I. Project Overview

Jinjiang City Hospital is a Grade II Class A general hospital with 600 beds. According to the needs of its own development, the hospital built a general inpatient building of 15 000m². The inpatient building has 12 floors above ground and 1 floor underground. The operating department is located on the 11th floor of the new inpatient building, and the purification air-conditioning machine room of the operating department is located on the sixth floor of the annex building. The total floor area of the entire operating department is approximately 1100m². According to the requirements of the hospital, a comprehensive clean operating department was to be built on this floor, including 6 operating rooms, operating room auxiliary rooms, and a postoperative intensive care unit (abbreviated as ICU ward) that can accommodate 6 beds. The 6 operating rooms include 1 Class Ⅰ operating room, 2 Class Ⅱ operating rooms, 2 Class Ⅲ operating rooms, and 1 Class Ⅳ operating room for general surgery.

In the design scheme, in addition to meeting the owner's requirements for the functional use of the clean operating department, the parameters and requirements of the Construction Standard for Hospital Clean Operating Rooms and the Technical Code for Construction of Hospital Clean Operating Rooms had to be implemented without compromise. The operating rooms should have complete functions, the systems should be advanced, and energy saving in operation should be considered. Efforts were made to realize the new concepts and new measures proposed by the "Standard" and the "Code", so as to maintain a domestically advanced level for a considerable period of time. Since the main structure of the entire 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 requirements of the hospital, the design work was completed in February 2002, construction began in the same month, and the project was completed in May 2002. In the same year, it passed the comprehensive performance acceptance of the National Construction Engineering Quality Supervision and Inspection Center, and it has been in use ever since, receiving favorable comments from the owner.

II. Floor Plan Layout

In the floor plan design scheme, we tried to make as few changes as possible to the original civil structure and the locations of water supply and drainage, while also meeting the requirements of the new standard. 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 standard and the code, and considering that in a non-infectious disease hospital the utilization rate of a negative-pressure operating room is not high, we set up an operating room with adjustable positive/negative pressure. This adjustable positive/negative pressure operating room was also designated as a Class Ⅱ operating room.

(2) The particularly clean Class Ⅰ and Ⅱ operating rooms were arranged at the end of the clean corridor, where the flow of people is relatively small. This not only protects these operating rooms from interference by other non-surgical personnel, but also helps to guarantee their cleanliness class and bacterial concentration, making them safer and more reliable, with advantages such as less interference and convenient operation and management.

(3) The pre-anesthesia room was set up next to the anesthesiologist's office for convenient 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 waking up.

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

III. Air-Conditioning and Purification System

(1) System division. According to the provisions of the new standard, and considering energy saving and the convenience of operation and management, the entire clean operating department and the ICU ward were divided into eight independent purification air-conditioning systems (J-1 to J-8):

Class Ⅰ operating room (1) and the extracorporeal circulation auxiliary room share one purification air-conditioning system (J-1);

Class Ⅰ operating room (2) has one purification air-conditioning system (J-2);

Class Ⅱ operating rooms (1) and (2) and the positive/negative pressure operating room each have a separate purification air-conditioning system (J-3 to J-5);

The 3 Class Ⅲ operating rooms share one purification air-conditioning system (J-6); Other auxiliary rooms of the surgical department share one air purification air conditioning system (J-7);

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

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 are not turned on, so as to achieve the purpose of energy saving. However, the auxiliary room systems serving the operating rooms must be turned on regardless of which operating room is in use. The ICU ward uses one system on its own, which also makes it independent so that it can be used alone when there are patients in the ward but no operations are being performed.

(2) System composition. Each operating room system consists of a fresh air system, an air purification air conditioning system, and an exhaust system within the operating room. The surgical department auxiliary room system and the ICU ward system each consist of a fresh air system and an air purification air conditioning system. Each system adopts an independent fresh air system; the fresh air units all adopt a new type of fresh air treatment measure with three-stage filtration of coarse, medium, and sub-high efficiency, but the fresh air units do not undertake the heat and moisture treatment of the air; the heat and moisture treatment is undertaken by the air conditioning units. The exhaust air 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 and heat 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 hospital's clean surgical department belongs to biological cleanrooms, in which 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.

(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 minimum air change rate requirement, must reach 24 air changes according to the national standard requirements. In addition, during surgery, personnel are concentrated in the operating room, 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 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 heat and moisture treatment process of the system is shown in Figure 2. The system adopts a secondary return air system.

Figure 2　Diagram of the Heat and Moisture Treatment Process of the System

IV. Indoor Air Distribution

(1) Air distribution form. For the air supply in clean operating rooms, according to the provisions of the national standard, the form of centralized arrangement above the operating table is adopted; 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 $leqslant 2text{m/s}$; the return air outlets adopt the vertical louver form that is not prone to dust accumulation, and coarse-efficiency filtered adjustable air outlets are adopted.

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); 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 storey height of Longyan First Hospital is relatively low and the beam height is relatively large, the elevation under the beams is the most The height at the low point is only 2.90 m, and in order to ensure that the normal use of the shadowless operating lamp in the operating room is not affected, the ceiling in the operating room is required to have an elevation of ≥2.80 m, which brings great difficulty to the design of the air supply system in the operating room; moreover, the traditional terminal air supply device itself requires a height of 500–600 mm. To solve this problem, we adopted a new type of nationally patented terminal air supply device—the leakage-preventing layer. The leakage-preventing layer air supply device consists of a HEPA filter box, a supply air plenum, a leakage-preventing layer air supply outlet, and air ducts connecting the HEPA filter box and the supply air plenum. In the conventional local Class 100 approach, in which HEPA filters serve as the terminal airflow distribution devices, the HEPA filters are arranged inside a plenum, with the principle shown in Figure 3 and Figure 4.

Figure 3　Schematic diagram of the leakage-preventing layer air supply device

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

V. Drawings of the Surgical Department

The plan view 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　Plan view of the clean operating room of Jinjiang Municipal Hospital, Fujian Province Figure 6　Floor Plan of the Clean Operating Department of Jinjiang Municipal Hospital, Fujian Province Figure 7　Zoning diagram of the clean operating department of Jinjiang Municipal Hospital, Fujian Province Figure 8　Flow Chart of the Clean Operating Department of Jinjiang City Hospital, Fujian Province