“Fume cupboards, also known as fume hoods or chemical hoods, are a type of ventilation system commonly used in laboratories and industrial settings to control and eliminate potentially hazardous fumes, vapours, or dust generated during experiments or procedures. Their primary purpose is to protect the user and the surrounding environment from exposure to harmful or toxic substances.
Here’s how fume cupboards work:
Enclosed workspace: A fume cupboard is essentially a ventilated, enclosed workspace with a clear glass or acrylic front panel that allows the user to observe and access the interior while keeping the harmful substances contained.
Ventilation system: Fume cupboards are connected to an exhaust ventilation system that continuously draws air from inside the cupboard and expels it outside or through appropriate filtration. The airflow direction is generally from the top to the bottom, preventing fumes from escaping into the laboratory.
Sash: The front panel, known as the sash, can be raised or lowered to control the size of the opening and regulate the airflow. A lower sash height restricts the movement of fumes and enhances containment.
Airflow velocity: The airflow velocity is carefully controlled to maintain a safe working environment. The design and dimensions of the fume cupboard, as well as the exhaust system’s power, ensure an adequate and consistent airflow.
Operator safety: The fume cupboard’s design protects the operator by directing harmful fumes away from them, minimizing exposure. The sash acts as a barrier and prevents direct contact with hazardous materials.
Exhaust system: The exhausted air is typically directed through ductwork to the building’s exhaust system, which carries it outside, away from inhabited areas. Some fume cupboards also use filtration systems to remove particulates and harmful substances before recirculating the air back into the laboratory.
Face velocity: Face velocity is an essential parameter used to assess the fume cupboard’s performance. It measures the velocity at which air is drawn into the fume cupboard’s opening. The face velocity should be maintained within specified limits to ensure effective containment.
It is crucial to properly maintain and use fume cupboards to ensure their effectiveness. Users must follow established safety protocols, keep the workspace uncluttered, and use appropriate personal protective equipment (PPE) when working with hazardous materials.
Fume cupboards are an essential part of laboratory safety and are used wherever hazardous substances are handled to protect researchers, workers, and the environment from potential harm.”