Home / Standards / GB/T 39749-2021 GB/T 39749-2021 Active Evaluation method and graduation for energy efficiency performance of insulating glass unit 中空玻璃隔热保温性能评价方法及分级 Standard Type GBT ICS 81.040 CCS Q30 Status 现行 Issue Date 2021-03-09 Implementation 2022-02-01 Responsible Dept 中国建筑材料联合会 Drafting Unit N/A