Monitoring and Laboratory Division April 25, 2002Planning and Technical Support DivisionMobile Source Control DivisionCalifornia Air Resources Board

Proposed Control Measure to Reduce Emissionsfrom Small Off-Road Engines (SORE)

Elements of SOREControl Measure

• Exhaust Element– Revises exhaust emission standards for non-handheld

equipment• Evaporative Element

– New evaporative emission standard for walk-behindmowers (WBMs)

– Requires new fuel tanks to meet a permeation standard(applicable to all handheld and non-handheld SOREcategories)

– Proposing design-based certification requirements

Goals of the Evaporative Element of SOREControl Measure

• Reduce diurnal evaporative emissions from non-handheld equipment by 70% (17.6 TPD)

• Reduce diurnal evaporative emissions fromhandheld equipment by 40% (1.5 TPD)

• Use readily available technology to reduceemissions

• Allow flexible certification requirements to reduceburden on industry

Status of the Regulatory Effort

• Identified evaporative emission processes• Finalizing OFFROAD emissions inventory• Developed evaporative emission test procedures• Quantified SORE evaporative emissions• Performed emission reduction testing• Developing draft regulatory language

Evaporative Emission Processes

• Running Loss Emissions– Evaporative emissions that occur during equipment

operation• Hot Soak Emissions

– Evaporative emissions that result from latent heat– Typically generated for a one-hour period after equipment

operation• Diurnal Emissions

– Evaporative emissions that result from daily temperaturevariations

– Includes permeation emissions (fuel line and tank)

Status of Inventory Development

• Contract testing at Automotive Testing Laboratories(ATL) nearly complete

• Will repeat wintertime testing with winter pump fuel(High RVP) to develop temperature correction factor

• Have requested a contract augmentation to performadditional tank replacement testing on handheld andlarge non-handheld equipment

• Performing data reduction to modify current OFFROADemission factors

In-House Evaporative Emissions Testing

• Baseline Emissions– Background diurnal emissions from new equipment– Summertime hot soak and diurnal emissions– Summertime ROG emissions using fuel containing ethanol– Fuel tank vented emissions– Wintertime hot soak and diurnal emissions– Fuel tank permeation emissions

• Emissions Reduction Testing– Walk-behind mowers– Barrier treated HDPE fuel tanks

• Manufactured at least one month prior to testing• Emissions less than 0.1 gram/day

Background Diurnal Emissions from New Equipment

0.014 0.016 0.017

0.026

0.066

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Chainsaw Leaf Blow er String Trimmer Mow er Front Engine Tractor

gram

s HC/

day

• Test fuel - summertime pump (low RVP, ~ 7 PSI)• Temperature profile - (65°F - 105°F - 65 °F)• Emissions below 1.0 gram/day except for leaf blowers

Summertime Diurnal Emissions(Handheld Equipment)

0.356

0.673

1.336

0.715

1.500

0.907

1.779

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Chainsaw Hedge Trimmer Leaf Blow er String Trimmer

gram

s HC

/day

• Test fuel - summertime pump (low RVP, ~ 7 PSI)• Temperature profile - (1-hour @ 95°F)

Summertime Hot Soak Emissions(Handheld Equipment)

0.097

0.066

0.113

0.071

0.163

0.0800.074

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

Chainsaw Hedge Trimmer Leaf Blow er String Trimmer

gram

s HC

/day

• Test fuel - summertime pump (low RVP, ~ 7 PSI)• Temperature profile - (65°F - 105°F - 65 °F)• Average diurnal emissions from new mowers 2.312 grams/day

Summertime Diurnal Emissions(Walk-Behind Mowers)

2.068 2.181 2.256 2.289 2.446 2.450 2.495

4.123

7.064

0

1

2

3

4

5

6

7

8

Law nboy Craftsman Craftsman YardMachine

YardMachine

YardMachine

Honda Murray(Used)

Murray(Used)

gram

s HC

/day

• Test fuel - summertime pump (low RVP, ~ 7 PSI)• Temperature profile - (1-hour @ 95°F)• Average hot soak emissions from new mowers 0.524 grams/day

Summertime Hot Soak Emissions(Walk-Behind Mowers)

0.412

0.580 0.546

0.406

0.614 0.632

0.475

0.699

0.528

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Law nboy Craftsman Craftsman YardMachine

YardMachine

YardMachine

Honda Murray(Used)

