I. Project Overview

The First Hospital of Longyan City is a large general hospital and the only tertiary hospital in Longyan City, Fujian Province. It has 1000 beds and a very large daily outpatient volume. In line with the needs of its own development, the hospital built a 25000m² comprehensive ward building. The ward building consists of two parts: the main building and the auxiliary building. The main building has 15 floors, while the auxiliary building, located at the southwest corner of the main building, has 3 floors; on floors 1～6, the main and auxiliary buildings are joined together. The operating department is arranged on the fifth floor of the main and auxiliary buildings, and the clean air-conditioning machine room of the operating department is located on the sixth floor of the auxiliary building. The total building area of the entire operating department floor is approximately 1500m². According to the hospital's requirements, a comprehensive clean operating department was to be built on this floor, comprising 8 operating rooms, operating room auxiliary rooms, and a postoperative intensive care unit (hereinafter referred to as the ICU ward) capable of accommodating 6 beds. The 8 operating rooms include 2 Class Ⅰ operating rooms, 3 Class Ⅱ operating rooms (one of which is a positive/negative pressure adjustable operating room), and 3 Class Ⅲ operating rooms.

In the design scheme, besides 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 were to have complete functions, the systems were to be advanced, and energy saving in operation was 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 that the facility would remain at an advanced domestic level for a considerable period of time. Since the main structure of the whole building had already been completed when the operating department was designed, the actual site conditions and factors such as the locations of water supply and drainage also had to be taken into account in the redesign. In accordance with the actual site conditions and the hospital's requirements, the design work was completed in March 2001; construction began in September of the same year, and the project was completed at the end of 2001. In 2002, it passed the comprehensive performance acceptance inspection of the National Building Engineering Quality Supervision and Inspection Center. It has been in use ever since and has been highly praised by the owner.

II. Floor Plan Layout

In the floor plan design, alterations to the original civil structure and the locations of water supply and drainage, among other things, should be kept to a minimum, while the requirements of the new standard must also be satisfied. In addition, 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) Based on the concept of the "negative pressure operating room" in the Standard for Construction of Hospital Clean Operating Rooms and the Architectural Technical Code for Hospital Clean Operating Rooms, and considering that in a non-infectious-disease hospital the utilization rate of a negative pressure operating room would not be high, we provided one positive/negative pressure adjustable operating room, and this positive/negative pressure adjustable operating room was also designated as a Class Ⅰ operating room.

(2) The particularly clean Class Ⅰ and Class Ⅱ operating rooms were arranged at the end of the clean corridor, i.e., in the auxiliary building, where the flow of people is relatively small. In this way, these operating rooms are protected from interference by other non-surgical personnel, which helps to guarantee their cleanliness class and bacterial concentration, making them safer and more reliable; they also enjoy the advantages of less interference and convenient operation and management.

(3) The pre-anesthesia room was arranged next to the anesthesiologists' office for ease of operation.

(4) The anesthesia recovery room was located close to the entrance and exit, making it convenient for patients to leave the operating department after regaining consciousness.

(5) In the floor plan, so that disinfected items could enter the clean area directly and the possibility of contamination could be reduced, a double-door high-pressure sterilizer was adopted for the disinfection of items.

III. Air-Conditioning and Purification Systems

(1) Division of systems. In accordance with the provisions of the new standard, 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 eight independent clean air-conditioning systems (J-1～J-8):

Class Ⅰ Operating Room (1) and the extracorporeal circulation auxiliary room share one clean air-conditioning system (J-1);

Class Ⅰ Operating Room (2) has one clean air-conditioning system (J-2);

Class Ⅱ Operating Rooms (1) and (2) and the positive/negative pressure operating room each have their own separate clean air-conditioning system (J-3～J-5); The three Class Ⅲ operating rooms share one air purification air conditioning system (J-6);

The other auxiliary rooms of the surgical department share one air purification air conditioning system (J-7);

The ICU ward and its auxiliary rooms form one air purification air conditioning system (J-8).

