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Excess Flow Valves – Implementation Challenges. Bill Norton PIPES Act of 2006 EFVs Anthony Cadorin City Of Mesa Sizing Procedures EFV Sizing. Excess Flow Valves. Bill Norton. Prior Legislation. RSPA Final Rule, February 3 rd 1998, Effective February 3 rd 1999
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Excess Flow Valves – Implementation Challenges Bill Norton • PIPES Act of 2006 • EFVs Anthony Cadorin • City Of Mesa Sizing Procedures • EFV Sizing
Excess Flow Valves Bill Norton
Prior Legislation • RSPA Final Rule, February 3rd 1998, Effective February 3rd 1999 • Required either notification of availability or installation
New Legislation Installation on single family residential service if: • Installed or replaced after June 1, 2008 • Operates continuously throughout the year at a pressure not less than 10 psig • Is not connected to a main with prior experience with contaminants • Non-interference with necessary operation or maintenance activities • Commercially available
New Legislation Further Considerations • Annually reportable • Reportable procedure has not been determined • Reference to Sec.9.(3)(A-B), and (6)
“The Big Day” June 1, 2008 PIPES Act of 2006
What is an EFV? • Self-actuating valve • In-line mechanical device • Responds to the high-pressure differential • Designed to activate when a rupture occurs • Stop or minimize the flow of gas
How EFVs Function Closed: Gas Flow Is Blocked Open: Gas Flows “Unobstructed” Activation is DIRECTLY dependent upon Gas Velocity
Types of EFVs • Positive Shutoff (EFVNB) • 100% shut off • Manually reset • Bleed-by (EFVB) • Approximately 97% shut off • Self-resetting • <20 standard cubic feet of gas per hour (Scfh) @ 10 psig
Sizes • Typical Sizes - 400 Series - 1000-1200 Series - 800 Series - 1800 Series • EFVs are designated using their size • I.e. 400 series • At 10 psig, 400 standard cubic feet of gas per hour (Scfh) will cause the excess flow valve to trip
Applications Mechanical Coupling Mechanical Tapping Tee PE Stick Fusion Tapping Tee Shut Off Valve
Who is using EFV’s? • Ohio ~450,000 • Pennsylvania ~200,000 • Massachusetts ~176,000 • Minnesota ~113,000 • Mostly Northeastern states • Voluntary; not state or federally mandated
Questionnaire • Conducted to determine industry standards • 14 operators surveyed across U.S. • Pacific Gas & Electric • NW Natural Gas • Citizens Gas & Coke • New Jersey Natural Gas • St. Lawrence Gas
Industry Preference • PE “sticks” or In-line: 86% • Ease of replacement • In-line and Tapping Tees: 7% • Tapping Tee: 7% • Positive Shutoff: 29% • Bleed-by: 71%
Common Basic Practices • Not installed where line pressure is 10 psig or lower • Unrealized trip flow rate • Pressure drop may affect flow rate • Design pressure minimum
Common Basic Practices • Not installed where a high amount of contaminants are in the line (water, dust, grease, etc.) • Spring failure • False trips • Valve malfunction
Common Basic Practices • Not installed on commercial applications • Transient nature of businesses • Additional load w/o notification • Breadth of capacity • Size of service line requirements
Common Basic Practices • Not installed in emergency situations Not enough time to properly size the EFV which could potentially result in tripping the EFV during normal operational use
Surveyed Issues • False Trips • Line contaminants • Improper Installation • Third Party Damages
Further Consideration Not installed on: • Multi-family homes • Branch services • Multi-metered manifolds
Challenges for Mesa • O & M; Construction Practices & Emergency Plan modifications • Pressure testing and purging procedures • EFV Sizing and installation • Bleed-by feature • Service annotation: Drawings and field • Training • Implementation
250 Class Service Meters 400 Class Service Meters 800 Class and 1000 Class Service Meters 1/2” CTS 600 Series 75 feet max. length 800 Series 45 feet max. length Not an option 1/2” IPS 800 Series 300 feet max. length 800 Series 300 feet max. length 1800 Series 70 feet max. length 1” IPS 1800 Series 750 feet max. length 1800 Series 750 feet max. length 1800 Series 750 feet max. length City of Mesa sizing table
Why a sizing table? • Meter size provides an upper limit on the amount of gas that a line will flow • Line size (diameter) sets up the maximum length that a given EFV will protect
250 Class Service Meters 400 Class Service Meters 800 Class and 1000 Class Service Meters 1/2” CTS 3/4” IPS 1” IPS Creating a sizing table for Gas City Δ Not an option Not an option Not an option
Creating a sizing table for Gas City • EFVs must be sized at the lowest predicted operating pressure • Gas City: 10 psig • Maximum load is determined by the meter • 400 Scfh per meter manufacturer • Go to EFV manufacturer’s flow rates for trip points
Creating a sizing table for Gas City Minimum system pressure: 10 psig EFV Inc. 400 Series EFV This EFV will work
Creating a sizing table for Gas City Maximum service length protected: • Gas City lowest predicted operating pressure: 10 psig • EFV Inc. 400 Series EFV maximum trip point @ 10 psig: 615 Scfh • Pressure drop across EFV: 0.66 psig per manufacturer (include in ΔP calculation • Use the “IGT improved” flow equation and solve for length “L”:
250 Class Service Meters 400 Class Service Meters 800 Class and 1000 Class Service Meters 1/2” CTS EFV Inc. 400 Series 300 feet max. length 3/4” IPS 1” IPS Creating a sizing table for Gas City Not an option Not an option Not an option
EFV ½” CTS 400 Series 300 ft. Maximum Length ¾” IPS 800 Series 300 ft Maximum Length 1” IPS 1800 Series 750 feet max. length Creating a sizing table for Gas City
Typical Appliance Loads 224 Scfh: 250 Class Meter 624 Scfh! New meter required!