IEC TS 60721-4-3:2023

Overview

IEC TS 60721-4-3:2023 is a Technical Specification that provides guidance for correlating and transforming the environmental condition classes defined in IEC 60721-3-3 into the environmental test procedures of the IEC 60068-2 series. Targeted at electrotechnical equipment intended for stationary use at weatherprotected locations, this TS recommends test procedures, severities and durations to help specification writers and test engineers convert field environmental classes into appropriate laboratory tests.

This first edition (2023) replaces IEC TR 60721-4-3:2001 (and its 2003 amendment), has been reworked technically, aligns severities with IEC 60721-3-3:2019, and retains figures only in Annex A (interdependence of temperature and humidity).

Key topics

• Correlation methodology: Principles to map IEC 60721 in-use classes (e.g., climate, mechanical, biological) to IEC 60068-2 test procedures.
• Recommended test procedures and severities: Suggested IEC 60068-2 tests and severity levels suitable for most electrotechnical products used in weatherprotected, stationary locations.
• Scope of conditions considered: Climate (temperature, humidity), mechanical (vibration, shock), biological, dynamic and air-pressure related effects.
• Test durations and application guidance: Practical guidance on typical test durations and the intent behind chosen durations (suitable for demonstrating effects under normal failure consequences).
• Guidance nature: Emphasizes the document is advisory - tests may be adapted where product safety, durability or higher failure-consequence demands require different severities or durations.
• Supporting information: Annex A contains a climatogram illustrating the relationship between air temperature, relative humidity and absolute humidity.

Applications

Who will use IEC TS 60721-4-3:2023 and why:

• Specification writers and product managers - to convert environmental class descriptions into concrete test requirements for datasheets and procurement.
• Test and qualification engineers - to select appropriate IEC 60068-2 procedures and recommended severities for environmental qualification.
• Design and reliability engineers - to assess environmental robustness for products in weatherprotected, stationary installations (e.g., indoor enclosures, sheltered equipment rooms).
• Compliance and certification bodies - as guidance when evaluating test plans and conformity assessment for normal failure-consequence products.

Practical uses include environmental test planning, writing test specifications, defining pass/fail criteria, and harmonizing field service conditions with laboratory tests.

Related standards

• IEC 60721-3-3:2019 (environmental classes - stationary, weatherprotected)
• IEC 60068-1:2013 (environmental testing - general & guidance)
• IEC 60068-2 series (specific environmental test procedures)
• IEC 60721-1 (environmental parameters and severities)
• IEC TR 60721-4-0 (introductory guidance to the 60721-4 series)

Keywords: IEC TS 60721-4-3:2023, IEC 60721-3-3, IEC 60068, environmental condition classes, weatherprotected locations, environmental tests, test severities, stationary use.