Design flow rate and layout spacing requirements for indoor hydrant systems in five-star hotels
I am fire protection expert Alexander Li. As a five-star hotel is a densely occupied public building with complex functions, the design of its indoor hydrant system directly affects the firefighting efficiency in the early stage of a fire and the safety of occupants. Design flow rate and layout spacing are the core parameters of system design and must strictly follow the codes, and be finely configured in combination with the hotel's actual layout (such as guest room areas, public areas, kitchens, back-of-house areas, etc.); otherwise, insufficient water pressure or unprotected blind spots may occur during a fire.
**Detailed Analysis:**
1. **Design Flow Rate Requirements**
According to Article 3.5.2 of the Code for Fire Protection Water Supply and Hydrant Systems (GB 50974-2014), a five-star hotel usually falls under "high-rise public building" or "Class I high-rise public building" (building height greater than 50 m, or any floor above 24 m with a floor area greater than 1,000 ㎡ for shops, exhibition, telecommunications, postal, finance and trade buildings, etc.).
- **Indoor hydrant design flow rate**: For a Class I high-rise public building, it shall not be less than 40 L/s, the number of fire nozzles in simultaneous use shall not be less than 8, and the minimum flow rate of each riser shall be 15 L/s.
- **Fire duration**: According to Article 3.6.2 of GB 50974-2014, for a Class I high-rise public building it shall not be less than 3 hours, and the fire water tank capacity shall be calculated accordingly.
- **Practical experience**: In five-star hotel design, I often encounter designers taking the lower limit of the code without considering high-risk areas such as ballrooms and large kitchens in the hotel. For example, a hotel ballroom with an area of 1,200 ㎡ was designed at 40 L/s per the code, but actual fire simulation showed that if 8 nozzles are used simultaneously, the flow rate needs to increase to 45 L/s to cover the far end. Therefore, it is recommended that at the preliminary design stage, hydraulic calculations be carried out for the largest fire compartment of the hotel (such as the ballroom and meeting rooms), and the flow coefficient be increased where necessary.
2. **Layout Spacing Requirements**
According to Article 8.4.2 of the Code for Fire Protection Design of Buildings (GB 50016-2014, 2018 edition) and Article 7.4.10 of GB 50974-2014:
- **Protection radius**: The layout spacing of indoor hydrants shall not be greater than 30 m, and it shall be ensured that the effective water columns of two nozzles reach any point on the same floor simultaneously. Effective water column length: for a Class I high-rise public building it shall not be less than 13 m (when the nozzle diameter is 19 mm).
- **Specific layout**:
- Hotel guest room corridors: Hydrants shall be installed on both sides or in the middle of the corridor, with spacing not greater than 30 m, and it shall be ensured that the hose length (usually 25 m) can cover the farthest guest room door.
- Public areas (lobby, restaurant): Hydrants shall avoid decorative columns and furniture obstruction, and be provided with conspicuous luminous signage.
- Equipment rooms (such as boiler rooms and transformer/distribution rooms): Hydrants shall be provided separately, with spacing per the code, but it is recommended to add water spray or gas extinguishing systems as supplements.
- **Practical case**: During a renovation of a five-star hotel, the original design hydrant spacing was 28 m, but at acceptance it was found that the giant crystal chandelier in the center of the lobby blocked the nozzle jet, so that the effective water column could not cover the area behind the chandelier. We adjusted the hydrant positions, reduced the spacing to 22 m, and added 2 hydrants before passing acceptance. This reminds us that layout spacing must be reviewed against on-site obstructions and cannot rely solely on drawings.
3. **Coordination with Other Systems**
- The hydrant system shall be interlocked with the automatic sprinkler system (GB 50084-2017). For example, when the corridor length in the hotel exceeds 20 m, the sprinkler system shall share the fire water pump with the hydrant system, but the flow rates shall be calculated independently and superimposed (Article 3.5.1 of GB 50974-2014).
- The head calculation of the fire water pump (Article 5.1.6 of GB 50974-2014) shall consider the water pressure at the most unfavorable hydrant (not less than 0.35 MPa, and effective water column 13 m). I once handled a case where the hydrant water pressure in the top-floor guest rooms of a hotel was insufficient because the pump head did not account for the pipeline friction loss (actual loss reached 15 m); it was finally solved by replacing the pump and optimizing the pipe diameter.
**Concluding Conclusion:** The indoor hydrant system design flow rate for a five-star hotel shall not be less than 40 L/s (Class I high-rise), the layout spacing shall not be greater than 30 m, and it shall be ensured that two nozzles cover simultaneously; in actual projects, hydraulic review and position optimization shall be carried out in combination with the hotel's functional zoning, obstructions and high-risk areas to avoid acceptance problems.
The above are reference opinions. The actual project situation still needs to be further comprehensively evaluated and implemented in combination with specific working conditions, on-site conditions and other factors.