EXPLANATORY STATEMENT
Issued by the authority of the Chief Metrologist
National Measurement Act 1960
National Measurement (Recognized-Value Standard of Measurement of Acceleration due to Gravity – Lindfield, NSW) Determination 2026
Purpose and Operation
The purpose of the National Measurement (Recognized-Value Standard of Measurement of Acceleration due to Gravity – Lindfield, NSW) Determination 2026 (the determination) is to legally define the magnitude of the acceleration in a vacuum of a body due to the gravitational attraction of the earth to support legally traceable measurements that depend on the value of that physical quantity.
The National Measurement Act 1960 - para 8A(1)(a) - Determination by the National Standards Commission - Recognized-Value Standard of Measurement of Acceleration Due to Gravity, made by the Chief Metrologist, dated 21 March 1985 (1985 determination), is repealed in the determination pursuant to subsection 8A(2) of the National Measurement Act 1960 (Cth) (the Act).
The position of Chief Metrologist is established, and the functions of the Chief Metrologist identified, in section 18A of the Act. Subsection 8A(1) of the Act gives the Chief Metrologist the power to determine that magnitudes of physical quantities specified in the determination and magnitudes of physical quantities as ascertained in accordance with a formula set out in the determination shall be recognized-value standards of measurement.
Subsection 8A(4) of the Act provides that a recognized-value standard of measurement is not subject to verification. This means that the magnitude of the physical quantity of the recognized-value standard is deemed to be that which is determined by the Chief Metrologist. A recognized-value standard of measurement is not determined by reference to, comparison with, or derivation from another standard of measurement.
This determination updates the previous determination made in 1985 to reflect changes to the magnitude of the acceleration in a vacuum of a body due to the gravitational attraction of the earth at a particular location in Australia.
In particular, this determination specifies the magnitude of the acceleration in a vacuum of a body due to the gravitational attraction of the earth at Absolute Gravity Station 200498.9905 in room C269 of the National Measurement Institute, 36 Bradfield Road, West Lindfield, NSW, is a Recognized-Value Standard of Measurement having a value of 9.7963779533 m·s-2 with an expanded uncertainty of 106 ×10-9 m·s-2. This value represents the most up to date measurement of the physical quantity at the specified location.
The determination will support applications including, the calibration and certification of force measurement systems and the production of certified reference materials.
The costs associated with incorporating the revised values of gravity into the operations of users of precise legally traceable measurement of gravity are minimal, and form part of the normal cost of maintaining up-to-date capabilities for these stakeholders.
Further details of the determination are outlined in Attachment A.
Authority
The determination is made by the Chief Metrologist, National Measurement Institute, under paragraph 8A(1)(a) of the Act. The determination is a legislative instrument for the purposes of section 8 of the Legislation Act 2003 (Cth).
Consultation
The National Measurement Institute undertook a public consultation from 24 November to 24 December 2025 to inform the remaking of the 2026 determination. The consultation was targeted towards stakeholders who currently reference the 1985 determination, including government agencies, measurement laboratories, and industry bodies. Three submissions were received, each of which supported the proposed changes to the instrument.
Statement of Compatibility with Human Rights
A Statement of Compatibility with Human Rights is set out at Attachment B.
Attachment A
Details of the National Measurement (Recognized-Value Standard of Measurement of Acceleration due to Gravity – Lindfield NSW)
Section 1—Name
This section provides that the name of the determination is the National Measurement (Recognized-Value Standard of Measurement of Acceleration due to Gravity – Lindfield, NSW) Determination 2026.
Section 2—Commencement
This section provides that the determination commences the day after registration.
Section 3—Authority
This section provides that the authority for the making of the determination is paragraph 8A(1)(a) of the National Measurement Act 1960 (the Act).
Section 4— Schedules
This section is a machinery provision that gives effect to the provisions in the Schedules to the determination.
Section 5— Definitions
This section sets out the terms referred to in the determination as follows:
Act means the National Measurement Act 1960.
The legislative note makes clear that ‘Recognized-value standard of measurement has the same meaning as in the Act.
Section 6—Recognized-Value Standard of Measurement of Acceleration due to Gravity
This section specifies the recognized-value standard of measurement of acceleration in a vacuum of a body due to the gravitational attraction of the earth as having a value of 9.7963779533 m·s-2 with an expanded uncertainty of 106 ×10-9 m·s-2.
This standard of measurement is calculated at the benchmark inscribed as “Absolute Gravity Station 200498.9905, Sydney, Commonwealth of Australia”, which is located in room C269 of the National Measurement Institute, 36 Bradfield Road, West Lindfield, NSW.
The legislative note clarifies that the expanded uncertainty is based on a standard uncertainty multiplied by a coverage factor of k=2, which provides a confidence level of 95%.
Schedule 1—Repeals
Item 1 repeals the National Measurement Act 1960 - para 8A(1)(a) - Determination by the National Standards Commission - Recognized-Value Standard of Measurement of Acceleration Due to Gravity (FLRI Ref: F2009B00176).
Attachment B
Statement of Compatibility with Human Rights
Prepared in accordance with Part 3 of the Human Rights (Parliamentary Scrutiny) Act 2011
National Measurement (Recognized-Value Standard of Measurement of Acceleration due to Gravity – Lindfield, NSW) Determination 2026
This Legislative Instrument is compatible with the human rights and freedoms recognised or declared in the international instruments listed in section 3 of the Human Rights (Parliamentary Scrutiny) Act 2011.
Overview of the Legislative Instrument
The National Measurement (Recognized-Value Standard of Measurement of Acceleration due to Gravity – Lindfield, NSW) Determination 2026 supports the national measurement system by formalising the values of absolute and relative gravity at the National Measurement Institute, 36 Bradfield Road, West Lindfield, NSW. This determination updates the previous determination made in 1985 to reflect changes to the magnitude of the acceleration in a vacuum of a body due to the gravitational attraction of the earth at a particular location in Australia with the most up to date measurement of the physical quantity at the specified location.
Human rights implications
This Legislative Instrument does not engage any of the applicable rights or freedoms.
Conclusion
This Legislative Instrument is compatible with human rights as it does not raise any human rights issues.
Dr Victoria Anne Coleman
Chief Metrologist