ISO 18566-1:2017

Overview

ISO 18566-1:2017 - Building environment design: Design, test methods and control of hydronic radiant heating and cooling panel systems (Part 1) - defines the vocabulary, symbols, comfort criteria, technical specifications and requirements for prefabricated hydronic radiant panels with an open air gap. The standard applies to water‑based (hydronic) free‑hanging radiant panels used as room‑periphery elements (ceiling, wall, floor) in residential, commercial and industrial buildings. It expressly excludes panels embedded in building structure and hybrid panels that combine thermal radiation with forced convection.

Key topics and technical requirements

• Definitions and symbols: standardized terms such as active length, active surface, mean water temperature, inlet/outlet water temperature, nominal cooling capacity, MRT (mean radiant temperature), OT (operative temperature), PMV/PPD.
• Comfort criteria: guidance on radiant temperature asymmetry, vertical air temperature difference and other occupant comfort limits used to evaluate panel performance.
• Technical specifications and installation:
  • Types of prefabricated radiant panels and their construction characteristics
  • Installation requirements for systems mounted to ceilings, walls or floors with an open air gap
• Performance requirements:
  • Thermal performance: test conditions and characteristic equations to determine heating and cooling capacity (detailed test methods are given in ISO 18566‑2)
  • Hydronic performance: water flow, pressure and connection component considerations
  • Acoustic performance: basic requirements to limit noise impact
• Safety and durability: factory test pressure, maximum operating pressure, durability and indoor environment impact
• Maintenance of conformity: information and documentation (e.g., panel information sheets) required for product certification and field verification
• Informative annexes: descriptions of panel types and example information sheet templates

Practical applications - who uses ISO 18566-1

• Manufacturers of prefabricated hydronic radiant panels - for product specification, factory testing and documentation
• HVAC engineers and system designers - to select and size ceiling‑mounted radiant systems and to ensure compliance with comfort criteria
• Test laboratories - to prepare for capacity and performance testing (complements ISO 18566‑2)
• Architects and building consultants - to integrate radiant panels into building designs while meeting occupant comfort and safety requirements
• Building owners and facility managers - for specification, procurement and operation guidance, including integration with building management systems (BMS)

Related standards

• ISO 18566‑2, ISO 18566‑3, ISO 18566‑4 (complementary parts addressing test methods, design procedures and control strategies)
• ISO 11855 (embedded radiant systems - different application)
• References: EN 14240, EN 14037 and ASHRAE/ANSI Standard 138 (standards cited in the ISO document)

For implementation or procurement, consult the full ISO 18566‑1:2017 document from ISO or your national standards body for authoritative requirements and test procedures.