Outdoor fire water flow for factory buildings
Enter the fire resistance degree, fire hazard class and building size. The tool computes the building volume, looks up the outdoor fire water flow for one fire, the 3-hour water storage and the main supply pipe size.
Factory of degree II, class C, 60 × 30 × 9.0 m (volume 16,200 m³): outdoor fire water flow 15 L/s, storage 162 m³ for 3 hours.
Preliminary results
| Step | Result | Basis |
|---|---|---|
| Building areaS = 60 × 30 | 1,800 m² | — |
| Building volumeV = S × 9.0 | 16,200 m³ | QCVN 06:2022/BXD |
| Volume column in the table16.2 thousand m³ | 5–20 thousand m³ | TCVN 2622:1995 ⚠ |
| Outdoor fire water flow (one fire)Degree II · C ⚠ | 15 L/s | QCVN 06:2022 · TCVN 2622 ⚠ |
| Water storageW = 3,6·Q·3 | 162 m³ | QCVN 06:2022/BXD ⚠ |
| Preliminary main pipev ≤ 2,5 m/s ⚠ | DN100 | BS 1387 |
Suggested materials
Glossary
What is the fire resistance degree?
The fire resistance degree rates how well the whole building withstands fire, in 5 degrees: degree I is the best, degree V the weakest.
It is set by the fire resistance (in minutes) of the main elements: columns, beams, load-bearing walls, floors and roof, using criteria R (load-bearing), E (integrity) and I (insulation), e.g. R 120, REI 60.
The weakest element sets the degree of the whole building. See Table 4 of QCVN 06:2022/BXD.
- Degree I – II
- Reinforced concrete frame, brick walls; or steel frame with approved fire-protective coating or cladding
- Degree III
- Non-combustible load-bearing structure with lower fire resistance, protected floors and roof
- Degree IV – V
- Unprotected steel-frame factory with metal roof; timber-structured buildings
Examples for reference only ⚠. The official degree is stated in the approved fire safety design.
What is the fire and explosion hazard class?
The hazard class rates a building (or room) by the substances inside and the production process, from A (most hazardous) to E (least). The higher the class, the stricter the requirements for fire water, separation distances and escape routes.
| Class | Characteristics | Examples |
|---|---|---|
| A | Flammable gases; flammable liquids (flash point ≤ 28 °C) that can form explosive mixtures | Light fuel depots, solvent paint shops, gas stations |
| B | Combustible dusts and fibres; liquids with flash point above 28 °C that can form explosive mixtures | Flour mills, cotton spinning, diesel storage |
| C | Combustible solids, hardly flammable liquids | Woodworking, paper, garment, plastics; packaged goods storage |
| D | Non-combustible materials in a hot or molten state, with sparks or flames | Forging, casting, hot rolling, welding, boilers |
| E | Non-combustible materials in a cold state | Cold machining, steel warehouses, non-combustible storage |
Official classification per QCVN 06:2022/BXD and the design ⚠. For buildings with rooms of different classes, the most hazardous room sets the class if it is large enough.
Frequently asked questions
How much outdoor fire water does a class C, degree II factory of 16,000 m³ need?
16,200 m³ falls in the 5–20 thousand m³ column; degree I–II class C needs 15 L/s for one fire. 3-hour storage: 3.6 × 15 × 3 = 162 m³.
Where do I find the fire resistance degree of a factory?
In the approved fire safety design. It depends on the fire resistance of load-bearing structures, walls, floors and roof per QCVN 06:2022/BXD.
What is the difference between hazard classes A, B, C, D, E?
A, B: explosive gases, vapours, dusts or flammable liquids. C: combustible solids and liquids such as wood, paper, textiles, plastics. D: non-combustible materials processed hot. E: non-combustible materials in a cold state.