Metric

The International System of Units (SI) is most often recognized by the name “Metric System.”
The metric system uses the decimal system to describe the measurements of a quantity.
This course will explain the SI system and other units considered metric.The most common metric units used for fire safety purposes are: liter, cubic decimeter, pascal, meter, and millimeter. Pay special attention to these sections.

This section will familiarize you with the International System of Units (SI) and other units associated with the metric system.

It will cover general information about the metric system, how it is designed, and how to use it.

Why use the Metric System?

Neutral and Universal
The metric system was designed with several goals in mind.
First, it was designed to be neutral. Designers and promoters of the metric system wanted the system to be universally adoptable by all countries.

Replicable

The units of measure must be replicable. Each country must have the ability to replicate the standard measures for itself. The metric system is designed so that the standard metric units can be reproduced in a lab.

Base Units

Meter	m	Length
Kilogram	kg	Weight
Second	s	Time
Ampere	A	Electrical Current
Kelvin	K	Thermodynamic Temperature
Mole	mol	Amount of Substance
Candela	cd	Luminous Intensity

The Gram

Also, note the gram (g) which is valued at 1/1,000 (10-3 ) of a kilogram. The gram is approximately equal to one milliliter of water.
For rule of thumb, it is equal to a paperclip, or a U.S. dollar bill. While it is not a base unit, it is in common usage and is sometimes confused as a base unit.

The Liter

The liter, like the gram, is not a base unit of the SI, but is in common usage. The liter is used to measure volume, most often liquids.Though not in the official SI system, liter is often used with the SI prefixes.

NOTE: The SI measurement for volume is a cubic meter; a liter is tenth of a cubic meter. One litre is denoted as 1 dm³, or one decimeter cubed.