I. Project Overview

The PLA General Hospital (commonly known as the 301 Hospital) is a large comprehensive hospital and the largest Class III Grade A hospital in the entire military.

(1) The medical building is a new construction project within the 301 Hospital, a national key project whose foundation was personally laid by leaders of the Central Military Commission in the autumn of 1991. It has a total floor area of 56 000m², with 2 floors underground and 14 floors above ground, 16 floors in total. Structurally, the building is divided into Sections Ⅰ, Ⅱ, Ⅲ, and Ⅳ, with construction planned in two phases. The first phase involved building Sections Ⅰ, Ⅱ, and Ⅲ, the main structure from the basement to the 14th floor, approximately 50 000m², which was completed and put into use in October 1994; the second phase involved constructing Section Ⅳ, from ground floors 1 to 4, which started in 1995, approximately 6 000m², and was completed and delivered for use within the same year.

(2) Except for the pediatric ward in Section Ⅰ (east section) on the fourth floor, the rest are medical technology rooms, with the fifth floor and above being wards. The "stem cell" transplantation ward is located in Section Ⅱ on the fifth floor, and the ICU monitoring ward is on the sixth floor. The operating department is located in Sections Ⅱ, Ⅲ, and Ⅳ on the third floor, and the corresponding Sections Ⅱ, Ⅲ, and Ⅳ on the fourth floor serve as the equipment floor for the operating room clean air-conditioning system units and the clean air-conditioning units of the stem cell transplantation ward, as well as the pipe transition floor of the ward building.

(3) A total of 20 operating rooms were set up, with 18 clean operating rooms completed in the first phase and 2 contaminated operating rooms scheduled for the second phase. The 18 clean operating rooms consist of 3 locally Class 100 clean operating rooms and 15 Class 10 000 clean operating rooms; among the Class 10 000 operating rooms, No. 6 is an X-ray radiation-shielded operating room. The clean inner corridor is divided into an inner part at Class 10 000 and an outer part at Class 100 000.

(4) The floor height of the operating department on the third floor is 3.5m; the fourth floor (Sections Ⅱ, Ⅲ, and Ⅳ with inverted beam structure) is the equipment floor, with a floor height of 3.3m.

(5) Operating room finishing

  1. The floor is made of domestically produced static-conductive PVC sheets, welded into one piece.
  2. The four walls and the suspended ceiling use 1.5mm thick aluminum alloy panels, with insulation boards behind the aluminum alloy panels, and the surfaces are sprayed with hygienic high-strength coating.
  3. The ceiling and floor are joined to the walls with R50 circular arcs; aluminum alloy panels are used at the top and stainless steel panels at the bottom, with the joints argon-arc welded into one piece and the weld seams ground and polished; the junction between the two facade walls is transitioned with arc transitions at internal and external corners.

(6) The clean operating department was finalized in May 1993 and the scheme design was carried out; construction started in August of the same year, and it was fully completed in October 1994, passing the testing by the "National Construction Engineering Quality Inspection and Testing Center" and passing the acceptance inspection in one attempt, with the cleanliness improved by one level and the bacterial concentration meeting NASA standards. According to feedback from the 301 Hospital: statistics over the more than two years from the start of operation to the end of 1996 showed that among a total of more than 18 000 Class I incision cases, there was not a single case of postoperative infection. The leaders of the General Logistics Department and the Central Military Commission were all very satisfied.

II. Plan Layout

Since a long time has passed since the delivery of this project, the documentation can hardly be complete; here, it is described only according to the relative plan positions of Sections Ⅱ and Ⅲ at that time.

(1) The 18 clean operating rooms and some auxiliary rooms are arranged within Sections Ⅱ and Ⅲ, while Section Ⅰ houses rooms for changing clothes and shoes, disinfection and supply, anesthesia, the nursing office, etc. The plan layout of the 18 clean operating rooms and their corresponding auxiliary rooms consists of a central clean corridor and soiled corridors looping around the south, north, and west. The north soiled corridor separates the clean operating area and the contaminated operating area into two zones, realizing the layout concept of a clear separation between clean and dirty flows. During the second phase of construction after the first phase was completed and put into use, the north doors of the operating rooms were closed; patients took the central elevator to the third floor, entered the clean corridor through the bed exchange area, and proceeded to the operating rooms; medical staff collected gowns, caps, and other items at the distribution area, entered the shoe-changing area, then changed into scrub suits and entered the clean corridor to the scrub room to wash their hands. After the second phase was completed, all the north doors and corridors of the first phase were fully opened through; patients then walked north from the elevator hall, passed through the outer corridor to the entrance of each operating room where beds were exchanged, and entered the operating room directly, without centralized bed exchange anymore. (2) Of the 18 operating rooms, No. 1～3, three rooms in total, are local Class 100 operating rooms, while the remaining No. 4～18, 15 rooms in total, are Class 10 000 operating rooms; the inner corridor is partitioned by doors into two areas, forming two clean zones: the inner corridor in front of the Class 100 operating rooms has Class 10 000 cleanliness, and the inner corridor outside the partition doors has Class 10 cleanliness.