Murray(Used)

gram

s HC

/day

• Test fuel - summertime pump (low RVP, ~ 7 PSI)• Temperature profile - (65°F - 105°F - 65 °F)• Large (> 0.5 gal) vented fuel tanks are a major source of emissions

Summertime Diurnal Emissions(Other Non-handheld Equipment)

7.3925.949

1.204

4.123

15.045

7.142

1.846

13.015

0

2

4

6

8

10

12

14

16

Generator Front Engine Tractor Edger Tiller

gram

s HC

/day

Diurnal Emissions from Passively Vented HDPE Off-Road Equipment Fuel Tanks

Grams Hydrocarbons = 2.9579*(Vapor Volume)

Grams Hydrocarbons = 2.3392*(Vapor Volume)

0

2

4

6

8

10

12

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Vapor Volume (gallons)

Tota

l Hyd

roca

rbon

s (g

ram

s)

Total Hydrocarbons (grams) Reddy Equation Estimate

• Test fuel - summertime pump (low RVP, ~ 7 PSI)• Temperature profile - (48.5°F - 69.5°F)• Emissions significantly lower

Wintertime Diurnal Emissions

3.573

2.239

0.8950.526 0.322

0

0.5

1

1.5

2

2.5

3

3.5

4

Generator Front Engine Tractor Mow er Leaf Blow er String Trimmer

gram

s HC/

day

Fuel Tank Permeation Emissions(Untreated HDPE Tanks)

• Tanks soaked for 30 Days• Certification fuel used for testing• Subjected to multiple diurnal profiles• Permeation result is the average daily weight loss divided by the

internal surface area• Thick Walled Tanks (> 0.125”)

– Avg. handheld permeation rate (6.39 grams/m2/day)– Avg. large non-handheld permeation rate (5.92 grams/m2/day)

• Thin Walled Tanks (< 0.125”)– Avg. small non-handheld permeation rate (10.60 grams/m2/day)

Fuel Tank Permeation Emissions(Fluorinated HDPE Tanks)

• 19 Tanks treated to level 5 fluorination• Tanks soaked for 30 days• Certification fuel used for testing• Subjected to multiple diurnal profiles• Permeation result is the average daily weight loss divided by the

internal surface area– Avg. permeation rate ~ 0.84 grams/m2/day– 92% Level of reduction

• Results for Typical HDPE Mower Tanks• 92% Level of reduction

Comparison of Untreated and Fluorinated HDPE Tanks

9.77 9.40

10.83

14.32

0.71 0.38 0.08 0.38

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

Tecumseh (0.25 gal) Tecumseh (0.375 gal) B&S (0.25 gal) Honda (0.29 gal)

gram

s HC

/squa

re m

eter

/day

Untreated

Treated

Emission Reduction Testing Summary forWalk-Behind Mowers (WBMs)

• Three pairs of popular mower engines tested (B&SIntek, Tecumseh Magna Torque, Honda GCV 160)

• Measured hot soak and diurnal emissions in SHED• Summer pump fuel used for testing• Equipment tested in four phases

– Baseline with no controls, phase I– With fluorinated tank, phase II– With fluorinated tank and PermBlok fuel line, phase III– With fluorinated tank, PermBlok fuel line, and controlled

venting mechanism, phase IV

Phase IV Configured Honda Mower

Mower Evaporative Emission Reduction Results(24-Hour Diurnal)

2.85

2.58

3.26

3.54

2.54 2.51

1.491.40

1.95 2.00

1.551.70

1.11 1.15

1.83 1.83

1.18

1.54

0.640.81

1.02 0.940.84 0.88

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

B&S #1 B&S #2 Tecumseh #1 Tecumseh #2 Honda #1 Honda #2

Gra

ms

HC

No ControlFluorinated Tank

Fluorinated Tank + PermBlok Fuel LineFluorinated Tank + PermBlok Fuel Line + Controlled Venting

Proposed1.0 Gram DiurnalStandard

Mower Evaporative Emission Reduction Results(1-Hour Hot Soak)

0.52

0.670.70

0.75

0.47

0.390.41

0.33

0.59

0.73

0.32

0.370.36

0.31

0.49

0.55

0.25

0.35

0.170.15 0.15

0.170.14

0.11

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

B&S #1 B&S #2 Tecumseh #1 Tecumseh #2 Honda #1 Honda #2

Gra

ms

HC

No ControlFluorinated TankFluorinated Tank + PermBlok Fuel LineFluorinated Tank + PermBlok Fuel Line + Controlled Venting

