Pumper Test Is But One Of UL Aids to Fire Service
In addition to observing certification tests of new and rebuilt pumpers where they are manufactured, Underwriters Laboratories Inc. evaluates and tests other equipment related to fire service water supply.
The UL pumper tests follow the procedures prescribed in NFPA 1901, “Standard for Automotive Fire Apparatus” for testing pumps. No evaluation of the vehicle itself is made by UL.
The pumper is operated to pump its rated capacity against a net pump pressure of 150 psi without interruption for two hours. Then the pump is tested for 30 minutes while delivering 70 percent of its rated capacity at a net pump pressure of 200 psi. During the next 30 minutes, the pump must deliver 50 percent of its rated capacity at a net pump pressure of 250 psi. A 10-minute overload test is also conducted to demonstrate the pumper’s ability to develop 10 percent excess power by discharging its rated capacity from draft at a net pump pressure of 165 psi.
A pump pressure control test is conducted to check the performance of the relief valve or governor. While pumping from draft and discharging rated capacity at 150 psi, all discharge valves are shut. The pump pressure must not rise more than 30 psi. While rated capacity is again being discharged at 150 psi, the pressure is reduced to 90 psi by using the throttle and the test procedure is repeated. The same procedure is conducted while the pump is delivering 50 percent of its rated capacity at 250 psi.
A vacuum test is conducted by capping all suction intakes and using the pump priming device to develop 22 inches of vacuum. With the pump disengaged, the vacuum must not drop more than 10 inches in 10 minutes. This test determines the tightness of the uncapped discharge valves and piping.
During a booster tank discharge test, the specified rate of flow must be maintained for at least 80 percent of the rated capacity of a 300-gallon or larger tank.
Certificate issued
When a pumper meets NFPA No. 1901 requirements for pumping capacity, Underwriters Laboratories issues a certificate to the fire department and furnishes copies to the manufacturer and the regional Insurance Services Office.
UL’s fire protection department has for many years been testing and evaluating water systems. They include pipes, hydrants and fire hose.
The “Standard for Safety for Steel Pipe for Underground Water Service,” UL-888, includes requirements for material, outside diameter and roundness, straightness, thickness, welds, protective coatings, and construction of pipe ends and gaskets. It also defines test criteria for longitudinal tension, traverse tension, traverse-weld tension, flattening and bending, hydrostatic strength, leakage, and assembled gasketed joints. In addition, the standard includes specific production control tests and inspections which the manufacturer is required to carry out on a regular basis.
UL-246, “Standard for Safety for Hydrants for Fire-Protection Service,” contains requirements for the materials, dimensions, composition and assembly of hydrant components. Included are corrosion tests on copper alloy parts containing more than 5 percent zinc, operation and leakage tests, hydrostatic pressqre tests, and specifications relating to type of head and operating torque. In addition, the manufacturer is required to carry out a schedule of bending or tensile strength tests on material samples as well as hydrostatic pressure and operation tests on finished samples.
Hose tests
Municipal fire hose is covered by UL-19, “Standard for Safety for Woven-Jacketed Rubber-Lined Fire Hose,” and forestry and the old-type standpipe hose are covered by UL-18, “Standard for Safety for Unlined Fire Hose.” Both standards contain requirements concerning sizes, materials and hydrostatic tests.
The hydrostatic pressure tests in UL-19 include proof pressure, burst, kink, elongation, twist, warp and rise. There also are cold resistance tests on the complete hose, adhesion and physical and accelerated aging tests on the lining material and rubber, and free sulfur evaluations of latex lining materials. For rubber-covered hose, there are adhesion and physical and accelerated aging tests of the covering material.
Except for the field testing of pumpers, the hydraulic test work discussed in this article has been conducted at UL’s Chicago office. Early this year, this work will be transferred to a hydraulics laboratory being constructed at UL’s Northbrook office.
Conclusion
Fire apparatus and related equipment require the highest degree of capability, reliability and effectiveness. Compliance with applicable national standards provide a sound basis for such reliability. The performance data associated with UL’s listing and certification programs for pumpers and associated hydrants, pipes, and hose provide an acceptable level of compliance.
