## California Air Resources Board

Public Workshop Enhanced Vapor Recovery 

## ISD Alarms and Emissions Related to Overpressure

November 6, 2015 in Sacramento November 10, 2015 in Diamond Bar

1

# Housekeeping

• Emergency Exits, Building Evacuation, Restrooms

• Hold questions and comments till end of each segment

• For those participating via conference call and webinar, email your comments during the presentation to george.lew@arb.ca.gov

• Presentation, webinar information, and conference call information is posted at http://www.arb.ca.gov/vapor/vapor.htm

2

# Purpose of Workshop

• Discuss findings from ARB studies

• Present ideas for possible solutions

• Request input from interested parties

• Identify and resolve issues prior to proposing a regulatory solution to our Board



### • Answer questions

3

# Discussion Topics

• Background

• Review of previous analysis and findings

• Presentation of new analysis and findings



### • Summary of major conclusions

• Presentation of solutions being considered



### • Next steps

4

# Background

5

## Enhanced Vapor Recovery (EVR) and In

- Station Diagnostics (ISD)

• Statewide ~ 7,500 gasoline dispensing facilities (GDF) are equipped with Phase II EVR and ISD

• ISD continuously monitors the performance of the vapor recovery system (VRS) and alerts the operator of potential equipment failures

• One of the ISD parameters involves continuous monitoring of pressure in the headspace of the underground storage tanks (UST)

6

# ISD Overpressure (OP) Alarm Criteria

Assessment Period Current ISD OP Alarm Criteria

Weekly 5% of UST pressure data above

1.5”WCG (Section 9.2.4 of CP

- 201 ) Monthly 25% of UST pressure data above

0.5”WCG (Section 9.2.4 of CP

- 201 ) Daily Daily assessment to identify vapor

processor malfunction (Section 9.2.5 of CP

- 201 )

7

# Definitions

 

### ISD OP Alarm Problem: A situation in which the 

### equipment inspection, testing, and troubleshooting conducted in response to an ISD OP alarm fails to identify an equipment 

### malfunction

 

### OP Emission Problem: A situation in which the emissions resulting from positive pressure in the 

### underground storage tank are of concern with regard to the regional ozone standard or near source risk due to benzene exposure

8

# Why Are We Concerned?

1. False ISD Alarms

• Alarms require service provider response, yet no trouble is found in winter time

• Costly and disruptive for GDF operator 

### 2. Air Quality Impacts

• Statewide ROG emissions from overpressure are estimated at 11 TPD winter and 1 TPD summer

• Potential near source health risk issues at worst case sites due to increased benzene exposure

9

## How Do Phase II Enhanced Vapor Recovery Systems Differ?

Assist Balance % of GDF Population 60% 40% Date Initially Certified September, 2005 April, 2008 Principal of Operation Active, requires vacuum pump in vapor return pathway Passive, requires low resistance vapor return pathway
Nozzle Vapor Pathway One way path, breathing losses from UST cannot

occur Two way path, allows breathing losses from UST
to occur

10

# Assist System: Pressure Driven

Emissions

11

# Balance System: Pressure Driven

Emissions

12

# Scope of OP Problem: Assist Systems

Severity of Overpressure Condition Estimated Population ( ~ 4500 sites, 60% )

Tier 1: No overpressure Alarms in December negligible pressure driven emissions. Little or no time at positive pressure. Population: ~1035 (23% of assist sites)

Tier 2: Overpressure conditions which produced alarms in December, but an efficiency loss less than 5%. Positive pressure occurs during overnight idle period. Population: ~1935 (43%, of assist sites)

Tier 3: Overpressure conditions which result in efficiency loss greater than 5% in winter months and/or potential concerns over elevated risk at the worst case sites. Positive pressure occurs for long periods of time during dispensing operations Population: ~1530 (34% of assist sites)

13South Coast Assist Site Pressure Comparison October and December

Ullage

Pressure

14

# Scope of OP Problem: Balance Systems

Severity of Overpressure Condition Estimated Population ( ~ 3000 sites, 40% )

Tier 1: No overpressure Alarms in December negligible pressure driven emissions. No positive pressure during dispensing operations. Population: ~ 300 ~10% of sites have high throughput Not expected to exhibit positive pressure while dispensing

