Abstract This report describes experiments performed in the ISO 9705 room. Combustion experiments were successfully carried out under conditions from well ventilated to oxygen depleted on five organic materials with different chemical composition, containing the heteroelements nitrogen, sulfur and chlorine, respectively. The materials studied were polypropene, Nylon, chlorobenzene, chloro-nitro-benzoic acid and tetramethylthiuram monosulfide. A special instrument, a phi-meter, was built and used to measure the equivalence ratio, a measure of the degree of ventilation. Under-ventilated conditions were achieved as planned. The results obtained were shown to have the expected trends and were reproducible in terms of their dependence on the degree of ventilation.