What laboratory fume chambers are?
Fume cupboard is laboratory equipment, where there is a closed chamber with exhaust system for working with volatile harmful substances in chemistry lab. According to classifications and standards, the ventilation system has a semi-open local suction made for carrying out industrial processes in laboratory conditions. Fume hoods are intended for use as part of an external exhausting system in clinical, diagnostic, dental, chemical and other laboratories or in pharmacy.
Fume extraction from the cabinet depending on the type of technological operations and requirements carried out in it, can be carried out naturally or mechanically. The amount of air removed from the box is determined by the toxicity of the produced harmful substances and the temperature inside the chamber. Such models are used for research and works that spread toxic fumes and gases harmful to human health and for testing the objects and materials that require the rapid elimination of auxiliaries from the glass desktop.
The main purpose of the laboratory fume chamber is to protect the environment and the operator from chemically harmful substances that can harm his health. Cupboards for laboratories are equipped with powerful modern exhaust and control systems, which effectively removes toxic fumes and gases from the working area in the table top where there is a HEPA filter.
Ventilation for laboratories is designed proceeding from the fact that all operations, accompanied by the release of flammable vapors or gases, are produced in fume hoods. Cupboards should be equipped with upper and lower suction to remove light and heavy gases from the working box. The hood must be illuminated with explosion-proof electric lamps. Wiring to it should be in lead pipes or insulated with asphalt or acid-resistant materials.
The front of the base module usually has a flap for convenient connection of laboratory instruments and switching on the backlight. Usually the wiring of all outlets and backlight pass through one flap. In an emergency, all laboratory instruments and backlight in fume cupboards can be turned off by pressing one toggle switch.
The benchtop working surface should be made of specialized laboratory plastic, ceramic laboratory tiles, high-alloy stainless steel or laboratory monolithic ceramics for work in conditions of medium aggression, with solutions of salts, organic and inorganic acids.
Each operator working with harmful substances must undergo an annual medical examination, and every six months if he works with especially harmful substances. All work, accompanied by the release of toxic fumes and gases, must be carried out in a cupboard with an intact system. The room of the laboratory should be equipped with a system with a lower and upper suction, which ensures an even flow of fresh air and removal of the contaminated and harmful one.
Laboratory fume hood types
There are two types of lab fume hood with two kinds of designs that have different sizes and slopes of the front walls.
— Version A is a fume cabinet with an inclined front wall and with a body length module of 900 mm.
— Version M is a cupboard with an inclined front wall with a body length module of 1200 mm.
— Version A is laboratory fume hood with a vertical front wall with a body length module of 900 mm.
— Version M is a cabinet with a vertical front wall with a body length module of 1200 mm.
There is also a kind of fume hood with other specifications that has another function. It is a cabinet for working with hot chloric and nitric acids or for perchloric acid. It is not intended for use with sulfuric and acetic acids, organic solvents or any combustible substances. When it heat, perchloric acid condenses on the cabinet parts in the piping system and a small powerful fan. Condensed vapors can react additionally with seals of the cabinet and other component materials, forming explosive perchlorates and ethers. Pipes with sinks and the hood are cleaned from the inside by successive spraying of water to prevent the accumulation of perchlorates. Solid stainless steel surfaces facilitate its cleaning process.