NMI Word Document Cover Template (Simple)

NMI Word Document Cover Template (Simple)

Discussion Paper

Density Measurement in the Retail Sale of Liquefied Petroleum Gas

November 2016

Contents

Introduction

The National Measurement Institute

Stakeholder Consultation

Submissions

Background

LPG Dispensers

Temperature Compensation

The National Trade Measurement Regulations 2009

Current Requirement

Alternative Methods

Questions

Next Steps

Introduction

The purpose of this discussion paper is to commence a review of the current requirements relating to the measurement of Liquefied Petroleum Gas (LPG) density when supplied for retail sale. More specifically, this paper is intended to seek stakeholder submissionsregarding current pattern approval requirements for LPG dispensers relating to the measurement of LPG density.

The discussion paper provides an overview of the current requirements and requests stakeholder submissionsregarding possibleamendments and improvements to these requirements. In support of such amendments, the discussion paper also seeks stakeholder proposals regarding innovative or alternative methods for measuring LPG densitywhich would reduce the overall regulatory burden on Australian industrywhilecontinuing to ensure fair and equitable measure in the retail sale of LPG.

NMI welcomes all stakeholder submissions regarding the current requirements for LPG dispensers as they relate to the measurement of LPG density. However, the following requirements are considered to be outside the scope of this discussion paper:

  1. the Accuracy class applicable for LPG dispensers (Class 1); and
  2. the requirement to correct the volume of LPG to 15°C at equilibrium vapour pressure.

The National Measurement Institute

The National Measurement Institute (NMI) is the Commonwealth Government agency responsible for the administration of the national trade measurement system. Key elements of this system are the pattern approval and verification of measuring instruments used for trade, including LPG dispensers.

Stakeholder Consultation

NMI has receivedsubmissions from a number of stakeholders regarding the issue of density measurement in the retail sale of LPG. More specifically,the submissions focused onthe requirement for LPG dispensers to incorporate a means of directly measuring density, thereby allowing for the volume of LPGto be corrected for temperature variations.

NMI is committed to being a responsive, responsible and best-practice regulator. As such, we recognise the importance of reviewing our requirements over time to ensure that they are still achieving the intended objective and are providing an overall benefit to Australian industry and the wider community.

To commence this review,NMI is seeking stakeholder submissions and comments on theappropriateness and effectiveness of the current requirements for LPG dispensersand whether these requirements could be amended to support alternative methods for the measurement or determination of LPG density.

Submissions

We encourage those who have a view on the issues and questions outlined in this discussion paper to make a written submission by Friday 16th December2016.

Submissions can be lodgedusing any of the following methods:

Email:

Website:

Mail:Legal Metrology Policy

National Measurement Institute

PO Box 264, Lindfield NSW 2070 Australia

Submissions received may be made public on the Department of Industry, Innovation and Science website and the NMI website unless otherwise specified. Submissions received may form part of subsequent response papers and project proposals.

Submissions should indicate whether any part of the content should not be publically disclosed.

Background

LPG Dispensers

The retail sale of LPG, particularly as a transport fuel, most commonly occurs via the use of a dedicated LPG dispenser, which incorporates a flow meter, calculator/indicator, temperature probe, density probe, indicating device, hose and other components.

In order to be used for trade in Australia, LPG dispensers are required to be pattern approved, verified and operate with a measurement errorno greater than ±1% of the volume of LPG that is dispensed and sold.

This maximum permissible error (MPE) is specified in the international standard OIML R 117 Dynamic measuring systems for liquids other than water, which is adopted in Australia as the pattern approval standardfor flow metering systems such as LPG dispensers.

In order to ensure thatan LPG dispenser operates within the MPE of ±1%, as required by the international standard, the flow meter is provided an MPE of ±0.6% of the volume dispensed. As such, the remaining operations of the dispenser, which primarily includes the calculation of volumetric corrections based upon measurements oftemperature and density, must be accurate towithin ±0.4% of the volume dispensed.

Temperature Compensation

When LPG is sold at a price based on volume (e.g. cents per litre), it is important that the volume of LPG dispensed is corrected to the equivalent volume at a standard temperature – in this case 15°C. This accounts for the variation of volume with temperature, and ensures fair and equitable trade of LPG across Australia regardless of the temperature of the LPG being sold. The compensation correction depends on the density of the LPG, which varies in turn with the composition of the gas.

