Fire Escape Stair and Protected Stair Requirements (BYKHY Articles 38-47)

Short answer: under Article 38(3) of the Turkish Regulation on Fire Protection of Buildings (BYKHY), no combustible material may be used in the walls, ceiling and floor of escape stairs; the stair is separated from other parts by walls with at least 120 minutes of fire resistance and smoke-tight doors with at least 90 minutes. Ventilation or pressurisation is mandatory under Article 45.

When is a stair an escape stair

Article 4(t) defines a fire escape stair as a stair arranged to be protected against fire and opening onto a safe area at natural ground level. Article 4(ee) describes a protected stair as a stair enclosed by a fire-resistant material or arranged so that it is not affected by fire.

Article 38(1) states that those common stairs of a building which are suitable for use in fire and other emergencies are accepted as escape stairs. Article 38(2) sets a critical principle: escape stairs are part of the escape route system as a whole and cannot be designed independently of the other escape route elements. For the escape route chain as a whole, see the article on escape routes and stairs.

For unprotected stairs the Regulation leaves a narrow opening. Under Article 31(7), open stairs not exceeding one floor are accepted as escape routes, provided they comply with the distances in Annex 5/B. However, the same paragraph requires that on floors with more than 50 occupants at least half of the escape routes, in terms of capacity and number, are protected.

Stair types and numerical limits

Article 41(9) also states that electrical and mechanical service shaft hatches cannot open into the escape stair enclosure or the fire lobby, and that combination boilers, air-conditioning outdoor units, meters and similar equipment cannot be placed there. This is one of the breaches met most often on site.

Fire lobby

Article 34(1) lists three functions of fire lobbies: preventing smoke from passing into escape stairs, use by fire-fighting and rescue personnel, and holding disabled and injured persons when necessary. Under Article 34(2), no combustible material may be used in the walls, ceiling and floor of the lobbies, and these lobbies are separated from other parts by walls with at least 120 minutes of fire resistance and smoke-tight doors with at least 90 minutes. Under Article 34(3), the floor area cannot be less than 3 m² or more than 6 m², and the dimension in the direction of escape cannot be less than 1.8 m. Article 34(4) gives separate values for the lobby in front of a firefighting lift: it cannot be less than 6 m² or more than 10 m², and no dimension may be less than 2 m. Article 34(5) requires the floor in the lift lobby to be given a fall towards the exit door not exceeding 1/200.

When the lobby is mandatory is set out in Article 34(7): in buildings with a firefighting lift and a structure height above 51.50 m, a fire lobby in front of the escape stair is mandatory, and the firefighting lift must open into the lobby in front of the fire escape stair. For the high-rise strategy as a whole, see the article on fire requirements for high-rise buildings.

The pressurisation link

Article 45(1) requires all protected escape stairs to be ventilated by natural or mechanical means or pressurised; the same paragraph also states that the stair and the occupied areas cannot share the same light well or shaft opening.

The cases where pressurisation is mandatory are in the first three paragraphs of Article 89, and each looks at a different quantity:

• Article 89(1): In all buildings except residential buildings, escape stairs are pressurised if the height of the stairwell is more than 30.50 m.
• Article 89(2): In buildings with more than 4 basement floors, the escape stairs serving the basement are pressurised.
• Article 89(3): Pressurisation of the escape stairs of residential buildings with a structure height above 51.50 m is mandatory.

The first paragraph gives one more measurement detail: even if the escape stair serving the basement and the upper floors is in the same enclosure, if it is separated at ground level by a smoke-tight wall with 120 minutes of fire resistance and a separate exit is provided, the height of the upper floors is taken as the basis for the stair enclosure. The background of the thresholds is covered in the article on pressurisation thresholds.

Article 89(6) requires that, if the fire lobby is also pressurised, a pressure distribution is set up in which the pressure on the stair side is higher than on the lobby side. Article 89(16) requires that, in stairs that are not pressurised, there is an openable window or a roof light above the stair providing permanent ventilation.

Doors and layout inside the stair

Under Article 47(1), the minimum clear width of escape route doors cannot be less than 80 cm and their height not less than 200 cm; doors must have no threshold, and revolving doors and turnstiles cannot be used as exit doors. Article 47(2) requires exit doors in spaces with an occupant load of more than 50 persons to open in the direction of escape, and doors to be opened by hand and not kept locked.

Article 47(3) requires escape stair and fire lobby doors to be smoke-tight and to have at least 60 minutes of fire resistance if they serve fewer than 4 floors and at least 90 minutes if they serve basement floors or more than 4 floors, and also to be fitted with self-closing devices.

Under Article 47(5), escape route doors opening onto a safe area at ground level and, where the number of people on a floor exceeds 100, stair, corridor and fire lobby doors must be openable in the direction of escape without using a door handle. Article 47(6) requires doors to open with a force of no more than 110 N; this value is the same as the 110 N limit in pressurisation.

Basement, ground floor and final exit

The weakest point of a stair is often its lowest end, and the Regulation ties this point down with two articles.

