Chemical Hood Vent Price-Accumax India

Thu Oct 09, 2025

Chemical Hood Vent

A Chemical Fume Hood (often just called a "fume hood" or "chemical hood vent") is a critical piece of laboratory equipment designed to protect users and the surrounding environment from exposure to hazardous fumes, vapors, gases, and dusts.

Here is a breakdown of its function, design, and common types:

1. Function and Purpose

Containment: Its primary role is to contain airborne hazardous substances generated during experiments or procedures.
Exhaust: It draws air from the laboratory into the enclosure and then exhausts the contaminated air away from the user, usually outside the building via a ventilation system.
Protection: The front glass "window," called the sash, acts as a physical barrier, protecting the user from splashes, minor explosions, and accidental releases.
Spill Containment: The design also helps contain chemical spills within the hood's workspace.

2. Basic Components

Enclosure: The workspace where chemicals are handled.
Sash: The movable glass window (vertical, horizontal, or combination) that can be raised or lowered to provide access and adjust the opening.
Baffles: Slots at the back of the hood that help direct the airflow evenly and efficiently.
Air foil: The curved edge at the bottom and sides of the hood's face that reduces air turbulence and helps maintain a smooth, uniform airflow into the hood.
Exhaust Fan/Blower and Ductwork: The system that pulls the contaminated air out of the hood and vents it.

Airflow Monitor/Alarm: A device that continuously monitors the air velocity (face velocity) and sounds an alarm if the airflow drops to an unsafe level.

3. Types of Fume Hoods

Fume hoods are broadly categorized based on their ventilation method and specific use:

Type	Description
Ducted Fume Hood (Traditional)	Connected to a duct system that exhausts contaminated air outside the building. This is the most common type for handling toxic and corrosive chemicals.
Ductless Fume Hood	Uses internal filters (like activated carbon or HEPA) to clean the air before recirculating it back into the room. Best for low-hazard, low-volume chemical use, and typically not recommended for highly toxic or volatile substances.
Constant Air Volume (CAV)	Exhausts a constant volume of air regardless of the sash position. When the sash is lowered, the air velocity at the face increases.
Variable Air Volume (VAV)	Automatically adjusts the fan speed (and air volume) based on the sash position to maintain a constant face velocity, offering significant energy savings when the sash is closed.
Specialized Hoods	Perchloric Acid Hoods have a wash-down system to prevent the buildup of explosive perchlorate crystals in the ductwork. Radioisotope Hoods are designed with seamless, stainless steel interiors for easy decontamination.

4. Safe Use Practices

To ensure maximum protection, users should always:

Check the Airflow: Verify the hood is pulling air (e.g., check the monitor or a light piece of tissue).
Work Deep: Perform all work at least 6 inches inside the hood's face.
Keep the Sash Low: Only open the sash to the minimum working height indicated by the certification sticker. Lower it completely when the hood is not in use.
Avoid Blockage: Do not place large equipment near the baffles or the hood face, as this can disrupt airflow.
Don't Use for Storage: Limit the storage of chemicals and apparatus inside the hood to maintain proper airflow.