The Ministry of Consumer Affairs, Food and Public Distribution has introduced the Legal Metrology (General) Sixth Amendment Rules, 2025, which will come into force on 1 April 2026. This amendment inserts PART XIII: EVIDENTIAL BREATH ANALYSER into the Eighth Schedule of the Legal Metrology (General) Rules, 2011, establishing comprehensive metrological and technical specifications for these instruments.
The new part of the rules specifies requirements for Evidential Breath Analysers (EBAs)—quantitative instruments used to measure alcohol concentration in exhaled human breath for compliance and public safety purposes.
I. Instrument Scope and Features
EBAs are classified as “evidential” instruments, meaning they are the principal means for obtaining a definitive breath alcohol measurement.
Key mandatory features for breath analysers include:
- Prohibiting the display or reporting of results that do not represent the final measurement result.
- Mandating the inclusion of a printing device.
- Prohibiting operation when no paper is detected in the printing device.
- Requiring further printed information in addition to the final measurement result.
- Requiring final measurement results to be displayed and reported in terms other than the alcohol content in exhaled human breath (e.g., physiological conditions such as percentage of blood or other quantities).
EBAs are categorized by their use case:
- Stationary EBA (Use-case 1): Intended for use in a fixed location with stable environmental conditions.
- Transportable EBA (Use-case 2): Easily transportable for mobile applications (e.g., in vehicles).
- Portable EBA (Use-case 3): Handheld devices powered by battery, intended for outdoor use.
II. Metrological Requirements
The rules set strict limits for the performance and accuracy of EBAs:
Measuring Range must be from 0.00 mg/L to at least 2.00 mg/L. The instrument must indicate when its upper limit is exceeded.
Scale Interval for displaying the final result in the measuring mode is 0.01 mg/L. In the metrological test mode, the EBA must display the result with a scale interval of 0.001 mg/L.
Masking Function is required to indicate 0.00 mg/L for measured mass concentrations equal to or less than a given low value. This must be deactivated in the metrological test mode.
Maximum Permissible Errors (MPE)
The MPE standards differ based on the instrument’s status:
| Status | Alcohol Concentration Reference Values | MPE (Positive or Negative) |
| Type Approval & Initial Verification | 0.000 mg/L – 0.400 mg/L | 0.020 mg/L |
| > 0.400 mg/L – 2.000 mg/L | 5% of the reference value | |
| Re-verification & In Service | 0.000 mg/L – 0.400 mg/L | 0.030 mg/L |
| > 0.400 mg/L – 2.000 mg/L | 7.5% of the reference value |
- The experimental standard deviation must be less than or equal to one-third of the MPE.
- The absolute value of long-term drift (determined over six months) must not exceed 0.020 mg/L.
- The memory effect from previous samples must not exceed pm 0.010 mg/L.
III. Technical and Operational Requirements
Protection Against Fraud and Software Integrity
Access to the metrological test mode must be restricted. It must be impossible to make adjustments without breaking the sealing.
The software must be unambiguously identified by its version number and a hash function/checksum, and this identification must be inextricably linked to the software itself. The software must be secured against unauthorized modification or loading.
When powered on, the EBA must automatically check its correct operation. If a defect is detected, the instrument must display an error message and prevent further measurement. A detected significant defect must be registered in an error log.
Exhalation Conditions
For a representative measurement, the EBA must provide an error message if the following manufacturer-specified conditions are not fulfilled:
- Exhaled Volume: Greater than or equal to 1.2 L.
- Flowrate: Greater than or equal to 0.1 L/s.
- Exhalation Time: Greater than or equal to 3 seconds.
Alcohol in the Upper Respiratory Tract
The EBA must be equipped with a function to automatically detect whether the measurement result is affected by the presence of residual mouth alcohol (alcohol in the upper respiratory tract). The technical documentation must clearly describe the method applied. The Annexure B provides details on test procedures like the Peak Method and the Two-measurement Cycle to test this detection capability.
IV. Verification and Testing
The rules mandate comprehensive testing for both initial verification and re-verification, ensuring the instrument conforms to the approved type and remains accurate.
- Initial Verification: Verifies that the EBA is correctly adjusted and conforms to the approved type. It requires a metrological examination including accuracy tests at a minimum of three concentrations with at least 3 repetitions at each concentration.
- Re-verification: Applies to an EBA after a previous verification (including mandatory periodic verification and verification after repair).
- Procedures: Testing is subject to strict reference conditions (e.g., ambient temperature 23C +/- 5C, relative humidity 50% +/- 30%). The tests cover accuracy, repeatability, drift, memory effects, and immunity to various disturbances (electromagnetic fields, electrostatic discharge, temperature, pressure, vibration, etc.).