PUBLIC WORKSHOP TO DISCUSS:

Overpressure Conditions at Gasoline Dispensing Facilities Equipped with Underground Storage Tanks and Phase II Enhanced Vapor Recovery including In-

Station Diagnostic Systems

December 12, 2017: Diamond Bar, CADecember 13, 2017: Sacramento, CA 1

Workshop Agenda

2

Topic Anticipated DurationIntroductory Remarks 10 minutesCARB Gasoline Vapor Recovery Program Presentation

50 minutes

Break 10 minutesCARB Advanced Clean Cars Program Presentation

50 minutes

Break 10 minutesComments and Questions 50 minutes

Housekeeping• Participant Sign-In, Emergency Exits, Restrooms• Hold questions and comments until the end• For those joining remotely (via “listen only”

conference line and webinar), email your comments and questions to vapor@arb.ca.gov

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

3

mailto:vapor@arb.ca.govhttp://www.arb.ca.gov/vapor/vapor.htm

Prior Workshops on Overpressure• November 2012- First Overpressure Workshop• September 2013- Planning for “Mega Blitz

2013/2014”• March 2014- Results of Mega Blitz and

Preliminary Emission Estimates• November 2015- Results of Mega Blitz, Assist

Nozzle ORVR Recognition Study, Identification of Capless Fill Pipe Designs, Concerns with Balance Systems

4

Discussion Topics

1. Refresher on Overpressure2. Activities Since Prior Workshop

November of 20153. Solutions Envisioned by CARB Staff4. Alternatives Considered5. Next Steps

5

Discussion Topic #1: Refresher on Overpressure

6

California’s Vapor Recovery Program• ~15 billion gallons of gasoline consumed/year• ~240 tons of V.O.C.’s reduced/day• ~10,000 gasoline dispensing facilities (GDFs)

with Phase II Enhanced Vapor Recovery• ~7,400 of these GDF equipped with In-Station

Diagnostic (ISD) systems

7

Phase II Enhanced Vapor Recovery Systems: Differences Between Balance and Assist

Assist Balance

% of CA GDF Population ~60% ~40%

Principal of Operation Active, requires vacuum pump for collection of vapors at the nozzle and vehicle interface

Passive, dispensing of gasoline displaces vapors which are captured by the nozzle

Vapor Pathway One way path, breathing losses from UST cannot occur at nozzle

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

Nozzle(s) Healy Model 900 VST-EVR-NBEMCO-A4005EVR

Processor(s) Healy Clean Air Separator Healy Clean Air SeparatorV-R Vapor PolisherHirt VCS-100VST ECS or Green Machine

8

In-Station Diagnostics (ISD) • Continuously monitors important vapor recovery system

parameters and alerts GDF operators of potential equipment failures

• Monitors pressure in the headspace of the underground storage tank (overpressure)

• Beginning in 2009, GDF operators:– Informed CARB of excessive overpressure alarms in the winter–Concerned about expense of responding to such alarms

• Advisory 405 released to provide temporary relief from the expense of alarm response

9

https://www.arb.ca.gov/vapor/advisories/adv405.pdf

ISD Overpressure (OP) Alarm CriteriaAssessment Period

Current ISD OP Alarm Criteria

Weekly 5% of UST pressure data above1.5”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)

10

http://www.arb.ca.gov/testmeth/vol2/cp201_april2013.pdfhttp://www.arb.ca.gov/testmeth/vol2/cp201_april2013.pdfhttp://www.arb.ca.gov/testmeth/vol2/cp201_april2013.pdf

Why Are We Concerned?1. Overpressure ISD Alarms

• Cost, no problem found with vapor recovery equipment in winter time

• Disruptive to GDF operations2. Air Quality Impacts

• Potential V.O.C. emission increases• Potential near source health risk issues at worst

case sites due to increased benzene exposure

11

• Primary Causes:• High Reid Vapor Pressure

(RVP) winter blend gasoline• Excess air ingested due to poor

nozzle seal or vented vehicle fill pipes

• Other Contributors:• GDF monthly throughput• GDF maintenance practices• GDF operating hours

What Causes Overpressure?

