So the question you probably have is why is the certification process such a minefield. Well that is simple, for an IR Window to be deemed acceptable to OSHA, it must be approved by a Nationally Recognized Testing Laboratory (NRTL). But;
- There are many NRTLs available to use for certification such as UL, FM, CSA and Intertek to name a few.
- All of these NTRL’s can certify an IR Window to their own standard but there are issues such as any certification from any NRTL would satisfy OSHA.
- However, the US market requires UL Certification.
So how does an IR Window obtain UL Recognition
- First of all we must decide on standards that will be pertinent to the applications of the product being tested.
- All IR Windows require certifying to UL50V but depending upon environmental and other requirements, additional standards may are available.
- Submission of the product for testing.
If successful a UL Recognized mark will be issued for the product range successfully tested. Sounds pretty simple right? Well let’s take a look of what’s really involved with an IR window becoming certified. There are a number of basic requirements that need to be considered when obtaining certification:
For products that are to be certified for indoor use:
- Metallic parts must be non-corroding
- Polymer parts must be flame retardant. I emphasize this terminology because you will see later on how that can be misconstrued.
- Protective covers are to remain in place during testing
For products submitted for outdoor certification:
- We have all of the above and in addition we now have that…
- Gasket or seal material must be subjected to accelerated aging tests
- And that the IR window must be subjected to environmental testing using the aged gaskets or seals, all dictated by the desired environmental Type designation.
Now that the above have all been satisfied and all requirements for the chosen standards have been met, the UL Certificate can be issued. All UL recognized components are issued with this document which shows product part numbers and standards tested to. The UL Certificate of Compliance does not always show the Type designation, and it is up to the manufacturer to inform the end user of what the product’s type designation is. On some of the IR Windows in the market including the CorDEX IW Series this can very clearly be found on the cover; TYPE 3,12. This is very important because the first rule of thumb to maintaining the environmental rating of the electrical gear is that the component’s rating must equal or exceed the rating of the gear itself.
If you install a Type 1 rated component into a Type 3 piece of electrical equipment, you have just de-rated the entire piece of electrical gear to Type 1.
The Type designation is contained in the UL report, and that information is not typically made available to end users. The main idea here is to make certain that a component that is going to be installed into a higher assembly has obtained the proper certification and Type rating.
So now let’s take a look at the next issue of “Markings”
There is a common misconception when it comes to the use of the terms “listed” and “recognized”. We are often asked “Is the IR window UL listed?” Naturally this is a concern for all end users because their electrical gear is UL “listed”.
The answer is no, and that is because a window alone cannot be listed. The CorDEX IR Windows are UL “recognized” as a component. The recognized component that becomes part of a higher assembly, which IS UL “listed” as a whole.
A simplified example would be to consider your car. The car as whole assembly would be considered a car. If you were to remove one of the headlights and take it into a parts store to buy a replacement you would not refer to that headlight as a car. The same goes for a component and an assembly.
There are special markings that coincide with a UL recognized component. As you can see in figure.1, the UL Recognized Component mark is shown and resembles a reversed UR. On the CorDEX IR Windows (figure.1) you will notice that the UR also has a “C” and a “U.S.” which means it is recognized as a component for Canada as well as the US.
Additional markings that can be found CorDEX IR Windows are the E number and warnings. The E number is the 6 digit UL file number which engineers can use to access further information on the window from the UL Online Certification Directory.
The warning shown on the CorDEX window states that the ‘Device is incomplete without the cover secured’. This is normal with crystal IR windows as the covers protects the crystal from impact, which is completely acceptable to UL as long as the cover is closed when not in use.
IR windows that do not include a crystal optic may have the same type of warning. The reason for those warnings may have to do with requiring the cover to maintain the environmental rating or to maintain the flame retardant properties of the component.