National foreword This standard has been published in accordance with a decision taken by CEN/TC 249 to adopt, without alteration, International Standard ISO 291 as a European Standard. The responsible German body involved in its preparation was the Normenausschuß Kunststoffe (Plastics Technology Standards Committee), Technical Committee Verhalten gegen Umgebungseinflüsse. 德國Binder KBF恒溫恒濕箱