12

Discussion Topic #2: Activities Since November 2015 Public

Workshop

13

Activities Since November 2015 Public Workshop

Vapor Recovery Related Field Studies:• Mega Blitz of December 2015• Evaluation of Assist Nozzle “EOR” Spout Assembly• Evaluation of Pressure Driven Balance Emissions

14

Mega Blitz December 2015

15

Data Collected From ~400 Sitesin Six Geographic Regions

Collaborative effort between CARB, Air Pollution Control Districts, and randomly selected GDF operators

ISD Data- All alarm history data available- Available pressure and ullage data- V/L data for recent fueling events

GDF Characteristics- Operating hours, monthly throughput- Gasoline brand and source- Inventory report with UST capacities

16

Mega Blitz 2013 vs 2015

DescriptionSouth Coast

Bay AreaSan

Joaquin Valley

San Luis ObispoNorthCoast

MojaveEl Dorado

Placer

San Diego

SacramentoYolo-Solano

Feather River

% of 7,400 GDF w/ ISD

40.3% 17.1% 11.3% 11.1% 8.3% 6.9%

% 395 GDF Used in 2013 Analysis

33.7% 15% 10.6% 9.3% 19.7%* 13%*

% of 329** GDF Used in 2015 Analysis

22% 16% 10.5% 9.4% 10%* 11%*

Statewide ~7,400 GDF are equipped with Phase II EVR with ISD , the 2013 data set represents a 5% sample size*San Diego and Sacramento regions were oversampled**Number of sites was reduced in 2015 largely due to conversion from assist to balance

17

Prevalence of OP Alarms Data Set OP Alarms October 2013

October2015

November 2013

November 2015

All Sites Combined (329)

Average Numberof Alarms Per Site 0.11 0.16 1.27 1.50

% of Sites With at Least One Alarm 6.4% 9.4% 50.8% 56.2%

Assist Sites(210)

Average Number of Alarms Per Site 0.16 0.22 1.80 2.18

% of Sites With at Least One Alarm 9.0% 13.3% 68.6% 79.0%

Balance Sites(119)

Average Number of Alarms Per Site 0.03 0.04 0.35 0.32

% of Sites With at Least One Alarm

1.7% 2.5% 19.3% 16.0%

18

Vapor to Liquid (V/L) Ratio Effect on Pressure While Dispensing

Observation at Assist Sites

PWDObserved in Dec 2013?

PWD Observed

in Dec 2015?

Site V/L Average 2015

SCAQMD

Site V/L Average 2015

SDCAPCD

No No 0.60 (22 sites) 0.61 (27 sites)

Yes Yes 0.65 (19 sites) 0.64 (8 sites)

19

Conclusions From Mega Blitz of 2015• Overpressure remains a winter time phenomena• Overpressure ISD alarm frequency has increased• Assist Sites

– PWD increased from 2013 to 2015 (34% to 44%) – 8% of sites had one or more leak alarm– 18% of assist sites converted to balance

• Balance Sites– Overpressure alarm frequency decreased slightly from 2013

to 2015– Percentage of sites with one or more leak alarms decreased

slightly from 2013 to 2015 (34% to 29%)

20

Evaluation of Assist NozzleEnhanced ORVR-Vehicle Recognition

(EOR) Spout Assembly

21

Expected “Vapor to Liquid” Ratio for ORVR Vehicles

• Phase II systems are designed to reduce the volume of vapor collected relative to volume of liquid dispensed (V/L) when fueling ORVR vehicles

• V/L ≥ 0.5 on ORVR vehicles results in excess air ingestion which leads to vapor growth inside UST

• Field data indicate GDFs that exhibit overpressure also have elevated V/L

22

V/L Ratio

Conventional vs ORVR Equipped Vehicles

Conventional Vehicle• Saturated vapors exit the vehicle fill pipe

during fueling, captured by the EVR nozzle, and returned to GDF tank

• Collection of saturated vapors do not result in vapor growth in GDF tank

• All vehicles prior to 1998, and certain later vehicles

ORVR Vehicle• Vapors captured by on-board

canister and later burned by the engine

• Phased in starting with 1998 model year

• If poor seal is formed at nozzle, excess air ingestion causes vapor growth in GDF tank

