Question

① What are the
safety
llules on hood?​

Answer 1

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As a general rule, keep sash heights as low as possible, or even completely closed, always making sure the sash is between you and your work. Do not ignore, override, or disable mechanical stops on the sash. Keep the hood sash clean and clear.

Answer 2

Answer:

What is a hood?

A hood - correctly called a local exhaust hood - is the point where contaminated air is drawn into the ventilation system. The sizes and shapes of hoods are designed for specific tasks or situations. The air speed (velocity) at the hood opening and inside the hood must be enough to catch or capture and carry the air contaminants. To be most effective, the hood should surround or enclose the source of contaminant or be placed as close to the source as possible.

What are the common types of hood?

The three common classes of hoods are:

Enclosing.

Receiving.

Capturing.

Enclosing Hood

Enclosing hoods, or "fume" hoods, are hoods surrounding the process or point where the contaminants are generated. Examples of completely enclosed hoods (all sides enclosed) are glove boxes and grinder hoods. Examples of partially enclosed (two or three sides enclosed) hoods are laboratory hoods or paint spray booths. The enclosing hood is preferred whenever possible.

Partially enclosed hood

Figure 1

Partially Enclosed Hood

Receiving Hood

These hoods are designed to "receive" or catch the emissions from a source that has some initial velocity or movement. For example, a type of receiving hood called a canopy hood receives hot rising air and gases as shown in Figure 2. An example is a canopy hood located over a melting furnace.