(3) All 18 operating rooms are clean operating rooms, and they, together with the corresponding auxiliary rooms, are arranged in Sections Ⅱ and Ⅲ; Section Ⅰ contains rooms for changing clothes and shoes, centralized disinfection, anesthesia, nurses' offices, etc. Medical staff collect gowns, caps and other items at the distribution area, enter the shoe-changing area, then enter to change into scrub suits, and proceed along the clean corridor to the scrub room to wash their hands.

III. Air Conditioning and Purification System

(1) System allocation. Except for operating rooms No. 8 and No. 9, which share one system (because there was really no space in the equipment floor), all the others are controlled one-to-one. Each system has its own independent fresh air, with a design fresh air volume of 500m³/h per operating room; each operating room has independent exhaust, with a design exhaust volume of 300m³/h per operating room. For the three local Class 100 operating rooms, the total supply air volume of each system is 10 000m³/h; each of the 15 Class 10 000 operating rooms has a supply air volume of 5 000m³/h (among which operating rooms No. 8 and No. 9 share one 10 000m³/h unit); the clean corridor and the auxiliary rooms have a separate unit of 10000m³/h.

(2) Cooling and heating sources for air conditioning. They are supplied by an independent system from the central supply station of this building; during seasonal transition periods, the central station has a small unit supplying the cooling and heating source for the surgical department, the stem cell transplantation center, and intensive care.

(3) Saturated steam is used for humidification.

(4) The fresh air units are equipped with three-stage filtration—primary, medium, and sub-high efficiency—but no cooling and heating source is provided.

(5) The exhaust units are provided with effective filtration, but they are not interlocked with the main units and are controlled separately.

(6) All the air handling units are domestically made units developed in accordance with hygienic standard requirements; they have been running well to date, with a DDC control system.

IV. Indoor Air Distribution

(1) All the clean operating rooms adopt centralized air supply at the center, with return air at the lower parts on both sides parallel to the operating table. The supply air area of the local Class 100 operating rooms is 2.7m×2.7m, and that of the Class 10 000 operating rooms is 2.7m×1.8m; the return air outlets are required to be installed with their bottom edge 150mm above the floor, the height of the return air outlets is 350mm, and power socket boxes are generally installed in the 200～300mm gap between the two return air outlets; the return air outlets are required to be openable vertical aluminum movable louvers with a plastic-spray finish, inside which non-woven fabric of primary and medium efficiency is attached to a layer of nylon mesh frame for support; the air velocity through the return air outlets is generally 0.8～1.2m.

(2) Since the architectural story height of the operating rooms is only 3.5m and the necessary clear height of the operating rooms (2.85m) must be guaranteed, the effective space inside the operating room suspended ceiling is very small—generally only 350～400mm—and it is difficult to achieve good results with the terminal HEPA filters whether they are arranged laterally or laid flat; under these specific environmental conditions, it was necessary to break with convention and adopt the following method: the HEPA filter boxes are installed in the equipment floor, and the airflow leaving the HEPA filter boxes passes beneath the floor slab down to the operating room ceiling and enters the plenum, then enters the operating room with uniform flow through the perforated diffuser plates; however, there is still a distance from the HEPA box outlet to the supply air plenum—the farthest is about 10m and even the nearest is 5m—and in between there are galvanized-sheet ducts, butt flanges, volume control dampers and other components, making it difficult to meet the cleanliness requirements and the uniformity at the terminal outlet. For this reason, a device known today as the leak-preventing layer was installed in the supply air plenum, which solved the above problems, and tests brought unexpectedly good results. Meanwhile, the HEPA filters can be replaced conveniently in the equipment floor without having to enter the operating rooms.

(3) The terminal perforated plates are made of 1mm-thick aluminum alloy sheets, machined with CNC equipment and finished with plastic spray coating; they are corrosion-resistant, resistant to acids and alkalis, and easy to clean; the perforated plates are removable, hung on the frame, and can be taken down easily for cleaning and disinfection. This surgical department is still in very good condition after being used up to now.

V. Drawings of the Surgical Department

The floor plan of the surgical department is shown in Figure 1. Figure 1　Floor Plan of the Clean Operating Department of the Chinese PLA General Hospital