Tier 2: Overpressure conditions which result in overpressure alarms and efficiency loss less than 5%. Exhibit slight positive pressure during dispensing operations We expect that most of the remaining 2700 sites will fall into tier 2, but further analysis is needed to estimate the number

Tier 3: Overpressure conditions which result in efficiency loss greater than 5% and/or potential concerns over elevated risk at worst case sites. Exhibit slight positive pressure during dispensing operations We expect that only a small percentage of the remaining 2700 sites will fall into this tier, but further analysis is needed to estimate the number

15South Coast Balance Site Pressure Comparison October and December

16

# Causes of Overpressure

• Primary cause is uncontrolled Reid Vapor Pressure 

### (RVP) of winter gasoline

• Secondary causes include:

– Type of Phase II EVR system installed (Assist or Balance)

– Excess air ingested when fueling vehicles equipped with on

- board refueling vapor recovery (ORVR)

– Gasoline throughput

– GDF maintenance practices

– GDF operating hours

17

# Review of Previous

Analysis and Findings

18

# Major Elements of OP Study

• Study Sites with Continuous Data Collection

• Vapor Recovery System (VRS) Performance Testing

• Reid Vapor Pressure (RVP) Sampling and Analysis

• Collection of ISD Alarm History, UST Pressure Data, and VRS Configuration from ~400 Sites

19

# Study Sites with Continuous

Data Collection

• Six sites in Northern California established Fall 2009



### • Five sites in Southern California established Fall 2013

• Each equipped with “PV Zero” vent valve, barometric/UST pressure monitor, & ISD data acquisition system



### • Data used to estimate pressure driven fugitive and vent line emissions

20

# Vapor Recovery System

Performance Testing

• Conducted at 15 Sites 

### Exhibiting PWD

• ISD Operability

• Nozzle Bag Test



### • CAS Integrity

• Vapor to Liquid (V/L) Ratio



### • Dispenser Integrity

• System Pressure Integrity

2122

### Data Collected From ~400 Sites in Six



### Geographic Regions

- Collaborative effort between ARB and Districts

- 14 ARB staff members

- 28 District staff members

ISD Data

- All alarm history data available (at least one year)

- Available pressure and ullage data

- Available records on last 10 deliveries to gather available data on fuel temperature

- V/L data on for recent vehicle fueling events

GDF Characteristics

- Operating hours

- Throughput

- Gasoline brand and source

- Inventory report with tank capacities

23

# Prevalence of OP Alarms:

Data Set OP Alarms October 2013 November

2013
Assist Sites (274) Average Number of

Alarms Per Site 0.16 1.84

% of Sites With at Least One Alarm 8.8% 69.7%

Balance Sites (121) Average Number of

Alarms Per Site 0.02 0.36

% of Sites With at Least One Alarm 1.7% 19.8%

2425

# Presentation of New



# Analysis and Findings

26

## Expected V/L Ratio During Refueling of ORVR Vehicles

• The assist nozzle is designed to reduce the V/L to < 0.5 when refueling ORVR vehicles

• Air ingestion and vapor growth occurs inside UST when V/L > 0.5 on ORVR vehicles

27

# Assist System

ORVR Recognition

• Tier 3 sites (PWD) exhibit higher V/L when compared to Tier 2 and Tier 1 sites

• The ability of the assist nozzle to identify ORVR vehicles has declined over the last several years

• ORVR vehicle identification can vary within the same make, model, and model year

28

## Assist Nozzle ORVR Recognition Study

• Conducted in January 2015, at six retail GDF located in San Diego region

• Total of ~ 1600 valid vehicle refueling observations, 85% ORVR, 15% Non

- ORVR

• Observed and recorded each vehicle refueling event followed by retrieval of V/L data from ISD

29

# ORVR Recognition Study Findings

• Percentage of ORVR vehicles with V/L ≥0.5 ( mis

- identification rate) was 30%



### • Percentage of ORVR vehicles with V/L ≥ 1.0 was 18%

• Capless fill pipes represented 4% of data set, 75 % had a V/L ≥ 1.0

30

## Trends in Assist Nozzle ORVR

Mis

- Identification Rate

Healy Assist Certification Between 2004 and 2015, ORVR penetration increased from 24% to 84% at sites studied.

