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4.3 Commentary

4.3.1 General
The Building Regulations 1991 Approved Document B 2000 Edition allows self-closing fire-resisting doors to be held open by electrically powered hold open devices actuated by an automatic fire detection and alarm system, in those situations where a normal self-closing device would be considered a hindrance to the normal approved use of the building.

Within the framework of the Construction Products Directive
(98/106/EEC), these devices have been identified as playing an essential role in the safety of buildings in the case of fire.
Compliance with BS EN 1155 and EN1634-1 will be deemed to satisfy the requirements of the Directive in this regard, and it is
therefore strongly recommended that proof of compliance be obtained for any electrically powered hold open device before it is specified or used.

Electrically powered hold open devices are available in a range of strengths (commonly referred to as sizes) which relate to the
available closing power of the door closer fitted, whether the closer is separately mounted or integral with the hold open device.
The minimum performance requirements are laid down in
BS EN 1155 and include levels of electrical performance, holding power, suitable door width and mass.
The following extract from BS EN 1155 shows the range of hold open power sizes and related maximum recommended door leaf widths, together with some of the relevant test parameters:

Table 1 BS EN 1155

Section 4 - Electrically Powered
                      Hold Open Devices