL, IEEE, CSA or ANSI) nor Europe (IEC), that would provide a means of performing a standardized test on just an IR window. Rather, the standards that exist are for testing complete switchgear assemblies for Arc Resistance. These tests are destructive in nature – an intentional bolted fault condition is created at a predetermined test voltage, available fault current magnitude and time duration. The IR Window is not in the current path of the fault; but, it will see the extreme pressures and temperatures created when the fault is initiated. The switchgear is what passes or fails the test. If that switchgear happens to have IR windows fitted in it and still passes the test, it gives that switchgear OEM the ability to sell the equipment with those particular IR windows fitted as an option to their client base. It does NOT mean that those IR windows are not Arc Resistant certified or Arc Tested for all applications with all OEMs.

The best analogy is the automotive vehicle crash test. Acme Air Bags is selected by Generous Motors to supply the front air bags. Generous Motors successfully crash tests their vehicle and it is certified by the National Highway Traffic Safety Administration – the body that created the test standard and overseas the testing. Despite this successful test, Acme cannot make blanket statements that his product meets NHTSA standards and will work in any and every car make/model. Similarly, IR Window manufacturers cannot make blanket statements about IR window Arc Ratings just because they did not cause one switchgear OEM’s destructive test to fail.

Can IR Viewing Panes Carry an Arc Rating? The Answer is NO!

So, why do customers continue to ask for this type of blanket statement or certificate? Frankly, it is because of the marketing statements made by some in the industry that lead them to believe that such documentation exists. This includes statements like:

* “Arc Flash Testing, IEC 62271-200 (KEMA) to 5kV, 63kA for 30 cycles at 60 Hz”

* “Torture TestedTM to the highest arc blast test ratings”

* “IEEE C37.20.7: 63kA for 30 cycles at 60 Hz Arc tested at KEMA”

* “Maintains panel arc test ratings up to 63 kA when properly installed.”

* “Arc flash tested against a 50KA short circuit for 1 second at 11KV”

I can’t decide which of these statements makes me cringe the most. I am flabbergasted that someone was able to trademark the phrase “Torture Tested” as this is the absolute worst kind of marketing-

speak. But the statement that the product, “Maintains panel arc test ratings up to 63 kA when properly installed,” is probably the most egregious overreach as it clearly indicates you can use this product anywhere without any risk of invalidating your switchgear arc resistant ratings. The other statements are less blatantly misleading but should be at least marked with an asterisk and a note that explains that these tests are related to switchgear tests and standards, not window tests and standards which don’t even really exist.

One further item of note – neither IEEE nor IEC issue any kind of certificates of compliance. The International Electrotechnical Commission (IEC) is a standards organization that writes and updates standards for all electrical, electronic and related technologies. Electrical equipment outside of North America is usually designed to meet IEC standards. Independent testing labs are the entities that actually perform the tests and can issue reports and certificates of IEC standard’s compliance. IEC 61439 is the standard for Low voltage switchgear (<1KV) while IEC 62271 includes sub documents relating to Medium and High voltage switchgear (>1KV up to 52KV). IEC 62271-200 specifically has test standards for Arc Testing of switchgear and is often cited by IR window manufacturers. IRISS has had switchgear tested to IEC 62271-200 successfully with several of our IR window products installed.

IEEE is the Institute of Electrical and Electronic Engineers and has a Standards Association (IEEE-SA) that develops global standards for industries and technology. One of the committees within IEEE-SA is the IEEE Switchgear Committee that develops and updates the C37 series of standards for Low and High voltage equipment. IEEE C37.20.2 has requirements for static load and impact testing of viewing panes which includes IR windows (these are actually window tests) while IEEE C37.20.7 has test requirements for arc resistance testing of switchgear which may have windows fitted.

So, as a buyer of IR windows, what should you do? You just did it – educate yourself about what these standards mean and, more importantly, what they don’t mean.

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