Fire Protection Systems: Why Horizontal Split Case Fire Pumps Are a Top Choice

Posted by angroup on January 25, 2024

Fire protection systems are a crucial part of any building's safety infrastructure. These systems are designed to detect, control, and extinguish fires to protect people and property. At the heart of many fire protection systems are fire pumps, which provide water at sufficient pressure and flow rates to put out fires. Split case pumps, in particular, have emerged as a top choice for fire protection systems due to their durable design, versatility, reliability, and energy efficiency.

In this article, we will examine why horizontal split case fire pump have become the pump of choice for fire protection systems. We will look at what makes split case pumps well-suited for firefighting applications, the key components and operating principles, installation considerations, and maintenance best practices. With an understanding of split case pump technology, building owners, designers, and managers can make informed decisions on fire protection to safeguard what matters most.

Overview of Split Case Pump Design

Split case pumps are centrifugal-style pumps characterized by a horizontal pump casing split into two separate chambers. The split casing allows easy access to the pump components for maintenance, repair, and inspection. Inside the casing, an impeller rotates at high speeds to draw water in through the pump eye and discharge it under pressure.

What sets split case pumps apart is their versatile, compact, and robust design. The pumps feature a horizontal shaft and foot-mounted configuration for flexibility in installation. Size for size, they can achieve higher head and flow compared to other pump types. The casings and bearing frames are rigid and rugged, enabling the pumps to withstand strain typical in high-demand firefighting applications.

Advantages for Fire Protection Systems

There are several key reasons why split case pumps make an excellent choice for systems designed to detect and combat fires:

  • High Capacity and Pressure - Firefighting requires high water flow rates often over 1,000 gallons per minute at pressures exceeding 100 psi. Split case pumps can deliver such high flow and pressure capacities reliably over time.
  • Self-Priming Ability - Split case pumps are self-priming, meaning they can evacuate air from the suction line to prime the system. This allows them to take in water even when not flooded at startup. The self-priming functionality is vital for fast water delivery when responding to fires.
  • Compact Size - The compact, horizontal configuration of split case pumps allows them to fit in tight spaces typical of mechanical rooms and fire pump houses. This facilitates installation and leaves room for ancillary fire protection equipment.
  • Energy Efficiency - With advanced hydraulic and mechanical sealing designs, split case pumps can operate efficiently for lower energy costs over lifecycles spanning 25-30 years. High efficiency is paramount for fire pumps, which must run weekly or monthly to ensure availability.
  • Durability & Reliability - Mission-critical fire protection systems require exceptionally durable and reliable pumps that can work on demand. Split case pumps feature rugged casings, heavy-duty bearings, mechanical seals, and shaft couplings allowing years of trouble-free operation.
  • Low Maintenance - Proactive maintenance is key for fire pump longevity, and split case pumps are designed for easy access and servicing of components. Important parts like seals, bearings, wear rings can be inspected and replaced with minimal downtime.

As evidenced, split case pumps offer well-rounded performance perfectly suited for fire protection systems in buildings and industrial plants. Next, we dive deeper into the components that set these pumps apart.

Key Components & Operating Principles

Split case pumps consist of several main parts working together to move water for fire suppression:

  • Pump Casing - Made of high-strength cast iron or steel to house all wet ends. Horizontal split enables easy access and maintenance. Key sections include the suction inlet, impeller housing, seal chamber and discharge outlet.
  • Impellers - Rotating components with vanes that impart velocity to liquid. Various impeller types optimize flow, head, efficiency, or solids handling capability. Common choice for fire pumps is closed vane impellers for balancing performance across operating range.
  • Pump & Motor Shaft - Transmits rotational power from motor to impeller. Often features replaceable shaft sleeves at the stuffing box and impeller to minimize wear.
  • Bearing Frame - Supports shaft and bearings. Rigid design helps dampen vibrations and shaft deflection.
  • Bearings - Heavy-duty anti-friction bearings support shaft, typically oil or grease lubricated. Roller and ball bearings handle radial loads, while thrust bearings take axial loads.
  • Mechanical Seals - Used at stuffing box location between pump casing and bearing frame. Seal faces keep liquid inside pump and casing isolated.
  • Coupling - Joins pump and motor shafts for torque transmission. Allows slight misalignment. Often flexible gear or grid types offering high flexibility.

The crux of the split case pump operation relies on converting rotational kinetic energy from the motor shaft to velocity energy in the moving fluid. This is achieved through impeller rotation and friction within the vaned passages imparting flow velocity to the water.

The kinetic energy of the flow gets converted to pressure energy by slowing the fluid using a specially shaped volute casing. As water gets pushed along the decreasing radius of the volute, its velocity decreases but static pressure builds. This boosts head for high-pressure discharge from the pump.

Well-designed split case pumps optimize flow paths and minimize turbulence for achieving high pump efficiency. The versatile pumps can meet varying pressure and capacity needs simply by adjusting motor speed or using a variable frequency drive.

Installing and Maintaining Horizontal Split Case Fire Pump

To leverage the full capabilities of split case pumps for firefighting, the installation configuration must enable optimal pump performance while allowing adequate access and upkeep activities.

Pumps are best located in mechanical rooms close to water sources or underground reinforced pump houses. The systems often have jockey pumps for basic needs, and main larger pumps triggered for higher fire demands. Pumps can be installed horizontally or vertically depending on available space.

It's vital for split case fire pumps to sit on level concrete foundations, with piping properly aligned to prevent strain at the casing. Installers must provide adequate NPSH margin by selecting suction piping lengths and diameters to minimize friction losses. Drip pockets ahead of pumps should have drain valves to remove accumulated air and dirt.

Discharge piping components like valves, sensors and fittings must sustain reaction forces. Hence the need for anchors, restraints, and supports. Wiring for power, controls, and monitoring should follow standards with proper wire & conduit sizing based on system voltages.

For maintenance, teams must stick to NFPA 25 inspection and testing recommendations, typically involving weekly to quarterly checks. This includes verifying packing lubrication, unusual vibration, bolt torques, and flange/gasket leakages. Teams combine time-based with run-time-based preventive maintenance approach tracking operating hours.

Periodic dynamic tests assess pump health via flow, discharge pressure and brake horsepower readings. Tests help detect dropping performance from impeller wear, mechanical seal leaks, or blocked water passages. For repairs, the split case design allows quick access by separating the pump halves to reach internal components.


As an integral part of fire protection, split case pumps enable reliable delivery of high-pressure flows to put out fires decisively. Their versatile design offers compactness, durability, efficiency, reliability and easy maintenance - attributes crucial for firefighting use cases.

With in-depth domain expertise, vendors like An Pump combine robust materials, fine engineering, quality manufacturing, and extensive testing to produce split case pumps purpose-built for 24x7 fire protection duties.

By understanding split case pump technology, stakeholders involved in building fire safety can make sound investments in equipment at the core of fire detection and suppression systems. Choosing these pumps backed by seasoned vendors gives peace of mind that people, assets, mission-critical systems and intellectual property remain safeguarded if the worst happens.

Need help selecting the right split case pumps for your fire protection systems ?
Contact us at or +86 15032857866;
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