Why do door closers go down to EN2 when EN3 is the legislated minimum?

It is widely believed in the construction industry that fire doors should be fitted with an EN3 door closer as a minimum and that the closer should never be adjusted below EN3. This is entirely understandable because BS EN 1154 does recommend that door closers on fire doors should be of a minimum EN3 power size. However, the guidance also states that fire doors should have a minimum closing force of 18Nm at the leading edge, and this is the measurement that counts because this is a measure of the actual performance of the door once installed.

A delicate balancing act

We all know that what works on paper doesn’t always work on site – once a door is fitted, there are many different variables that can come into play and affect the force with which it closes. This means that 18Nm, the actual closing force of the door once fitted, is a far more accurate and meaningful measurement than EN3, which is the power size of the door closer measured on a test rig in UKAS accredited lab conditions. Once a fire door is fitted, it must have a minimum closing force of 18Nm as stated in the guidance, but if subject to Approved Document M it must also comply with BS 8300 regulations assisting the less able – a door closer must allow ease of opening as well. 

EN2 can achieve 18Nm

EN3 door closers actually have a closing force range of 18-26Nm. If an EN3 door closer is fitted to a narrow door, for example less than 950mm wide, the closing force is going to be at the upper end of that scale. This means that the door is going to be much harder to open and in this case the door closer should be adjusted down to EN2 to allow ease of opening. You can adjust the closer down to EN2 and still achieve a closing force of 18Nm.

We have come across installers who are very reluctant to do this because of the guidance to use minimum of EN3 door closers on all fire doors. We have even come across specifiers who are reluctant to specify EN2-4 door closers because they are very focused on EN3 being the minimum requirement.

Why would a door be narrower?

Narrower doorways are often found in older properties, so it is not uncommon to come across this issue when retro-fitting fire doors. But this situation could apply to any half-leaf door that is subject to fire regulations, for instance in a hospital or care home where wide doorways are often fitted with a full-size and half-leaf door.

Rutland recommendation

We have established that whilst EN3 is a well-intended guide, it can be misleading and result in non-compliant opening forces according to BS8300. The better measurement to go by is the stated minimum of 18Nm closing force. In order to achieve the delicate balancing act between ease of opening and ensuring reliable closing, Rutland recommends making a calculated estimate of the power required using the table below as a guide.  Then choose an adjustable power closer, such as the TS.11204, giving you flexibility either side of your estimate and allowing fine adjustment on site, once the door is fitted. 

Power size (EN)

Max door weight (kg)

Max door width (mm)

1

20

750

2

40

850

3

60

950

4

80

1100

5

100

1250

6

120

1400

*An abridged table based on guidance given in BS EN 1154

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