Pump Technology That Minimizes Fire Damage

In the event of a fire, fire pumps can be used to combat the fire before emergency services arrive at the scene, minimizing the damage caused by fires. Masdaf, which provides effective fire-fighting solutions with fire pumps developed to world standards, has highlighted 4 selection criteria necessary for fire pumps chosen for buildings or industrial facilities to operate with high performance and meet expectations. With superior pump technologies in water resource management; Masdaf offers energy and water resource-efficient, environmentally friendly sustainable solutions, and aims to ensure building safety by providing timely response capabilities against fire disasters that may occur in buildings and industrial facilities. Factories, residential buildings, shopping centers, schools, hospitals, airports and many other facilities face fire hazard at any time. In the event of fires in such living spaces, combating the fire with fire pumps before emergency services arrive at the scene is of great importance both for protecting structures and for the safe evacuation of people living in the building from the scene.

"Fire pumps are an indispensable component of all building design and implementation"

"Fire pumps, which are used in pressurizing water-based fire extinguishing systems in buildings and industrial facilities and provide effective fire-fighting solutions, form the most important part of water-based fire extinguishing systems. With an effectively operating fire pump, it is possible to minimize damage caused by fires," said Ezgi BABA, Product Manager of Masdaf Building Technologies Group, noting that fire pumps are an indispensable component of all building design and implementation. Ezgi BABA made the following statement on the subject: "A fire pump forms the most important part of a water-based fire extinguishing system. When the water source is insufficient for the system it supplies, it is used to bring the water to the required pressure. The most commonly used fire standards in Turkey and the World are known as NFPA 20 and UL/FM. The most commonly used pump types are end-suction pumps, split case pumps, inline pumps and turbine pumps. There are many types of fire pumps. Selecting the correct pump type for the installation project is necessary to avoid excessive costs and insufficient performance that could damage your system. As important as selecting the correct pump is providing the correct operating conditions required by the pump. If the correct operating environment is not provided, the pump's performance decreases and it cannot meet expectations." Ezgi BABA pointed out 4 fundamental criteria consisting of NPSH value control, water velocity at suction and pressure loss in the discharge line, motor selection, and UL/FM-certified pump and equipment to verify the correctness of the fire pump selected for buildings or industrial facilities:

NPSH value control

"The NPSH (net positive suction head) value is of great importance in preventing cavitation in pumps. In fire pumps, this value should be checked not only at the operating point; for pumps compliant with NFPA 20, at the point providing pressure above 65% at 150% flow. For example, if the pump NPSH value at this point is ≥8, it is necessary to create positive head at the pump's suction. Otherwise, the pump will not operate as required during a fire; it cannot reach the 150% safety point. If sufficient positive head cannot be provided at suction, the pump's NPSH value should be selected as small as possible. When examining the NPSH value calculation for the installation, on the pump's suction side; a resistant condition is present that is maximized with water velocity at 150% flow point, encompassing valve calculations, reduction, pipe diameter, friction losses, distance and similar factors. This resistance can reach high values in meters. As seen in the example, an operating condition with 8 m NPSH value depends on the (+) head on that pump's suction side. Although NFPA regulations require positive head at suction, this value (positive head at suction) can decrease during a fire. Looking at UL/FM regulations, the pump is guaranteed a (-) 4.5 meter suction lift value at the 150% flow point and this is verified with certification tests.

Water velocity at suction and pressure loss in the discharge line

According to NFPA 20, at 150% flow, the water velocity in the pump suction piping can be a maximum of 4.6 m/s. For this reason, if there is a large proportional difference between the nominal size of the pump suction flange and the piping diameter that will achieve this velocity, serious pressure loss will occur. Similarly, if on the discharge side the pump's nominal diameter is below what it should be, for example; If a pump selected at 2000 gpm (454 m3/h) flow has a discharge flange size of DN 125. Q (flow) = A (area) . V (velocity) 454*1.5 /3600 = π.0.1252 . V → V ˃13 m/s This creates serious pressure loss in the pump outlet reduction, preventing the pump performance from being transmitted to the system.

Motor Selection

Fire pump motor selections are made differently than standard centrifugal pumps due to certification requirements. According to NFPA 20; the pump must be able to maintain the required pressure even with 150% flow demand in case of possible increased flow requirement during extinguishing, providing a minimum of 65% of the desired pressure. At lower capacities, pump outlet pressure should not exceed 140% of nominal pressure to protect the installation. For a fire pump to be NFPA 20 compliant, the motor should not be selected below the power the pump draws at 150% flow and minimum 65% pressure. Otherwise, the motor will be insufficient and the system will be at risk. Motor selection also brings panel selection with it. Inadequate panel selection leads to the use of inadequate switching equipment. Furthermore, for fire pump motor power selection to comply with UL/FM, in addition to meeting the conditions required by NFPA 20, the pump motor power must be selected at peak power. Because under normal conditions it can theoretically intersect the curve at 150% flow; however, in reality the pump can operate to the end point of the curve. To operate at the end point, peak power motors must be used. Below are the pump curves and motor power selection points that should be present; UL/FM-certified Pump and Equipment NFPA (National Fire Protection Association); is an international non-profit organization dedicated to addressing deaths, injuries, property and economic losses resulting from fire, electricity and related hazards. UL is an independent certification organization that prepares safety and security standards and tests the reliability of products within the scope of these standards. FM Approved is the unit of FM Global (insurance company against fire, natural disasters and similar risks) that certifies industrial commercial products and services for companies. For this reason, all equipment recommended as NFPA-compliant is designed for fire protection. However, not all equipment with UL and FM logos is intended for fire protection. The standard document numbers of UL and FM related to fire protection appear both in product certificates and on product labels. Document numbers: UL 218 Fire Pump Control Panel UL 448A Fire Pump Coupling and Shaft UL 1004-5 Fire Pump Electric Motor UL 1247 Fire Pump Diesel Motor UL 448 Centrifugal Fire Pump FM 1321 Electric Control Panel FM 1323 Diesel Control Panel FM 1333 Fire Pump Diesel Motor FM 1336 Fire Pump Coupling and Shaft FM 1311 Split Case Centrifugal Fire Pump FM 1312 Vertical Turbine Centrifugal Fire Pump FM 1313 Positive Displacement Fire Pump FM 1319 End-suction Centrifugal Fire Pump FM 1371 In-line Centrifugal Fire Pump Design compliance of certified products with the relevant standard is under the manufacturer's control. However, correct pump selection concerns both the manufacturer and the installer. Because if the correct pump is not selected, the installation work will be of no consequence. Although a fire pump is not technically a fire extinguishing product, it plays an important role in preventing fire from spreading. Considering that fire spreads within seconds, every second is of great importance in the operation of these products. Correct product selection saves lives."