Laboratory fume hoods are a type of ventilation system with the primary function to exhaust chemical fumes, vapors, gasses, dust, mist and aerosol. Fume hoods also serve as physical barriers between reactions and the laboratory, offering a measure of protection against inhalation exposure, chemical spills, run-away reactions and fires.
A typical fume hood has a box like structure with a moveable sash window. Experimental procedures are performed within the hood which is consistently and safely ventilated, usually by means of an extract blower and ductwork. Chemical fumes are exhausted and diluted many times over in the atmosphere and have a negligible effect on human health. When environment concerns are of importance, an extract treatment system, often referred to as a scrubber is installed to remove most of the vapors from the exhaust air stream.
We provide kinds of fume hood for your choices
• Distillation Fume Hood
A distillation hood is characterized by a low worktop height which results in a large working height for the operator. This allows tall distillation equipment to be installed and mounted in the work chamber. Otherwise, it has similar features to that of a standard fume hood.
• Perchloric Acid Fume Hood
Perchloric acid reacts violently with organic materials. Dried perchloric acid is also highly explosive. Therefore, perchloric fume hoods require built-in water wash down systems in order to prevent perchlorate salt deposits. Interior liners are made of acid resistant materials like stainless steel. Interior corners are coved to aid in cleaning. All procedures that use perchloric acid must be confined to a perchloric fume hood, to prevent dangerous reactions with other chemicals.
• Radioisotope Fume Hood
Radioisotope fume hoods are constructed specifically to protect users from radioactive materials. They have specially constructed worktops to withstand the weight of lead shielding plates, and may also have lead laced sashes. Interiors are made of stainless steel with coved corners to aid in decontamination.
• Acid Digestion Fume Hood
Acid digestion fume hoods have special liners manufactured of acid resistant materials such as unplasticized PVC. For acid digestion applications involving high service temperatures, other materials such as PVDF may be used. Sashes may be made of polycarbonate to resist hydrofluoric acid etching.
• Floor Mounted Fume Hood
Floor mounted fume hoods are used for applications which require large apparatus. As the name implies, these hoods are floor mounted without any work surface. This facilitates the transfer of equipment and materials into, and out from the hood. Floor mounted hoods are sometimes referred to, although wrongly, as walk-in fume hoods.
• Demonstration Fume Hood
A demonstration hood has all 4 sides made of safety glass, and this hood is commonly used in educational institutions to allow students to easily view the teachers’ demonstrations inside the fume hood from all angles, enhancing efficiency in teaching laboratories.
• Ductless Fume Hood
Ductless fume hoods utilize activated carbon filtration to adsorb chemical vapors and fumes. These hoods recirculate air to the laboratory, and are growing in popularity because of energy savings and the green movement.
Fume hoods should be suitably sited to ensure maximum containment. Locate hoods to avoid crosscurrents at the hood face due to pedestrian traffic, doors and supply air diffusers. Sufficient laboratory supply air must be available to allow hoods to operate at their specified face velocities.
A fume hood is not designed to contain high velocity releases of particulate contaminants unless the sash is fully closed. The hood is not capable of containing explosions, even when the sash is fully closed. If an explosion hazard exists, the user should provide anchored barriers, shields or enclosures of sufficient strength to deflect or contain it. Such barriers can significantly affect the airflow in the hood.
A conventional fume hood must not be used for perchloric acid. Perchloric acid vapors can settle on ductwork, resulting in the deposition of perchlorate crystals. Perchlorates can accumulate on surfaces and have been known to detonate on contact, causing serious injury to researchers and maintenance personnel. Specialized perchloric acid hoods, made of stainless steel and equipped with a wash down system must be used for such work.
