Hi,
I will try to answer these questions in as non-commercial manner as possible, but to be upfront from the start I work for Hawk IR International, manufacturer of Hawk IR Sightglasses.
Firstly, IR Ports;
a) No IR port, of any kind can hold any NEMA/UL50 Type rating other than Type 1 (indoor) as they are nothing more than a hole. When supplied with covers, the environmental integrity of the entire device maybe increased BUT as a manufacturer of IR ports we do not advocate the use of this kind of device in any kind of outdoor application from a pure common-sense standpoint i.e. if the cover is left off, or is removed - for whatever reason - there is an open hole in the switchgear which, should it rain for example, would be very bad. Electricity and water do not mix well.
IR Ports should only be used indoors.
b) No IR port can hold any kind of arc-blast\calorie rating, again this is common sense stuff, an open hole o series of holes cannot ever provide protection from an arc-fault event. The philosphy behind NFPA70E is that should there be a "clear path to arc" between live electrical equipment and the "operator" then PPE should be worn. With IR ports, the same PPE should be worn as if the infrared scan were being performed with the cover open EXCEPT in circumstances when convection cooling vents are installed in LV switchgear, in this case the IR port when in the open position (cover removed) must prevent the penetration of a finger into the switchgear, in order to retain the original protection concept of the equipment.
What do we mean by "Protection Concept"? Well, if a low voltage (<=600V) board incorporates convection vents, then the safety of the operator under an arc-fault condition, even with the covers closed is minimal as there is a path to arc via the convection vents. This is one of the reasons why there are defined boundary's and locked doors to prevent access to switchgear even if the covers are closed.
PPE must be selected carefully when using IR Ports, maintaining the original protection concept of the switchgear is paramount with IR Ports. If there are no "holes" then none should be introduced, if there are "holes" i.e. convection vents, then IR ports can be used so long as the port does not allow finger penetration into the switchgear.
IR Windows
a) IR windows can be rated for outdoor use, make sure you match the Type rating of the IR window with that of your switchgear and insist on a certificate from the manufacturer. There are companies who provide European certified IR windows (IP-Rated) and try claim this is equivalent to NEMA/UL50, it is not. As an end-user you ma be liable for de-rating switchgear, especially outdoor equipment, if you install a European certified component onto a NEMA piece of equipment.
b) IR windows can be blast tested. Once a series of tests have been performed it is possible to calculate an equivalent calorie/cm2 withstand capability of the optic material and equate this to the PPE requirement on that circuit. Again, request third party certification of any blast-tests, from a liaility standpoint you as the customer must show due diligence in order to provide best protection to your personnel and back the decision up with facts. If there is an incendent and OSHA investigate, then you may need to provide certification proof of your choices.
I could go on but at the risk of getting commercial I will stop here, we have a large number of papers, both technical and otherwise on this subject, please dont hesitate to contact me for more information or visit our website
Thanks for reading.
Best Regards,
Tony Holliday MIEEE MIDiagE
Hawk IR International Ltd.
Web.