1.1 Metric Units
Most common and standard unit is the metric unit system, where the base unit is meters (abbreviation “m”) according to SI definitions. Meter is defined as “Length travelled by light in of a second”.
Few common breeds of meter are:
- Kilometer (km) = 1000 m
- Centimeter (mm) = m
- Millimeter (mm) = m
The practical smallest unit which can measured using a simple tape or ruler is millimeters. Beyond that will require special measuring devices like micrometer screw gauge, etc. Therefore, for the purpose of architectural presentation drawings, measuring architectural work, millimeters will be used to express dimensions in most of the situations.
1.2 Imperial Units
In Sri Lanka, however, some traditional masons, carpenters still rely on the old imperial measurement system (i.e. feet and inches). This is mainly because it is easier to visualize since the measuring system is based on things that make sense (Foot). However, the main disadvantage of this unit system is that there is no proper definition for the unit where definitions differ from country to country. Therefore, using this unit for overseas projects will create problems on expressing dimensions. However, according to the metric system, the foot is defined as follows:
1 Foot = 0.3048 m (Symbol – Single Quote “‘”)
1 Inch = Foot (Symbol – Double Quote “””)
The practical smallest unit which can be measured by a ruler is inch or sometimes inch. However, most common smallest imperial unit used in construction is of an inch and is identified in Sinhalese as “නූල”.