I. Project Overview

Beijing Anzhen Hospital is a Grade III Class A general hospital with 47 clinical nursing departments and 800 beds. The general surgical operating department is located on the 2nd and 3rd floors of the inpatient building. The air-conditioning machine room for the operating department on the 2nd floor is located on the 1st floor, while the air-conditioning machine room for the operating department on the 3rd floor is located on the 4th floor. The total building area of the operating department floors is approximately 8000m². The 2nd floor comprises 10 operating rooms and a 200m² intensive care unit with 15 beds. Among them, there is 1 Grade Ⅰ lead operating room, 1 Grade Ⅲ positive/negative pressure convertible operating room, 1 Grade Ⅲ lead-protection operating room, and 7 Grade Ⅲ operating rooms; the 3rd floor comprises 10 operating rooms and a 700m² intensive care unit with 40 beds. Among them, there is 1 Grade Ⅰ lead-protection operating room, 3 Grade Ⅰ operating rooms, and 6 Grade Ⅲ operating rooms.

In the design scheme, in addition to satisfying the owner's requirements for the functional use of the clean operating department, the parameters and requirements of the "Standard" and the "Code" had to be implemented to the letter; the operating rooms needed complete functions, the systems needed to be advanced, and energy saving in operation had to be considered. The new concepts and new measures put forward in the "Standard" and the "Code" were to be realized as far as possible, so as to maintain a domestically advanced level for a considerable period of time. Meanwhile, since the main structure of the entire building had already been completed when the operating department was designed, the actual site conditions and the locations of water supply and drainage, among other factors, also had to be taken into account in the redesign.

II. Floor Plan Layout

In the floor plan design scheme, alterations to the original civil structure and the locations of water supply and drainage were kept to a minimum as far as possible, while the requirements of the new standard still had to be met. In addition, in order to reduce the possibility of postoperative infection, patients should be able to enter the ICU ward directly from the operating rooms through a clean corridor.

Features of the operating department layout:

(1) According to the concept of the "negative-pressure operating room" in the Construction Standard for Hospital Clean Operating Rooms and the soon-to-be-issued Architectural Technical Code for Hospital Clean Operating Rooms, and considering that in non-infectious-disease hospitals the utilization rate of negative-pressure operating rooms is not high, we set up one operating room with adjustable positive/negative pressure; this positive/negative pressure adjustable operating room was also designated as a Grade Ⅱ operating room.

(2) The anesthesia recovery room is located close to the entrance and exit, making it convenient for patients to leave the operating department after they have recovered from anesthesia.

(3) In the floor plan, in order to allow disinfected items to enter the clean area directly and to reduce the possibility of contamination, a double-door autoclave is used for the disinfection of items.

III. Air-Conditioning and Purification System

(1) System division. In accordance with the provisions of the Architectural Standard for Hospital Clean Operating Rooms, and taking into account energy saving and the convenience of operation and management, the entire clean operating department and the ICU ward are divided into 26 independent air-conditioning and purification systems in total:

2nd floor: Operating Rooms No. 1 and No. 2 share one air-conditioning system;

Operating Room No. 3 has one air-conditioning system;

Operating Rooms No. 4, No. 5, and No. 6 share one air-conditioning system;

Operating Rooms No. 7, No. 8, and No. 9 share one air-conditioning system;

Operating Room No. 10 has one system;

The clean corridor is divided into 2 air-conditioning systems;

The ICU has one air-conditioning system;

The changing area has one air-conditioning system;

The office area has one air-conditioning system.

3rd floor: each operating room has its own system, 10 air-conditioning systems in total;

The clean corridor is divided into 2 air-conditioning systems;

The ICU has one air-conditioning system; The changing area and the office area are served by one air conditioning system.

In this way, whichever operating room is in use, its corresponding system is turned on, while the purification systems of the operating rooms not in use remain off, so as to achieve the purpose of energy saving. However, the auxiliary room systems serving the operating rooms must be turned on no matter which operating room is in use. The ICU ward uses one system on its own; it can also be separated out to operate independently when there are patients in the ward but no surgeries are being performed.