No competition between vehicle and station vapor recovery

Potential competition between vehicle and station vapor recovery

23

Development of EOR Spout Assembly• ORVR Recognition Study 2015-San Diego (VR-OP-A3)• Controlled Fueling Evaluation 2015-Sacramento (VR-OP-A4)• EOR Nozzle Evaluation 2015/2016-Limited to three test

sites, “tail end” of winter fuel period (VR-OP-A5)• EOR Nozzle Evaluation 2016/2017-Expanded to seven test

sites, full winter fuel period (VR-OP-A6)

24

https://www.arb.ca.gov/vapor/op/op.htmhttps://www.arb.ca.gov/vapor/op/op.htmhttps://www.arb.ca.gov/vapor/op/op.htmhttps://www.arb.ca.gov/vapor/op/op.htm

In Addition to EOR Spout Assembly:Assist System Optimization

• Each test site optimized as follows:• Nozzle V/L ratio setting “dialed down”

between 0.95 to 1.0 (allowable range is 0.95-1.15)

• Dispenser leak integrity, fuel dispensing rate, and alignment of nozzle vapor boot verified

• ISD operability and PV vent valve verified• EOR Spout Assembly Configurations

• Field retrofit –can be installed onto existing nozzle body, if existing nozzle did not respond to V/L adjustment, must be replaced

• Factory assembled- brand new nozzle25

Results of EOR Spout Assembly Evaluation (seven site average)

Parameter/BenchmarkBefore

EOR(Blitz Data)

AfterEOR

(Continuous)Average UST Headspace Pressure (“WCG) +2.2 -1.6

Percentage of Time UST Pressure Exceeds the Gross ISD OP Alarm Threshold

71% 15%

Site Average Vapor to liquid Ratio 0.65 0.55

Percentage of Fueling Events with V/L Ratio Less Than 0.5

50% 64%

Percentage of Days GDF Exhibited Pressure Increase While Dispensing

100% 22%

26

EOR Spout Assembly Conclusions• Effective in lowering UST pressure, site average V/L

ratio, OP alarm frequency, and PWD, but did not fully eliminate the occurrence of alarms and PWD

• Optimization of Phase II vapor recovery system also contributed to improved performance

• Field retrofit and factory assembled configurations both performed well, but factory is superior

• EOR spout assembly certified by CARB in August of 2017 via EO VR-201-V and VR-202-V

• Informational Bulletin released on December 4, 2017

27

https://www.arb.ca.gov/vapor/eos/eo-vr201/eo-vr201.htmhttps://www.arb.ca.gov/vapor/eos/eo-vr202/eo-vr202.htmhttps://www.arb.ca.gov/vapor/vapor.htm

Evaluation of Pressure Driven Balance Emissions

28

Questions Prompting Investigation of Balance System Pressure Driven Emissions

• GDF equipped with balance systems do not experience a high frequency of overpressure alarms

• Operate at slightly positive pressure for ~ 25% of time with winter fuel and ~ 13% of the time with summer fuel

• Unlike the assist nozzle, the balance nozzles allow both inward and outward flow of gasoline vapors

• Does slight positive pressure and outward flow at the nozzle significantly impact balance system vapor collection efficiency? (VR-OP-B1)

29

https://www.arb.ca.gov/vapor/op/op.htm

2015 CARB Emission Testing of Balance Systems at Slightly Positive UST Pressure

30

Baseline Testing at Vacuum Testing at Slight UST Pressure

VST EMCO VST EMCO

ORVR Non-ORVR

ORVR Non-ORVR

ORVR Non-ORVR

ORVR Non-ORVR

Balance NozzleEmission Factorlbs./1,000 gallons

0.03 0.13 0.06 0.16 0.27 1.33 1.34 2.55

Efficiency Loss Due to Nozzle Emissions

0.5% 2.1% 0.8% 2.1% 4.2% 21.0% 19.1% 36.2%

Application of 2015 Balance System Emission Test Data

• Prior emission estimates assumed percentage of time at positive pressure was equal to the volume of gasoline dispensed at positive pressure

• Further refinement of emission techniques:– Emissions should only include the volume of fuel

dispensed at positive pressure (VDAPP)– Include volume of reverse flow released through

the nozzle when positive pressure exists (RIFE)

