JJG 99-2022
Weights (English Version)

Standard No.

JJG 99-2022

Language

Chinese, Available in English version

Release Date

2022

Published By

National Metrological Verification Regulations of the People's Republic of China

Latest

JJG 99-2022

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Introduction

Interpretation of the core content of the regulations

Technical elements	JJG 99-2022	JJG 99-2006	Main changes
Definition of terms	Clarify that "agreed mass" replaces "converted mass"	Use the concept of converted mass	Align with the international recommendation OIML R111-1:2004
Magnetic requirements	Newly added Gauss meter method to measure polarization intensity	Specific method not specified	Strengthening magnetic control (Table 3/4)
Density detection	6 measurement methods (including acoustic volume method)	4 traditional methods	Method 4 is suitable for weights with adjustment cavity

Key implementation points

Agreed quality verification process

1. Environmental control: E1 level requires temperature fluctuation ≤0.5℃/4h (Table 9)
2. Magnetic screening: Polarization intensity ≤2.5μT (E1 level)
3. Density verification: 8,000kg/m³ benchmark value (Formula 5)
4. Mass comparison: ABBA cycles ≥ 3 times (Table 17)

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Technical evolution analysis

Air buoyancy correction: The CIPM-2007 formula (Appendix D) is used to replace the original CIPM-81/91 formula. Correction is required for altitudes above 330m (6.5.2.2)

Uncertainty calculation: A new magnetic susceptibility contribution component is added (Appendix C.4.5), requiring U≤|MPE|/3 (5.2)

Verification result processing

Weight grade	Certificate content	Period (year)
E1	Correction value + actual volume value	2 (milligram group)
M1	Maximum allowable error	1

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Solutions to common problems

Problem 1: Density measurement of weights with adjustment cavity
Solution: Preferentially use the acoustic volume method (7.3.4.5) to avoid liquid penetration

Problem 2: Abnormal value of ABBA cycle
Solution: Calculate max(Δm)-min(Δm)/2√3 according to formula (C.2)

JJG 99-2022 Referenced Document

• JJF 1001 General Terms in Metrology and Their Definitions
• JJF 1059.1 Evaluation and Expression of Uncertainty in Measurement
• JJF 1094 T.S. for Evaluation of the Characteristics of Measuring Instruments*， 2025-05-03 Update

JJG 99-2022 history

• 2022 JJG 99-2022 Weights
• 2006 JJG 99-2006 Weights Regulation of weights
• 1990 JJG 99-1990 Verification Regulation of Weights

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