Fire protection systems are essential for safeguarding lives and properties from the ravaging effects of fire. One critical component of these systems is the jockey pump. This small but vital pump plays a significant role in maintaining system pressure, ensuring the system’s readiness in an emergency. This article delves into the workings, applications, and importance of jockey pumps in fire protection systems.
Figure | Purity jockey pump-PV
The Role of a Jockey Pump
The primary function of a jockey pump is to maintain the pressure within the fire protection network by addressing small leaks and pressure drops. These pumps are designed to operate at a higher pressure but lower flow rate compared to the main fire pump. Once activated, a jockey pump can quickly repair minor leaks and restore system pressure within a few seconds, subsequently stopping automatically. This rapid response helps to keep the fire protection system primed and ready without the need for the main pump to engage unnecessarily.
How Jockey Pumps Work
Jockey pumps are equipped with sensors that continuously monitor the pressure within the fire network. When the system pressure drops below a predetermined level, the jockey pump activates to increase the pressure back to the desired setting. The pump stops automatically once the set pressure is reached, ensuring that the system maintains optimal readiness. These pumps often share an electrical control panel with the main pumps, allowing for automatic or manual operation and monitoring of start counts and potential leak indicators.
Figure | Purity jockey pump-PV Components
Applications of Jockey Pumps
According to NFPA 20 standards, jockey pumps should be used in scenarios where maintaining high water pressure in the fire protection system is crucial. This helps prevent water hammer effects, which can damage the system and reduce its effectiveness. Jockey pumps are particularly important in high-rise buildings, large commercial facilities, and industrial sites where consistent water pressure is essential for the proper functioning of fire suppression systems.
Types of Jockey Pumps
Jockey pumps come in various types, each suited to different applications:
1. Regenerative Turbine Pumps: These are cost-effective and have low horsepower requirements. However, they necessitate a pressure relief valve to ensure safety and proper operation.
2. Vertical Multi-stage Pumps: Known for their high reliability and ease of maintenance, these pumps are slightly more expensive but provide excellent performance in maintaining system pressure.
3. Submersible Multi-stage Pumps: Ideal for situations where water pressure is insufficient, these pumps are designed to be submerged in water, making them suitable for underground water supplies.
Key Requirements for Jockey Pumps
Several critical requirements must be met for jockey pumps to function effectively within a fire protection system:
Centrifugal-Type Pumps: Jockey pumps should be centrifugal pumps to ensure consistent pressure maintenance.
No Backup Power: These pumps do not require an alternate or standby power source.
Approved Controllers: The pump controller must meet specific regulatory standards but does not need to be listed for fire pump service.
Isolation Valves: An isolation valve should be installed on the suction side of the jockey pump, along with a check valve and isolation valve in the discharge pipe.
Individual Pressure Sensing Line: Jockey pumps must have their own pressure sensing line, ensuring accurate pressure monitoring.
Sizing of Jockey Pumps
Proper sizing of jockey pumps is crucial for their effectiveness. The pump should be capable of replenishing the water loss in the fire protection system and maintaining the desired pressure. For systems serving above-ground piping, the pump should provide a flow rate less than that of a single fire sprinkler. In the case of underground mains, the pump should make up the allowable leakage rate within 10 minutes or at a flow rate of 1 GPM, whichever is larger. A good rule of thumb is to size the jockey pump to 1% of the fire pump’s rated capacity, with a discharge pressure at least 10 PSI higher than the main fire pump to prevent false starts.
Importance of Jockey Pumps
The significance of jockey pumps in fire protection systems cannot be overstated. They ensure the system remains pressurized and ready to respond effectively in an emergency. Whether the system is at rest or active, jockey pumps play a crucial role in maintaining pressure. Frequent starts of the jockey pump may indicate system leaks, necessitating a thorough inspection. In the event of a fire, when the sprinkler network is triggered, both the main pump and jockey pump work in tandem to ensure adequate pressure is maintained throughout the system.
In conclusion, jockey pumps are indispensable for the optimal functioning of fire protection systems. They maintain system pressure, prevent unnecessary activation of the main pump, and ensure the system is always ready to respond in an emergency. By understanding their role, operation, and importance, we can better appreciate the critical function they serve in safeguarding lives and property.
Post time: Jul-03-2024
