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Service and maintenance for radiation protection doors
Safety standards of radiation protection doors
In order to meet the safety standards of radiation protection doors, in the European Economic Area, and Switzerland, the requirements of Directive 2006/42/EC (Machinery Directive) have to be fulfilled completely. In order to fulfill the requirements of the safety act with a radiation protection door, the requirements of the guiding standard EN 13241 and the other standards mentioned therein have to be met.
Furthermore, the Machinery Directive claims, that an individual risk assessment has to be performed. Derived from this risk assessment, there is no way to protect the closing edge with a contact-free safety presence sensor. There always has to be a limitation of the doors clamp forces. You can find more on this topic, in the extra chapter below.
To avoid costly downtimes and possible termination of your insurance coverage, you should check whether your radiation protection gate meets the following (important) requirements.
- Safety devices must be provided, which prevent crushing, shearing, knocking over and pulling in, as well as resulting fractures or contusions of the head.
- Main safety feature of such heavy doors is the limitation of the clamp forces. The requirements according to EN standard 12453 have to be met. Which limits clamp forces below 400 Newton during the first 0.75 seconds and afterwards below 150 Newton.
- The applicable standard EN 13241 requires a first inspection of the operational forces by a certified testing centre. Test records of the measured clamp forces, of the installed radiation protection door have to be handed over to the customer, together with the documents as listed below.
- Non-contact safety features, like a light curtain or presence sensors, can provide additional safety. But cannot compensate missing limitation of clamp forces.
See below „Why non-contact safety presence sensors cannot compensate missing limitation of clamp forces.“ - The mechanical lifetime of a door must be ensured for a certain number of operating cycles, given that the required maintenance procedures are executed. We design our doors for a period of 15 years of continuous functioning. Also for the supporting elements and the fasteners we provide dynamic verifications.
- The radiation protection door must be able to be opened in the event of power failure, or the break of a suspension or a wheel.
- For outdoor applications, the manufacturer has to consider wind loads and the heat transfer coefficient of the door leaf.
- The electromagnetic compatibility in terms of the EMC directive must be given.
- After the user briefing the operating company of a gate system has to receive an operating manual according to EN 82079, instructions for regular maintenance, a log book, a spare parts list, all circuit diagrams as well as a Declaration of Conformity about fulfilling all safety-relevant requirements.
- Only after consideration of the safety features above, the door has to be marked with a CE sign.
A review by the TÜV has shown that all our doors fulfil the requirements of the Machinery Directive.
Why can non-contact safety presence sensors, for radiation shielding doors, not compensate missing limitation of clamp forces
Compared with common power operated doors, radiation shielding doors possesses two additional safety-relevant features. On one hand, door leafs can have a depth of more than 300 mm, up to 2000 mm and on the other hand, door leafs weight more than 10 kN, up to 1300 kN.
These enormous depth of the leaf grant space for a person to stand in between the inner and outer end of the sliding door leaf, without being recognized by a non-contact safety presence sensor. Non-contact safety presence sensors are installed at the front side, and, or at the back side of the door. The intermediate space is not monitored. Without a working clamp force limitation, a person could be crushed between the closing edge and the wall.
Also narrower door leafs are not safe with a solely non-contact safety presence sensor. Given the case that a person grabs into the area of the doors front edge near to the shearing edge, while the door is closing, and triggers the non-contact safety device, because of the significant mass the stopping distance could be too long to prevent a crushing or shearing of limbs.
Complementary be mentioned, that someone grabbing into the danger closing edge isn’t unusually. Maybe you’ve already seen someone grabbing into closing elevator doors, trying to trigger the light curtain and reopening the door for another person standing outside. With light elevator doors that may only lead to a mild clamping, but in case of heavy shielding doors this may result in serious injuries.
A relief for both cases is a limitation of the clamp forces, in compliance with EN 12453.
An expert opinion available to us, which has examined the described issue, comes to the following conclusion. “The operational safety can’t be solely implemented by non-contact safety features. An effective safety feature is the limitation of the clamp forces. The resultant clamp forces have to meet the restrictions of EN 12453.”