1. Type
The pass box in the biomedical industry is divided into three types: self-cleaning type, air intake type, and exhaust type. The self-cleaning type, including a self-circulating air purification system composed of a fan and a high-efficiency air filter, can purify the air inside the pass box. The air intake type, including a fan and a high-efficiency air filter, can take air from the adjacent area with higher cleanliness in whole (or in part), can purify the air inside the pass box and the air discharged from the pass box, and exhaust it to the original clean area or other suitable location. The exhaust type, including a high-efficiency air filter and an air supply and exhaust system, can purify the air inside the pass box and the air discharged from the pass box, and exhaust it to the outdoors or other suitable locations.
2. Dimensions and structural requirements
The deviations of the external dimensions and channel dimensions shall comply with the tolerance grade "L" specified in GB/T 1184-1996; the flatness of the outer wall and each wall panel in the channel shall comply with the tolerance grade "L" specified in GB/T1184-1996.
The structure has corresponding requirements for the cavity support frame, sealing door, and outer cover.
The six inner walls of the pass box are referred to as the cavity. The four corners of the inner surface of the cavity should adopt an arc angle transition structure; the cavity joint welds should be continuous and smooth, and the welds should be polished after welding to meet the airtightness requirements.
The structure that maintains the safe use and transportation of the pass box product is referred to as the support frame. The frame should be corrosion-resistant and meet the product structural safety. The welding welds should be firm and reliable, and the welds should be polished after welding.
The doors that can be opened and closed installed at the front and rear ends of the pass box are referred to as sealed doors; the sealed doors should be corrosion-resistant, wear-resistant, non-cracking, non-reflective, impact-resistant, smooth and waterproof, and easy to clean; the sealed doors are strong and can ensure the airtightness of the cavity.
The outer wall layers on the four sides of the pass box are referred to as the outer cover. The outer cover should be easy to clean, pollution-free, and corrosion-resistant.
The disinfection device should determine the commonly used physical, chemical, and biological disinfection methods, sterilization rate, and cleanliness of the pass box according to the specific requirements of different industries for disinfection. The transfer window is equipped with a reserved channel for the injection of sterilizing gas (steam), and the seal of the channel opening should meet the sealing requirements of the cavity.
According to the use requirements of the pass box, ventilation devices including fans, filters, valves and air ducts shall be equipped; the air supply and exhaust requirements of the pass box shall be met; the purification, disinfection and sterilization self-circulation requirements of the pass box shall be met; the fan shall be a high-efficiency and low-noise fan; and reasonable vibration and noise reduction measures shall be adopted for fan installation.
The pass box shall be equipped with an air filter device that meets the cleanliness requirements of the cavity, and the high-efficiency filter used shall comply with the provisions of GB/T 13554; it shall have the functions of high-efficiency filtration for air intake and high-efficiency filtration for exhaust, so that the cleanliness of the space for transferring items in the cavity matches the controlled environment. The high-efficiency filter shall be able to perform integrity detection; the high-efficiency filter shall be equipped with online differential pressure detection.
The sterilization device shall determine the commonly used physical, chemical and biological disinfection methods and sterilization rates of the pass box according to the specific requirements of different industries for sterilization; it can kill various bacteria, viruses, spores and other microorganisms on the surface and inner cavity of the object, and the killing level shall meet the process requirements.
The pass box in the biomedical industry shall be equipped with electrical or mechanical devices to achieve interlocking functions. The sealed door cannot be opened during equipment operation. Under normal use, the front and rear sealed doors cannot be opened at the same time; if the front and rear sealed doors need to be opened at the same time for maintenance, the safety management regulations of the relevant places shall be complied with; after the sealed door of the low-level cleanliness area is opened, if a complete disinfection and purification process is not run, the sealed door of the high-level area cannot be opened. The cavity should have an interface for verification.
III. Material requirements
The cavity of the pass box and the parts in contact with the transferred items should be resistant to oxidation, corrosion, wear, cracking, non-reflective, impact-resistant, smooth and waterproof, easy to clean, with stable material performance, no pollution to sterilized items, and no substances that cause environmental or health deterioration; the inner surface of the cavity should be smooth, dust-free, and dust-free, and the surface roughness of the inner surface of the cavity should be Ra≤0.4μm; the visible glass of the pass box should use safety glass, and the safety level should meet the requirements of GB16753.1; the performance of the pass box sealing strip should meet the airtightness requirements.
IV. Use environment
Ambient temperature: 5℃~40℃; relative humidity: 30%~80%. 5. Electrical components and control
Electrical safety shall be implemented in accordance with GB4793.1. The wires used in the pass box shall meet the requirements of GB4793.1; the main power supply, fan and lighting shall all use full-pole switches that cut off or connect all poles of the power supply at the same time, and the switches shall pass safety certification; circuits such as the main power supply, fan and lighting shall be equipped with overload protection devices such as circuit breakers; fault alarms, status indications and records shall be set according to the requirements of the pass box's use function; the equipment should be equipped with a touch screen to display the equipment's operation process and automatically record the sterilization process parameter data.
