(1) Except as permitted in Sentence (2), doors providing access to floor areas from exit stairs shall not have locking devices to prevent entry into any floor area from which the travel distance up or down to an unlocked door is more than 2 storeys.
(2) Doors referred to in Sentence (1) are permitted to be equipped with electromagnetic locks provided they comply with Sentences 3.4.6.16. (4) and (5).
(3) Doors referred to in Sentence (1) shall be identified by a permanently mounted sign on the stair side to indicate that they are openable from that side.
(4) Locked doors intended to prevent entry into a floor area from an exit stair shall,
(a) be identified by a permanently mounted sign on the stair side to indicate the location of the nearest unlocked door in each direction of travel, and
(b) be openable with a master key that fits all locking devices and is kept in a designated location accessible to firefighters or be provided with a wired glass panel not less than 0.0645 m2 in area and located not more than 300 mm from the door opening hardware.
(5) Where access to a floor area is required by Sentence (1), access through unlocked doors to the floor area from at least one other exit shall also be provided.
(6) In a building not more than 6 storeys in building height, doors providing access from exit stairs to a floor area containing a hotel are permitted to have locking devices to prevent entry into the floor area provided the requirements in Clause (4) (b) are complied with.