Humidity Plus (Calculates Unknown Psychrometric Values)

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  • Relative Humidity
    Air (or empty space, or any other gas) has a given capacity to hold water vapour. This capacity, depends mainly on temperature.
    In general, the hotter the air, the more water vapour it can hold. At any given temperature, air that contains its full capacity of water vapour, is said to be "saturated".

    The "relative humidity" of the air expresses how fully saturated it is with water vapour.
    A variety of other ("absolute") measures are used to express how much mass of water vapour is actually present (irrespective of temperature or level of saturation).

    This program calculates the values of (see list below) in accordance with the functions, constants and polynomials defined in BS 1339 Part 1 (2002)

    Other polynomials can be selected :

    BS 1339 default constants can be selected or varied for the following :

    Variables determined :


    • Pressure units : Pa, kPa, MPa, mbar, m H O, mm Hg, kgf/cm, atm, in H O, in Hg, lbf/in, lbf/ft
    • Temperature units : C, F, K, R
    • Density units : kg/m, g/m, lb/ft, gr/ft
    • Specific volume units : m/kg, dm/kg, ft/lb, in/lb
    • Mixing ratio units : kg/kg, g/kg, lb/lb, gr/lb
    • Specific energy units : kJ/kg, J/kg, Btu/lb, ft lbf/lb
    • Altitude units : mm, cm, metre, km, inch, feet, mile
    • Altitude calculated to ISA : ISO
    • Results can be copied to the Clipboard
    • Print results
    New for :   New for 2008   Main menu   Home page