31

Why is VDAPP Important?• Phase II Vapor Recovery Systems are certified to be at least 95%

efficient when refueling non ORVR equipped vehicles• As VDAPP increases, overall system efficiency is diminished.• The following table assumes an ORVR penetration of 80% and

uses emission factors presented in prior slide:Percentage of Volume Dispensed at Positive Pressure

Phase II Vapor Recovery System EfficiencyGDF Equipped with VST Nozzles

GDF Equipped with EMCO Nozzles

5% 96% 94%10% 95% 92%15% 94% 90%20% 93% 87%25% 92% 85%

32

Why is RIFE Important? • Pressure driven emissions that occur outside of time periods

identified by ISD as dispensing events• Typical GDF which dispenses 150,000 gallons per month (37,500

gallons per week), a relatively small volume of vapor released via reverse flow can also diminish system efficiency:

Gallons of Vapor Released Per Week

EfficiencyLoss

Emission Factor Attributed to ReverseIdle Flow

50 0.1% 0.01 lbs./1,000 gallons

200 0.5% 0.05 lbs./1,000 gallons

500 1.3% 0.13 lbs./1,000 gallons

1,000 2.7% 0.25 lbs./1,000 gallons

33

Data Used to Estimate Balance System Pressure Driven Emissions

• VDAPP based on 2013 and 2015 Mega Blitz data • RIFE required establishment of new study sites• 11 new study sites were established with

continuous data collection of ISD information during winter 2016-2017– Sites varied by throughput and geographic location– Nine sites with Healy CAS processor– One site with Hirt VCS 100 processor– One site Veeder-Root Vapor Polisher processor

34

85 Mega Blitz Sites(20-CAS, 65 Canister)

10 Study Sites(9-CAS, 1 Canister)

Time Period of Data Collection 30 hours 10 to 15 Weeks

Dates of Data CollectionDec 7 - 17, 2015 Nov 13, 2016 –Feb 26, 2017

Average VDAPP for Sites 280,000 gallons/month 3.5% 4.7%

RIFE Analysis No Yes

35

VDAPP – 10 Study Sites vs 85 Blitz Sites*

*An eleventh study site was equipped with the Hirt VCS 100 vapor processor which maintains a slight vacuum within the UST, results are discussed later in presentation.

Comparison of VDAPP

Distributions

8.8%

14.7%

7.4%

16.2%

27.9%

17.6%

4.4%1.5% 0.0% 1.5% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

0%

5%

10%

15%

20%

25%

30%

0 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-10 10-15 15-20 20-25 25-30 30-35 35-40 >40% VDAPP

68 Days from 10 Sites Collected Dec 11-17, 2016; 91 kgal/mo < TP < 524 kgal/moAve 2.85% Std Dev 1.80%

2.4% 3.5%

10.6% 9.4%7.1%

11.8%

5.9%3.5%

7.1%

27.1%

3.5% 3.5%1.2% 2.4% 0.0% 1.2%

0%

5%

10%

15%

20%

25%

30%

0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-10 10-15 15-20 20-25 25-30 30-35 35-40 >40% VDAPP

30 Hr Data from 85 sites collected Dec 7-17, 2015; 76 kgal/mo < TP < 508 kgal/moAve 9.08% Std Dev 7.39%

Mega Blitz 2015

5.2%3.1%

5.2%

10.4% 11.5% 9.4% 8.3% 7.3% 6.3%9.4%

14.6%

6.3%

2.1% 1.0% 0.0% 0.0% 0.0%0%

5%

10%

15%

20%

25%

30%

0 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-10 10-15 15-20 20-25 25-30 30-35 35-40 >40%VDAPP

