ISO 14903-2025 PDF

Full title and description

St ISO 14903-2025 — Refrigerating systems and heat pumps — Qualification of tightness of components and joints. This International Standard specifies the procedure for type-approval qualification of the tightness of hermetically sealed and closed components, joints and parts used in refrigerating systems and heat pumps, including metal flexible piping, and sets limits and acceptance criteria for component tightness and assembly tightness.

Abstract

ISO 14903:2025 defines a qualification procedure and acceptance criteria for verifying the tightness of hermetically sealed and closed components, joints and parts (for example fittings, bursting discs, flanged or fitted assemblies) used in refrigerating systems and heat pumps. It is applicable to joints up to DN 50 and to components with internal volume up to 5 litres and mass up to 50 kg, and it provides additional requirements for mechanical joints that can be considered hermetically sealed. Components shown to comply with ISO 14903:2017 before the 2025 publication date are considered to comply with this edition.

General information

• Status: Published / In force.
• Publication date: 10 January 2025.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 27.080 (Heat pumps); 27.200 (Refrigerating technology).
• Edition / version: Edition 3 (2025).
• Number of pages: 29 pages.

Scope

Applies to the qualification procedure for type approval of the tightness of hermetically sealed and closed components, joints and parts used in refrigerating systems and heat pumps (including metal flexible piping). The standard is limited to joints with nominal diameter up to DN 50 and to components having an internal volume not greater than 5 litres and a mass not greater than 50 kg. It does not cover tightness of flexible piping made from non‑metallic materials (see ISO 13971).

Key topics and requirements

• Qualification procedure and test methods for assessing component and joint tightness (type‑approval testing).
• Defined acceptance criteria and tightness levels for components and assemblies.
• Test conditions and stress profiles representative of normal operation and manufacturer‑specified fitting procedures.
• Limits of applicability (DN 50; internal volume ≤ 5 L; mass ≤ 50 kg).
• Information that suppliers must provide to testing authorities (assembly instructions, allowable stresses, sealing materials, etc.).
• Additional requirements for mechanical joints that can be regarded as hermetically sealed joints.
• Relationship and alignment with relevant parts of the ISO 5149 series (safety/environmental requirements for refrigerating systems and heat pumps).

Typical use and users

Used by manufacturers of refrigerating and heat‑pump components (fittings, valves, assemblies), testing and certification laboratories, conformity assessment bodies, HVAC/R design engineers, procurement and quality teams, and regulators who need consistent, internationally‑recognised procedures for tightness qualification and type approval.

Related standards

Closely related to the ISO 5149 series (safety and environmental requirements for refrigerating systems and heat pumps) and to ISO 13971 (requirements and qualification for flexible pipe elements and non‑metallic tubes). It is also used alongside regional standards addressing refrigeration safety and environmental protection (for example EN 378 in Europe).

Keywords

tightness qualification, hermetic components, refrigerating systems, heat pumps, type approval, joints, fittings, DN 50, component testing, ISO 14903:2025

FAQ

Q: What is this standard?

A: ISO 14903:2025 is an international standard that specifies the qualification procedure and acceptance criteria for the tightness of hermetically sealed and closed components and joints used in refrigerating systems and heat pumps.

Q: What does it cover?

A: It covers type‑approval tests, acceptance criteria and supplier information requirements for components and joints up to DN 50, and components with internal volume up to 5 litres and mass up to 50 kg; it includes metal flexible piping but excludes non‑metallic flexible piping (covered by ISO 13971).

Q: Who typically uses it?

A: Component manufacturers, test laboratories, certification bodies, HVAC/R engineers, compliance and procurement teams, and regulators involved in refrigeration and heat‑pump systems.

Q: Is it current or superseded?

A: ISO 14903:2025 is the current published edition (published 10 January 2025) and supersedes/replaces ISO 14903:2017; components meeting the 2017 edition before the 2025 publication date are considered to comply with the 2025 edition.

Q: Is it part of a series?

A: Yes — it is intended to be used in conjunction with the ISO 5149 series (safety and environmental requirements for refrigerating systems and heat pumps) and with standards covering flexible piping (ISO 13971) and regional safety standards such as EN 378.

Q: What are the key keywords?

A: tightness qualification; hermetic; joints; fittings; refrigerating systems; heat pumps; type approval; DN 50; ISO 14903:2025.