In laboratory renovation, the layout planning of laboratory furniture serves as the foundation, but the selection of fume hoods is equally critical. As the “safety core equipment” of laboratory furniture, fume hoods not only protect personnel from harmful gases, vapors, or microorganisms but also stabilize the experimental environment to ensure data accuracy.
This article shares seven key considerations for choosing fume hoods based on practical laboratory needs, helping you precisely match suitable products and avoid common pitfalls.
1. Determine the laboratory type before selecting the fume hood orientation
The first step in choosing a fume hood is always to “align with laboratory purpose”—different laboratory types require vastly different fume hood functions. Selecting the wrong one not only wastes resources but may also create safety hazards.
For instance, in a chemistry lab handling common organic solvents like ethanol or acetone, a standard chemical fume hood suffices. However, if strong acids (e.g., sulfuric acid), strong bases (e.g., sodium hydroxide), or highly corrosive gases (e.g., chlorine) are involved, a corrosion-resistant hood (such as one with a polypropylene cabinet) is essential to prevent leaks from damaged surfaces.
Consider a biological laboratory: For common microorganisms (e.g., E. coli), a BSL-2 biosafety cabinet suffices. However, when handling highly pathogenic microorganisms (e.g., SARS-CoV-2, HIV), BSL-3 or BSL-4 biosafety cabinets are required. These cabinets establish strict biological barriers to prevent microbial escape.
Simply put, before selecting a fume hood, ask yourself two questions: “What are the primary experiments conducted in my laboratory?” and “What hazardous substances (gases, liquids, microorganisms) will be encountered during these experiments?” Clarifying these points will help you determine the appropriate type of fume hood.
2. Safety is the top priority for fume hoods—don’t overlook these details
Regardless of the fume hood type, “safety” remains the primary consideration. However, safety standards vary across different models, requiring targeted verification.
For chemical fume hoods, focus on two key metrics:
First, “gas exhaust capacity”—ensuring 100% removal of hazardous gases with no residual buildup. Second, “leak-proof design”, such as the tightness of door seals and the absence of gaps at cabinet joints to prevent gas leakage. Additionally, prioritize chemical fume hoods compliant with the ANSI/AIHA Z9.5 standard, the globally recognized laboratory ventilation safety specification that maximizes safety assurance.
For biosafety cabinets, the core requirement is “biological barrier performance”. First, confirm the cabinet’s biosafety level (BSL-1 to BSL-4), which must match the laboratory’s biological risk level; Second, verify compliance with the NSF/ANSI 49 standard, which requires biosafety cabinets to filter 99.97% of 0.3-micron particles to prevent microbial spread. Furthermore, negative pressure design is critical—the cabinet interior must maintain stable negative pressure to prevent air leakage.
3. Ventilation Performance Determines Effectiveness—Keep a Close Eye on These 3 Metrics
The “ventilation capacity” of a fume hood directly impacts its performance—if ventilation is poor and harmful gases cannot be effectively removed, even the safest design is useless. When selecting a fume hood, focus on the following three key metrics:
(1) Airflow Velocity: Maintained at 0.5–1.0 meters per second
The airflow velocity inside the fume hood must not be too high or too low. When the velocity falls below 0.5 meters per second, harmful gases cannot be effectively removed and may accumulate within the hood. Conversely, a velocity exceeding 1.0 meters per second causes turbulent airflow inside the hood, potentially allowing harmful gases to escape through the door opening.
It is recommended to select fume hoods equipped with “air velocity monitoring functionality”. This feature provides real-time air velocity readings and triggers an alarm if readings deviate from the standard range, facilitating timely adjustments.
(2) Exhaust Airflow: Aligned with Experimental Requirements
Calculating exhaust airflow requires considering both the fume hood dimensions and experimental intensity. For example, a fume hood measuring 1.5 meters wide and 0.8 meters deep, with an opening height of 0.7 meters and an air velocity of 0.8 meters per second, would require an exhaust airflow of approximately 1.5 × 0.7 × 0.8 × 3600 = 2520 cubic meters per hour.