In this way, whichever operating room is in use, its corresponding system is turned on, and the purification systems of the unused operating rooms are kept off, so as to achieve the purpose of energy saving. However, the auxiliary room system 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, so it can also be operated independently and used alone when there are patients in the ward but no surgeries are being performed.

(2) System composition. The operating room systems each consist of a fresh air system, an air purification air conditioning system, and an exhaust system within the operating room. The systems for the auxiliary rooms of the surgical department and the ICU ward each consist of a fresh air system and an air purification air conditioning system. Each system adopts an independent fresh air system, and the fresh air units all adopt a new 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 an exhaust air treatment measure 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 and heating sources and humidification source. The cooling and heating sources of the air conditioning system are provided by the air-cooled chilled/hot water units of the entire building. Since this project is located in a southern city, it is quite suitable to adopt air-cooled chilled/hot water units that provide chilled water in summer and hot water in winter. The clean surgical department of a hospital belongs to biological cleanrooms, where bacterial growth should be avoided as much as possible; therefore, the humidification of each system should not adopt the form of water humidification, but should adopt the form of steam humidification. Since the hospital has no steam source, electrode humidifiers are installed in the air conditioning units of each system. The air heat and moisture treatment process is shown in Figure 2. The Class Ⅰ operating room adopts secondary return air, with the fresh air ratio kept unchanged throughout the year.

(4) Selection of the system form. Since the air change rates of the clean operating rooms are all relatively large, even the Class Ⅲ operating room, which has the smallest air change rate requirement, must reach 24 air changes per hour according to the national standard. In addition, since personnel are concentrated in the operating room during surgery, the required fresh air volume 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 the air purification air conditioning systems adopt the secondary return air system. Considering the practical operability in operation, the primary and secondary return air ratios and the fresh air volume are fixed throughout the year. The system heat and moisture treatment process 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 concentrated air supply device centrally arranged above the operating table is adopted, while the return air adopts the form of continuously arranged return air outlets at the lower part on both sides of the operating table. The size of the concentrated air supply device should meet the dimensional requirements of the national standard; the return air velocity is ≤2m/s; the return air outlets adopt the vertical louver form that is not prone to dust accumulation, and adopt adjustable air outlets with coarse-efficiency filtration.

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

(2) Air supply devices of the clean operating rooms. Since the structural story height of the First Hospital of Longyan City is relatively low and the beams are relatively deep, with the lowest elevation under the beams being only 2.90m, and in order to ensure that the normal use of the shadowless lamps in the operating rooms is not affected, the ceiling elevation in the operating rooms is required to be ≥2.80m, which poses great difficulty for the design of the air supply system in the operating room, and the traditional terminal air supply device itself requires a height of 500～600mm. To solve this problem, we adopted a new type of nationally patented terminal air supply device—the leak-prevention layer. The leak-prevention layer air supply device consists of a HEPA filter box, a supply air plenum, a leak-prevention layer air supply outlet, and air ducts connecting the HEPA filter box and the supply air plenum. The conventional local Class 100 approach, which uses HEPA filters as the terminal airflow distribution devices, arranges the HEPA filters within a single plenum; the principles are shown in Figure 3 and Figure 4.

Figure 3　Schematic diagram of the leak-prevention layer air supply device

Figure 4　Schematic diagram of the conventional clean operating room air supply device

V. Surgical Department Drawings

The detailed drawing of the clean operating room is shown in Figure 5.

The plan view, zoning diagram, and flow diagram of the clean surgical department are shown in Figure 6, Figure 7, and Figure 8

Figure 5　Detailed drawing of the clean operating room of the First Hospital of Longyan City, Fujian Province Figure 6 Floor plan of the clean operating department of the First Hospital of Longyan City, Fujian Province Figure 7　Zoning Diagram of the Clean Operating Department of the First Hospital of Longyan City, Fujian Province Figure 8　Flow Chart of the Clean Operating Department of the First Hospital of Longyan City, Fujian Province