The National Trade Measurement Regulations 2009

The National Trade Measurement Regulations 2009 (Cth) require that where LPG is sold by volume, it must be sold by the amount of litres that it would occupy at a temperature of 15°C at equilibrium vapour pressure.

In other words, where LPG is sold by volumethere must be a correctionapplied to the measured volume of LPG (at any temperature) in order to determine the volume the LPGwould occupy at 15°C.

In order to perform this volume correction, measurements of LPG temperature and density shouldbe made. These measurements are used by the calculator/indicator of the dispenser to provide an indication of corrected LPG volume at 15°C. It is this corrected volume that is used for trade purposes.

Current Requirement

In order to satisfy the requirement that LPG be sold at a volume corrected to 15°C, NMI requires that LPG dispensers include a means of directly measuring the temperature and density of the LPG flowing through the dispenser. In the case of LPG density, this may be achieved by the use of a density probe, fitted in the dispenser. Alternatively, dispensers may incorporate a mass-flow meter which measures density as part of the mass-flow measurement process.

Compliance with this requirement is assessed during the pattern approval examination of the design of LPG dispenser. In order to be pattern approved, LPG dispensers are required to incorporate a means of measuring the density and temperature of the LPG being dispensed and sold.

The use of density probes and mass flow meters in LPG dispensers provides for a consistent and effective means of compliance with this requirement.

Thecurrent requirement was formally introduced in 1997 as a result of the adoption of OIML R 117, with exemptions provided for LPG dispensers approved prior to that date. In practice, this means that all LPG dispensers approved after 1997 include a means of measuring LPG density, either via the use of a density probe or a mass-flow meter.

Alternative Methods

NMI isseeking stakeholder input and proposals regardingviablealternative methods of measuring, determiningor accounting for LPG density, other than via direct measurement by a density probe incorporated in the dispenser.

Any viable alternative method would need to ensure that the overall MPE of the dispenser does not exceed ±1%, and that the measurements and calculations required for the temperature correction of LPG volume do not exceed ±0.4%.

NMI is also seeking stakeholder comments regarding whether any viablealternative methods would necessitate amendments to the current requirements in order to be implemented. Finally NMI would welcome stakeholder comments regarding potential costs and benefits that would result from any viablealternative methods.

It is anticipated that any potential innovative or alternative methods would aim to reduce the overall regulatory burden on Australian industry while maintaining fair and equitable measurement in the retail sale of LPG.

Questions

NMI welcomes all stakeholder submissions regarding the current requirement for LPG dispensers to include a means of measuring density as well as proposed alternative methods of measuring or determining density in the retail sale of LPG.

In addition to any general submissions on the topic, NMI encourages stakeholders to provide answers to the following questions:

  1. Should the current requirement to include a means of density measurement (e.g. via a probe)in LPG Dispensers be maintained? If so, why?
  2. What are the current costs and/or savings incurred by your business as a result of this requirement?
  3. What are the current benefits realised by your business as a result of this requirement?
  1. Should the current requirementto include a means of density measurement (e.g. via a probe) in LPG Dispensers be amended? If so, why?
  2. If so, what alternative methods could be developed and implemented to directly measure, determine or otherwise account for LPG density in order to ensure ongoing correct measurein the retail sale of LPG?
  1. What are the costs and/or savings that would be incurred by your businessas a result of such alternative methods?
  2. What are the benefits that would be realised by your businessas a result of such alternative methods?

Note:Any alternative methods would need to ensure the maximum permissible error of the LPG dispenser does not exceed ±1% (as per OIML R 117).

If your company supplies and/or purchases LPG:

  1. How many LPG dispensers do you maintain on your site(s)?
  2. What is the average quantity of LPG that your company supplies and/or purchases per year?
  3. How frequently is LPG delivered to your site(s)?
  4. Does the density of the LPG that you supply and/or purchase vary from delivery to delivery?
  5. Are you able to supply information on the range of LPG densities that your company supplies and/or purchases?

Next Steps

NMI will undertake a thorough review of all submissions received to this discussion paper, and release a response paper. Depending on the nature and content of the submissions received to this discussion paper, subsequent consultation processes may be required in order to complete the review.

NMI willadvise all interested stakeholders of any subsequent consultations if and when they occur.

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