Expanding The Use Of Excess Flow Valves (EFVs) - Amazon Web ...
Expanding The Use Of Excess Flow Valves (EFVs)
Matt Stennett Chief Engineer Middle Tennessee Natural Gas Utility District
MTNG Current Practices
• We currently have 5,500 EFVs installed on single‐family residences – ¾” PE Dresser Medium Capacity or UMAC Series 700
MTNG Current Practices
• We have a small handful of EFV’s on larger homes – 1” PE UMAC Series 2600
MTNG Current Practices • We also have 70 EFVs on the high‐ pressure side of farm taps – ¾” steel UMAC Series 1800
DIMP Confirms Other Outside Forces Leaks 35
30
25
# of Leaks
Crossville Dayton
20
McMinnville Smithville
15
Sparta District Linear (District)
10
5
0 2000
2002
2004
2006
2008
2010
2012
2014
APGA Benchmarking Other Outside Force Benchmarking 0.006
OOF Leaks per Mile of Main
0.005
0.004
MTNG 0.003
National Average Tennessee Average
0.002
0.001
0 2012
2013
Concerns • Dirt in gas either clogging the EFV closed or lodging it open • EFVs closing on their own (for whatever reason) and losing customers • Contractors hitting a line and burying it back without telling us because it’s not blowing hard • Making purging difficult/impossible • Customer usage growing past what an EFV is rated for, and having to change out the EFV after losing customer • Losing track of where we have installed EFVs, and having that cause us problems
Reality
Concern #1: • Dirt in gas either clogging the EFV closed or lodging it open
• Never happened in 5,500 cases over 5 years
Concern #2: • EFVs closing on their own (for whatever reason) and losing customers
• Has happened twice in 5,500 cases over 5 years – That’s a 0.04% failure rate
Concern #3: • Contractors hitting a line and burying it back without telling us because it’s not blowing hard
• •
4 cases of excavation damage where contractor re‐buried cut line because they thought it was retired We’ve had 1,447 cases of excavation damage since we started installing EFVs – That’s a 0.3% failure rate in reporting
• To be fair, we also had a contractor re‐bury and walk away from a BLOWING line they hit that did NOT have an EFV installed
Concern #4: • EFVs make purging difficult or impossible
• Proper training helps greatly, but you do have to be careful while purging
Concern #5: • Customer usage growing past what an EFV is rated for, and having to change out the EFV after losing customer
• Has never happened yet – but it’s only been 5 years. Growth is usually slow.
Concern #6: • Losing track of where we have installed EFVs, and having that cause us problems
• We use metal tags on risers, and record data in GIS system – no problems yet – Still need mapping improvements
So Now What? • So far this year we installed 900 ¾” PE service lines – Assuming most of those were single‐family residences and already had EFV’s installed
New Rule Impact
• This year we have also installed (12) 2” PE service lines and (1) 6” PE service line – These will need EFV’s and/or curb valves in the future – We already installed a valve on the 6” service
Not Big Enough
• UMAC Series 700 EFV only flows 830 SCFH before tripping – Not big enough to meet 1,000 SCFH new criteria – Will protect 4,000’ of ¾” PE service line at 20 psig or greater
The Simplest Answer • UMAC Series 1800 EFV flows 2,500 SCFH before tripping
• Is available in ¾” and 2” sizes • Will protect up to 450’ of ¾” PE service line at 20 psig or greater • Would allow us to put an EFV on everything but our largest customers – AL‐2300 and smaller meters
Can it be that simple? • Our average service line length overall is 192’ • Our average installed in 2014 is 227’
• Our longest service line installed in 2015 was 2,846’ • Our longest in 2014 was 2,678’ • We have 130 services mapped over 1,000’ • We only have 30% of our services mapped
Split Approach • UMAC Series 1800 – Installed on every new service under 450’ – AL‐1400 and smaller meters
• UMAC Series 700 – Installed on every new ¾” service over 450’ – AL‐425 and smaller meters
We Prefer EFVs to Curb Valves
• Not in the code yet, but hopefully APGA’s comments will help get an either/or addition to allow EFVs OR curb valves
Curb Valve Policy
• Install manual valves on any service with an AL‐ 2300 or larger meter • We installed 6 of those in 2015
Matt Stennett Chief Engineer [email protected]