30 Hr Data from 96 sites collected Dec 3-17, 2013; 50 kgal/mo < TP < 425 kgal/moAve VDAPP 7.95% Std Dev 5.42%

Mega Blitz 2013

Study Sites 2016

36

Effect of VDAPP & RIFE on Balance SystemWinter Season Emissions

Source of Data Percent VDAPP RIFE

Emission Factor

Efficiency Emission Factor

VST EMCO VST EMCO

10 Study Sites - Average (Hirt not included) 2.9% 0.04 96.4% 95.3% 0.35 0.44

10 Study Sites - Worst Case(Hirt not included) 5.0% 0.09 95.4% 93.8% 0.44 0.59

Hirt Study Site 0.4% 0.08 96.5% 96.1% 0.33 0.37

Blitz Sites - Average 9.1% 0.04 95.0% 92.4% 0.48 0.73

VDAPP from Highest 10 Blitz SitesRIFE from Highest Study Site

30.4% 0.09 89.8% 81.6% 0.97 1.75

37

Emission Factor is expressed at pounds per thousand gallons of gasoline dispensed

Observations Mega Blitz vs Study Sites• Statistical analysis shows study sites represent a

subset of the overall GDF population and are not appropriate for a statewide emission estimate

• Average VDAPP and variation in VDAPP is significantly higher for Mega Blitz vs Study Sites

• Study sites provide the only estimate for RIFE• A low bias is likely in the RIFE emission estimate.

38

Balance System Emission Evaluation Conclusions

• Information collected to date is inconclusive• Need for additional studies in 2017/2018:

– Establish study sites at the upper end of the VDAPP distribution shown by the Blitz data

– Measure evaporation rate at balance & assist sites• Accurate estimates of vapor processor

emissions may not be possible using ISD data alone

39

Discussion Topic #3:Solutions Envisioned by CARB Staff

40

Goal: Provide GDF Operators With “Menu of Options”

Low Cost & Complexity

Moderate Cost & Complexity

High Cost &

Complexity

ExamplesAssist Balance

EOR Nozzle &

Optimize

One WayCheck

Valves?

ISD Software/

PV Zero

ISD Software?

High Capacity

VaporProcessor

VaporProcessor?

41

42

Non ISD Equipped;; 26%

ISD & Balance Equipped; 27%

ISD & Assist Equipped; 47%

Statewide GDF Population: 10,000

43

Non ISD Equipped; 26%

Balance No OP Alarms; 22%

Assist No OP Alarms; 10%

Balance With OP Alarms; 4%

Assist With OP Alarms; 17%

Assist With OP Alarms & PWD;

21%

Statewide GDF Population: 10,000

Balance Equipped Sites*

44

Balance With OP Alarms; 4%

Description of Vapor Recovery Equipment Upgrade

One way check valves?Emission Based ISD Software?

Estimated CostPer Facility

TBD?

*Solutions envisioned by CARB staff for balance equipped sites are currently uncertain, pending results of additional winter 2017/2018 field studies.

Assist Equipped Sites with OP Alarms

45

Assist With OP Alarms; 17%

Description of Vapor Recovery Equipment Upgrade

• EOR Nozzle • ISD Software

Upgrade • PV Zero

Estimated CostPer Facility

• EOR Nozzle ~$4,000

• ISD Software and PV Zero ~$5,500

Assist Equipped Sites with OP Alarms & PWD

46

Assist With OP Alarms & PWD; 21%Description of Vapor Recovery Equipment Upgrade

• EOR Nozzle • ISD Software

Upgrade • PV Zero• High Capacity

Processor Estimated CostPer Facility

• EOR Nozzle: ~$4,000

• ISD Software and PV Zero ~$5,500

• High Capacity Processor: TBD

Proposed Emission-Based ISD Overpressure 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

• Set at an efficiency loss threshold due to pressure driven losses

• Provide information to assess site specific health risk impacts

47

Preliminary Cost Estimate

Potential SolutionEstimatedCost Per Site*

Estimated Assist Site Population

EstimatedBalance Site Population

Install EOR Nozzles and Optimize Vapor Recovery System(10 nozzles/site)

$4,000 ~3,700 Not Applicable

Install Revised ISD Software and PV Zero Vent Valve

$5,500 ~2,000 TBD**

Install High Capacity Vapor Processor

$15,000 -$50,000

TBD TBD**

48

*Cost information is based on surveys conducted by CARB staff in 2014, numbers will be updated at a later date**Additional studies in 2017/2018 are needed to make determination

