Sprinkler systems and standpipe systems often have a fire pump as part of the water supply for the systems. If you have a fire pump as part of your fire protection system, you should know some basic facts to help you manage this important equipment.
Fire pump or booster pump?
A fire pump takes its water supply from a non-public source. This can be a river, pond, water storage tank or wellfield. The water supply must be able to support the fire pumps rated flow capacity. The supply must have an adequate volume of water to last for the duration of time in the fire protection system design. The duration can be between 30 minutes and 120 minutes. A fire pump is the sole source of water for the fire protection system. If your fire pump fails, you have no water supply for fire protection.
A booster pump is a more common arrangement where the pump takes its water supply from the city water system. Duration is generally not an issue as the city supply is generally adequate for the volume of water required. The pump is used to boost the pressure from the water supply system. If the booster pump fails, you will still have city water pressure in the system. Your system will be deficient in water delivery, but some water may be delivered.
Pump Ratings
A pump for fire protection is rated for a specific flow rate in GPM at a particular pressure measured in PSI. A 1000 @ 60 pump will deliver 1,000 gallons per minute (GPM) at 60 pounds per square inch (PSI) of water pressure. The rating is a design element of the fire protection system and was selected at the time of the system’s installation. Pumps are also rated for the speed at which the pump operates in revolutions per minute (RPM). These three rating points are fixed, and the pump is tested to see that it matches the flow and pressure when operating at the design speed.
Power Supply
Fire protection pumps are generally powered by a diesel engine or an electric motor. In either case a controller is used to automatically start the pump when needed. The controller also has the ability to manually start the pump. Controllers have stop switches and disconnects to shut off the pump. The controllers and drivers of the fire pump must be listed for fire protection service.
Diesel engines require a fuel supply that is adequate for the duration of the fire protection system water supply design. Since diesel pumps are routinely started and run for tests, the fuel supply must also be adequate to perform these tests. Fuel quality is important, and the fuel tank must be leak tight and have a level indicator to monitor fuel availability.
Electric pumps have a controller that has start, stop, and test provisions. The electrical supply is designed to be resistant to fire damage and mechanical damage. If the power supply for the property is not considered reliable, a generator will be needed to support the fire pump. Some insurance rating tools penalize buildings that rely on an electric pump and that lack an emergency generator.
Testing
Fire pumps require routine testing to assure proper performance. NFPA 25, The Standard for Inspection, Testing and Maintenance of Water Based Fire Protection Systems, details the required testing. This document will highlight the weekly, monthly, and annual tests. Regardless of power supply an initial acceptance test is required to duplicate the fire pumps performance ratings and to run the pump under load for a period of time to allow evaluation of the mechanical conditions.
Electric pumps must be tested monthly and operated for no less than 10 minutes. The pump must be started automatically. This can be done with no flow conditions
A diesel pump should be operated weekly for no less than 30 minutes. This can be done with no flow condition. The pump must be started automatically.
For both types of pumps an annual full flow pump test to verify operations and ratings of the pump.
Accurate pump testing procedures are critical to monitoring the condition of a fire protection pump.
Data should be recorded during these tests that include suction and discharge pressures observed. Some controllers have automatic testing and data recording features to automate this process. Annual flow tests should be compared to prior tests to verify pump performance has not degraded.
What can affect a pump’s performance?
Fire protection pumps are generally very reliable. There are some conditions that can adversely affect a pump’s performance. This list is only those conditions that are most common. NFPA 25 has an appendix dedicated to pump troubleshooting.
For diesel pumps these commonly include:
Poor battery maintenance that affects starting
Poor fuel quality or quantity
Lack of routine maintenance on the diesel engine itself, oil changes, cooling system and other mechanical parts
For electric pumps the common issues include:
Degraded or damaged electrical supply
Loose or corroded electrical connections
For either system there are common problem areas
Controller maintenance and component failure in the controller that prevents automatic starts
Mechanical failure of pump to driver connection due to lack of lubrication of misalignment.
Degraded water supply that prevents pump from meeting rated flows
Damage to or an obstruction in the pump itself
The Driehaus Difference
We want our clients to understand the basics of fire protection pumps and the required testing and maintenance that is required. This is a common source of recommendations from insurance carriers and deficiencies can adversely affect your fire insurance premiums. Call us at 513-977-6860 or contact us via our website at www.driehausins.com