Similar International Standards
ISO 4064-1:2014ISO (International Organization for Standardization)
HighCurrent
Water meters for cold potable water and hot water — Part 1: Metrological and technical requirements
IS 6784:2016 is based on an earlier version (2005) of this foundational global standard for water meters.
OIML R 49-1:2013OIML (International Organization of Legal Metrology)
HighCurrent
Water meters intended for the metering of cold potable water and hot water. Part 1: Metrological and technical requirements
Harmonized with ISO 4064, this provides the international recommendation for legal metrology of water meters.
EN ISO 4064-1:2017CEN (European Committee for Standardization), Europe
HighCurrent
Water meters for cold potable water and hot water - Part 1: Metrological and technical requirements
The direct European adoption of the ISO standard, making it the mandatory reference for water meters in the EU.
AWWA C708-15AWWA (American Water Works Association), USA
MediumCurrent
Cold-Water Meters—Multijet Type
Specifically covers multi-jet meters, but uses different accuracy classifications, test protocols, and units (US customary).
Key Differences
≠IS 6784 uses an older metrological classification system (Class A, Class B) based on flow rates Qmin, Qt, Qn, and Qmax, derived from ISO 4064:2005. Modern international standards like ISO 4064:2014 use a flowrate ratio 'R' (Q3/Q1), offering more flexible and granular accuracy classes (e.g., R100, R160, R250).
≠The specification for pressure loss differs. IS 6784 specifies a maximum loss of 0.025 MPa (0.25 bar) at the nominal flow rate (Qn). ISO 4064:2014 defines pressure loss classes (e.g., Δp 63) indicating a maximum loss of 63 kPa (0.63 bar) at the permanent flow rate (Q3), which is a different reference flow rate.
≠IS 6784 specifies a single maximum working temperature of 45 °C. ISO 4064 formally defines temperature classes, such as T30 (for water up to 30 °C) and T50 (for water up to 50 °C), allowing manufacturers to certify meters for specific temperature ranges. The IS 6784 requirement falls within the T50 class but does not use this nomenclature.
≠While both standards have requirements against magnetic interference, modern ISO/OIML standards include more detailed and rigorous tests for immunity to both static and alternating (50/60 Hz) magnetic fields, reflecting the increased prevalence of strong magnets (e.g., neodymium).
Key Similarities
≈Both IS 6784 and its international counterparts define the same Maximum Permissible Error (MPE) limits: ±5% in the lower flow zone (from Qmin to Qt) and ±2% in the upper flow zone (from Qt to Qmax/Q4).
≈The fundamental constructional requirements are aligned, specifying features like a dry-dial indicating device, a protective sealed register, tamper-evident features, and a durable, corrosion-resistant body.
≈The requirement for pressure tightness is consistent. Both standards mandate that the meter body must withstand a high static hydraulic pressure (typically 1.6 MPa or 16 bar) for a specified duration without any leakage or damage.
≈All standards mandate clear and permanent markings on the meter, including nominal size (DN), direction of flow, manufacturer's name, serial number, and the metrological class/ratio, ensuring proper identification and installation.