What Is the Recommended Fire Pump Starting Method?

In fire protection systems, the reliability of fire pumps is non-negotiable. One of the most important considerations in ensuring this reliability is selecting the right fire pump starting method. Improper starting techniques can lead to equipment damage, increased inrush current, and system failure during critical moments. So, what’s the recommended method for starting a fire pump?

NFPA 20 Requirements for Fire Pump Starting

According to NFPA 20, the standard for the installation of stationary pumps for fire protection, fire pumps must start automatically when a pressure drop is detected in the fire protection system. But the type of starting method—how the motor starts—is not strictly prescribed, allowing flexibility as long as the method is reliable, failsafe, and ensures immediate operation.

Common Fire Pump Starting Methods

1. Across-the-Line (Direct-On-Line) Starter

• How it works: The motor receives full voltage at startup.

• Pros: Simple and inexpensive.

• Cons: High inrush current; can cause mechanical stress.

• Use case: Small motors or where the electrical supply can handle the load.

2. Star-Delta Starter

• How it works: Starts the motor at a reduced voltage and transitions to full voltage.

• Pros: Reduces starting current and mechanical stress.

• Cons: Slight delay in torque delivery during switching.

• Use case: Commonly used in fire pumps with medium-sized motors.

3. Auto-Transformer Starter

• How it works: Uses a transformer to reduce voltage during startup.

• Pros: Smooth start; reduced current and torque at startup.

• Cons: More expensive and complex.

• Use case: For systems requiring very low starting current.

4. Soft Starter

• How it works: Gradually increases voltage using solid-state components.

• Pros: Smooth acceleration; protects motor and piping from hydraulic shock.

• Cons: Higher cost.

• Use case: Increasingly popular for electric fire pumps where reducing mechanical stress is important.

Choosing the Right Starter: Key Factors

• Pump motor size

• Available power capacity

• Project requirements and client preferences

• Compliance with NFPA 20 and local codes

• Pump duty (electric or diesel)

In many modern installations, star-delta and soft starters are the preferred options. Soft starters, in particular, are gaining popularity due to their ability to reduce wear and tear, lower inrush current, and extend the pump’s life.

Conclusion

The recommended fire pump starting method depends on the specific needs of your fire protection system, motor size, and power conditions. However, NFPA 20-compliant starting techniques like star-delta and soft starters offer the best balance of reliability and equipment protection. Always consult with a certified fire pump expert or system integrator to ensure the best performance and compliance.