ISO/PAS 24499:2024 PDF

Overview

ISO/PAS 24499:2024 - Method of test for burning velocity measurement of A2L flammable gases - is a Publicly Available Specification from ISO (first edition, May 2024) that defines a laboratory method to measure the of slow-burning refrigerants (A2L class) for safety classification and engineering use. The method targets refrigerants with BV below 10 cm/s and documents practical limits (lower measurable BV approximately 3–4 cm/s). The standard describes a vertical open-ended glass tube technique with optical imaging to quantify flame propagation through a quiescent, well-mixed refrigerant–air column.