Fire egress is one "hot" topic!

Due to the many authorities having an input on the subject, the situation has become very complex. As kown well by JOMY engineers, one can always find in all those regulations some "best practices" to apply.

Examples of some legislations:

Europe

• The European regulation on construction - products, Nr. 305/2011, gives the instructions concerning the obligation or the interdiction to add a CE-mark on a product;
• …

Federal Government of Belgium

• The basic laws concerning fire and explosion prevention are written out in the law of Juli 7,1994 which was adapted in the law of December 7, 2016;
• The Belgian codex for the well being at the workspace - Book 3;
• …

Belgian regional government

• Very specific regulation concerning hospitals, schools, resting houses, hotels, B&B,...;
• Flemish law of september 19, 2008 concering fire safety in child care facilities;
• Walloon law of December 18, 2003 concerning tourist accommodations;
• …

The municipal level

• Police regulations can differ from one city to another;
• Example: the Antwerp police codex contains "Rules concerning student homes";
• Example: the Gent police rules contain directives for "Fire prevention in public places";
• …

Some examples of standards

• NBN NEN 3509: Stairs in dwellings and apartment buildings - Vocabulary and dimensions;
• NBN S21-204: Fire protection in buildings - School buildings - General requirements an fire reaction;
• NBN EN 1991-1-1 and NBN 1991-1-1-ANB Eurocode: General actions - Densities, self-weight, imposed loads for buildings;
• EN ISO 14122-3 Veiligheid van machines - Permanente toegangsmiddelen tot machines - Deel 3: Trappen, steektrap / trapladders en leuningen;
• DIN 18 065: Building stairs;
• ISO 8421-6: Fire protection -- Vocabulary -- Part 6: Evacuation and means of escape.
• …

Technical informations / specifications (some examples):

• WCTB TV 198 - Accessibility of staircases
• …

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 10m² for buildings that are not publicly accessible;
  • 1 person per 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 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	<= 30m	<= 20m
To the nearest stair	<= 45m	<= 30m
To the other stair	<= 80m	<= 60m
Maximal distance for a dead-end evacuation road	<= 15m

Access

• Access to the evacuation stairs via a door or corridor:
  • The door needs to be Rf ½ h for buildings higher then 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 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 (>=25m) even prohibited. A spiral stair must have a thread of at least 24cm on the walk line, located 0.4m to 0.6m from the handrail or the spindle and at least 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 (< 10m), and when there is no risk of falling.
• The minimum height for escape stairs is 1m on the landings and 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 <= 80mm (<= 70mm in Wallonia).
  • There must be no horizontal elements that could be used as a step by children.
  • Height of 1.1m instead of 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.