EN ISO 4064-4:2025 PDF

Overview

EN ISO 4064-4:2025 (identical to ISO 4064-4:2024) defines the non‑metrological requirements for water meters used to measure the volume of cold potable water and hot water in fully charged, closed conduits. It complements ISO 4064‑1 by addressing technical characteristics, pressure‑loss criteria, connection interfaces and dimensional requirements for in‑line, concentric and cartridge meters, including meters with electronic or hybrid (mechanical + electronic) designs.

Key topics and requirements

• Scope: Applies to water meters that indicate integrated volume and can withstand specified pressures and temperatures.
• Pressure and temperature limits:
  • Maximum admissible pressure (MAP): ≥ 1 MPa (10 bar); 0.6 MPa for meters for pipe DNs ≥ 500 mm.
  • Maximum admissible temperature (MAT): cold potable meters - 30 °C; hot water meters - up to 180 °C depending on class.
• Meter types covered: Mechanical, electrical/electronic, and hybrid meters; electronic ancillary devices are also covered (generally optional unless required by regulations).
• Dimensional and connection requirements:
  • Meter size defined by thread size or flange nominal size.
  • Threaded connections to conform with ISO 228‑1.
  • Flanged connections to conform with ISO 7005‑2 / ISO 7005‑3.
  • Detailed overall dimensions, clearances and tolerances are specified (see tables and figures).
• Design variants: Rules for in‑line meters, concentric/cartridge meters and exchangeable metrological modules with guidance on manifolds, interfaces and adaptors (informative annexes cover practical connection solutions).
• Pressure‑loss and technical characteristics: Specifies acceptable pressure‑loss performance and technical characteristics relevant to safe installation and operation.

Applications and who uses this standard

• Meter manufacturers: design, dimensioning and certification of cold and hot water meters (mechanical, electronic, hybrid).
• Water utilities and suppliers: procurement specifications, compatibility checks and selection of meters for distribution systems.
• Installers and system designers: ensure correct flange/thread interfaces, clearances and pressure/temperature class matching.
• Test laboratories and conformity assessors: verify non‑metrological performance, pressure‑loss and mechanical interfaces.
• Regulators and procurement officers: reference for mandatory ancillary devices or national requirements tied to meter utilization.

Related standards

• ISO 4064‑1 / OIML R 49‑1 - metrological and technical requirements (complementary).
• ISO 228‑1 - pipe threads (threaded connections).
• ISO 7005‑2 / ISO 7005‑3 - metallic flanges (cast iron; copper alloy).
• EN ISO 4064‑4:2025 supersedes the 2014 edition and is issued by CEN under the ISO/CEN Vienna Agreement.

This standard is essential when specifying, installing or manufacturing water meters to ensure mechanical integrity, correct interfaces and safe operational limits for both cold potable and hot water applications.