Know the Difference: Clean Bench vs. Biosafety Cabinet

Know the Difference: Clean bench vs. Biosafety Cabinet

In a laboratory setting, ensuring safety and maintaining sterility are critical. Clean benches and biosafety cabinets are important tools to achieve these goals, but they each serve different purposes.

The Structure of a Clean Bench

A clean bench (also called a laminar flow bench) consists of key components working together to create a unidirectional airflow over the work surface, minimizing contamination by sweeping away particulate matter.

Component	Description
Enclosure	Acts as a barrier for the sterile work area; made of high - grade stainless steel or powder - coated steel (for durability and easy sterilization), designed to minimize particle accumulation.
Fans	Adjustable speed centrifugal blower producing 90 - 120 fpm airflow, ensuring uniform laminar flow and reducing turbulence.
Prefilters	Capture 80 - 90% of particles ≥5 microns, extending HEPA filter life.
HEPA Filters	Remove 99.97% of particles ≥0.3 microns; tested to standards like IEST - RP - CC001.
Power	Supplies power for fans, lighting, and digital controllers; uses 120V or 230V outlets (varies by model/region).

How Clean Benches Work and Classifications

Clean benches maintain constant laminar airflow directed at the work surface, removing airborne contaminants. Classified by particle control ability (per ISO 14644), they focus on product protection (not user protection) and are used in Electronics, microbiology, and pharmaceutical preparation.

How Clean Benches Work

Applications and Controls of Clean Benches

Key Applications

Microelectronics: Assembly/testing of sensitive components (dust-sensitive); requires iso class 1 or 2 air cleanliness.
Drug Preparation: Preparing non-hazardous drugs; requires ISO Class 5 (old Class 100) cleanliness; monitors airflow velocity and filter replacement.
Food Industry: Quality control and packaging (especially ready-to-eat foods); requires iso class 7 (old class 10000) cleanliness to prevent microbial/dust contamination.

Applications of Clean Benche

Operational Controls

Include monitoring colony counts, regulating airflow speeds, controlling noise/vibration, and ensuring adequate lighting—all to maintain performance and safety compliance.

Structure and Function of Biosafety Cabinets

Biosafety cabinets (BSCs) protect users, products, and the environment via scientific design, preventing laboratory contamination and ensuring safe work with hazardous materials.

Function of Biosafety Cabinets

System/Component	Features & Functions
Air Filtration System	HEPA filters remove ≥99.97% of ≥0.3 micron particles; airflow rate: 0.3 - 0.5 m/s (varies by model).
exhaust system	Safely removes contaminated air (no recirculation); uses secondary filtration or independent exhaust. Flow rate: 200 - 600 m³/h; exhaust port diameter: 150 - 200 mm.
Window Systems	Adjustable shatterproof glass (6 - 8 mm thick) with ≥45° opening angle; prevents contaminant escape.
Lighting	Standard lighting (750 - 1000 lux) for visibility; UV lighting (15 - 30W) for sterilization (off during operation).
Control Panel	Adjusts airflow/lighting; digital displays (±0.1°C temp, ±0.1 m/s airflow); alarms for airflow issues, filter replacement, and UV lamp life.

Classification and Application of Biosafety Cabinets

Classified by NSF49 standards into Class I, II, and III, each offering different protection levels for specific biosafety needs.

Application of Biosafety Cabinets

Class I
Protection Features: Protects personnel and environment (not products); airflow enters from outside (may contaminate samples).
Application Scenarios: BSL-1/BSL-2 labs; handles low-risk chemicals/non-sterile operations (prevents aerosol hazards).
Class II
Protection Features: Protects personnel, products, and environment; uses diverted/filtered airflow to prevent cross-contamination. Subtypes: A1, A2, B1, B2 (B2 is full exhaust for volatile chemicals/radionuclides).
Application Scenarios: BSL-2/BSL-3 labs; handles bacteria, viruses, sterile drug preparation, clinical experiments.
Class III
Protection Features: Highest containment; fully closed environment with glove ports (no direct contact).
Application Scenarios: BSL-4 labs; handles high-risk pathogens (e.g., Ebola virus) for top-safety research/production.

Comparative Analysis: Clean Benches vs. Biosafety Cabinets

Aspect	Clean Bench	Biosafety Cabinet
Main Function	Provide high - Clean air for product protection	Protect personnel, products, and environment
Air Filtration	High - efficiency filters (ISO Class 5)	HEPA filtration (prevents cross - contamination)
Safety	No biological protection for users/environment	All - round biological protection
Cost	Low (purchase and maintenance)	High (especially high - class models)
Operation Complexity	Simple (no special training needed)	Requires professional training and strict procedures
Applicable Scenarios	Electronic assembly, non - hazardous experiments	BSL - 1 to BSL - 4 tasks (hazardous biological materials)

Selection Strategy

Choose based on experimental needs, safety requirements, and budget:

Experimental materials: Clean bench for non - hazardous materials needing high cleanliness; biosafety cabinet for biohazardous materials (match class to risk level).
Safety needs: Biosafety cabinet if both samples and operators require protection.
Budget: Clean bench for limited budgets (no hazards); biosafety cabinet for comprehensive protection (higher cost).
Application scenarios: Select equipment matching required protection level (e.g., BSL - 4 tasks need Class III cabinets).