Overview of Fire Pumps and Water Storage Tanks

Transcription

1 Overview of Fire Pumps and Water Storage Tanks M. Steven Welsh, P.E. Registered FPE Koffel Associates, Inc. Expertly Engineering Safety From Fire Outline Introduction Water Tank Design Coordinating with other trades Deficiencies Koffel Services Consulting Design Construction Period Services 1

2 My Background Graduated with Bachelor of Science in Fire Protection Engineering from the University of Maryland at College Park in Worked in the United Kingdom. Worked for sprinkler contractor. Employed with Koffel for 9 years. Registered engineer (DE and MD) Standards NFPA 20, Standard for the Installation of Stationary Pumps for Fire Protection, 2013 Edition NFPA 22: Standard for Water Tanks for Private Fire Protection, 2013 Edition Typical Arrangement 2

3 Typical Arrangement Exterior Fire Pump House and Tank Typical Arrangement Electric Centrifugal (horizontal split-case) Typical Arrangement Centrifugal Cutaway: pressure is developed principally by an action away from center. 3

4 Typical Arrangement Parts of Packing Typical Arrangement Vertical In-line Typical Arrangement Diesel 4

5 Typical Arrangement Vertical Turbine Typical Arrangement Vertical Turbine Cutaway Typical Arrangement Packaged System 5

6 Typical Arrangement Bolted Steel Typical Arrangement Bolted Steel Typical Arrangement Pressure Tank 6

7 Typical Arrangement Fiberglass-Reinforced Plastic Tanks New vs. Existing New Work Existing Document existing conditions Check servicing Sizing Pumps and Tanks Sprinklers Standpipes Special hazards Firefighting 7

8 Sizing Pumps and Tanks Sizing Pumps and Tanks The performance of the pump when applied at capacities over 140 percent of rated capacity can be adversely affected by the suction conditions. Application of the pump at capacities less than 90 percent of the rated capacity is not recommended. 8

9 Bypass: Where the suction supply is of sufficient pressure to be of material value without the pump, the pump shall be installed with a bypass [ ] Elbows and tees with a centerline plane parallel to a horizontal split-case pump shaft must 10 times the suction pipe diameter away from the pump s suction flange [ ] X 9

10 Elbows and tees with a centerline plane perpendicular to the horizontal split-case pump shaft are permitted at any location 10

11 X Strain Relief: where the pump and its suction supply are on separate foundations with rigid interconnecting pipe, the pipe must be provided with strain relief [ ] Valves: outside screw and yoke (OS&Y) gate valve must be installed in the suction pipe [4.14.5] 11

12 12

13 Eccentric tapered reducer or increaser required at pump suction to avoid air pockets [ ] Eccentric tapered reducer 13

14 Eccentric tapered reducer No requirement at pump discharge, typically concentric 14

15 Pressure gauges [4.10] Circulation Relief Valve: installed on the discharge side of the pump before the discharge check valve, valve shall provide flow of sufficient water to prevent the pump from overheating when operating with no discharge, nominal size of 0.75 inch(19 mm) [4.11] 15

16 Circulation Relief Valve: Check Valve: required in the pump discharge assembly. [4.15.6] Gate or butterfly valve: required in the pump discharge assembly. [4.15.7] 16

17 Pressure Maintenance Pumps: sized to replenish the fire protection system pressure due to allowable leakage and normal drops in pressure, no listing required [4.25] The jockey pump stop point should equal the pump churn pressure plus the minimum static supply pressure. The jockey pump start point should be at least 10 psi (0.68 bar) less than the jockey pump stop point. The fire pump start point should be 5 psi (0.34 bar) less than the jockey pump start point. 100 psi pump at churn, 50 psi minimum from city Jockey pump stop = 100 psi + 50 psi = 150 psi Jockey pump start = 150 psi 10 psi = 140 psi Fire pump start = 140 psi 5 psi = 135 psi 17

18 Fire Department Connection Fire Department Connection Test Header 18

19 Fire Department Connection and Test Header Maximum Pressure for Centrifugal Pumps [4.7.7] The net pump shutoff (churn) pressure plus the maximum static suction pressure, adjusted for elevation, must not exceed the pressure for which the system components are rated. Maximum Pressure for Centrifugal Pumps [4.7.7] Variable speed pressure limiting control drivers, as defined in this Standard, shall be acceptable to limit system pressure. 19

20 Pressure Regulating Devices: No pressure regulating devices must be installed in the discharge pipe [ ] Exceptions Pressure Regulating Devices, exceptions: Where a diesel engine fire pump is installed and where a total of 121 percent of the net rated shutoff (churn) exceeds system rating Where an electric variable speed pressure limiting controller or a diesel pressure limiting driver is installed Nameplate [4.9] 20

