Depending on the type of fume, you can use a number of different ventilation systems to control it. This includes variable air volume (VAV) systems and chemical fume hoods.
Variable air volume (VAV) systems
Using a variable air volume (VAV) system to regulate the volume of air emitted from a fume hood has many advantages. It is energy efficient, provides a high degree of flexibility in controlling airflow, and reduces carbon emissions. A VAV system also protects the user from potentially harmful fumes.
Variable air volume (VAV) systems use a closed loop control system to minimize the exhaust volume. The temperature of the air entering the VAV box is measured and used as a control signal to modulate the damper position and heating control.
The VAV box’s inlet is typically powered by a fan. This fan is controlled by an actuator, which moves the damper. This control can be pneumatic or digital.
A variable air volume system can reduce carbon emissions by up to 85%. This is because the system modulates airflow depending on the temperature, occupancy, and pressure.
The air flow sensor, which is placed on the back of the VAV, measures the average air velocity and calculates the flow rate into the VAV terminal. The controller receives this information, and modulates the damper and heating control to meet the demands of each zone.
Chemical fume hoods
Having a chemical fume hood in your lab can minimize the risk of exposure to harmful fumes. However, it is important to understand how to use these hoods properly.
Proper use requires understanding of chemical hazards, how to use your fume hood and what to look for when using it. Fortunately, there is a simple online training program offered by the Environmental Health & Safety (EH&S) department.
First, the hood must be cleaned before you start work. Keeping your hood clean and well maintained is key to preventing chemical spills. Using a chemical fume hood correctly also requires using personal protective equipment (PPE) in accordance with the lab hazard assessment.
Chemical fume hoods also require adequate air flow and containment. If the airflow is not adequate or the hood does not have proper containment, air will escape and fumes will contaminate the room. This can result in health hazards for lab workers.
A performance indicator can tell you how much air your fume hood is able to pull in. The most common type of indicator is a differential pressure manometer.
Welding fumes
During welding, the welding rod and filler metals produce a variety of potentially toxic gases. The welding process also produces ultraviolet light, which reacts with nitrogen in the air to form nitrogen oxides. These gases can irritate the respiratory tract and cause eye and nose irritation.
The International Agency for Research on Cancer recently released a large study on welding fumes. It shows that welding fumes have the potential to cause lung cancer. They also found that there were significant differences in the types of fumes produced. These differences could be due to the metal content of the weld wire.
In addition, some studies have shown that welding fumes may be associated with reproductive and immunosuppression disorders. Prolonged exposure to welding fumes has been linked to kidney damage, ulcers, and urinary tract cancer.
Welding fumes are made up of a mix of gases, metallic oxides, and complex oxides of electrode materials. They are not always visible to the naked eye, but can be found in a transmission electron microscope.
Perchloric acid vapors
Using Perchloric Acid can cause severe burns to your eyes and respiratory tract. It should be stored separately from other chemicals and should not be handled with strong dehydrating agents. Anhydrous perchloric acid can be explosive when mixed with organic materials. Using a specially designed fume hood is essential.
Perchloric acid vapors condense into perchlorate salts at elevated temperatures. Perchlorate salts can be explosive and can form in ventilation systems or exhaust systems. They can also explode spontaneously by impact or contact with flames.
Perchloric acid has a number of applications in science and technology. It is used in liquid crystal displays, and in some syntheses. It is used as a precursor to ammonium perchlorate, which is used in solid rocket fuel. It is also used as an etching agent for liquid crystal displays.
Perchloric acid is a strong Bronsted-Lowry acid, which has a vapor pressure of -17OC. At 20oC, 70% perchloric acid can’t evolve gaseous HClO4. Perchloric acid vapors condense at elevated temperatures into perchlorate salts. These salts can be explosive, causing serious injury to researchers. They can also form in exhaust systems and ductwork.