"1.The positive pressure of not less than 10Pa shall be maintained in clean area compared with unclean area. The positive pressure of not less than 15Pa shall be maintained in clean area compared with the outside or the area connecting to the outside. The extrusion difference should not be greater than 30Pa.
洁净区对与其相通的非洁净区应保持不小于10Pa的正压，洁净区对室外或对与室外直接相通的区域应保持不小于15Pa的正压，所有挤压差均不应大于30Pa。
2.The buffer room should be set between clean area and unclean area with area not less than 3m2, the cleanliness level should be at the same level as the side with high cleanliness and should not be higher than 1000.
洁净区与非洁净区之间应设面积不小于3m2的缓冲室，其洁净度级别应与洁净度高的一侧同级，并不应高于1000级。
3.The number, size and air cleanliness level of operation room in the clean operation department should be determined according to the nature, scale, level and financial conditions of the hospital. For a comprehensive hospital, if class I clean operation room is required, the number of such clean operation room should not exceed 15% of the total number of clean operation room, but at least l room is necessary. One negative pressure clean operation room is optional if the condition permits. For specialist hospitals, the number of especially clean operation room should be determined based on the actual needs.
洁净手术部中洁净手术室的数量、大小及空气洁净度级别，宜依据医院的性质、规模、级别和财力来决定。对于综合医院，需建I级洁净手术室时，该类洁净手术室间数不应超过洁净手术室总间数的15％，至少l间；有条件时根据需要可设l间负压洁净手术室。对于专科医院，特别洁净手术室应根据实际需要确定建设数量。
Cleanliness Room Purity Ranking and Wind Change Times / 洁净室净化级别及换风次数
Class 级别 ------- Number of the wind change／hour 换风次数
100 Class 级 ------ More than 100 / hour 100次以上 / 小时
1000 Class 级 ------ 50-60 / hour 50-60次 / 小时
10000 Class 级 ------ 20-25 / hour 20-25次 / 小时
100,000 Class 级 ------ 15-20 / hour 15-20次 / 小时
300,000 Class 级 ------ More than 10 / hour 10次以上 / 小时
1,000,000 Class 级 ------ More than 10 / hour 10次以上 / 小时"