Partner Reported Opportunities (PROs) PRO Fact Sheet No. 603 for Reducing Methane Emissions 

Install Excess Flow Valves 

Estimated 

Gas Price 

Annual 

Methane 

Savings 

Value of 

Annual

 Gas Savings* 

Estimated 

Implementation 

Cost 

Incremental 

Operating Cost 

Payback 

(years) 

$7.00/Mcf 160 Mcf $1,200 $6,300 $0 6 Years 

$5.00/Mcf 160 Mcf $850 $6,300 $0 8 Years 

$3.00/Mcf 160 Mcf $510 $6,300 $0 13 Years 

Economic and Environmental Benefits 

Economic Evaluation 

Additional Benefits 

 Avoidance of catastrophic events in gas service lines 

Estimated annual methane emission reductions 160 Mcf per installation of 350 excess flow valves 

Methane Savings 

* Whole gas savings are calculated using a conversion factor of 94% methane in pipeline quality natural gas. 

Technology/Practice Overview 

Description 

Gas line breaks from ground movement, 

natural disasters, or third party damage 

can result in potentially catastrophic 

events from gas release into the 

atmosphere. Partners reported

automating shutoff of a ruptured gas 

service line by installing excess flow

valves. 

The excess flow valve responds to the

high pressure differential, created when 

a line is severed, by snapping shut to 

stop the flow of gas. Therefore, the 

amount of gas that would have otherwise 

escaped into the atmosphere in the event

of a rupture is retained within the closed 

system. The valves do not protect 

against slow leaks such as those caused

by corrosion or loose fittings. 

Operating Requirements 

Excess flow valves should be tested and 

proven at the time of installation and at 

periodic intervals not to exceed one year. 

Applicability 

These safety valves may be applied to all 

gas service lines. 

Methane Emissions 

The amount of avoided methane 

emissions is a function of the service line 

diameter and pressure. Based on the 

formula in the Pipeline Rules of Thumb 

Handbook (4th Edition, page 278), 16 

Mcf per hour is emitted from a 1⁄2 inch 

service line at 50 psig. This is the 

estimated hourly gas savings when an 

excess flow valve is activated in response 

to a rupture along the service line. 

Compressors/Engines 

Dehydrators 

Directed Inspection & 

Maintenance 

Pipelines 

Pneumatics/Controls 

Tanks 

Valves 

Wells 

Other 

Applicable Sector(s) 

Production 

Processing 

Transmission 

Distribution 

Other Related Documents: 

None 
 

 

 

PRO Fact Sheet No. 603 Continued 

Install Excess Flow Valves (Cont’d) 

Economic Analysis 

Basis for Costs and Emissions Savings 

Typical methane emissions reductions of 16 Mcf per year,

costs, and payback apply to installing 350 excess flow

valves, of which 1 is activated in a year. The valves are 

installed on a 50 psig, 1⁄2 inch service line. 

One partner reported the capital cost of an excess flow 

valve to be approximately $18 per valve. By installing

350 valves, the cost would be approximately $6,300. 

The same partner reported emissions savings of 0.46 Mcf 

per excess flow valve installed, which is approximately 

160 Mcf in savings from installing 350 excess flow valves. 

Discussion 

The primary consideration for companies when installing

excess flow valves is to avoid catastrophic events, not 

reduce methane emissions. The economics of this PRO 

are based on the assumption that excess flow valves are 

installed on new and replacement high-pressure service 

lines. 

The average methane content of natural gas varies by natural gas 

industry sector. The Natural Gas STAR Program assumes the 

following methane content of natural gas when estimating 

methane savings for Partner Reported Opportunities. 

Production 79 % 

Processing 87 % 

Transmission and Distribution 94 % 

Methane Content of Natural Gas 

2011 2