external firing meaning in English

外部燃烧

Test methods for external fire exposure to roofs
屋顶外部着火的试验方法
External firing boiler
外燃锅炉
Fire tests on building materials and structures - classification and method of test for external fire exposure to roofs
建筑材料和构件的燃烧试验.外部屋顶着火试验方法和分类
Fire classification of construction products and building elements - part 5 : classification using data from external fire exposure to roofs tests ; german version en 13501 - 5 : 2005
施工产品和建筑部件的燃烧性能分类.第5部分:对外部屋