Abstract: To guarantee northern fireman's better fighting efficiency in cold environment, the fire protective clothing and inner clothing's warmth retention properties were studied in this paper. Firstly, northern fireman's warmth retention requirement was determined based on questionnaire survey and relative standard. Tests show that current clothing test data couldn't meet warmth retention requirement. Secondly, fireman's underwear, fire- retardant sweater, floccules vest and fire protective clothing were improved by introducing polyimide fabric and new structure. Finally, different improved clothing composition was calculated respectively. Optimized compositions were recommended to different areas to guarantee northern fireman's better fighting efficiency.

Key words: fire fighting, fire-retardant sweater, floccules vest, fire protective clothing, polyimide