I. The first step in selection: Confirm 4 basic operating condition parameters
Operating area size: Determine the effective air supply length and width of the laminar flow hood, the air supply range must completely cover all operation stations, and it must not only partially cover;
Target cleanliness level
ISO5 (100-level / A-class sterile area): H14 high-efficiency filter, stable wind speed of 0.45m/s;
ISO7~ISO8 local purification: Optional H13 high-efficiency filter;
Installation method: Ceiling suspension / Floor support / Mobile; Confirm ceiling load-bearing capacity, on-site installation space;
Environmental conditions: Whether VHP hydrogen peroxide fumigation, high humidity, acid-base environment, whether explosion-proof is required.
II. Key configuration selection comparison
1. Fan: EC motor VS AC motor
AC fan: Lower procurement cost; poor speed regulation accuracy, high energy consumption, unable to be remotely controlled in groups, mostly used for small and simple projects;
EC brushless fan (recommended for mainstream projects): Energy-saving, stepless speed regulation, supports 0~10V analog signal / RS485 networking, automatic wind speed compensation; filter dust accumulation automatically adjusts speed, stabilizes surface wind speed; suitable for long-term continuous operation pharmaceutical factories, lithium battery factories.
2. Filter sealing form
Conventional compression type high efficiency: Generally for electronic workshops, non-GMP projects; Sealing has potential risks, leak detection is difficult;
Superfine glass fiber filter paper: Conventional normal temperature clean room;
3. Filter material selection
Ultra-fine glass fiber filter paper： General temperature-controlled clean rooms；
PTFE coated high-efficiency filter material： Long-term VHP fumigation， high humidity disinfection areas， resistant to moisture， not prone to microbial growth.
4. Box material selection
SUS304 stainless steel： Pharmaceutical， medical device， areas requiring frequent disinfection； Inner wall arc， seamless welding；
Aluminum-coated zinc plate / Cold-rolled steel plate spray paint： Ordinary electronic workshops， dry environment， budget control projects.
III. Vertical laminar flow hoods vs Horizontal laminar flow hoods， how to choose?
Vertical flow (priority recommended for medicine， aseptic processes)
Air flow from top to bottom， the dust and particles generated by personnel are carried downward by the air flow， less likely to contaminate the product； Open operation risks are lower；
Horizontal flow (restricted scenarios for use)
Air flow blows towards the operator， the dust and aerosols generated by the process are easily blown directly at the operator； Not suitable for open operation of toxic raw materials， sterile drugs； Only suitable for electronic assembly without dust and biological hazards.
IV. Common selection misunderstandings
❌ Misunderstanding 1： Just fit the equipment size， no extra margin
The surrounding area of the equipment must be reserved ≥150mm safety buffer zone to avoid turbulent airflow at the edges forming vortices；
❌ Misunderstanding 2： Select H13 filter for A-level area instead of H14， unable to meet the new GMP aseptic appendix；
❌ Misunderstanding 3： Ignore the configuration of uniform flow membrane； Without uniform flow membrane， the wind speed will be severely uneven， local turbulence will occur；
❌ Misunderstanding 4： Ordinary laminar flow hoods are directly used for powder weighing； Powder feeding operation conditions should use negative pressure weighing hoods， not positive pressure laminar flow hoods， dust will spread and contaminate the workshop.
V. Industry standard configuration reference
Aseptic pharmaceutical filling A-level laminar flow hood：
304 stainless steel box body + EC fan + G4 primary efficiency + F9 medium efficiency + H14 liquid tank high efficiency + differential pressure monitoring + PAO detection port
Lithium battery， electronic workshop local 100-level：
Aluminum-coated zinc box + EC fan + G4 + F8 + H13 without partition for high efficiency
General laboratory local purification: AC fan, compression-type high-efficiency filter
