A notable shift recently took place in the industry: As of May 2023, Clarke Fire Protection Products officially stopped using Falk T-style grid couplings for their fire pump assemblies.
If you manage, service, or specify Clarke diesel fire pumps, here is everything you need to know about this transition, why it matters, and how it impacts your existing and future installations.
The Role of the Legacy Falk Coupling
For years, the Falk T-style grid coupling (specifically the Steelflex series) was a standard component in many Clarke fire pump setups. Positioned between the diesel engine driver and the fire pump, the coupling's job is to seamlessly transmit torque while accommodating slight shaft misalignments and absorbing shock loads.
Grid couplings are robust and handle high-torque applications exceptionally well. However, they are inherently metal-on-metal components. The flexible steel grid that locks the two hubs together requires a specific environment to operate smoothly—namely, rigorous and regular grease lubrication.
Why the Change?
The transition away from grid couplings aligns with broader industrial trends prioritizing lower maintenance and higher misalignment tolerance.
Here are the primary drivers behind phasing out grid-style couplings in modern fire protection:
Maintenance Overhead: Falk grid couplings require routine lubrication to prevent the metal grid and hub teeth from wearing down. In emergency standby systems like fire pumps, maintenance teams prefer "install it and forget it" components. Missing a grease interval on a grid coupling can lead to premature wear or failure during a pump run.
Alignment Sensitivity: While grid couplings allow for some flexibility, modern elastomeric couplings or universal-joint driveshafts offer superior tolerance for angular and parallel misalignment, reducing the time and precision required during engine-to-pump alignment.
Vibration Dampening: Newer flexible coupling designs often utilize rubber, urethane, or composite elements that inherently dampen engine vibration and run quieter without the need for a protective grease barrier.
What This Means for Your Facility
The discontinuation of the Falk T-style coupling primarily affects new orders and future replacement parts. Here is how you should handle the transition based on your current setup:
For Existing Installations
If you have a Clarke Fire engine installed prior to May 2023 that utilizes a Falk grid coupling, don't panic. Your equipment is still perfectly viable and fully compliant, provided you maintain it.
Keep Greasing: Ensure that the coupling is packed with the manufacturer-recommended grease during your routine NFPA 20 preventative maintenance checks.
Check the Seals: Inspect the coupling guard and seals for any signs of leaking grease, which indicates that the grid may be running dry.
For New Installations
If you are specifying or receiving new Clarke Fire pump drivers manufactured after May 2023, you will see alternative drive solutions in place of the old Falk grid.
Update Your Manuals: Ensure your on-site maintenance documentation reflects the new coupling style.
Adjust PM Schedules: Your new coupling will likely have different maintenance requirements. For instance, if an elastomeric coupling is used, you'll be checking for rubber degradation or element fatigue rather than re-packing grease.
Moving Forward
Changes in OEM components are a routine part of industrial evolution, designed to make systems safer and easier to maintain. As the industry moves away from heavily lubricated couplings toward low-maintenance alternatives, facilities stand to benefit from reduced upkeep and enhanced standby reliability.
If you are due for a coupling replacement on an older Clarke engine, reach out to your authorized Clarke Fire service dealer to confirm the correct retrofit kit or replacement assembly for your specific engine model.
Pro Tip: Have questions about your fire pump's maintenance schedule or alignment tolerances? Always consult your Clarke Fire Operations and Maintenance manual or reach out to a certified fire protection technician to keep your system in prime, inspection-ready condition.
