Units and Conversions | CE 008

One of the most important part of civil engineering is being accustomed with various units and their conversions. Detailed discussions regarding this have already been done in previous post [CE 007]. Name of unit must be quoted in each and every measurement, except millimeter where only the numbers suffice. For example, 300 meter, 300 feet but only 300 means 300 millimeter. This rule will be followed in this blog. There are plenty of quantities vis-a-vis, plenty of units. Of which, a few units related to length, area, volume and weight are represented below.

Length: MKS System

1 kilometer    = 10¹   hectometer

= 10²   decameter

= 10³   meter

= 10⁴   decimeter

= 10⁵   centimeter

= 10⁶   millimeter

1 millimeter  = 10^-1  centimeter

= 10^-2  decimeter

= 10^-3  meter

= 10^-4  decameter

= 10^-5  hectometer

= 10^-6  kilometer

Macro Length

1 decameter  = 10¹  meter

1 hectometer = 10²  meter

1 kilometer   = 10³  meter

1 megameter = 10⁶  meter

1 gigameter   = 10⁹  meter

1 terameter   = 10¹² meter

1 petameter  = 10¹⁵ meter

1 exameter    = 10¹⁸ meter

1 zettameter = 10²¹ meter

1 yottameter = 10²⁴ meter

Micro Length

1 decimeter   = 10^-1  meter

1 centimeter  = 10^-2  meter

1 millimeter   = 10^-3  meter

1 micrometer = 10^-6  meter

1 nanometer  = 10^-9  meter

1 picometer   = 10^-12 meter

1 femtometer = 10^-15 meter

1 attometer   = 10^-18 meter

1 zettometer = 10^-21 meter

1 yoctometer = 10^-24 meter

Surveying Work

Apart from various lengths and types of tapes, two types of chains are used in surveying work. One is 20 m long with 100 links @ 200 each. Another is 30 m long with 100 links @ 300 each. The 20 m chain is more popular.

Length: FPS System

1 foot     = 12 inches

I yard     = 3 ft

1 rod      = 5.5 yards

1 chain   = 22 yards = 66 ft

1 furlong = 10 chains = 220 yards = 660 ft

1 mile    = 8 furlongs = 1760 yards
              = 5280 feet = 63,360 inches

Surveying Work

Apart from various lengths and types of tapes, two types of chains are used in surveying work, viz., 100 feet long Engineer’s chain and 66 feet long Gunter’s chain, which is more popular. Engineer’s chain contains 100 links @ 1 foot each.  

Gunter’s chain

1 link      = 7.92 inches

1 rod      = 25 links = 16.5 ft

1 chain   = 100 links = 66 ft

1 furlong = 10 chains = 660 ft

1 mile     = 8 furlongs = 80 chains = 8000 links

Ocean Depth

1 fathom = 6 feet

1 mile = 80 chains = 320 rods = 880 fathom

1 league = 3 miles = 2640 fathoms
               = 240 chains = 960 rods

Nautical mile

A nautical mile is the distance on the sea surface corresponding to 1 minute (1/60 degree) of arc of longitude at equator. Knot is the rate of travelling over the sea surface i.e. nautical mile per hour.

1 nt. mile (Int.) = 1.1507 miles at land

1 nt. mile (U.K) = 1.1515 miles at land

Conversions of Length Units

1 millimeter  = 0.03937 inch

1 meter = 1.0936 yards = 3.2808 feet
             = 39.37 inches

1 kilometer = 0.54 nt. mile = 0.62137 mile
                  = 1093.61 yards = 3280.833 feet
                  = 39,370 inches

1 inch = 2.54 cm = 25.4 mm

1 foot = 30.48 cm = 304.8 mm

1 yard = 0.9144 m = 91.44 cm = 914.4 mm

1 mile = 1.6093 km = 1609.347 m
          = 1609347 mm

1 nt. mile (INT) = 1.852 kilometer

1 nt. mile (UK)  = 1.853 kilometer

Units of Land Area

Internationally, area of land of any shape is expressed by hectare and are (pronunciation air) in metric system and by acre in British system.Many local units for area are available in different countries of the world. Local units like decimal, bigha, katha, chhatak etc. are popular in many states of India including West Bengal as well as in Nepal and Bangladesh. 1 hectare is an area equivalent to 100 m x 100 m. 1 are is an area equivalent to 10 m x 10 m. 1 acre is an area equivalent to 1 chain x 1 furlong i.e., 66 ft x 660 ft i.e., 43560 sq ft.

