Initial NVFEL Evaporative Emission Test Results from Marine Fuel Tanks n Test Procedures n Baseline Emissions n Pressure Relief Valves n Limited Flow Orifices n Volume Compensating Bag n Insulation n Permeation n Future Testing n Examples of Certification Meeting Between Industry and EPA August 7, 2001

Test Procedures n F (22-36 C) diurnal n highest of 3 days (1 day used here to save time when testing pressure strategies) n measured in SHED n certification fuel n soaking required to stabilize permeation Sealed Housing for Emission Determination 40% fill 9 RVP gasoline

Test Tanks and Baseline Emissions Moeller, blow molded, portable tank, 6 gallon 2.3 g/gal/day* *adjusted from 50% to 40% fill Ezell, aluminum, installed tank, 17 gallon 2.2 g/gal/day Inca, rotationally molded, installed tank, 23 gallon 2.5 g/gal/day Inca, rotationally molded, installed tank, 31 gallon have not tested yet Wade-Reddy Model 2.3 g/gal/day

Pressure Relief Valves n We modified an automotive cap with to allow us to vary the spring tension n Tests performed on aluminum fuel tank to remove the variable of permeation Pressure Relief Evaporative Emission Test Data Aluminum Marine Fuel Tank Pressure Relief Setting [psi] HC [grams/gallon/day]

Limited Flow Orifices n Looked at three orifice sizes –orifice limits rate of vapor leaving tank –this increases the pressure in the tank n 25 micron –peak delta P of 3.1 psi (did not start test at zero psi, so will retest) –0.24 g/gal/day (probably good--appears sonic flow maintained) n 75 micron –peak pressure of 1.6 psi –1.2 g/gal/day

Pressure, Temperature, and HC Traces Temperature Emissions Pressure (1.4 psi peak) Temperature Emissions Pressure (1.6 psi peak)

Volume Compensating Bag n Purpose of bag is to expand and contract to minimize pressure build-up n We tested a 1.5 gallon bag in 6 gallon tank n Peak pressure 0.8 psi n 0.4 g/gal/day (likely permeation) n 3 day test n Tedlar bag We are looking into other bag materials

Insulation n The purpose of the insulation is to minimize the change in temperature the fuel sees through the day n We insulated the flat plastic tank with 3 inches construction foam (R-15) and saw about a 50% reduction in emissions n We are looking into insulation that may be more appropriate for this application n Initial testing on a PWC suggests fuel temperature follows ambient temperature

Permeation n EPA testing –new blow molded tank showed low permeation –new rotationally molded tank showed higher permeation –currently soaking 3 plastic tanks to stabilize permeation rates –looking into impermeable materials/treatments n Other data –1992 data on high-density polyethylene automotive tank 3.0 g/day on a 22 gallon tank (0.14 g/gal/day) –1986 USCG data on 3 rotationally molded tanks at 104 F 18 g/day on a 12 gallon tank (1.5 g/gal/day) 25 g/day on an 18 gallon tank (1.4 g/gal/day) 20 g/day on an 18 gallon tank (1.1 g/gal/day) n Suggests permeation may be significant contributor to evaporative emissions

Future Testing n Collecting more data to better define a correlation between technology combinations and emissions for the purposes of design-based certification n Permeation testing (and materials investigation) n Investigate insulation further n Diurnal and LFO tests on the plastic tanks n Open to other technology options –bladder, floating vapor barrier, others?

Example of Design-Based Certification n NOTE: we are still refining our design criteria and will continue to do so as we collect more data n EXAMPLE –Baseline = 2.2 g/gal/day aluminum tank –If targeting a 50% reduction n COULD USE: –R-15 insulation with LFO to prevent convection –1.5 psi pressure relief valve –possibly R-10 insulation with 1.0 psi pressure relief valve –(with a plastic tank, may need to use non-permeable material or target lower diurnal emissions to offset permeation)

Example of Credits Calculation for ABT n Consider averaging to a 50% reduction from 2.2 –product of ten 100 gallon tanks and five 50 gallon tanks –want to avoid new technology on 50 gallon tanks n Calculating Debits –5 tanks X 60 gallons X ( g/gal/day) = 330 n Need to make up with credits –330 / (10 tanks X 100 gallons) = 0.33 g/gal/day – = 0.77 g/gal/day n If certified 100 gallon tanks to 0.7 g/gal/day –10 tanks X 100 gallons X ( g/gal/day) = 400 –would be able to bank or trade = 70 credits