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B Y J A M E S E . D I P P I N G Domestic booster pump system sizing faces two main challenges: maintaining flow and maintaining pressure to meet building requirements. Sustaining pump system flow can be a fairly simple task due to generous fixture unit require- ments in codes and American Society of Plumbing Engineers' guidelines for fix- ture unit to GPM conversion, but main- taining pressure, on the other hand, has taken center stage as the greatest chal- lenge to booster pump design today. How is it possible to control the pump to maintain pressure, while getting the right force of flow to the top of the building? The answer lies in the pump's controls, sequencing and technology. Breakthroughs in manufacturing processes and technology over the last decade, both in plumbing materials and larger system configurations, have en- hanced the reliability and performance of plumbing equipment, mechanics and controls. Here's a list of the Top 5 trends in pump systems and why implementing them into your next project will make everything run — and flow — just right. TREND #1: VERTICAL MULTI-STAGE PUMPS. These pumps will last longer, be quieter and require less maintenance over time. Because vertical multi-stage pumps typically have a loading of 360 degrees, they are regularly balanced by nature of design and force is applied evenly throughout the pump — they are equally loaded and equally balanced. Transi- tioning away from end-suction and hori- zontally laid pumps to vertical multi- stage pumps will enhance reliability and system longevity. TREND #2: THE CARTRIDGE SEAL. Once vertical multi-stage pumps are installed, it's a natural transition from a three-piece seal to a cartridge seal (a cartridge seal can't be used with a hori- zontal end-suction pump). The cartridge seal will cut the time it takes to replace the seal by 75 percent. Changing out hori- zontal end-suction pumps requires the pump to be fully disassembled, primed and reconfigured, which can take up to eight hours, while the cartridge seal for a 150-horsepower motor can be pre- ordered and changed in 45 minutes. TREND #3: FROM BRONZE TO STAINLESS STEEL. Today's plumbing engineers are moving to stainless steel pumps because they're lead free. But, there are other benefits as well: stainless steel impellers are stamped and laser welded, as opposed to cast and machine welded. Stamped impellers are considerably more precise and flexible during the manufacturing process and therefore can greatly im- prove in-building pumping efficiencies and overall pump performance. Typical bronze domestic booster pumps have efficiencies in the 68-70 percent range, peaking at 74 percent, but stainless steel pump efficiencies fall in the 72-80 percent range, which is con- siderably more efficient. Just by improv- ing the performance of the impellers, the overall energy usage of the pump will be minimized. Stainless steel impel- lers come in a pre-assembled kit and can be dropped into a pump as needed, providing easy repair and replacement. Like the cartridge seal, bronze pumps have to be pulled apart, assembled and pieced back together. TREND #4: VARIABLE FREQUENCY DRIVES. An alternative to the traditional constant speed pumps, variable frequency drives have been considered a best practice for a while, but are now required by the U.S. Department of Energy, per ASHRAE 90.1-2010, for all pumping systems in- cluding domestic water pumps. Offering huge energy savings, VFDs operate the pump at the system's demand instead of 100 percent capacity, delivering precise system control. TREND #5: DIGITAL TOUCH- SCREEN CONTROLS. Moving away from yesterday's relay logic, today's plumbing controls are dig- ital touch-screen, human-to-machine interfaces, acting as the "motherboard" of the pump. The HMI allows operators to walk up to the pump system, exam- ine its touch screen or tablet and learn about the different ways the system is operating. By digitally monitoring all the variables, new opportunities for energy management can be cultivated. For example, plumbing data can be monitored and logged. It's possible to see how the pump performs at different times of the day, at times where differ- ent flow and pressure rates are demand- ed, etc. If there's a booster pump system at 30, 60 and 100 percent capacity, the HMI can be used to alter its output or performance directly and quickly, sim- ply by changing set points and can even be programmed to do this automatically based on imputed parameters. With re- lay logic, pneumatic gauges would have to be sent and adjusted until the right balance was finally achieved. Owners, facilities personnel and de- sign engineers have come to realize that even more efficiency (and real return on investment) can be gained from pump- ing systems when implementing today's newest plumbing technologies. By employing vertical multi-stage pumps, cartridge seals, stainless steel equip- ment, VFDs and digital touch-screen controls, correct booster pump pressure can be achieved throughout the facility, helping a pump system perform at its best, not just go with the flow. James E. Dipping, P.E., CPD, LEED AP BD+C, ARCSA®AP, is a vice president and plumbing discipline lead at Environ- mental Systems Design, Inc. in Chicago, Illinois. Top 5 trends for today's in-building pump systems PERFORMING under pressure pumps / f r o m t h e c o v e r /from the cover /feature PHOTO COURTESY OF METROPOLITAN INDUSTRIES Dual skids comprise a quadri-plex vertical multi-stage booster pump system with variable speed drives and single-point control. 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