197 ACCESS STAIRCASES- TECHNICAL INFORMATION - 2023 STAIRCASES ARTICLE CO 38: calculations of exit aisles 1. Levels, rooms, sectors or compartments must be served under the following conditions, according to the number of people they can accommodate: a) From 1 to 19 people: - by an exit aisle the width of which equals one exit unit. b) From 20 to 50 people: - either by two exit aisles leading outdoors or on different rooms not in a dead end. One of these exit aisles must have a width equal to one exit unit; the other can be an ancillary exit aisle; - or for rooms on upper floors, by a staircase having a width of one exit unit plus an ancillary exit aisle if the bottom deck of the level accessible to the public is situated more than eight metres above ground, or if article CO 25 on compartments applies, or for rooms below ground level, by a staircase having a width of one exit unit plus an ancillary exit aisle. c) From 51 to 100 people: - by two exit aisles of one exit unit or one of two exit units. In the latter case, this exit aisle must also have an accessory exit aisle. d) More than 100 people: - by two exit aisles up to 500 people, plus one exit aisle per 500 people or fraction of 500 people above the first 500. The width of exit aisles must be calculated with a ratio of one exit unit for 100 people or fraction of 100 people; below 501 people, the number of exit units is increased by one unit. ARTICLE CO 55: straight staircases 1. Straight staircases intended for public circulation must be designed with steps meeting best industry practice and flights with no more than 25 steps, with the exception of passageways leading to seats on stadium terraces. If the width of the staircases exceeds four exit units, they must be separated by one or more handrails separating whole numbers of exit units, and there cannot be more than four of them. Staircases can be replaced with ramps having a maximum gradient of 12%. As far as possible, the directions of flights of stairs must alternate. Steps must be at least 13 cm high but no more than 17 cm. Step height and width must satisfy this ratio: 0.60 m ≤ 2H + G ≤ 0.64 m. These heights and widths must be consistent on the same flight of stairs, however this requirement is not mandatory for the first step. 2. Landings must have a width equal to that of the staircases; in the case of non-opposing flights, their length must be greater than 1 m. EXIT UNITS AND HEADROOM min. 0.90 m 1 EU 1.10 m max. Headroom = min. 2.25 m min. 1.40 m 2 EU min. 0.80 min. 1.20 1.00 1.50 min. 1.80 m 3 EU min. 1.60 2.00 1.10 m max. no. x min. 0.60 m no. EU 0.10 max 0.10 max 1.10 m max. Headroom = min. 2.25 m Headroom = min. 2.25 m
RkJQdWJsaXNoZXIy OTQ2MzM=