NMMA Testing

All testing conducted in 2005

Canister Efficiency Testing

The mass of hydrocarbons that the test canister holds divided by the total amount of hydrocarbons sent to the test and slave canister times 100.

Formula used to determine canister efficiency

The marine canister must demonstrate a minimum of 50% efficiency when tested per the following procedure:

1. Use nominal carbon BWC (e.g. 9.2 BWC - 9.3 BWC), nominal carbon fill, nominal canister housing.
2. Stabilize the canister by loading to a 2 gram breakthrough with a 50/50 mixture of butane/nitrogen for a minimum of 10 cycles. The load rate shall be 15 grams/hour followed by a 100 bed volume purge at 22.7L/min.
3. Weight test canister and a purged slave canister which is used to measure test canister breakthrough amount.
4. Connect test canister vapor inlet tube to fuel tank or proper volume for canister size (1 liter of canister volume for every 25 gallon of fuel tank volume). Fuel tank should be 40% full of 9 RVP test fuel.
5. Connect air inlet of test canister to a purged slave canister.
6. Place fuel tank, test canister, and slave canister inside a variable temperature camber.
7. Temperature cycle the chamber from 72-96-72°F per the EPA diurnal temperature profile.
8. Measure the weight gain of the test canister and the slave canister after the chamber has been heating for 12 hours.
9. Disconnect the slave canister from the test canister for the cool down portion of the diurnal. This allows the test canister to be passively purged by the fuel tank. Purge the slave canister for 300 bed volumes at 22.7 L/min. to prepare it for the next day. Re-weigh the slave canister after purge.
10. Repeat steps 4 through 8 for a total of 5 days.
11. Calculate test canister efficiency for the 5th day.

Testing Results

• The canister at the end of testing has met the EPA minimum efficency requirement of 50%.
• Refueling rates were not affected.