Article 24(6) of the Turkish Regulation on Fire Protection of Buildings (BYKHY) leaves the maximum compartment area required in buildings to the Annex 4 table. The table sets no limit for dwellings and enclosed car parks; the tightest limits are found in storage buildings (1,000 or 5,000 m²) and healthcare buildings (1,500 m²). Where suitable fire control systems are installed, these values are doubled or become unlimited.
For the definition of a compartment, the fire resistance periods of walls and floors (Annex 3/B, Annex 3/C) and the hazard classes (Annex 1), see: What is a fire compartment?
Annex 4: Maximum compartment areas in buildings
| Building use class | Maximum compartment area (m²) | Footnote |
|---|---|---|
| Dwellings | Unlimited | |
| Accommodation | 4,000 | (1) |
| Institutional: healthcare buildings | 1,500 | (1) |
| Institutional: educational facilities | 6,000 | (2) |
| Office buildings | 8,000 | (1) |
| Commercial buildings (4) | 2,000 | (2) |
| Assembly: food and drink, entertainment, museums and exhibition venues | 4,000 | (2) |
| Assembly: other assembly buildings | 6,000 | (2) |
| Industrial buildings: Ordinary Hazard-3 and above | 6,000 | (2) |
| Industrial buildings: Ordinary Hazard-1 and Ordinary Hazard-2 | 15,000 | (3) |
| Storage: Ordinary Hazard-3 and above | 1,000 | (2) |
| Storage: Ordinary Hazard-1 and Ordinary Hazard-2 | 5,000 | (3) |
| Enclosed car parks | No limit |
Annex 4 footnotes:
- (1) If suitable fire control systems (automatic detection, sprinkler system, smoke extraction system and the like) are installed, the compartment area may be doubled.
- (2) If suitable fire control systems are installed, the compartment area is unlimited.
- (3) If the building is single-storey, there is no limit. If suitable fire control systems are installed, the compartment area is unlimited.
- (4) Excluding fruit and vegetable markets, fish markets, meat exchanges, places holding metal spare parts and similar places.
Hazard classes (Ordinary Hazard-1, 2, 3 and above) are determined according to Annex 1.
Other paragraphs of Article 24
- Article 24(1): The minimum fire resistance periods of compartment walls and floors are given in Annex 3/B.
- Article 24(2): Walls shared by two or more buildings, and the walls and floors of boiler rooms, car parks, main electrical distribution rooms, in-building transformer stations, medium-voltage substations, generator rooms and similar enclosed spaces with a fire hazard, have the properties of a compartment wall.
- Article 24(3): Common walls belonging to two or more buildings are built as fire-resisting walls; every wall separating semi-detached houses is a fire wall.
- Article 24(4): In non-residential buildings with a building height of more than 21.50 m and in residential buildings with a building height of more than 30.50 m, on the floors above these heights at most three floors are arranged as one fire compartment.
- Article 24(5): Atrium spaces are permitted only in buildings whose uses fall in the low and medium hazard classes; smoke control in atria is provided by natural or mechanical means.
- Article 24(7): The fire resistance of the elements enclosing a compartment is also continuous at the junctions; there can be no non-fire-resisting openings between compartments.
Practical scenario: logistics warehouse
In a warehouse falling in the Ordinary Hazard-3 and above class, the Annex 4 limit is 1,000 m². When suitable fire control systems (for example automatic detection, sprinklers and smoke extraction) are installed, footnote (2) makes the compartment area unlimited; a 20,000 m² warehouse can be planned as a single open volume once the hazardous spaces of Article 24(2) have been separated. In an Ordinary Hazard-1/2 warehouse the limit is 5,000 m², and if the building is single-storey, footnote (3) means this limit does not apply in the first place.
Field note
The most frequent debate is about the scope of the phrase "suitable fire control systems" (unofficial translation). The Annex 4 footnote lists automatic detection, sprinkler system and smoke extraction system as examples, using "and the like". According to the explanation in the Guide, it is not mandatory to plan all the systems listed in the footnote; the relevant fire brigade unit assesses, under the relevant articles of the Regulation, which fire control systems are needed according to the building's characteristics, such as its height, area and the materials used or stored. For this reason, the systems on which an increased limit relies should be written into the project report with their justification, and the fire brigade's opinion should be obtained at an early stage. The continuity requirement of Article 24(7) (penetrations, junctions) must in every case be shown separately.
Checklist
- Have the use class and hazard class (Annex 1) been selected correctly?
- Have the Annex 4 limit and the relevant footnote been written into the project report?
- Has it been stated which fire control systems the increased limit relies on, and has the assessment of the relevant fire brigade unit been obtained?
- Have the fire resistance periods of the compartment elements been taken from Annex 3/B (Article 24(1))?
- Has continuity at service penetrations and junctions been shown (Article 24(7))?
FAQ
What is the maximum storage compartment area under BYKHY?
Under Annex 4, the maximum is 1,000 m² in storage buildings of Ordinary Hazard-3 and above, and 5,000 m² in Ordinary Hazard-1 and Ordinary Hazard-2 storage buildings. If suitable fire control systems (automatic detection, sprinkler system, smoke extraction system and the like) are installed, the area is unlimited; for OH-1/2 storage there is also no limit if the building is single-storey.
What happens to the compartment area when sprinklers are installed?
Under the Annex 4 footnotes, the compartment area in accommodation, healthcare and office buildings may be doubled (footnote 1); in the education, commercial, food and drink, assembly, industrial and storage classes it becomes unlimited (footnotes 2 and 3). The condition is that suitable fire control systems (automatic detection, sprinklers, smoke extraction and the like) are installed; according to the explanation in the Guide, not all the listed systems are mandatory, and the relevant fire brigade unit assesses which systems the building needs.
Where are the fire resistance periods of compartment walls given?
Under Article 24(1), the minimum resistance periods of fire compartment walls and floors are given in Annex 3/B. Article 24(7) requires the fire resistance to be continuous at the junctions as well, and no non-fire-resisting openings between compartments.
References
- Turkish Regulation on Fire Protection of Buildings (BYKHY), Official Gazette 19.12.2007/26735 and amendments; Article 24, Annex 1, Annex 3/B, Annex 4. mevzuat.gov.tr
- Guide to the Regulation on Fire Protection of Buildings (Ministry of Environment, Urbanisation and Climate Change, General Directorate of Professional Services, r2, December 2024), explanation of Article 24(6).
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Download MEP Calc on the App StoreSources are listed in the References section at the end of the article. Quotations from the regulation are unofficial English translations of the Turkish text. This article is for general information; for article numbers, thresholds and exemptions, the current regulation and standard texts published in the Official Gazette govern, and design must be carried out by an authorised engineer.