31

# Differences in ORVR V/L



# by Model Year

Model Year Duration Number

of ORVR Events ORVR

V/L Number of ORVR Events with V/L Greater Than 0.5 Percent of

ORVR Events with V/L Greater Than 0.5

2000

- 2011 838 0.49 222 27%

2012

- 2015 496 0.61 189 38%

32

## ORVR Vehicle Refueling Experiment ( Summer 2015 )

Step 1: Remove existing fuel from ORVR vehicle of interest Step 2: Dispense fuel under controlled conditions

Step 3: Record volume dispensed, vacuum generated, time, and vehicle information Step 4: Retrieve ISD data, determine V/L ratio 33

## Breakthrough/Key Finding

V/L can vary depending on whether nozzle is securely latched or loosely latched in the vehicle fill pipe

Item Description
5 Nozzle Latch Ring
C Fill Pipe Locking Lip

34

# Secure Latch vs Loose Latch

Gap

Nozzle Secure Latch Nozzle Loose Latch

35

## ORVR Vehicle Refueling Experiment



## August 2015 (Certified Nozzle)

Vehicle Make/Model Secure/Loose Latch Nozzle Boot (InH 2 0 ) Avg V/L

Nissan Altima Secure

- 1.35 0.43

Nissan Altima Loose 0.00 1.10
Toyota Corolla Secure

- 1.74 0.24
Toyota Corolla Loose 0.00 1.09
Toyota Prius C Secure

- 1.48 0.25
Toyota Prius C Loose 0.00 1.14

Honda Civic Secure

- 1.37 0.46

Honda Civic Loose N/A * 0.49
*Vacuum needle came loose during fueling

36

## ORVR Vehicle Refueling Experiment 

## September 2015 (Prototype Nozzle)

Vehicle Make/Model Secure/Loose Latch* Nozzle Boot (InH 2 0 ) Avg V/L

Nissan Altima Secure

- 0.96 0.21

Nissan Altima Loose

- - Toyota Corolla Secure

- 1.57 0.18
Toyota Corolla Loose

- - Toyota Prius C Secure

- 1.48 0.19
Toyota Prius C Loose

- -
Honda Civic Secure

- 0.85 0.27

Honda Civic Loose

- - *Loose latch not possible

37

# ORVR Vehicle Refueling Experiment Conclusions

• ORVR vehicle mis

- identification can vary within the same vehicle make, model, and model year

• ORVR vehicle mis

- identification issue appears to be related to two potential causes:

– Engagement of nozzle “latch ring” with fill pipe “locking lip” (loose latch vs secure latch)

– Vehicle fill pipe design (open path to atmosphere)

• Prototype nozzle performed well, FFS pleased with results and will establish R&D test site

38

## Questions Regarding

Balance System

• Although balance systems don't experience a high frequency of overpressure alarms, they operate at slightly positive pressure for ~ 25% of time with winter fuel and ~ 13% of the time with summer fuel

• Is outward flow (reverse flow) at the nozzle 

### preventing the overpressure alarm from occurring?

• If so, should we be concerned about these 

### emissions?

3940

# Primary Objectives of Balance System Testing

• Determining if the release of vapors through the balance nozzle explains the difference in frequency of overpressure that is observed at GDF with balance systems vs GDF with a ssist systems



### • Determine the mass of vapor that can be emitted when UST is held at a slight positive gauge pressure (0.1 to 0.3 “WCG)

41

# Balance System Testing
( July 2015 )



### • Phase II efficiency testing conducted on 60 cars under normal operating conditions to establish baseline, then on 200 cars at slightly positive UST
pressure



### • Both VST and EMCO nozzles tested

• Pump used to bubble air through liquid gasoline at bottom of underground storage tank



### • Pressure switch used to turn pump on at pressure below 0.1 “WCG and turn pump off at pressure above 0.3 “WCG

42

# Balance System Testing

43

## Slight UST Pressure Results in Reduced 

## Nozzle Collection Efficiency and Higher Emissions During Fueling Events

44 # of Events Dispensed

Gasoline Volume (gallons) Efficiency Loss

Based on UEF = 7.65 lb/kgal Dispenser

VR Line Pressure ("WCG)

Ave. Max. Min.