(2) System composition. Each operating room system consists of a fresh air system, a purification air conditioning system, and an exhaust system within the operating room. The systems for the operating department auxiliary rooms and the ICU ward each consist of a fresh air system and a purification air conditioning system. Each system adopts an independent fresh air system, and all fresh air units adopt a new type of fresh air treatment measure with three-stage filtration of coarse, medium, and sub-high efficiency; however, the fresh air units do not undertake the heat and moisture treatment of the air, which is undertaken by the air conditioning units. The exhaust units of each operating room system adopt exhaust air treatment measures with two-stage filtration of sub-high efficiency and medium efficiency. The air purification treatment process is shown in Figure 1.

Figure 1　Schematic diagram of the air purification treatment process

(3) System cooling source, heat source, and humidification source. The cooling source of the air conditioning system is provided by three screw-type water chillers serving the entire building, located in the refrigeration machine room on basement level 2. The heat source is the heat exchange station on basement level 1. The chilled water supply temperature is 7℃ and the return water temperature is 12℃; the hot water supply temperature is 60℃ and the return water temperature is 50℃. The cooling and heat sources are provided by Party A up to the machine room.

(4) Selection of the system type. Since the air change rates of the clean operating rooms are all relatively large, even the Class Ⅲ operating room, which has the lowest air change rate requirement, must still reach 24 air changes per hour as required by the national standard. In addition, since personnel are concentrated in the operating room during surgery, the fresh air requirement is large, and the heat loads from personnel, lighting, and equipment are all relatively large. Therefore, in order to achieve the purpose of energy saving, all purification air conditioning systems adopt a secondary return air system. Considering the practical operability of operation, the primary and secondary return air ratios and the fresh air volume are fixed throughout the year.

The heat and moisture treatment process of the system is shown in Figure 2.

Figure 2　Schematic diagram of the system heat and moisture treatment process

IV. Indoor Air Distribution

(1) Air distribution form. For the air supply in clean operating rooms, according to the provisions of the national standard, a centralized arrangement above the operating table is adopted, while the return air adopts the form of return air outlets continuously arranged at the lower parts on both sides of the operating table. The size of the centralized air supply device meets the dimensional requirements of the national standard; the return air velocity is ≤2m/s; the return air outlets adopt a vertical louver form that is not prone to dust accumulation, and adjustable air outlets with coarse-efficiency filtration are used.

Other clean auxiliary rooms adopt an air distribution form with supply air uniformly arranged at the upper part and return air from both lower sides (or a single lower side), while the clean corridor and the semi-clean corridor adopt an air distribution form of top supply and top return.

(2) Air supply devices of the clean operating rooms. The ceiling elevation of the operating room is required to be 3.0m, and the ceiling height of the operating room auxiliary area is 2.7m. The air supply device adopts a centralized air supply ceiling for the operating room. The flow diagram of the air conditioning system is shown in Figure 3. Figure 3　Air-Conditioning Purification System Flow Chart

V. Operating Department Drawings

The floor plan of the operating room is shown in Figure 4; the floor plans, zoning diagrams, and flow charts of the clean operating department on the second and third floors are shown in Figures 5 to 10.

Figure 4　Detailed Drawing of the Clean Operating Room of Beijing Anzhen Hospital Figure 5　Floor Plan of the Clean Operating Department on the Second Floor of Beijing Anzhen Hospital Figure 6 Floor Plan of the Clean Operating Department on the Third Floor of Beijing Anzhen Hospital Figure 7　Zoning Diagram of the Clean Operating Department on the Second Floor of Beijing Anzhen Hospital Figure 8　Zoning Diagram of the Clean Operating Department on the Third Floor of Beijing Anzhen Hospital

  • Clean Area
  • Quasi-clean Area
  • Non-clean Area Figure 9 Flow chart of the clean operating department on the second floor of Beijing Anzhen Hospital Figure 10 Flow chart of the clean operating department on the third floor of Beijing Anzhen Hospital