Costing and Estimation ofWorks - Afforestation, Reforestation and Forest Restoration in Arid and Semi-arid Tropics - page 193

Table 7.15 (continued)
Unit Definition Value in metric unit

kilovolt (kV) 1,000 V = 1kV 1kV

megavolt (MV) 1,000 kV = 1MV 1MV

Temperature
kelvin (K) Basic unit K

Celsius ( ◦ C)

Celsius = kelvin + 273.15 K + 273.15

Fahrenheit ( ◦ F)

Freezing = 32, boiling = 212 (F − 32)/1.8 Celsius

centigrade (C) 100 centigrade = 99.99 Celsius K + 273.16

Illumination/light flux
lumen

=

1 lm 1 cd-usa

Brightness/luminous intensity
lux 1 lm/m 2 = 1 lux

foot-candle 1 lm/ft 2 = 1 foot-candle

candela 1 cd = 1/683 W/usa 1 cd

lambert 1 lm/sq cm = 1 lambert

Sound loudness
decibel (dB) 0 = imperceptible, 130 = painful 1 dB

Speed/velocity
kilometre per hour (kmph) Basic unit 1 kmph

mile per hour (mph) Basic unit 1.61 kmph

knot (kn) 1 knot = 1 nautical mile per hour 1.85 kmph

Fuel consumption
kilometre per litre (km/l) Basic unit 1 kmpl

mile per gallon (mpg) Basic unit 2.82 mpg

Area of land is usually expressed in hectares. In many places the acre may be
better understood, or it can be some other area unit. However, one should be wary of
using such local units because these may not be same across all places—for example,
a bigha of land in different places in India may mean different square metres. The
units of area and their interrelationships have been laid down in Table 7.15 .
Wherever reference is made to measurement of land in this topic, it is the horizon-
tal plane projection of the area that is meant, rather than the actual surface area of the
ground. In highly undulating and rugged terrain, the actual land surface area may ex-
ceed its plane area (the area as projected on the horizontal plane) by as much as 30 %.
Calculated spacing of plants and plant densities in such cases may not exactly tally.
Measurement of volumes is important in calculating quantities like soil work and
potting mix. For example, filling of polypots involves calculation of total volume of
potting mix as well as the volumes of the individual components of the mix. The
personnel concerned should be familiar with the units to be used for such measure-
ment. The various units in volumetric measurement and their interrelationships have
been laid out in Table 7.15 . It would be of interest to note that the percentage errors
in volumetric quantities, such as the volume of a pit, will be three times as high as
the percentage errors in their corresponding linear measurement.
It is common in industry and trade to express thickness of metal wires and sheets
in terms of gauge. Often the meaning of such gauges may not be apparent. Many