ISO 4064-5:2025

Overview

ISO 4064-5:2025 - Water meters for cold potable water and hot water: Part 5: Installation requirements - specifies criteria and recommendations for the selection, installation and first operation of water meters used in fully charged, closed conduits. The standard applies to mechanical, electrical/electronic and hybrid water meters (including electromagnetic meters and optional electronic ancillary devices) that indicate integrated volume. It aims to ensure accurate, constant measurement and reliable reading across a range of field conditions while noting that national regulations override where applicable.

Key topics

• Scope and applicability
  • Covers cold potable water and hot water meters, irrespective of measuring technology.
  • Applies to single, combination and concentric meters and associated ancillary devices.
• Selection criteria
  • Factors manufacturers and users must consider: available supply pressure, water temperature and quality (suspended particles), acceptable pressure loss, expected flow rates (Qmin, Qn, Qmax), ambient mechanical/electrical/climatic conditions, space and pipework, power and data transmission availability.
• Associated fittings and layout
  • Upstream and downstream fitting requirements to preserve metrological performance (filters, straight pipe runs, isolation valves, etc.).
• Installation requirements
  • General siting, orientation, protection, and access for reading and maintenance.
  • Special guidance for electromagnetic meters and meters operating in parallel or groups to avoid interactions that affect accuracy.
• Hydraulic disturbances
  • Identification of common disturbances (surges, turbulence) and recommended methods to mitigate them.
• First operation and commissioning
  • Procedures and protections for new or repaired meters during first operation; includes guidance on frost protection, reverse flow prevention, anti-fraud measures, cartridge meters and exchangeable metrological modules.
• Safety and access
  • Personnel safety, manhole installations, requirements for larger diameters (pipes > DN 40), and electrical-hazard protections.

Practical applications and users

ISO 4064-5:2025 is used by:

• Water meter manufacturers (to provide correct installation guidance and product information)
• Utilities and water authorities (to specify procurement and installation best practice)
• Installers and plumbing engineers (for siting, fitting and commissioning)
• Test laboratories and metrology bodies (to assess installation-related influences on accuracy)
• Regulators and consultants (to reference national compliance and safety requirements)

Related standards

• ISO 4064-1 / OIML R 49-1 - Metrological and technical requirements
• ISO 4064-4:2024 - Non-metrological requirements
• ISO 20456 - Guidance for electromagnetic flowmeters
• National regulations and OIML guidance (note: national rules take precedence)

Keywords: ISO 4064-5:2025, water meters installation, cold potable water, hot water, electromagnetic meters, meter selection, first operation, associated fittings, hydraulic disturbances.