1 chhatak * = 45 sq ft

1 katha * = 16 chh = 720 sq ft

1 bigha * = 20 katha = 320 chh = 14400 sq ft

* Valid at least in West Bengal and a few other states/country but not everywhere.

1 acre = 43560 sq ft = 4840 sq yd
          = (1/640) sq mile

1 decimal = (1/100) acre = 435.6 sq ft

1 are   = 100 sq m = 0.01 hectare
          = 0.0001 sq km

1 decare = 1000 sq m = 10 are = 0.1 hectare
              = 0.001 sq km

1 hectare = 10000 sq m = 100 are

               = 10 decare = 0.01 sq km

Conversions

1 sq km   = 0.3861 sq mile

1 sq mile = 2.59 sq km

1 sq m = 1550 sq inch = 10.7639 sq ft

 = 1.196 sq yd

1 sq yd = 0.8361 sq m

1 sq ft  = 0.0929 sq m

1 hectare = 2.471 acre = 247.1 decimal

               = 7.475 bigha = 149.5 katha
               = 107636 sq ft

1 acre = 0.4047 hectare = 40.47 are
          = 4047 sq m

Liquid Volume: MKS System

1 kiloliter       = 10¹   hectoliter

= 10²   decaliter

= 10³   liter

= 10⁴   deciliter

= 10⁵   centiliter

= 10⁶   milliliter 

1 milliliter     = 10^-1  centiliter

= 10^-2  deciliter

= 10^-3  liter

= 10^-4  decaliter

= 10^-5  hectoliter

= 10^-6  kiloliter

1000 liter      = 1 cum

Liquid Volume: FPS System

1 gallon (UK) = 4 quart = 8 pint = 32 gill
                    = 160 fl oz = 277.42 cu in
                    = 0.1605 cu ft

1 barrel (UK) = 36 gallon

1 gallon (US) = 4 quart = 8 pint = 32 gill
                    = 128 fl oz = 231 cu in
                    = 0.1337 cu ft

1 barrel (UK) = 31.5 gallon

1 gallon (UK) = 1.2 gallon (US)

1 gallon (US) = 0.833 gallon (UK)

Conversions

1 gallon (US)  = 3.785 liter

1 gallon (UK) = 4.546 liter

1 liter           = 0.22 gallon (UK)

1 liter           = 0.26 gallon (US)
1 cum           = 35.315 cu ft

Weight: MKS System

1 kilogram     = 10¹   hectogram

= 10²   decagram

= 10³   gram

= 10⁴   decigram

= 10⁵   centigram

= 10⁶   milligram

1 milligram   = 10^-1  centigram

= 10^-2  decigram

= 10^-3  gram

= 10^-4  decagram

= 10^-5  hectogram

= 10^-6  kilogram

100   kg        = 1 quintal

1000 kg        = 1 metric ton

Weight: FPS System

1 dram          = 27.344 grains

1 ounce (oz)  = 16 drams = 437.5 grains

1 pound (lb)  = 16 oz = 7,000 grains
1 stone         = 14 lbs = 224 ounce

1 quarter      = 28 lbs = 448 oz

1 cwt           = 4 quarters = 112 lbs      

1 ton            = 20 cwt = 2,240 pounds

Conversions

1 kilogram   = 35.274 oz = 2.204 lbs

1 lb             = 0.4536 kg = 453.6 gm

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