Fire Evacuation in Apartments and Industrial Buildings

Hereunder you will find some "best practices". JOMY does not take any responsibility concerning your personnal application of these, indeed, we strongly recommend that you check with your local authorities first.

Number of persons to evacuate

• The dimensioning of fire escapes must correspond to the number of individuals to be evacuated. This number is determined by the surface area of the compartment as follows:
  • 1 person per 107ft² (10m²) for buildings that are not publicly accessible;
  • 1 person per 32ft² (3m²) for buildings that are publicly accessible.
  • More specific numbers apply when a fixed interior design foresees another occupation.

Number of evacuation roads

• Generally, there should be at least two independent, non-intersecting escape routes.
• For compartments with 500 or more persons:
  • 500 - 999 persons: 3 evacuation roads;
  • 1000 - 1999 persons: 4 evacuation roads;
  • 2000 - 2999 persons: 5 evacuation roads;
  • Etc.
• There are cases where a single fire escape route will suffice:
  • Buildings with a height under 10m with fewer than 100 persons;
  • Buildings between 32 to 82ft (10 to 25m) with less than 50 persons and that are accessible by the fire services's ladders placed on the street side.
• Even in these cases, the fire department (and good prevention) often requires a second escape route.

Location of the emergency stairs

• The escape stairways should go in opposite areas of the space.
• The maximum distance from the escape route to the stairway is fixed (not for technical rooms):

	Use of the buidling
	By day	By night
To the road that connects the two stairs	<= 98ft (30m)	<= 65ft (20m)
To the nearest stair	<= 147ft (45m)	<= 98ft (30m)
To the other stair	<= 262ft (80m)	<= 197ft (60m)
Maximal distance for a dead-end evacuation road	<= 49ft (15m)

Access

• Access to the evacuation stairs via a door or corridor:
  • The door needs to be Rf ½ h for buildings higher then 82ft (25 m);
  • The doors may never be locked in the evacuation direction.
• Retractable stair flights and paneling/enclosure of the lower flight are accepted.
• Stairs for a building higher than 82ft (25m) need to allow access to the roof (when the roof is flat).

The useful width of a stair (UW)

• The UW is determined by the number of persons to be evacuated from the compartiment at full capacity. The sum of the UW of all descending stairs has to be at least equal to the number of persons to be evacuated from the largest compartment, multiplied by 1.25cm (ΣUW = number x 1.25cm).
• The minimum UW is 80cm, which corresponds to an evacuation of 64 persons (80/1.25). UWs can be seen in multiples of 60cm (the "transit unit"), as follows:
  • UW = 80cm for 64 persons per compartment per stair
  • UW = 120cm for 65 to 96 persons per compartment per stair
  • UW = 180cm for 97 to 144 persons per compartment per stair
  • Etc.
• In reality, there are often exceptions to the rule:
  • Depending on the available space and number of persons to be evacuated, UWs of 90, 100, and 110cm may be used.
  • In schools and daycares, a UW of 120cm is provided, even when the number of persons to be evacuated is less than 64 per compartment.
• Different stairs of the same compartment must have the same UW, plus or minus 60cm.
• The value of 1.25cm per person is only valid for descending stairs, for ascending stairs this factor is 2cm, and for flat walkways 1 cm per person.

Configuration

• The stairs must be able to carry a uniformly distributed load of 102 lb/ft² or 500 Kg/m² on each flight (the surface projected on the horizontal plane) and on the landings. They must also support a point load of 441lb or 200Kg applied anywhere on the steps or landing deck.
• At least one side must permit the free flow of air.
• Spiral stairs are generally not advised and for tall buildings (>= 82ft or 25m) even prohibited. A spiral stair must have a thread of at least 9.4" (24cm) on the walk line, located 1' 3.7" (0.4m) to 1' 11.6" (0.6m) from the handrail or the spindle and at least 1"1.8' (0.35m) from the outer edges of the steps.

Inclination

• Usually, an incline of 37° is requested (or about 75%).
• For medium and high-rise buildings (> 10m), an incline of 45° may be acceptable (confirm with authorized fire department). Sometimes, the stairs can only be used by persons with good mobility. For rising staircases, an incline of 45° is acceptable.
• Inclines greater than 45° must be avoided.

Treads

• The tread "a" and the riser "o" must meet the following formula: 600 <= a + 20 <=660 [mm].
• Risers are not necessary.
• A stair flight may have a maximum of 17 steps. If a greater height needs to be bridged an intermediate landing has to be provided.

Guardrails

• Always provide 2 guardrails per stair. Exception: One guardrail is sufficient for stairs with UW < 120cm, low buildings (< 33ft or 10m), and when there is no risk of falling.
• The minimum height for escape stairs is 3.3ft (1m) on the landings and 2.9ft (0.9m) on the stair flights, measured on the stair nose.
• When used by children (schools, nurseries, etc):
  • The maximum gap between the vertical bars is <= 3.1" (80mm).
  • There must be no horizontal elements that could be used as a step by children.
  • Height of 3' 7" (1.1m) instead of 3' 3" (1m).
  • A second guardrail that can be used by children must be provided (below the main guardrail).

Materials

• Materials must be of class A0 (non-flammable material, such as aluminum, steel, or concrete).
• There are no fire resistant requirements for outdoor stairs.
• Stable materials without detoriation due to ageing.

Stability

• The stairs must be able to carry a uniformly distributed load of 102 lb/ft² or 500 Kg/m² on each flight (the surface projected on the horizontal plane) and on the landings. They must also support a point load of 441lb or 200Kg applied anywhere on the steps or landing deck.
• The guardrails need to be able to withstand a horizontally applied uniform load of 220.4lb or 100 Kg/m, without permanent deformation.