What made me the engineer I am today? I believe it was my participation in the Professional Development Center (PDC) internship program at the Naval Facilities Engineering Command (NAVFAC). In terms of training large numbers of FPEs, I firmly believe that this program took over where the insurance industry left off.
Let me explain. Through the 1970s, the best place to get a relatively fully-rounded experience in the field of fire protection engineering was to go to work for one of the major insurance companies involved in the highly-protected risk (HPR) business. Companies like Factory Mutual, Industrial Risk and Kemper sent hundreds of well-trained FPEs out into the world. Three of my first four bosses started in that industry. However, during the 1980s, there seemed to be fewer and fewer jobs for new FPEs in the insurance business. It seems that the bean counters at these companies started to view these engineers, who could help control losses, as unnecessary; something they needed less of. They were making oodles of money collecting premiums, so why bother about loss control.
Enter the PDC program
Nowadays it is very common to find graduates of the NAVFAC PDC program in major FPE positions around the country, occupying positions formerly held by those from the HPR industry.
What was good about the PDC program is that I was shown all major aspects of the profession. The Navy FPE program took a cradle-to-grave approach to engineering. FPEs would survey navy bases to determine what fire protection deficiencies existed, i.e. lack of water supply, no fire alarm reporting, building life safety issues and protection. The recommendations from these surveys would turn into projects for renovation and repair. The FPE would be involved in the design, either as a reviewer of an A-E work product or as part of an in-house design team. The FPE would then conduct the acceptance tests of fire protection systems. And to get to the grave part of cradle-to-grave, if there was a major fire, the NAVFAC FPE would participate in the investigation, looking for the engineering lessons-learned.
The PDC program was also a hands-on program. Young engineers spend much time in the field, conducting fire hydrant flow tests, testing fire sprinkler and fire alarm systems, witnessing hangar foam system testing and many other things.
Anyway, nothing was more exciting to a young engineer than to go out into the field and see how all this stuff worked. On one occasion in 1980, I was sent to Guam to witness a fire pump acceptance test. I have the privilege of working with one of the experts in the fire pump field at the time. Mr. Norman Barrett was the technical representative for Patterson Fire Pumps. As he ran through the testing of the fire pump system, he took the time to share his knowledge and experience with me.
Fast forward to 2017. A couple of months ago, I had occasion to witness an acceptance test of a fire pump system for a 40-story high-rise condominium in Honolulu. Funny how the more things change the more they stay the same. Fire pump acceptance testing has not changed much since 1980.
The procedures for fire pump field acceptance are very well-detailed in Chapter 14 of NFPA 20, 2016 Edition, specifically Sections 14.1 and 14.2. Any engineer involved in witnessing/conducting a fire pump acceptance test should carefully review this section.
Figure A.18.104.22.168(a) contains a Sample Centrifugal Fire Pump Acceptance Test Form. This form provides a very useful checklist for the test.
As with any fieldwork, safety must be a primary concern. Fire pump systems move large volumes of water and high pressures. It can also involve high voltage electrical equipment. Situational awareness is essential.
Prior to the fire pump acceptance test, ensure that suction piping has been flushed in accordance with 14.1.1, and that suction and discharge piping has been hydrostatically tested in accordance with 14.1.2. These tests must be properly documented. Figure A14.1.3(a) Contractor’s Material and Test Certificate for Fire Pump Systems provides a convenient form for the contractor to document these tests.
Due to environmental regulations flushing is becoming increasingly difficult to do. To comply with their NPDES permits, contractors must keep all water flow on site. So, to stay in compliance, plan the flushing discharge location early (hopefully it will be raining that day.)
Probably the most important thing contributing to the success of a fire pump field acceptance test is having qualified persons present to operate the equipment and perform the test. Paragraph 14.2.1 states:
14.2.1 The pump manufacturer, the engine manufacturer (when supplied), the controller manufacturer, and the transfer switch manufacturer (when supplied) or their factory-authorized representatives shall be present for the field acceptance test.
