Why do we use fume hoods?
Purpose. Chemical fume hoods, when used properly, are one of the most reliable engineering controls in the laboratory. They protect workers by: Containing vapors, dusts, gases, and fumes generated within the hood, and removing them as air flows into the hood and then out via the laboratory exhaust system.
What is a fume hood and how does it work?
Fume hoods are designed to provide personnel protection from toxic or volatile chemicals by continuously delivering airflow away from the user to the work area. Air is then filtered and/or treated by the building’s exhaust system before exiting the facility.
What is the primary function of a fume hood sash?
Fume Hood Sashes: What Are They? The sash refers to the front window or door of a fume hood. The glass window slides open and closed, allowing access to the workstation. The sash window provides both containment and protection from hazardous materials.
What does fume hood mean?
A fume hood, technically a laboratory chemical hood, is a type of local exhaust ventilation system (engineering control). A properly used and properly functioning fume hood exhausts hazardous gases, dusts, mists, and vapors from a confined location and helps protect workers from inhalation exposure.
How do you test a fume hood?
Testing ProcedurePosition the sash so that the fume hood opening is 18 inches.Puff smoke around the opening of the hood by using the Ventilation Smoke Tubes. Divide the fume hood opening into nine squares.Turn the Alnor thermoanemometer to the Temperature position to check the battery.
What are fume hoods made of?
Specialized perchloric acid hoods, made of stainless steel and equipped with a wash down system must be used for such work. Many fume hoods are equipped with flat or rounded sills or air foils which direct the flow of air smoothly across the work surface.
Can you store chemicals in a fume hood?
One of the things we find frequently when performing lab safety audits is chemicals (and other items) stored in the fume hoods. In case there is a spark or electrical malfunction in the hood, flammable or reactive chemicals could cause hazardous reactions in the hood.
How much does fume hood cost?
How Much Does A Fume Hood Cost?Fume Hood SizeLow Price AverageHigh Price Average4′ Fume Hood$5, Fume Hood$7, Fume Hood$9,
Where do fume hoods vent to?
A fume hood is a ventilated enclosure in which gases, vapors and fumes are contained. An exhaust fan situated on the top of the laboratory building pulls air and airborne contaminants through connected ductwork and exhausts them to the atmosphere.
How should a fume hood be left when not in use?
Fume hoods are designed so that when they are not in use the sash should be shut. There is an airfoil sill at the bottom of the sash in all modern fume hoods so that even when the sash is shut, air will still be pulled from the room to exhaust any hazardous vapors.
How are high efficiency fume hoods different from regular fume hoods?
Efficient Low-Flow Fume Hoods Consume 50% Less Energy High-performance fume hoods can operate at 60 fpm, which is the lowest fume hood face velocity requirement recommended, allowing the fume hood to consume 50% less energy than conventional hood designs.
How often should a fume hood survey be conducted?
every three months
How do you use a fume hood?
Ensure that windows and doors near the fume-hoods are CLOSED. Always keep work at least 15cm in from the opening of the fume hood. Use the sash as a safety shield when boiling materials or conducting an experiment with reactive chemicals. Always keep sash as low as possible.
Where should your head be when working with the fume hood?
Safety glasses (goggles), lab coats, and appropriate chemical gloves must be worn when working in, on, or around the fume hood. Do not put your head in the hood, beyond the sash opening.
How do you clean a fume hood?
Clean the interior and exterior surfaces and sash periodically and after spills using deionized water; then wipe the areas down with a soap solution and rinse. NOTE: Personnel should wear appropriate PPE when cleaning the fume hood to protect themselves from the chemicals.
What is the best use of a fume hood?
Laboratory Fume Hoods. A properly operating and correctly used fume hood can reduce or eliminate exposure to volatile liquids, dusts, and mists. It is advisable to use a laboratory hood when working with all hazardous substances.
What helps to optimize the flow of air in a chemical fume hood?
To optimize the performance of the fume hood, follow the practices listed below:Normal baffle position all slots are evenly opened.High temperature work such as using hot plates; lower slots are minimized since heated vapors tend to rise.Heavy gasses and vapors are better captured when upper slots are minimized.
What is one way in which low flow fume hood design differs from standard fume hood design?
A Low Air Flow fume hood operates at a lower rate than a standard unit meaning they take up less space in a lab and can save up to 40% on an energy bill. They reduce energy intake by reducing the amount of conditioned air required to fill a room.
How do you check fume hood face velocity?
8:41Suggested clip · 101 secondsFume Hood Testing According to ANSI/ASHRAE 110 Standard …YouTubeStart of suggested clipEnd of suggested clip
How do you calculate CFM for a fume hood?
Air volume passing through a fume hood is generally equal to the area of the sash opening multiplied by the average velocity desired. For example, if 100 feet per minute (fpm) is required and the hood has a sash opening of 7.5 square feet, then the hood’s air volume is 750 (7.5 x 100) cubic feet per minute (CFM).