Discussion Topic #4: Alternatives Considered

49

Alternatives Considered

• Limit RVP of winter blend gasoline• Decommission Phase II Vapor Recovery

including ISD• Extend Advisory 405-D indefinitely• Retain current ISD requirements and require

high capacity vapor processors across the board

• Seeking public input on other alternatives

50

Discussion Topic #4: Next Steps

51

Next Steps1. Additional field studies seek to eliminate

remaining uncertainty on balance system emissions

2. Investigate feasibility of estimating pressure driven emissions at non-ISD equipped sites

3. Implementation of solutions will take several years due to regulatory and certification process

52

53

0%

10%

20%

30%

40%

50%

60%Pe

rcen

tage

of G

DF E

xper

ienc

ing

Win

ter

OP

Alar

ms

Anticipated Timeline For Implementation of Overpressure Solution

OP Alarm Frequency

● Board Hearing

● OAL Adoption of Regulation● Certification of ISD Software & High Capacity Processors

● Rescind Advisory 405-D

● First Year of Implementation

● Second Year of Implementation

● EOR Nozzle Implementation

● Third Year of Implementation

● Full Implementation

More Information

• General Vapor Recovery Program Inquiries:vapor@arb.ca.gov

• Overpressure Related Inquiries:John MarconiJohn.Marconi@arb.ca.gov

• Overpressure Webpage:https://www.arb.ca.gov/vapor/op/op.htm

54

mailto:vapor@arb.ca.govmailto:John.Marconi@arb.ca.govhttps://www.arb.ca.gov/vapor/op/op.htm

Public workshop to discuss: ��Overpressure Conditions at Gasoline Dispensing Facilities Equipped with Underground Storage Tanks and Phase II Enhanced Vapor Recovery including In-Station Diagnostic Systems������December 12, 2017: Diamond Bar, CA�December 13, 2017: Sacramento, CA�Workshop AgendaHousekeepingPrior Workshops on OverpressureDiscussion TopicsDiscussion Topic #1: �Refresher on OverpressureCalifornia’s Vapor Recovery ProgramPhase II Enhanced Vapor Recovery Systems: Differences Between Balance and AssistIn-Station Diagnostics (ISD) ISD Overpressure (OP) Alarm CriteriaWhy Are We Concerned?What Causes Overpressure?Discussion Topic #2: �Activities Since November 2015 Public WorkshopActivities Since November 2015 Public Workshop Mega Blitz December 2015Data Collected From ~400 Sites� in Six Geographic RegionsMega Blitz 2013 vs 2015Prevalence of OP Alarms Vapor to Liquid (V/L) Ratio Effect on Pressure While Dispensing Observation at Assist SitesConclusions From Mega Blitz of 2015Evaluation of Assist Nozzle� Enhanced ORVR-Vehicle Recognition (EOR) Spout AssemblyExpected “Vapor to Liquid” Ratio for ORVR VehiclesConventional vs ORVR Equipped VehiclesDevelopment of EOR Spout AssemblyIn Addition to EOR Spout Assembly:�Assist System OptimizationResults of EOR Spout Assembly Evaluation (seven site average)EOR Spout Assembly ConclusionsEvaluation of Pressure Driven Balance EmissionsQuestions Prompting Investigation of Balance System Pressure Driven Emissions2015 CARB Emission Testing of Balance Systems at Slightly Positive UST PressureApplication of 2015 Balance System Emission Test DataWhy is VDAPP Important?Why is RIFE Important? Data Used to Estimate Balance System Pressure Driven EmissionsVDAPP – 10 Study Sites vs 85 Blitz Sites*Comparison of VDAPP DistributionsEffect of VDAPP & RIFE on Balance System� Winter Season EmissionsObservations Mega Blitz vs Study SitesBalance System Emission Evaluation ConclusionsDiscussion Topic #3:�Solutions Envisioned by CARB StaffGoal: Provide GDF Operators With �“Menu of Options”Slide Number 42Slide Number 43Balance Equipped Sites*Assist Equipped Sites with OP AlarmsAssist Equipped Sites with OP Alarms & PWDProposed Emission-Based ISD Overpressure Alarm CriteriaPreliminary Cost EstimateDiscussion Topic #4: �Alternatives ConsideredAlternatives ConsideredDiscussion Topic #4: �Next StepsNext StepsSlide Number 53More Information