For the condo project, I was able to attend the fire pump start-up performed by the tech reps prior to the acceptance test. After checking out the fire pump and controller, I watched as they checked to make sure the pump rotation was correct. After briefly starting and stopping the fire, the tech rep checks the pump shaft rotation. Sure enough, the pump was rotating backward. A quick adjustment of the power conductors had the pump rotating in the proper direction.
Prior to the start of the acceptance test, the responsible engineer should check the installation for compliance with the contract plans and specifications as well as the approved contractor’s fire pump submittal documents.
After all things are in order, the test can begin. Oh, one more thing before starting the test: Make sure the pump rep provides you a copy of the manufacturer’s certified pump curve.
There are three group types of testing that are required for fire pump system acceptance:
1. Controller Tests
2. Flow Test
3. Alternate Power Supply Tests
The fire pump must be operated a minimum of 12 times, with at least 6 automatic starts and 6 manual starts. You not-so-old-timers may remember when NFPA 20 required 10 manual and 10 automatic starts. The pump should run at least five minutes for each start. For electric fire pump controllers that provide soft start and soft stopping, it is advisable to provide enough time between starts for the motor to “cool-off.”
Note that for electric fire pump controllers, paragraph 22.214.171.124 calls for tests of the manual emergency operation handle. Operation of this switch will cause an across-the-line start of the motor. Before doing this test with a fire pump with a large motor, please consider the impact such a start will have on the power system.
Fire pump controller supervisory signals must be tested. For electric drive controllers see 10.4.6 and 10.4.7. For engine drive controllers see 12.4.1 and 12.4.1. Signal tests for engine drive controllers needs to include going through the cranking-cycle through to failure to start.
Also note that half of the start-stops need to be done using the alternate power supply, if one is provided. Alternate power supply tests need to include a test of loss of primary power and transfer to alternative power while the fire pump is operating under peak load.
Starts-and-stops should also include starting the fire pump and bringing it up to rated speed under conditions of the fire pump flowing at peak load.
Main pressure relief valves
Nowadays it is relatively rare to have a fire pump system with a pressure relief valve. If you happen to have one make sure the functions prescribed in Figure A.126.96.36.199(a) have been performed.
Fire pump flow testing
As with flushing, fire pump flow testing should be planned, keeping in mind that the water will likely not be permitted to be discharged off the public site.
A.188.8.131.52 of NFPA 20 provides a step-by-step procedure for the fire pump flow test and for analyzing the results.
As a reminder, safety must be considered in the planning of flow tests. When flowing from UL playpipes care must be taken to ensure the playpipes are firmly secured. Ideally, playpipes connected directly to hose valves on the fire pump test header provides a safe way to flow water. Another relatively safe method of flow, and seemingly more common method, is to use hose monsters.
Fire pumps with constant speed drivers need to be tested at Churn (no flow), 100 percent of rated capacity and at overload (150 percent of rating capacity). Fire pumps with variable speed drivers must also be tested with flows of 25 percent, 50 percent, 75 percent and 125 percent of rated capacity. Record the pressure at the fire pump suction and discharge, as well the motor (or engine) rpm. Electric drive controllers also record the current drawing (Amps) on each phase and voltage phase to phase. Electric drive controllers with digital readouts on the controller door of volts and amps greatly simplify getting these measurements.
Once the flow tests are completed it is used to develop the fire pump curve per the sample procedure outline in Section A.184.108.40.206. The resulting curve is then compared to the manufacturer’s certified pump test curve. If your curve equals or exceeds the shop curve at each point, the pump passes.
The fire pump tech representative for the fire pump at the condo test was Hank Gellert of Gellert Company Honolulu. Hank has been working with fire pumps as long as I can remember. On that day, the fire pump system passed with flying colors, and Hank managed to teach me a couple of new things about fire pumps. Nice to know that some things never change.
Samuel S. Dannaway, P.E., FSFPE, is a licensed fire protection engineer and mechanical engineer with bachelor’s and master’s degrees from the University of Maryland Department of Fire Protection Engineering. He is a past president and Fellow of the Society of Fire Protection Engineers. He is vice president of Fire Protection Technology at Coffman Engineers Inc., a multi-discipline engineering firm with over 360 employees across eight offices. Dannaway can be reached at firstname.lastname@example.org.