Under Article 46(2)(a), if the normal floor stair serves the basement and serves more than 4 floors including basement floors, a fire lobby is provided at the basement floors for entry to the stair, except for special cases for residential buildings. Article 46(2)(b) requires that, to prevent people leaving the upper floors from going down to the basement, the landing at ground level is separated from the basement stair by a door or similar physical barrier, or visible directional guidance is provided.

Article 41(2) states that where an escape stair discharges into a circulation area at ground level, the distance between the point where the stair arrives and the open air outside cannot exceed 10 m; in sprinklered buildings this distance can be up to 15 m. The same paragraph requires an outward-opening door wide enough for the occupant load discharging from the internal escape stairs.

Article 71(1) makes lighting of all escape routes and escape stairs mandatory; for the layout logic, see the article on emergency lighting and exit signs.

Field note

In a hotel project the enclosure, doors and pressurisation had been set up correctly. At commissioning, the pressure difference measured with all doors closed fell well short of the 50 Pa required by Article 89(5). The fan, ducts and dampers were correct. The problem was an unsealed service penetration through the enclosure wall. In the same building a meter panel had also been placed in the enclosure, contrary to Article 41(9).

A second example: three of the floor doors did not close fully under pressure; the cause was not the closer setting but the thickness of the carpet under the doors. Article 47(3) requires doors to be self-closing, and Articles 89(7) and 47(6) require the door force not to exceed 110 N.

The lesson: pressurisation is not a fan selection but a matter of airtightness and door behaviour. Before moving to commissioning, visually check every penetration of the enclosure and open and close each floor door one by one under pressure.

Checklist

• ☐ Enclosure wall 120 minutes; doors smoke-tight and 60 or 90 minutes according to the number of floors served (Article 38(3), Article 47(3))
• ☐ No combustible material seen in the walls, ceiling and floor (Article 38(3))
• ☐ No service shaft hatch opening into the enclosure and no equipment placed in it (Article 41(9))
• ☐ Fire lobby area and dimension in the direction of escape measured (Article 34(3), Article 34(4))
• ☐ Need for pressurisation assessed separately against stairwell height, number of basement floors and structure height (Article 89(1), 89(2), 89(3))
• ☐ Closed door 50 Pa, open door 15 Pa, door force 110 N and 1 m/s air velocity per door measured (Article 89(5), 89(7), 89(8))
• ☐ Basement flight seen to be separated at ground floor by a door or directional guidance (Article 46(2))

FAQ

What fire resistance does an escape stair enclosure need?

Under BYKHY Article 38(3), no combustible material may be used in the walls, ceiling and floor of escape stairs; these stairs are separated from other parts by walls with at least 120 minutes of fire resistance and smoke-tight doors with at least 90 minutes. Article 47(3) sets the door requirement at at least 60 minutes when serving fewer than 4 floors and at least 90 minutes when serving basement floors or more than 4 floors.

What should the dimensions of a fire lobby be?

Under BYKHY Article 34(3), the floor area of fire lobbies cannot be less than 3 m² or more than 6 m², and the dimension in the direction of escape cannot be less than 1.8 m. Article 34(4) gives different values for the lobby in front of a firefighting lift: it cannot be less than 6 m² or more than 10 m², and no dimension may be less than 2 m.

When is stair pressurisation mandatory?

Under BYKHY Article 89(1), in all buildings except residential buildings, escape stairs must be pressurised if the height of the stairwell is more than 30.50 m. Article 89(2) requires pressurisation of the escape stairs serving the basement in buildings with more than 4 basement floors, and Article 89(3) requires pressurisation of the escape stairs of residential buildings with a structure height above 51.50 m.

What values must pressurisation achieve?

Under BYKHY Article 89(5), the pressure difference between the stair enclosure and the occupied areas of the building must be at least 50 Pa with all doors closed and at least 15 Pa with a door open. Article 89(7) requires the force applied to the door handle not to exceed 110 Newtons, and Article 89(8) requires an average air velocity of at least 1 m/s with each door fully open.

References

1. Turkish Regulation on Fire Protection of Buildings (BYKHY), Official Gazette 19.12.2007/26735 and amendments; Articles 4(t), 4(ee), 31(7), 33(2), 34(1)–34(7), 38(1)–38(3), 40(1), 40(2), 41(1), 41(2), 41(3), 41(5), 41(9), 42, 43, 45(1), 46(2), 47(1), 47(2), 47(3), 47(5), 47(6), 71(1), 89(1)–89(16), Annex 5/B. mevzuat.gov.tr (consolidated text)

SprinkCalc — Fire Sprinkler Design Across Three Standards

SprinkCalc covers hazard classification, design density and area, K-factor selection, water demand and hydraulic calculations for NFPA 13, FM Global and BS EN 12845 in a single iOS app, and exports a professional PDF report.

Download SprinkCalc on the App Store

MEP Calc — 110+ Engineering Calculators

MEP Calc bundles 110+ engineering modules in one iOS app: 21 fire calculations plus heating, cooling, HVAC, plumbing, steam and natural gas.

Download MEP Calc on the App Store