How is an escape calculation done?
The Turkish Regulation on Fire Protection of Buildings (BYKHY) asks four questions of every storey: how many people can be present, how many exits are needed, how wide those exits must be and how far anyone walks to reach one. This calculator applies the new-building rules of Part Three (Articles 30–52) with Annexes 5/A and 5/B, and quotes the article behind every result. It is the preliminary sizing step for the evacuation plan and the number of escape stairs in a fire strategy.
1. Occupant load (Annex 5/A)
Occupant load is the floor area divided by the Annex 5/A factor in m² per person: 10 for offices, 5 for shops, 1.5 for classrooms, restaurants and conference halls, 30 for stores and car parks. The first four rows of the table (halls, dance halls and bars, exhibitions and studios, terminal waiting halls) use net area; all others use gross area. Where the number of people is fixed, for example by fixed seating, that number is used, but never less than the table gives. Service rooms that are not used at the same time, such as toilets, changing rooms and stores, may be left out (Art. 31/6). The calculator rounds each area's result up; since the text has no rounding rule, the unrounded total is also shown in the formula and an Interpretation line appears if rounding once would change the 50/500/1000/2000 thresholds. Annex 5/A has no dwelling row, so for an apartment storey the number of persons is entered as a design assumption in “stated number of persons”.
2. Number of exits (Article 39)
Unless stated otherwise, every building has at least two protected exits. A space holding more than 50 people (more than 25 in high-hazard spaces) needs at least 2 exits, more than 500 needs 3 and more than 1000 needs 4. In an undivided space the two exits must be at least half the diagonal apart, or one third in a sprinklered building. Where two exits are required, each must take at least half the total load (Art. 33/4).
The single-exit cases behind “unless stated otherwise” are written out in the text and applied with their conditions: a ground-floor shop with fewer than 50 people and less than 25 m to the outside door (32/8); a dwelling with a structure height below 21.50 m, where no second exit is required (48/5-a; 48/1 for dwellings of up to 4 storeys including basements); a hotel with fewer than 20 beds, a structure height below 15.50 m and a protected or pressurised stair (50/1-a); and factories, shops, stores and offices meeting all five conditions of Article 52. If a storey holds more than 50 people (25 in high-hazard spaces), 39/2 still requires two exits. Interpretation: the first sentence of 50/1-a requires two exits per storey in hotels of more than two storeys, so the tool does not apply the single-stair exception to hotels of three or more storeys.
3. Exit width (Articles 32/2 and 33)
Capacity is counted in 50 cm unit widths. The total width is the number of people on the storey divided by the persons per unit width from Annex 5/B, multiplied by 0.5 m:
W = N ÷ (persons per unit width) × 0.5 mAnnex 5/B gives the persons per unit separately for final exit doors, other doors and corridor doors, escape stairs, and ramps and corridors. The formula result is then checked against the minimums. No escape route may be narrower than 80 cm; with 50–500 people each route is at least 100 cm, with 501–2000 at least 150 cm and with 2001 or more at least 200 cm. A route that also serves rooms as a corridor or hall needs 110 cm, high-rise buildings need 120 cm (33/2) and hospital corridors 2 m (49/2). A single-leaf door has a clear width between 80 and 120 cm, and stairs wider than 200 cm are split by handrails into lanes of 100–160 cm.
The “other doors, corridor doors” column of Annex 5/B is for storey-exit and escape-route doors (stair, lobby and corridor doors); room doors are outside it, are sized for the room's own load and need at least 80 cm clear (47/1). Interpretation: because 33/1 says “no exit … may be narrower than these values” and 32/2 uses “exit” for exit doors, the tool applies the 100/150/200 cm single-route minimum and the 120 cm high-rise minimum to storey-exit and final-exit doors as well as stairs and corridors; the other reading (doors: formula and 80 cm only) is available as an option. A ground-floor final exit must also take the load discharging from the internal escape stairs (41/2); that load is added to the final-exit row through a separate input.
4. Escape distance (Annex 5/B)
Escape distance is the walking route from the furthest point of a space to the nearest storey exit, with the furthest point taken 40 cm in from the enclosing walls (Art. 32/6). The limit depends on whether escape is possible in one or two directions and on whether the building is sprinklered. On a large floor subdivided into rooms and corridors, a direct-line distance is acceptable if it does not exceed two thirds of the limit (Art. 32/5). In the table, distances read "unsprinklered / sprinklered" and the width columns give persons per 50 cm unit.