If experiments generate significant amounts of hazardous gases (e.g., large volumes of volatile organic solvents), the exhaust airflow rate should be appropriately increased. Conversely, if gas emissions are minimal, the exhaust rate can be reduced to prevent energy waste.
(3) Negative Pressure Control: Essential for High-Risk Experiments
When handling highly hazardous chemicals (such as highly toxic gases) or highly pathogenic microorganisms, a “negative pressure fume hood” must be selected. This type of fume hood uses a variable-frequency fan to maintain stable negative pressure inside the cabinet. Even if the cabinet door has a slight gap, external air will flow into the cabinet instead of harmful gases escaping outward.
Models with “real-time negative pressure monitoring” are recommended. Should the negative pressure drop below the required level, the equipment will immediately trigger an alarm, prompting personnel to halt experiments and perform maintenance.
4. Dimensions and Layout Must Fit the Laboratory—Don’t Just Go for “Bigger”
Many people assume that “bigger is better” when selecting fume hoods. However, the dimensions of a fume hood must align with the laboratory’s available space and workflow. Otherwise, it can hinder operational efficiency and even pose safety hazards.
(1) Dimensions: Select based on laboratory space and experimental requirements
Common widths for fume hoods on the market are 1.2m, 1.5m, and 1.8m, with depths typically ranging from 0.8m to 0.9m and heights around 2.3m (including exhaust ducting).
- Small laboratories (≤20m²): Prioritize 1.2m-wide fume hoods to avoid excessive space consumption;
- Medium-sized laboratories (20-50 m²): Opt for 1.5-meter-wide fume hoods to balance operational needs and space utilization;
- Large laboratories (>50 m²) or those requiring simultaneous multi-group experiments: Consider 1.8-meter-wide fume hoods or configurations combining multiple 1.2-1.5-meter units.
Additionally, account for the dimensions of laboratory equipment—if large instruments (e.g., rotary evaporators, gas chromatographs) must be placed inside the fume hood, ensure sufficient depth and height to prevent equipment protrusion beyond the hood’s boundaries, which could compromise capture of hazardous gases.
(2) Placement: Away from Airflow Disturbance Sources
The positioning of fume hoods is also critical. They should be placed away from “airflow disturbance sources” such as air conditioning vents, doors, windows, and fans. External air currents can disrupt the exhaust airflow of the fume hood, leading to the overflow of harmful gases.
It is recommended to place the fume hood in a corner of the laboratory or in an area away from doors and windows. Additionally, ensure at least 1 meter of operational space around the fume hood to facilitate easy access and operation for laboratory personnel, preventing collisions with the hood door due to crowded conditions.
5. Energy efficiency should not be overlooked, as it can save significant costs over the long term
Laboratory fume hoods typically require 24-hour operation (especially for experiments involving continuous generation of hazardous gases), resulting in substantial energy consumption. Selecting energy-efficient fume hoods not only reduces laboratory operating costs but also minimizes environmental impact.
(1) Prioritize fume hoods equipped with “variable frequency fans”
Conventional fume hood fans operate at a fixed speed, running at maximum airflow regardless of experimental requirements, resulting in high energy consumption. In contrast, variable frequency fume hoods adjust fan speed based on actual needs—for instance, automatically reducing speed and exhaust volume during experimental pauses, then resuming normal speed when experiments resume. Statistics show variable frequency fume hoods achieve over 30% greater energy savings than conventional models.
(2) Select models with “automatic sensor cabinet doors”
Some high-end fume hoods feature infrared or motion sensors that automatically open the cabinet door when personnel approach and close it or reduce the opening height upon departure to minimize exhaust airflow. This design further reduces energy consumption while preventing waste caused by forgotten doors.
