ATEX, fiber optics and our conduits
Fiber optic cables are getting used more and more in a lot of different industries. Although this kind of cable has a lot of potential and a lot of upsides, there are also a couple of downsides that need to be taken in to consideration. Especially when working in an ATEX hazardous environment or application. So let us tell you how to protect these optic fiber cables, starting with a bit of general information.
- ATEX Ex i, where the ‘i’ stands for ‘intrinsic safe’, means that the power on an intrinsic safe electrical circuit will not have enough energy to generate a spark, thus making it a safe circuit to be used in a ATEX hazardous environment.
- Fiber optics have no electrical current, but the ‘light’ in a fiber optic cable could have enough energy to create an ignition or spark in an ATEX hazardous area. This can be very dangerous, because a spark could ignite a flame or even an explosion.
- Our conduits provide mechanical, thermal, electrical and chemical protection for all kinds of cables. The protection is mostly done by protecting the surface or cover of the cable. For fiber optics we must protect the cable from over bending, so it becomes an “anti-bending” system, which is a form of mechanical protection.
Why is this important?
The intensity/energy in a fiber optics cable can have enough power to cause an explosion, so protecting the fiber optic cable from over bending is not the only goal that we have to achieve with our cable protecting systems.
The Norm IEC/EN 60079-28 is the specific norm for protecting fiber optics classified as Ex op. Underneath you can find the descriptions of the 3 sub-levels of Ex op:
- Ex op is: inherent safe. Good for constricting and limiting the power/intensity of the light signal.
- Ex op pr: protected. Making sure that the light signal stays in the “container”.
- Ex op sh: with interlock. Building in a safety/interlock that switches the signal off immediately.
We highly recommend the Ex op pr. way of protecting. With this form of protection, you are making sure that the cover of the cable is protected, but also prevent the cable from over bending, breaking the fiber and keeping the light signal where it belongs, inside the cable itself. It is not allowed to run a fiber optics cable through an ATEX zone without a way of protecting this cable and it must be conform to one of the protection levels described in the Norm IEC/EN 60079-28.