Middle Tennessee Natural Gas 615‐597‐4300
Matt Stennett Chief Engineer Middle Tennessee Natural Gas Utility District
MTNG Current Practices
• We currently have 5,500 EFVs installed on single‐family residences – ¾” PE Dresser Medium Capacity or UMAC Series 700
MTNG Current Practices
• We have a small handful of EFV’s on larger homes – 1” PE UMAC Series 2600
MTNG Current Practices • We also have 70 EFVs on the high‐ pressure side of farm taps – ¾” steel UMAC Series 1800
DIMP Confirms Other Outside Forces Leaks 35
30
25
# of Leaks
Crossville Dayton
20
McMinnville Smithville
15
Sparta District Linear (District)
10
5
0 2000
2002
2004
2006
2008
2010
2012
2014
APGA Benchmarking Other Outside Force Benchmarking 0.006
OOF Leaks per Mile of Main
0.005
0.004
MTNG 0.003
National Average Tennessee Average
0.002
0.001
0 2012
2013
Concerns • Dirt in gas either clogging the EFV closed or lodging it open • EFVs closing on their own (for whatever reason) and losing customers • Contractors hitting a line and burying it back without telling us because it’s not blowing hard • Making purging difficult/impossible • Customer usage growing past what an EFV is rated for, and having to change out the EFV after losing customer • Losing track of where we have installed EFVs, and having that cause us problems
Reality
Concern #1: • Dirt in gas either clogging the EFV closed or lodging it open
• Never happened in 5,500 cases over 5 years
Concern #2: • EFVs closing on their own (for whatever reason) and losing customers
• Has happened twice in 5,500 cases over 5 years – That’s a 0.04% failure rate
Concern #3: • Contractors hitting a line and burying it back without telling us because it’s not blowing hard
• •
4 cases of excavation damage where contractor re‐buried cut line because they thought it was retired We’ve had 1,447 cases of excavation damage since we started installing EFVs – That’s a 0.3% failure rate in reporting
• To be fair, we also had a contractor re‐bury and walk away from a BLOWING line they hit that did NOT have an EFV installed
Concern #4: • EFVs make purging difficult or impossible
• Proper training helps greatly, but you do have to be careful while purging
Concern #5: • Customer usage growing past what an EFV is rated for, and having to change out the EFV after losing customer
• Has never happened yet – but it’s only been 5 years. Growth is usually slow.
Concern #6: • Losing track of where we have installed EFVs, and having that cause us problems
• We use metal tags on risers, and record data in GIS system – no problems yet – Still need mapping improvements
So Now What? • So far this year we installed 900 ¾” PE service lines – Assuming most of those were single‐family residences and already had EFV’s installed
New Rule Impact
• This year we have also installed (12) 2” PE service lines and (1) 6” PE service line – These will need EFV’s and/or curb valves in the future – We already installed a valve on the 6” service
Not Big Enough
• UMAC Series 700 EFV only flows 830 SCFH before tripping – Not big enough to meet 1,000 SCFH new criteria – Will protect 4,000’ of ¾” PE service line at 20 psig or greater
The Simplest Answer • UMAC Series 1800 EFV flows 2,500 SCFH before tripping
• Is available in ¾” and 2” sizes • Will protect up to 450’ of ¾” PE service line at 20 psig or greater • Would allow us to put an EFV on everything but our largest customers – AL‐2300 and smaller meters
Can it be that simple? • Our average service line length overall is 192’ • Our average installed in 2014 is 227’
• Our longest service line installed in 2015 was 2,846’ • Our longest in 2014 was 2,678’ • We have 130 services mapped over 1,000’ • We only have 30% of our services mapped
Split Approach • UMAC Series 1800 – Installed on every new service under 450’ – AL‐1400 and smaller meters
• UMAC Series 700 – Installed on every new ¾” service over 450’ – AL‐425 and smaller meters
We Prefer EFVs to Curb Valves
• Not in the code yet, but hopefully APGA’s comments will help get an either/or addition to allow EFVs OR curb valves
Curb Valve Policy
• Install manual valves on any service with an AL‐ 2300 or larger meter • We installed 6 of those in 2015
Matt Stennett Chief Engineer [email protected]
Middle Tennessee Natural Gas 615‐597‐4300