(3) Consider “Heat Recovery Function”
For laboratories located in cold regions, fume hoods with a “heat recovery function” are recommended. These hoods capture heat from exhaust air and reuse it for laboratory heating, reducing winter heating energy consumption and yielding significant long-term electricity savings.
6. Material and construction quality determine the service life of fume hoods
Laboratory environments are complex, with fume hoods exposed daily to chemicals, water, high temperatures, and other factors. Poor material quality can easily lead to corrosion, deformation, aging, and other issues, shortening the service life. When selecting a fume hood, pay close attention to the materials used in the following three key areas:
(1) Cabinet Body: Prioritize corrosion-resistant materials
- General Chemistry Labs: Epoxy resin-coated cabinets suffice, resistant to organic solvents and weak acids/bases, offering high cost-effectiveness;
- Highly Corrosive Labs (e.g., handling sulfuric acid, nitric acid): Select polypropylene panel cabinets, resistant to strong acids and alkalis, with extended service life;
- Biological laboratories: 304 stainless steel cabinets are easy to clean, corrosion-resistant, and meet the sterile requirements for microbiological experiments.
(2) Countertop: Balancing Corrosion Resistance and Heat Resistance
The countertop serves as the “core work area” of the fume hood, requiring both corrosion resistance and heat resistance. Common countertop materials include:
- Solid chemical-resistant board: Resistant to general chemicals and heat (≤135°C), offering high cost-effectiveness for standard laboratories;
- Ceramic countertop: Resists strong acids and alkalis, withstands high temperatures (≤1200°C), and offers high hardness, suitable for highly corrosive and high-temperature experiments;
- Epoxy resin countertop: Strong corrosion resistance, withstands high temperatures (≤200°C), and can be customized into irregular shapes, suitable for special experimental requirements.
(3) Hardware Components: Opt for Stainless Steel
For hardware components such as hinges, handles, and screws in fume hoods, select 304 stainless steel to prevent rusting or chemical corrosion. This is particularly crucial for cabinet door hinges, which undergo frequent opening and closing. Inferior hinges may loosen easily, compromising the door’s seal integrity.
7. Filters and Accessories for Enhanced Practicality
Beyond basic functionality, fume hood filters and accessories further improve safety and practicality. We recommend selecting these based on your specific experimental requirements.
(1) Filters: Select based on pollutant type
- Organic gases (e.g., ethanol, toluene): Use activated carbon filters to adsorb organic molecules and reduce harmful gas emissions;
- Particulate matter (e.g., dust, microorganisms): Use HEPA filters with 99.97% filtration efficiency, suitable for biological labs or dusty experiments;
- Mixed contaminants (gases + particulates): Use a “activated carbon + HEPA” combination filter to address both filtration needs.
Note: Filters require regular replacement. We recommend selecting fume hoods with “filter life alerts” to prevent safety hazards caused by filter failure.
(2) Practical Accessories: Optional based on experimental requirements
- Sink + Drain Rack: Ideal for chemistry labs, facilitating post-experiment cleaning of glassware. The drain rack allows water to drip off, keeping the countertop dry;
- UV Lamp: Suitable for biology labs. Activating the UV lamp after experiments disinfects the cabinet interior, preventing microbial contamination;
- Power Outlet: Install waterproof, corrosion-resistant outlets inside the fume hood for connecting equipment (e.g., stirrers, pipettes).
- Reagent Rack: Mount racks inside or above the hood to store frequently used reagents, minimizing travel time for retrieval.
Finally: Choosing the right fume hood means selecting the right “safety barrier” for your laboratory.
A fume hood is not merely a simple “exhaust device”; it is the core safeguard for laboratory safety and experimental accuracy. From laboratory type to safety standards, from laboratory type to safety standards, from ventilation performance to material quality, every detail matters when selecting a fume hood.
Remember: A good fume hood not only protects the health of laboratory personnel but also enables more efficient experiments and more accurate data.
