A cleanroom, also known as a dust-free room or sterile room, primarily serves to control indoor contamination. Without a cleanroom, contamination‑sensitive components cannot be manufactured in large volumes. A cleanroom must feature a well‑sealed environment, with parameters such as air cleanliness, temperature, humidity, pressure, and noise levels controllable as required. The design of a cleanroom should adhere to both economic and scientific principles.

1. Basic Requirements for a Sterile Room

(1) The aseptic room shall consist of two chambers: an inner chamber serving as the aseptic area, and an outer chamber functioning as a buffer zone. The room volume should not be excessively large to facilitate air sterilization. The inner chamber should measure 2 m × 2.5 m, with an area of 5 m², while the outer chamber should measure 1 m × 2 m, with an area of 2 m²; both chambers should ideally be no higher than 2.5 m and be equipped with a suspended ceiling.

(2) An inner door shall be provided to minimize air turbulence, and it shall be located at a position far from the workbench. The intermediate door shall be a sliding door, with its access point situated at a location well away from the center on the interior side.

(3) A small window should be installed in the wall or “partition” separating the inner room from the outer room, providing a necessary passage for transferring materials between the two areas during the inoculation process, thereby reducing the number of personnel entering and exiting the inner room and minimizing contamination. The window shall measure 60 cm wide, 40 cm high, and 30 cm thick, with double‑leaf frames mounted on both the interior and exterior sides.

(4) The aseptic chamber is small and tightly sealed; after prolonged use, the internal temperature can become quite high. Therefore, a ventilation window should be provided. This window should be installed in the ceiling at the entrance to the inner chamber and feature a double‑layer design: an external louvered shutter and an internal pull‑out sash. After use and prior to sterilization, the ventilation window may be opened to ensure air circulation. If conditions permit, a constant‑temperature and constant‑humidity unit may also be installed.

2. Equipment and Instruments in the Sterile Room

(1) Workbenches in aseptic rooms, regardless of material or intended use, must have smooth surfaces and level countertops.

(2) Install one ultraviolet lamp (typically 30 W) in both the inner chamber and the outer chamber. The UV lamp in the inner chamber should be mounted directly above the workstation, at a height of 2 meters from the floor, while the UV lamp in the outer chamber may be installed at the center of the outer chamber.

(3) The outer room shall be equipped with dedicated work uniforms, shoes and caps, masks, porcelain salt, towels—towels soaked in lysol—and a sprayer, as well as a 5% acid solution.

(4) The inner room shall be equipped with an alcohol lamp, common inoculation tools, a stainless steel knife, scissors, forceps, 70% alcohol swabs, industrial alcohol, a glass holder, a dedicated wax pencil, a notebook, pencils, label paper, glue, a waste paper basket, and other necessary supplies.

Sterilization and Disinfection in the Sterile Room

(1) Fumigation: This is one of the methods used to sterilize aseptic rooms. When an aseptic room has been in use for an extended period and becomes heavily contaminated, fumigation should be carried out for sterilization. Formaldehyde, lactic acid, or sulfur can be used for fumigation.

(2) Spraying: Perform this step prior to each use of the sterile room. The spray agent causes airborne particles and microorganisms to settle, prevents fine dust on work surfaces and floors from becoming suspended in the air, and also has a disinfecting effect. A 5% carbonic acid spray may be used.

(3) Ultraviolet irradiation: Perform this before each use of the sterile room. Ultraviolet light has excellent germicidal efficacy. Under normal circumstances, the UV lamp should be left on for 30 to 60 minutes.