Technical Bulletin - How to use back-check correctly and make sure it is properly certified. A couple of points about back-check which, when fitted within a door closer, can be a very useful feature. A door closer is designed to control the movement of a door during the closing cycle. However, door closers with the Back-check feature can also ‘dampen’ the doors movement during the opening cycle after a specified angle (approx. 75⁰) When you open a door, without back-check, it swings in an uncontrolled movement until it is stopped. This can be by an adjacent wall, a piece of furniture, the doorframe, or perhaps even a person standing in the way. Obviously the last thing you want is for a door to start inflicting damage on the surrounding area or someone nearby. For this reason back-check can be a very useful feature within a door closer as it can slow the door down as it approaches a set angle to prevent it hitting a wall or adjacent item. Back-check is also very desirable on external fire doors as it can prevent a door swinging violently out of control when hit with a gust of wind, reducing the risk of strained hinges or damage to the doorframe. Similarly, in any environment where people may be rushing through a door – a school for example – back-check can reduce accidents and injuries. The back-check feature can come in two guises; fixed or adjustable. In short, fixed back-check begins to slow the opening action down at approximately 75°, so in normal use you would hardly know it was there. Adjustable back-check can have the deceleration of the door increased or decreased depending on the environment. In either case, if the door is ‘flung’ or pushed open spiritedly, back-check will help catch this movement and cushion the door until it reaches the door stop or runs out of momentum. Used correctly, the back-check feature in a door closer helps to reduce the momentum of a door as it approaches the door stop, thus minimising damage to the door , hinges and frame fixings and preventing it bouncing back sharply towards the person using the door. However, back-check is not a substitute for a door stop, which should always be specified for any door which is at risk of hitting a wall or other item. Unfortunately this is not always the case; back-check is quite often used where a door stop was left off the installation list, or even when someone realises the door may cause a lot of very expensive damage and use the back-check feature as a stop-gap solution. So remember, you should only use back-check to help slow a door down as it opens and always fit a door stop to halt a door damaging the surrounding area or people nearby, but never rely solely on back-check to control how far a door opens. Another point to remember is that back-check is not always certified (tested) on some door closers. Just because the door closer is CE marked it must never be assumed the certification includes the back-check or indeed other functions. To meet CE standards the back-check function should have gone through a 100,000 test cycle to EN1154. However, some brands offer door closers with a CE marking and back-check – yet the back-check function may not have been part of the test. In this instance the door closer would have been tested with the back-check function disengaged. Common problems with door closers not having a back-check function tested but engaged by the installer or user on a fire door can include; arm failure, internal piston / pinion damage – potentially stopping the unit from sealing a fire door in its frame and last but not least, any certification being invalidated. So it’s very important that you check the manufacturer’ Declaration of Performance (DoP) and – vitally – the Construction Product Regulation (CPR) paperwork from a UKAS certification body, to ensure any door closer featuring back-check has been thoroughly tested and certified. As the global leader in door opening solutions, we can help ensure the right door closer is selected. For friendly help and advice, don’t hesitate to contact us at email@example.com.