# Presentation: 552825

## LPG Liquid-Measuring DevicesPart 5:  Test

- NIST Weights and Measures Division
- LPG Short Course
- May 2005

## LPG Meter Test - Overview

- Describe procedures for conducting performance tests specified in the EPOs
- Understand the purpose of testing the performance of LPG liquid-measuring systems
- Analyze and interpret test results

## Normal Test (“Fast Test”)

- Conducted at maximum discharge flow rate developed under the conditions of installation
- Maximum discharge rate of installation can’t exceed _rated_ maximum discharge rate
- Tests at flow rates down to and including one-half the sum of the maximum discharge flow rate and rated minimum discharge flow rate are “normal” tests
- Example:
- Max Installation Flow Rate = 60 gal per min
- _Rated_ Min Flow Rate  =   20 gal per min
- Breakpoint  (60 + 20)/2 = 40 gal per min
- Handbook 44 References:  N.4.1.

## Special Test (“Slow Test”)

- Conducted to develop operating characteristics of the device & any accessories
- Examines meter performance at slower flow rates
- Coupled with results of normal test, *provides an indication of meter condition*
- Includes any test other than that in N.4.1.
- Always conducted with automatic temperature compensator _deactivated_
- Regulate flow by manipulating prover inlet valve
- Handbook 44 References:  N.4.2.

## Repeatability (N.4.1.2., T.3.)

- Tests conducted at approximately same rate & draft size
- All other conditions of the test are the same
- Minimum of three consecutive drafts
- The range of tests (spread) shall not exceed 40 percent of the absolute value of the maintenance tolerance.
- For example, on 100-gal test draft:
- 0.40 x 231 cu in = 92.4 cu in
- Each individual test must be within applicable tolerance

## Test Draft Size (N.3.)

- Test draft size must be equal to the amount delivered by the device in one minute at its normal discharge rate.

## Testing - Overview

- Wet prover once for each meter tested
- Accuracy tests include at least 3 test drafts:
- 2 Normal Tests (at maximum flow rate)
- 1 with ATC activated
- 1 with ATC deactivated
- 1 Special Test (at a flow rate at or near minimum flow rate marked on device)
- ATC deactivated
- Repeatability Tests for any result close to or outside of tolerance

## Nontemperature-Compensated Meters

- First Run:
- Normal Test, Full Flow
- Record temperature at meter at 1/3 and 2/3 prover capacity
- Normal tolerance applies
- Second Run:
- Normal Test, Full Flow (Repeated)
- Record temperature at meter at 1/3 and 2/3 prover capacity
- Normal tolerance applies
- Third Run:
- Special Test, Slow Flow
- Special tolerance applies

## Temperature-Compensated Meters

- First Run:
- Normal Test, Full Flow
- Normal tolerance applies
- Second Run:
- Normal Test, Full Flow – ATC _Deactivated_
- Normal tolerance applies
- _Difference_ between 1st and 2nd run cannot exceed ATC Tolerance (T.4.)
- Third Run:
- Special Test, Slow Flow – ATC _Deactivated_
- Special tolerance applies

## Information Recordedat the End of the First Draft

- actual discharge rate
- temperature of product at meter at 1/3 and 2/3 prover capacity (will be 60 °F for ATC runs)
- temperature of prover immediately after delivery
- pressure in metering system tank and in prover immediately after delivery
- prover reading, nearest 0.05 gal
- register reading to nearest 1/10 of quantity interval (e.g., 0.1 gallon if in whole gallons; 0.01 gallon if in 0.1 gallons)

## Three Corrections to Make

- 1) Product Temperature
- 2) Prover Pressure
- 3) Prover Temperature

## #1:  Correction for Product Temperature

- For change in product volume between meter and prover due to temperature differential
- _Compensated_ (ATC-activated) drafts:
- Use Table 4 (ASTM Table 24) to correct prover volume to 60 °F
- _Uncompensated_ drafts:
- Use Table 2 to correct for difference between prover & meter

## #2:  Correction for Prover Pressure

- For expansion/contraction of prover caused by pressure
- Use table prepared when prover was calibrated (Table 1)

## #3:  Correction for Prover Temperature

- For thermal expansion/contraction of prover caused by temperature
- If low-carbon steel, use Table 3
- If prover is of different material, use a table with appropriate values or use coefficient of expansion marked on prover

## Concluding the Test

- have operator reactivate ATC
- seal meter
- disconnect prover
- if no more tests at this location, bleed hoses
- after meter and prover are secure, proceed to “Post-Test Tasks”

## Typical meter performance curve

## Meter Performance Curves

- curve “a” is a new or recently adjusted meter
- curve “b” is a meter that is out of tolerance, but that can be adjusted
- curve “c” is a badly worn meter
- simply readjusting will not correct
- readjusting meter may bring the meter within tolerance, but.....recall G-UR.4.1.

## G-UR.4.1. Maintenance of Equipment

- Equipment must be maintained in proper operating condition
- Equipment in service at a single place of business found to be in error predominantly in a direction favorable to the device user shall not be considered “maintained in a proper operating condition.”

## Badly Worn Meter

## General Post-Test Tasks

- Install security seals on equipment as appropriate
- Record audit trail information, if equipped
- Record final totalizer readings
- Evaluate results
- Determine appropriate compliance action
- Notify owner/operator
- Mark device to indicate disposition
- Complete & submit report form and other paperwork

## Security Means

- Check for/apply physical security seal to meter & temperature compensator (G-UR.4.5., S.2.2., S.2.6.2.)
- e.g., lead-and-wire, plastic wire, etc.
- Record audit trail information, if device is equipped (G-S.8.)
- Record event counter information
- Review event logger, if equipped
- Retain information and compare it with audit trail information on future inspections

## Test - Overview

- Wet prover
- Normal Test
- Run 2 normal tests
- Special Test
- Repeatability Test
- Corrections
- Product temperature
- Prover pressure
- Prover temperature
- Evaluate results
- Post test tasks