A fume hood is designed to extract and contain, or ventilate, contaminants from a working environment. Ensuring that these devices function at their highest level is crucial for protecting workers from ingesting airborne, toxic substances.
Chemical fume hoods are among the most pervasive pieces of laboratory equipment in research laboratories. They are used to preserve air quality in laboratory environments such as clean rooms, workspaces, and small enclosures by circulating fresh air and extracting harmful fumes and particulates.
Typically, fume hoods are integrated with additional benchtop laboratory equipment such as sample handling chambers. These draw air through filtration membranes at low velocities, relying on the negative pressures of sample chambers to reliably contain hazardous off-gases and particulates. Larger systems can be embedded into permanent ventilation shafts to vent fumes, gases, and particulates for larger working environments.
Often, fume hoods are shared between personnel and even between laboratories. This can be detrimental to the device’s performance, although there are numerous factors that can contribute to reduced capacities of your laboratory equipment.
Maintaining Air Flow
- A fume hood is designed to extract and contain, or ventilate, contaminants from a working environment. Ensuring that these devices function at their highest level is crucial for protecting workers from ingesting airborne, toxic substances.
- This demands a constant flow of air into the hood at a predefined velocity for the specific application.
- Laboratory equipment for fume extraction demands that the right airflow velocity is maintained.
- Too little flow can enable ambient air currents to overpower the draw of the fume hood. Too much flow can result in turbulent conditions within the sample chamber.
- Either scenario can allow contaminants to enter working environments.
- The average recommended fume hood velocity for general chemicals is approximately 0.3 meters per second (m/s).
- For extremely toxic, hazardous, or radioactive substances, a flow rate of 0.5m/s is recommended.
- A fume hood blower should be able to consistently maintain these flow rates to ensure optimal equipment performance.
Tips for Maintaining Airflow
- The portability of laboratory equipment is rarely seen as a drawback, but it can result in operators taking setup shortcuts to maximize their worktimes.
- Placement of the fume hood is critical for ensuring a smooth, aerodynamic flow into the handling chamber.
- Make sure the fume hood is placed away from doors and exits that could contribute to non-uniform ambient eddies and air currents.
- The National Fire Protection Association suggests installing chemical vapor control laboratory equipment over three meters away from any door or exit.
- For the same reason, we also recommend setting up the fume hood away from high traffic areas and other equipment that could block the constant flow of air to the blower.
Scientific Instrument Center, Inc. certifies fume hoods, biosafety cabinets, and clean rooms. Certifications are to meet ANSI/ASHRAE 110 for fume hoods and NSF 49 for biosafety cabinets like isolator type cabinets repair in Ohio. Clean rooms are certified to the requirements of ISO 14644 and USP 797 for pharmacies. Decontamination and all service can also be performed on biosafety cabinets, and fume hoods as well. Also includes certification of all laminar flow benches, grossing stations, and isolator type cabinets.
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