Distribution of Uncontrolled Evaporative Emissions from WBM(Average of 2.879 grams HC per 24-hour Diurnal Test)

1.198

0.242

0.589

0.850

Fuel Tank Permeation (42%)Fuel Line Permeation (8%)Fuel Tank Venting (20%)Cabuertor Venting (30%)

**

** Remaining emissions attributed to carburetor

Previously Proposed Diurnal Standard for WBMs

• Maximum allowable diurnal emissions– (1.0 grams HC/day)

• Result must be obtained with a 40 CFR Part 86compliant SHED

• Temperature profile - (65°F - 105°F - 65 °F)• Test fuel - California certification fuel• Fill level - tank will be tested at a 50% Fill Level• Diurnal test must be performed after a 1-hour hot soak

test and subsequent 2-hour cold soak at 65 °F

New Proposal

• Design-Based Standard– Requires no SHED testing by manufacturers– Manufacturers not held to a specific numerical standard– Certification protocol to be developed– ARB performs in-use testing

• Design Standards would apply to all non-handheldportable equipment

Example of Design Requirements forWBMs

• Certify by design– Use or specify a fuel tank that is automatically sealed when

equipment is stored– Use or specify a fuel tank that meets a prescribed level of

treatment– Use or specify a SAE 2260 category 1 low permeation fuel

line– Use or specify a tethered fuel cap

Our Estimated Costs of EvaporativeControls

• Cost to Comply with the Permeation Standard ($2.00- $3.00 per tank)

• Cost to Comply with the Design-Based Standard($15.00 per unit)– Controlled venting mechanism - ($7.00 - $10.00)– Low permeation fuel line ($2.00)– Compliant fuel tank ($2.00 - $3.00)

• We Request Industry Estimates of the Cost toProduce Equipment that Meets the Proposed Design-Based Requirements

SORE Emissions Inventory andAnticipated Reductions

Estimated 2020 Population

2356902

3263808

1583165

0

500000

1000000

1500000

2000000

2500000

3000000

3500000

Handheld Equipment Walk-Behind Mowers Non-Handheld Equipment (ExcludingWBMs)

Est. 2020 Population

SORE Emissions Inventory andAnticipated Reductions Cont.

Estimated 2020 SORE Emissions TPD

3.7

23.4 23.3

2.2

5.87.0

0.0

5.0

10.0

15.0

20.0

25.0

Handheld Equipment Walk-Behind Mowers Non-Handheld Equipment (ExcludingWBMs)

Est. Uncontrolled EmissionsEst. Controlled Emissions

Estimated 2020 Benefit TPD

1.5

17.616.3

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

Handheld Equipment Walk-Behind Mowers Non-Handheld Equipment (ExcludingWBMs)

Est. Benefit TPD

Next Steps

• Conduct Additional Testing– Emission reduction testing with fuel containing ethanol– testing to ascertain barrier durability– Evaporative emission testing with catalysts– Development of wintertime correction factor for the

OFFROAD model• Develop Certification Procedures and Alternatives• Develop Control Measure Cost Estimate• Draft Proposed Regulatory Language and Staff

Report

Current Schedule

Event or Task Target Date

Additional Testing June, 2002

Draft Regulatory Language July, 2002

Third Workshop September, 2002

Board Consideration December, 2002

Contacts and Additional InformationEvaporative Emissions InformationGeorge Lew (916) 327-0900 glew@arb.ca.govDean Bloudoff (916) 323-1169 dbloudof@arb.ca.govJames Watson (916) 327-1282 jwatson@arb.ca.govFax (916) 322-2444

Emissions Inventory InformationMark Carlock (626) 575-6608 mcarlock@arb.ca.govArchana Agrawal (626) 450-6136 aagrawal@arb.ca.govWalter Wong (626) 450-6184 wwong@arb.ca.gov

OREFT WEB Page URLhttp://www.arb.ca.gov/msprog/offroad/sore/sore.htm

Conceptual WBM CertificationScenario

EngineManf.

Fuel TankManf.

Fuel LineOEM

Certifies VentingMechanism

CertifiesTank @ Level 5

Certifies use ofLow Perm Fuel Line

OEM IntegratorSubmits OneCertificationApplication

Fuel TankTreatment

Facility

ARB Approves Design