What the tool does
Turkey's Regulation on the Fire Protection of Buildings (BYKHY) ties every provision on flammable and combustible liquids to the liquid's class. The tool first finds the class under Article 113, then, for the storage location you choose, gives the limit for that class, the notification and permission status under Annex 11 and, for outdoor tanks, the Annex 12/C distances, each with its article reference. It works for one liquid in one location; mixed storage has to be assessed separately.
Article 113: class
| Class | Flash point | Boiling point | Article |
|---|---|---|---|
| IA | below 22.8 °C | below 37.8 °C | 113/1-b-1 |
| IB | below 22.8 °C | 37.8 °C or above | 113/1-b-2 |
| IC | above 22.8 °C, below 37.8 °C | — | 113/1-b-3 |
| II | 37.8 °C or above, below 60 °C | — | 113/1-a-1 |
| IIIA | 60 °C or above, below 93 °C | — | 113/1-a-2 |
| IIIB | 93 °C or above | — | 113/1-a-3 |
Class I (IA, IB, IC) liquids are "flammable" (parlayıcı), Class II and III are "combustible" (yanıcı). A substance with a flash point below 37.8 °C whose vapour pressure at that temperature exceeds 276 kPa falls outside the liquid classes and the tool gives no limits for it. Class II and IIIA liquids used heated above their flash point count as Class I (113/2). As the article names no subclass, the tool asks which subclass to apply; the default is IA, the strictest reading.
Limits by storage location
| Location | Limit | Article |
|---|---|---|
| Corridor, stair, basement, escape route, hall, workplace, public area | Not permitted | 115/1 |
| Storage room or cabinet (building with secondary processes) | IA 100 L in original containers; IB–IIIA 500 L in total in original containers or 2,500 L in portable tanks | 115/2 |
| Retail sales area | 5 L per m² of floor area; IA at most 100 L, IB–IIIA 1,000 L, IIIB 2,500 L | 115/3 |
| Storage building | At most 5 piles, 3 m apart; Annex 12/A per pile; 12,500 L in total expressed as Class IA | 118/2 |
| Separated area in a factory or workshop | 60 min: up to 15 m², 70 L/m² (protected 175); 120 min: up to 50 m², 140 L/m² (protected 350) | 118/3, Annex 12/B |
| Outdoor above-ground tank | Annex 12/C distances and bunding | 119 |
Under 115/2 and 115/3 the area is separated from other uses by walls and floors of at least 90 minutes' fire resistance, and the liquid is kept in a cabinet rated 200 °C for 10 minutes. A storage building has at least 120 minutes' fire resistance; a building storing Class I liquids has no basement, Class II may not be stored in a basement and Class IIIA and IIIB are limited to 40,000 L there (118/1).
Annex 12/A: per pile (litres)
| Class | Original containers | Portable tanks |
|---|---|---|
| IA | 2,500 | — |
| IB | 5,000 | 7,500 |
| IC | 10,000 | 5,000 |
| II | 30,000 | 40,000 |
| IIIA | 100,000 | 150,000 |
| IIIB | 200,000 | 300,000 |
The IA-equivalent ratios are in 118/2: IB/2, IC/4, II/12, IIIA/40, IIIB/80. In a storage building the tool divides the quantity equally between the piles and checks both the pile limit and the 12,500 L IA-equivalent limit.
Annex 11: notification and permission
Annex 11 is not a maximum; it is read with Article 114/1. Above the lower value of the range the store must be notified; above the upper value, or where the location is neither of the two in the table, fire-brigade permission is also needed. Class IIIA and IIIB are outside this duty.
| Location | Class IA (L) | Class IB, IC, II (L) |
|---|---|---|
| Stores at or above ground level | 20 – 60 | 100 – 300 |
| Outdoor stores | 20 – 200 | 40 – 600 |
Where Class I or II liquids are filled in an enclosed space at more than 200 L per hour and more than 1,000 L is present, fire-brigade permission is needed (114/2).
Annex 12/C: outdoor tank distances
Distances are the shortest measured from the tank's outer shell. To a neighbouring plot boundary, main road or railway they rise from 1.5 m (1,000 L or less) to 55 m (11,375,001 L or more), and to the site office from 1.5 m to 20 m. The table gives no tank-to-tank distance up to 1,000 L; it is 1 m for 1,001–45,000 L, 1.5 m for 45,001–115,000 L and above 115,000 L a quarter of the sum of the adjacent tank diameters.
Reading decisions in the tool
- Exactly 22.8 °C: the text says "below" for IA/IB and "above" for IC; the tool takes the more hazardous class and warns.
- 114/3 and IIIB: the paragraph names IIIB but gives no ratio; the tool does not do mixed-storage sums.
- 115/3, 5 L per m²: applied to the total quantity.
- 118/2: the text says "flammable liquid"; the tool applies the pile and IA-equivalent limits to all classes.
- Annex 12/A, IC in portable tanks: the printed value (5,000 L, below IB) is used with a warning.
- Guide Figure 119.1: the row limits at 45,000, 115,000 and 7,550,000–7,750,000 L are printed differently from the annex table; the tool follows the annex table and the 2015 text and shows the figure's value in a warning.
Frequently Asked Questions
Which BYKHY class is diesel?
The class comes from the flash point: between 37.8 °C and 60 °C it is Class II. The Guide lists diesel as a Class II example; still, use the flash point on the product's own safety data sheet. Used heated above its flash point, it counts as Class I (113/2).
Is Annex 11 the maximum quantity allowed?
No. With Article 114/1 it sets notification and permission thresholds: above the lower value the store is notified, above the upper value or in a location not in the table fire-brigade permission is needed. Maximum quantities come from Article 115 and Annex 12.
Is the Annex 12/A value the total for the room?
No, it is per pile. One enclosed space may hold at most 5 piles, 3 m apart, and no more than 12,500 litres in total expressed as Class IA (118/2).
How much liquid can a workshop hold?
In an area separated from the process area, per Annex 12/B: with 60 minutes' fire resistance up to 15 m² at 70 L/m² (175 with fixed protection), with 120 minutes up to 50 m² at 140 L/m² (350 with fixed protection). IA and IB together may not exceed the Annex 12/A value.
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