Accurate measurements, large and small, are critical for design and execution of any construction project. Thickness of paint, powder coating etc. is measured in microns (human hair is about 75 microns or 0.075 millimetre), thickness of boards, diameter of steel bars etc. are stated in millimetres and the dimensions of land for a project site will of course be in metres. Volumetric measurements (cubic metre, litre etc.) are used for wood, aggregates, concrete, liquids etc.

The table shows some (not an exhaustive list) of the official units of measurements we come across in construction

LENGTH - METRE / CENTIMETRE /MILLIMETRE

AREA - SQUARE METRES

VOLUME - CUBIC METRES / LITRES

MASS / WEIGHT - KILOGRAMME /TONNE

ANGLES - DEGREES

POWER - KILOWATT / HORSEPOWER

CURRENT - AMPERES

VOLTAGE - VOLTS

BRIGHTNESS - LUMENS (LUX IS LUMENS PER SQM)

AIR CONDITIONER CAPACITY - TONS / BTU (British Thermal Unit)

GENERATOR / TRANSFORMER CAPACITY - KVA (KiloVoltAmpere)

TENSILE STRENGTH OF STEEL - NEWTON/SQMM

COMPRESSIVE STRENGTH OF CONCRETE - NEWTON/SQMM

SOME HISTORY – TURNING THE CLOCK BACK

It is really interesting to look at how methods of measurements evolved over time.

In ancient times the human body ruled when it came to measurements. The length of a foot, the width of a finger, and the distance of a step were all accepted measurements. The ‘cubit’ was the length of the forearm from the elbow to the tip of the middle finger, the equivalent of ‘MUZHAM’ in Malayalam and “HAATH’ in Hindi. The UK and Ireland still use ‘STONE’ (one stone is 6.35 kilograms) for human body weight.

The decimalised metric system is now the official system worldwide; the USA being one of just three countries which still follow the Imperial (British) system. The British themselves, have changed to the metric system officially but schools also teach the commonly used Imperial units. In India, the metric system was adopted by Parliament in 1956 with the Standard Weights and Measures Act which came into force in October 1958. This act has been amended multiple times over the years.

AN IMPERIAL HANGOVER

Even after so many years, we often use the old imperial system, in language phrases or for real measurements.

Look at the phrases ‘A scream that can be heard a mile away can scare you to an inch of your life’, or ‘Good builders go an extra mile to produce high quality buildings’. To use kilometre and centimetre in these expressions is odd. An ‘ounce of kindness’ sounds so much better than “a millilitre of kindness’, and I’d rather order ‘a pint of beer’ instead of ‘568 millilitres of beer’. Ton is the heavyweight saviour for the metric system, scoring with ‘tons of work to finish’ and ‘with tons of love’

It is ‘mileage’ for fuel economy and the figure is, strangely enough, stated in kilometres per litre. When you say ‘32’ (pounds per square inch is unsaid) to the man filling air in your car tyre, you actually mean 2.2 kilograms per square centimetre of pressure. Measuring temperature is also curiously multi-unit. Body temperature is still in Fahrenheit (102 degrees fever) but atmospheric temperature is in Degree Celsius.

The unit of time, the ‘second’ is an abstract measurement and now almost universal, but to define it you have to get into the Caesium 133 atom and measure its hyperfine transition frequency. No, I’m not going there!

The duality of measurement units is encountered quite a lot in the construction industry as well. An apartment is always 1000 square feet and not 92.902 square metres, although the latter is used in all official documentation. Materials like flooring tiles, roofing sheets, plywood, glass etc. are sold per square foot. The same goes for labour rates quoted by piece work contractors for plastering, painting etc. Many thickness and diameter measurements are still stated in inches. Carpenters and Fabricators are more comfortable with the Imperial system still. The unit of volume, say for aggregates or earth for filling is commonly in cubic feet.  The depth and diameter of open wells in Kerala are stated in ‘kolu’ literally meaning stick, which is 2 1/2 feet or approximately 75 cm long.

Engineering Professionals like me who have been trained in the Metric System, learn over time to convert from one system to the other on the fly with reasonable accuracy.

When in doubt I use  https://www.unitconverters.net/ which has an extensive list of units and offer speedy and convenient conversions.

Hope you enjoyed the read. If you have any questions about anything at all concerning construction or interiors, do reach out to us at www.fromthegroundup.in and we will do our best to answer them.

Cheers

Zachariah Abraham

Managing Partner, A & T