Baseline ORVR Events 30 386 0.5%

- 0.64

- 0.16

- 1.14

Baseline Non

- ORVR Events 30 409 1.9%

- 0.44 0.00

- 1.00

Pressurized ORVR Events 99 1246 10.5% 0.15 0.22 0.09

Pressurized Non

- ORVR Events 96 1471 25.4% 0.19 0.29 0.0945

# Balance System Testing Conclusions

• Pressure driven emissions from balance systems are on the same order of magnitude as pressure driven emissions from assist systems

• The outward flow through the balance nozzle is sufficient to release the vapors produced by evaporation in the UST

• This is the reason that the balance systems exhibit lower UST pressures and fewer overpressure alarms than the assist systems

46

# Summary of

Major Conclusions

47• OP is driven by RVP and is primarily a winter problem

• Current pressure based ISD alarm standards can be more stringent than needed to ensure acceptable system performance

• Poor seal at ORVR fill pipe a major contributor

• Both balance and assist systems are affected

• Emission estimates characterize extent of problem:

– Regional Basis (Ozone AAQS) : Minor impact 1 ton per day statewide in summer months

– Site Specific Basis (Benzene Risk): Potentially significant at worst case sites

. Statewide 11 tons per day in winter months 

# Major Conclusions

48

# Presentation of Solutions

Being Considered

49

# Potential Solutions

1. Address loose latch problem on assist nozzles to 

### lower air ingestion and on balance nozzles to reduce emissions at positive pressure
2. Revise ISD alarm thresholds to be emission



### based rather than pressure

- based
3. Certify high capacity processors capable of handling worst case vapor production caused by 

### evaporation
4. Adopt new vehicle fill pipe performance standards to ensure new model ORVR vehicles and EVR nozzles control V/L to less than 0.5

50

# Address Loose Latch Problem

• Ensure that fuel cannot be dispensed unless a good seal is made between nozzle and vehicle

• Relatively low cost for nozzle spout kit



### • Assuming natural turnover, 4 years for 100% implementation



### • Lower ORVR V/L will reduce UST pressures and pressure driven emissions

51

# Emission

- Based ISD Alarm Criteria

Current ISD Threshold Proposed ISD Threshold

Percentage of time at
pressure:

• 5% of time greater than 1.5 ”WCG over seven days

• 25% of time greater than 0.5 ”WCG over 30 days Summer: Efficiency loss due to pressure driven losses

Year Round: Emission rate to limit health risks due to benzene

Estimated cost of implementing revised alarm criteria $5,500 per site

52

# High Capacity Processors

• Costs $12K to $50K per site depending on the processor system chosen

• Could completely eliminate pressure driven 

### emissions regardless of all other factors (GDF parameters, vehicle fleet, fuel RVP etc.)

• Only needed at sites which continue to have overpressure emission alarms with new criteria

53

## N ew V ehicle F ill P ipe

Performance S tandards

• Required to ensure nozzle vehicle compatibility into the future

• Necessary since vehicle designs change on a 

### frequent basis

• Long implementation time frame since vehicle 

### lives are greater than 10 years

• Does not address incompatibility associated with earlier model year vehicles

54

# Next Steps

55

# Further Analysis Planned

• Study loose latch prevalence in balance nozzles

• Download ISD data from ~400 sites to check current alarm and PWD trends

• Evaluate performance of improved nozzles & high capacity processors

• Assess health risk issues

• Develop amendment for ORVR vehicle fill pipe standards

• Estimate effectiveness and cost of each proposed solution

56

# Next Steps

• Field testing of potential solutions (new nozzles and high capacity processors)

• Review and refine emission estimates

• February 2016

- Informational update to the Board

• Spring 2016

- Workshop on effectiveness of proposed solutions

• Summer 2016

- Workshop on proposed regulatory language

• Late in 2016

- Propose regulatory amendments to the Board

57

# Contact Us

Lou Dinkler l ouis.dinkler@arb.ca.gov



### John Marconi john.marconi@arb.ca.gov

Gurj Bains gurjeet.bains@arb.ca.gov

58