Key Updates to UL 1484 6th Edition

22 Jul 2025

Optional 21-Day Corrosion Test Simplifies Compliance for Gas and Combination Alarms

The 6th Edition of UL 1484, released on April 28, 2025, introduces a key update that could significantly streamline the certification process for manufacturers of gas and combination carbon monoxide (CO)/gas alarms: the addition of an optional 21-day corrosion test.

Previously, UL 1484 mandated only a 10-day corrosion cycle for gas alarms, a protocol often considered more severe than longer-duration alternatives. While legacy AC-powered devices using tin-oxide sensors typically withstood the 10-day test without issue, many newer DC-powered designs utilizing electrochemical sensors have encountered greater challenges under these conditions.

The update addresses a long-standing complexity for manufacturers of combination CO/gas alarms. Prior editions required products to undergo both the 10-day gas alarm corrosion test and a separate 21-day CO alarm test, essentially two distinct test cycles. This dual requirement added cost, increased testing complexity, and extended certification timelines.

With the 6th Edition, the standard now permits manufacturers to use a single, optional 21-day corrosion test for gas alarms. This change allows combination CO/gas devices to meet both gas and CO alarm corrosion testing requirements through a unified test cycle. The result: simplified testing, reduced costs, and faster time to market.

At Intertek, we understand how updates to safety standards directly impact product design, development schedules, and certification strategies. The introduction of this optional 21-day test offers welcome flexibility, particularly for manufacturers of DC-powered devices featuring electrochemical sensors.

Our Life Safety & Security experts are here to guide you through these changes. Whether you need assistance with pre-testing consultation, accelerated corrosion testing, or a complete certification roadmap, Intertek is ready to support your path to compliance.