| Use class | One direction (m) | Two directions (m) | Final exit door | Other doors | Stairs | Ramps, corridors | Dead end (m) |
|---|---|---|---|---|---|---|---|
| High-hazard premises | 10 / 20 | 20 / 35 | 50 | 40 | 30 | 50 | 10 / 20 |
| Industrial buildings¹ | 15 / 25 | 30 / 60 | 100 | 80 | 60 | 100 | 15 / 20 |
| Dormitories | 15 / 30 | 45 / 75 | 50 | 40 | 30 | 50 | 15 / 20 |
| Shops, stores, supermarkets | 15 / 25 | 45 / 60 | 100 | 80 | 60 | 100 | 15 / 20 |
| Office buildings | 15 / 30 | 45 / 75 | 100 | 80 | 60 | 100 | 15 / 20 |
| Car parks and storage | 15 / 25 | 45 / 60 | 100 | 80 | 60 | 100 | 15 / 20 |
| Schools and education | 15 / 30 | 45 / 75 | 100 | 80 | 60 | 100 | 15 / 20 |
| Assembly buildings | 15 / 25 | 45 / 60 | 100 | 80 | 60 | 100 | 15 / 20 |
| Hospitals, care homes | 15 / 25 | 30 / 45 | 30 | 30 | 30 | 30 | 15 / 20 |
| Hotels, guest houses | 15 / 20 | 30 / 45 | 50 | 40 | 30 | 50 | 15 / 20 |
| Apartment buildings | 15 / 30 | 30 / 75 | 50 | 40 | 30 | 50 | 15 / 20 |
¹ In industrial buildings that do not produce readily ignitable materials, the one- and two-direction distances may be increased by one half. External escape galleries use the sprinklered-building values; open car parks use the sprinklered car-park values. The stair value in the hospital row was raised from 15 to 30 by amendment.
Worked example: a 1,200 m² office floor
A 1,200 m² gross office floor with a corridor layout in an unsprinklered building:
- Occupant load: 1,200 ÷ 10 = 120 people; above 50, so at least 2 exits.
- Stairs: 120 ÷ 60 × 0.5 = 1.00 m. With 50–500 people each route is at least 100 cm, so two stairs need 2.00 m in total.
- Corridors: the formula gives 120 ÷ 100 × 0.5 = 0.60 m, but a corridor that also serves rooms must be at least 110 cm each, 2.20 m in total.
- Escape distance: 45 m in two directions, 15 m in one; dead ends 15 m. If the building were sprinklered: 75, 30 and 20 m.
At this scale the minimum widths govern, not the formula. The formula takes over in crowded halls: a 1,500 m² net conference hall holds 1,500 ÷ 1.5 = 1,000 people, needs 3 exits and about 1,000 ÷ 60 × 0.5 ≈ 8.33 m of stair width.
Common mistakes
- Mixing up the load factor and persons per unit. m² per person is in Annex 5/A; persons per unit width is in Annex 5/B.
- Sizing stairs from the door column. The stair column is the lowest figure in every row and usually governs.
- Using sprinklered distances in an unsprinklered building. The sprinklered column applies only if the building is sprinklered, or under the note for open car parks and external galleries.
- Using net area where gross is required. For offices, shops or stores, net area understates the number of people.
- Comparing a direct-line distance with the full limit. Direct-line distances are checked against two thirds of it.
- Taking the formula as the final width. The 80, 100, 110, 120, 150 and 200 cm minimums override it on smaller floors.
Existing buildings follow the different escape rules of Part Ten, Chapter Two (Articles 146–159 and Annex 14); this calculator applies the new-building provisions. Check whether the building needs sprinklers with the Turkish fire code sprinkler requirement checker.
Frequently Asked Questions
How is the escape route width calculated?
Under BYKHY Article 33/1 the total width is the number of people on the storey divided by the persons per unit width from Annex 5/B, times 0.5 m. It is then checked against the minimums: 80 cm; 100 cm for 50–500 people, 150 cm for 501–2000 and 200 cm for 2001 or more; 110 cm for a route that also serves as a corridor and 120 cm in high-rise buildings.
What is the occupant load factor?
It is the floor area per person (m² per person, Art. 4/bb), given in Annex 5/A: for example 10 for offices, 5 for shops, 1.5 for restaurants and conference halls and 30 for stores and car parks. The first four rows use net area, the rest gross area.
What is the maximum escape distance?
It depends on the use, the number of escape directions and sprinklers (Annex 5/B). Offices: 15 m in one direction (30 m sprinklered) and 45 m in two (75 m sprinklered); shops: 45 m in two directions (60 m sprinklered); hospitals: 30 m in two directions (45 m sprinklered).
How many exits does a storey need?
Under Article 39, at least 2 protected exits unless stated otherwise; a space above 50 people (25 in high-hazard spaces) needs at least 2, above 500 needs 3 and above 1000 needs 4. A single exit is only possible where the text allows it: small ground-floor shops (32/8), dwellings with a structure height below 21.50 m (48/5-a), small low hotels (50/1-a) and factories, shops, stores or offices meeting every condition of Article 52.
How do sprinklers change the escape distance?
In a sprinklered building the longer Annex 5/B column applies; for offices the two-direction limit rises from 45 m to 75 m. The minimum spacing of two exits in an undivided space also drops from half to one third of the diagonal (39/3), and the distance from a stair to open air may be 15 m instead of 10 m (41/2).
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