Design Requirements for Fire Pump Rooms
The fire pump room is the core of the fire protection system and a critical factor determining whether the entire fire protection system can function effectively. Therefore, it is a core issue that must be mastered in both design and construction, and even in architectural certification exams. Below is a summary of the key considerations for fire prevention in the building structure and fire protection facilities of fire pump rooms.
- Fire Resistance Rating for Independent Fire Pump Rooms:
Fire pump rooms constructed as standalone buildings shall have a fire resistance rating of not less than Grade II.
Purpose: To ensure that internal equipment can operate normally during a fire and that the safety of the pump room is not compromised by external fires, protecting both equipment and personnel entering the room for operations.
- Location of Fire Pump Rooms in Buildings:
Fire pump rooms attached to buildings shall not be located on the third basement floor or below, or on underground floors where the vertical distance between the indoor ground and the outdoor entrance/exit ground exceeds 10m.
Rationale: This facilitates timely access to the fire pump room by operators during a fire.
- Emergency Exit Requirements:
Evacuation doors shall lead directly to the outdoors or to a safe exit.
Explanation:
"Lead directly to the outdoors" means the door allows direct access to outside the building without passing through other rooms or spaces (e.g., an evacuation door near the main entrance on the ground floor).
"Lead directly to a safe exit" means the door connects via an evacuation corridor directly to the entrance of an evacuation staircase, without passing through other spaces.
- Fire Separation from Adjacent Areas:
Fire pump rooms attached to buildings shall be separated from other areas by fire-resistant partitions with a fire resistance rating of not less than 2.00 hours and floors with a rating of not less than 1.50 hours.
Simplified Memory Aid: Fire pump rooms follow the "215 rule" for building fire protection ("215" refers to 2.00h partitions and 1.50h floors).
- Fire Door Requirements:
Fire pump rooms shall be equipped with Class A fire doors.
Note on Code Conflicts:
GB50016-2014 Building Code states that doors from ventilation, air conditioning, and power distribution rooms into the building shall be Class A fire doors, while doors from fire control rooms and other equipment rooms shall be Class B.
GB50974 Fire Water Supply and Hydrant System Technical Code specifies Class A fire doors for fire pump rooms.
Recommendation: Prioritize the stricter requirement and install Class A fire doors for fire pump rooms.
- Flood Prevention Measures:
Fire pump rooms shall adopt technical measures to prevent water inundation.
Background: This requirement stems from lessons learned in major fire incidents where fire pump rooms and control rooms were flooded or rendered inoperable by water ingress, compromising fire suppression efforts.
Measures:
(1) Rationalize the floor and location of the pump room during design.
(2) Install thresholds, drainage systems, and other measures to prevent water accumulation from fire suppression systems (e.g., sprinklers) from flooding equipment, pumps, power supplies, and electrical panels.
- Finishing Materials:
All interior finishes in fire pump rooms shall use Class A non-combustible materials.
Rationale: Fire pump rooms are critical for maintaining system operation and safety.
- Design of Water Tank Inlet, Outlet, and Overflow Pipes:
The bell mouth of the fire pump suction pipe shall be submerged at least 600mm below the minimum effective water level in the tank. For installations with a vortex preventer, the submersion depth shall be at least 200mm.
The outlet pipe of the tank shall be positioned as far as possible from the inlet pipe to promote optimal water circulation. If circulation is insufficient, measures to prevent short-circuiting shall be implemented.
Overflow pipes shall not be fitted with valves, shall have insect-proof grilles at the outlet, and shall use indirect drainage.
- Suction Trough, Vent Pipe, and Manhole Setup:
Suction Trough (Well):
Reinforced concrete tanks typically include a suction trough (well), usually buried (0.8–1.0m below the tank floor).
The effective volume of the suction trough shall be calculated as 3 minutes of the design flow rate of the largest pump.
The dimensions shall accommodate the installation of the pump suction pipe.
Vent Pipes:
Often overlooked in design, vent pipes are essential for both domestic and fire water tanks.
Pipe diameter and quantity (minimum 2 pipes) shall be determined based on the maximum ventilation volume required for the largest inlet or outlet flow.
Pipe ends shall be fitted with insect-proof grilles.
Manhole:
A manhole with a ladder shall be installed at the top of the tank, positioned near the inlet float valve for easy maintenance.
- Pump Selection and Layout in the Pump Room:
Domestic Water Pumps:
Variable frequency or pressure-stack (non-negative pressure) systems are commonly used.
For variable frequency systems, main pumps are selected based on the maximum second-by-second flow rate of the building (or zone) and the head at the most unfavorable point.
For pressure-stack systems, the pump head shall be determined by the pressure required at the most unfavorable point (adjusted for municipal water pressure where applicable).
Fire Pumps:
Designers typically select one primary and one standby pump based on calculated water demand and head for indoor hydrants or sprinklers.
Cost and Practicality Considerations:
If hydrant and sprinkler systems have similar flow rates and heads, a shared standby pump can be used, sized for the largest pump.
For high-power pumps (e.g., 110kW or above), consider using two smaller pumps (half the flow rate, same head) with a "two-primary, one-standby" configuration to reduce generator capacity requirements due to high starting currents (5–6 times operating current).
Layout Requirements:
Ensure adequate spacing between pumps and from walls as per codes.
Avoid obstructions to access pathways and facilitate installation of suction pipe valves.
Use independent suction pipes for fire pumps and minimize bends to enhance water intake reliability.
- Drainage Design in the Pump Room:
Gravity Drainage: Prioritize direct gravity drainage to outdoor sewer systems.
Basement Pump Rooms: Install sewage lift stations if outdoor drains are below the pump room’s discharge elevation.
Typical Setup: Drainage ditches with grated covers and sumps with submersible pumps.
Sump Pump Selection:
Size pumps based on the maximum of tank overflow, discharge, and other inflows.
Use a "one-primary, one-standby" configuration with a signal level to trigger both pumps simultaneously during major leaks.
Sump Volume: Calculate as 5 minutes of the largest pump’s discharge capacity, with a maximum of 6 starts per hour.
- Fire Pump Control:
Operation Modes: Fire pumps shall support manual forced start/stop and automatic activation but shall not have automatic shutdown functionality (shutdown must be manual).
Automatic Activation Triggers:
Pressure switches on the fire pump discharge main (connected to the control cabinet via pressure sensors).
Flow switches on the outlet pipe of the high-level fire water tank.
Pressure switches on alarm valves.