6. Installation requirements
The equipment installation shall comply with the requirements of GB 50231; after the equipment is in place, it should be convenient for the docking of the supporting external transport vehicle and the pick-up and placement of the transferred items; sufficient logistics and maintenance space should be left on both sides of the equipment.
VII. Other requirements
If the equipment has disinfection, sterilization, and verification quality inspection, it should ensure that the disinfection and sterilization effects meet the process requirements; the disinfection and sterilization devices should have protective devices and be easy to replace. When there is a large pressure difference on both sides of the biosafety pass box that hinders the normal opening of the window door, a pressure relief device should be installed.
VIII. Technical requirements
1. Appearance
The appearance of the pass box should be flat and smooth, without blind cleaning areas, obvious scratches, rust spots, and indentations. The components of the pass box should be affixed with component identification, and the text and graphic symbols that explain the function should be correct, clear, upright, and firm. Warning signs should be affixed to the parts involving disinfection and sterilization devices. The position of external accessories should be reasonable, and the joints and pipes should be reliably blocked.
2. Performance
The pass box control system should have manual mode and automatic mode; the touch screen operation buttons should be easy to operate; the controller timer should have an error less than 5% of the preset value. The center wind speed of the nozzle has the function of an air shower room, that is, the pass box that sprays high-speed clean air through the nozzle to purify the surface of the transferred items, and the center air supply speed of the nozzle should not be less than 20m/s. The ventilation frequency in the pass box channel should be higher than 50 times/h; the ventilation frequency of the pass box with air shower room function should be higher than 1000 times/h.
The installation structure of the transfer window filter should reduce the leakage rate and meet the following performance requirements:
a) The leakage rate of the scannable detection filter at any point should not exceed 0.01%.
b) The leakage rate of the detection point of the non-scannable detection filter should not exceed 0.005%.
The cleanliness of the cavity of the biological and medical pass box should match the controlled environment. The recommended cleanliness level and the number of sedimentation bacteria colonies are shown in Table 2. The minimum ultraviolet sterilization dose of the pass box with ultraviolet disinfection function should meet the requirements of Table 3. The sterilization rate of the pass box for the black variant of Bacillus subtilis spore-stained slides should be ≥99.9%.
Cleanliness level and sedimentation bacteria colony count of medical pass box
2. When the pass box is tested by smoke test method, there should be no visible leakage in all gaps. The air tightness of the biosafety pass box must be implemented in accordance with the requirements of the "Technical Specifications for Biosafety Laboratory Buildings" GB50346 and the "General Requirements for Laboratory Biosafety" GB19489. The pass box should determine the pressure difference between the inside and outside of the cavity according to the user's requirements, and confirm through testing that the pressure difference under normal operating conditions can be maintained stably. When the pass box is operating normally, the noise value at 1m horizontally outside the center of the door should not be greater than 60dB (A). For a pass box with a self-cleaning function, the self-cleaning time required to achieve a cleanliness level that matches the controlled environment should not be longer than the set time for disinfection and purification of the pass box.
The doors at both ends of the transfer window should have an interlocking function. If the door at either end of the pass box is opened, the door at the other end cannot be opened; when the door of the low-level cleanliness area of the pass box is opened, a complete disinfection and purification process should be carried out, and the door of the high-level area is allowed to be opened. When the pass box is powered off or the self-locking function of the door fails, the doors at both ends should comply with the relevant site safety management regulations before they can be opened manually. The transfer window with air shower function should also meet the following requirements: when the pass box is in the air shower state, the doors at both ends should be locked; when the air shower of the pass box stops, the door should be delayed for at least 5s before opening.
Grounding resistance: The resistance between the accessible metal surface and the ground of the power plug should not be greater than 0.1 Ω.
Insulation resistance: The insulation resistance between the power input terminal and the outer cover or exposed conductive part should not be less than 2.0MΩ. Leakage current: The leakage current of the accessible surface should not be greater than 10mA. The voltage between the live parts and the metal casing should withstand 1500V.
Disinfection time: The pass box should set the disinfection action time according to the disinfection method or the type and concentration of the disinfectant. The control system should take technical measures to limit the disinfection action time to prevent the risk of insufficient disinfection time and incomplete disinfection due to equipment failure or misoperation.
Anti-ultraviolet leakage: When any door of the pass box is opened, the ultraviolet lamp must stop working; the pass box door with ultraviolet lamp should use anti-ultraviolet glass or anti-ultraviolet film, and the ultraviolet leakage should be ≤5μW/㎝² at 30cm from the periphery of the pass box.
Fire and explosion prevention: The mechanical and electrical components and disinfection and sterilization measures of the pass box should meet the fire and explosion prevention requirements of the relevant places; flammable and explosive disinfectants shall not be used for spraying disinfection when the pass box door is closed; electrical components that are prone to high temperature and arcing should be completely separated from the pass box cavity space.