21 - Diesel - Diesel Requires sprinkler protection [ ] Enclosing diesel engine pump drivers and day tanks - Diesel Exhaust Piping: [11.5.2] Each pump engine must have an independent exhaust system. A flexible connection with a section of stainless steel, not less than 12 in. (305 mm) in length must be made between the engine exhaust outlet and exhaust pipe. The exhaust pipe shall be covered with hightemperature insulation or otherwise guarded to protect personnel from injury. Exhaust pipes passing directly through combustible roofs or walls must be guarded at the point of passage 21

22 - Diesel - Diesel Exhaust Discharge Location: [11.5.3] Exhaust from the engine shall be piped to a safe point outside the pump room and arranged to exclude water. Exhaust gases shall not be discharged where they will affect persons or endanger buildings. Flow Meter 22

23 Vertical Turbine Pump: Suction Screening: where the water supply is obtained from an open source such as a pond or wet pit, the passage of materials that might clog the pump shall be obstructed [ ] Tank Design 23

24 Tank Design OSHA-compliant (29 CFR 1910) standard railing shall be placed around the roof manholes and other accessories that require access [ ] Tank Design Tank Design Where the steel roof is essentially airtight, there must be a substantial vent above the maximum water level [4.15.1] 24

25 Tank Design Tank Design Water-Level Gauge: suitable design [14.1.8] Tank Design Water-Level Gauge: suitable design [14.1.8] 25

26 Tank Design Controlling Valve: [ ] Tank Design Anti-Vortex Plate Assembly [ ] Tank Design A permanent pipe connected to a water supply shall be provided to fill the tank [14.4.1] The means to fill the tank shall be sized to fill the tank in a maximum time of 8 hours [14.4.2] 26

27 Tank Design Overflow: the overflow pipe shall be of adequate capacity for the operating conditions and shall be of not less than 3 inches (75 mm) [14.6] Tank Design Tank Riser Drain: A drain pipe of at least 2 inch (50 mm) must be connected into the tank discharge pipe near its base [14.7.4] Tank Design - Heating Tanks that are subject to freezing shall be heated [16.1.1] The heating system must be of such capacity that the temperature of the coldest water in the tank or tank riser, or both, is maintained at or above 42 F (5.6 C) during the coldest weather 27

28 Tank Design - Heating Coordination with Other Trades Fire-Resistive Construction [NFPA 20, 4.12] 2-hour High-rise building Not full sprinkler protected. Outdoor: 50 feet (15.3 m) away from any fire exposures Otherwise, 1-hour Coordination with Other Trades Ventilation for diesel fire pumps shall be provided for the following functions: [ ] To control the maximum temperature to 120 F (49 C) at the combustion air cleaner inlet with engine running at rated load To supply air for engine combustion To remove any hazardous vapors To supply and exhaust air as necessary for radiator cooling of the engine when required 28

29 Coordination with Other Trades Fire alarm must monitor for the following supervisory signals: [NFPA 20, ] Fire Pump Running Loss of Phase Phase Reversal Connected to alternate source (if applicable) Nothing else is required to be supervised Jockey Pump running should not be monitored Coordination with Other Trades Power [NFPA 20, 9.2] A normal source of power from a continually available source Must be reliable Dedicated source Identifiable and remote disconnecting means Coordination with Other Trades Structural for tanks Dead Load Live Wind Snow 29

30 Coordination with Other Trades Drainage [NFPA 20, ] Floors must be pitched for adequate drainage of escaping water away from critical equipment such as the pump, driver, controller, and so forth. Must discharge to a frost-free location. Deficiencies Corrosion and damage packing 30

31 Deficiencies Parts of Packing Deficiencies Damaged packing and improper packing drainage Deficiencies Fire pump based not secure 31

32 Deficiencies Fire pump is dirty Deficiencies Fire pump is dirty Deficiencies No drain for circulation relief valve 32

33 Deficiencies Rock in impeller Deficiencies No service clearance for controller, 3 feet [NFPA 70] Future Questions. Join our LinkedIn Discussion Groups Life Safety Code People can join the group and submit their questions or People can linkedin@koffel.com and submit anonymously Smoke Management Proposed Changes to the IBC Ask the Expert FAQ.Koffel.com 33

34 Follow us on LinkedIn Thank You M. Steven Welsh, P.E. Registered Fire Protection Engineer Expertly Engineering Safety From Fire 34