This part of IEC 60216 covers the minimum requirements for ventilated and heated multichamber ovens used for thermal endurance evaluation of electrical insulation and of any other appropriate thermal conditioning application where the use of single-chamber ovens is inappropriate. It covers ovens designed to operate over all or part of the temperature range from 20 K above ambient to 500 °C. It gives acceptance tests and in-service monitoring tests for both unloaded and loaded multichamber ovens and conditions of use.