Nebraska RMFD Test Results

1
Nebraska RMFD Test Results

• Variables that Affect the
• Accuracy of Tests

2
Testing Protocol

• 5 Meters at 3 locations for 52 weeks
• Unleaded, E10 and Diesel Fuel
• Conditions monitored
• Barometric pressure
• Ambient Temperature
• Pump Pressures (closed and open nozzle)
• Fuel Temperatures at 5 and 30 Gallons
• Fuel Temperature in the storage tanks

3
Testing Protocol (Continued)

• Three wet-down drafts of 5 gallons recording each
  drafts errors
• Fuel temperature 1st wet-down draft
• Three fast-flow drafts of 5 gallons recording
  each drafts errors
• Fuel temperature 3rd fast-flow draft
• Three slow-flow drafts of 5 gallons recording
  each drafts errors
• Over 2000 tests for five dispensers
• Temperature corrections made for prover capacity

4
Observations

• Product temperature changed with the seasons, as
  expected
• First drafts may not reflect device performance
• Delivery errors appear to change with
  temperature Why?

5
Product Temperature for3rd Fast-Flow Test Draft
(30 gal)
6
(No Transcript)
7
(No Transcript)
8
Norfolk Unleaded Wet-Down and Fast-Flow Tests
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Aurora Unleaded Wet-Down andFast-Flow Tests
10
Omaha Diesel Wet-Down andFast-Flow Tests
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Norfolk Unleaded Test Results
12
Norfolk Unleaded Test Results
Zero
You cannot predict the relationship of the first
wet-down test result to subsequent results.
13
Aurora Unleaded Test Results
Zero
You cannot predict the relationship of the first
wet-down test result to subsequent results.
14
Omaha Diesel Fuel
Zero
You cannot predict the relationship of the first
wet-down test result to subsequent results.
15
Norfolk UnleadedProduct Temperature
Correlation Coefficient 0.836
16
Norfolk UnleadedAir Temperature
Correlation Coefficient 0.837
17
Additional Nebraska Testing

• Tested three dispensers each week from September
  - November 2006
• Used three Seraphin Special J provers and two
  high-sensitivity neck test measures
• Recorded air product temperature, barometric
  pressure and relative humidity
• Test procedure
• Three preliminary tests and then four fast flow
  tests using first prover
• One wet-down test on each of the other standards
• Four fast-flow tests with each of the other
  standards
• Air and product temperature taken for each test
• Approximately 260 tests

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Approximately Equal Air and Product Temperatures
Example
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Warm Air and Cold Product
Example
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Cold Air and Warm Product
Example
21
Analyses Performed

• Single and multiple variable regressions
• Explored relationships for delivery error and
• Air temperature
• Product temperature
• Relative humidity
• Barometric pressure
• Combinations of the variables

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Summary Observations

• Barometric pressure and relative humidity are not
  statistically significant variables
• Correlation coefficients for delivery errors
• Highest and consistent relative to air
  temperature
• Inconsistent and lower relative to product
  temperature
• Lower than air temperature coefficients relative
  to the difference of air and product temperature
• Slope coefficients for product temperature vary
  significantly
• Slope coefficients for air temperature more
  consistent

23
Product Temperature and Delivery Error
Slope coefficients are similar, but not
consistent for all dispensers. Product
temperature is probably not the critical factor.
24
Air Temperature andDelivery Error
Slope coefficients are reasonably consistent for
all dispensers. Air temperature is probably the
critical factor.
25
Conclusions

• Variations in field test results over time are
  primarily due to changes in the product volume
  due to temperature changes from the time the
  product is metered until the product is measured
  in the prover.
• A small amount of the variation may be due to
  changes in meter accuracy with respect to
  temperature.

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Recommendations for Testing

• Conduct one preliminary run on a dispenser to
  stabilize the temperature
• Product may have been sitting in the hose and
  dispenser piping for some time
• Prover or test measure may have been exposed to
  sun, heat or cold
• Run an official test
• If the results are near the tolerance limit, then
  repeat the test.

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Putting Your Inspection Results to Work

• What Do the Data Tell Us?

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Nebraska RMFD Records

• Track inspections by station owner
• Inspection results by manufacturer and model
• Record fast- and slow-flow errors
• Type of action (pass/fail) and violation, if
  applicable

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Pump Inspection Results 2006Fast-Flow Delivery
Errors
Zero
6
-6
281 meters or 1.4 were out of tolerance for
under delivery
237 meters or 1.18 were out of tolerance for
over delivery
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Fast-Flow Errors Manufacturer E
Zero
-6
6
31
Fast-Flow Errors Manufacturer H
Zero
6
-6
32
Fast-Flow Errors Manufacturer J
Zero
-6
6
33
Fast-Flow Errors by Owner
Zero
6
-6
34
Fast-Flow Errors by Owner
Zero
6
-6
35
Compliance Rates by Manufacturer
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Rejection Codes by Manufacturer
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Pump Inspection Results 2006Slow-Flow Delivery
Errors
Zero
6
-6
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Difference in Fast-Flow and Slow-Flow Delivery
Errors for 2006
Zero
6
-6
Examples (Slow-Flow Error) (Fast-Flow
Error) (2 in3) (-2) 4 in3 (1) (-4)
5 in3
40
SF - FF Errors by Owner
Zero
6
-6