🪵 3B — Gases & Liquids

How is heat release rate related to oxygen?

More available oxygen generally allows a higher heat release rate; HRR decreases when available oxygen is consumed and not replenished.

Why are gaseous fuels especially dangerous?

They are already in the physical state required for flaming combustion.

What is vapor density?

The density of a gas compared with the density of air.

What is the vapor density of air?

1.

What happens to gases with vapor density less than 1?

They tend to rise.

What happens to gases with vapor density greater than 1?

They tend to sink.

What happens to heated gases?

They expand and become less dense.

What happens to cooled gases?

They contract and become more dense.

What is specific gravity?

The ratio of the mass of a given volume of liquid to the mass of an equal volume of water at the same temperature.

What is the specific gravity of water?

1.

What happens to liquids with a specific gravity less than 1?

They are lighter than water and tend to float on it.

What happens to liquids with a specific gravity greater than 1?

They are heavier than water and tend to sink.

What happens to liquid fuel before it can burn?

It must vaporize into a gaseous state.

What is vaporization?

The transformation of a liquid into a vapor or gaseous state.

What is vapor pressure?

The pressure exerted by vapors escaping from a liquid.

What does high vapor pressure indicate?

The substance evaporates easily and may present a greater flammability hazard.