These parameters specify the radiant characteristics of the installed plant and the incidental gains.
Radiant Proportion
This parameter specifies the proportion of the emitter's output which is in the form of radiant energy. Typical values for different types of gains are provided in the table below.
View Coefficient
This parameter is used solely for the calculation of mean radiant temperature and resultant temperature. It specifies the degree to which radiation from the emitter contributes to the occupants' perception of the radiant environment.
The view coefficient is a number which normally lies in the range 0 to 1. For most purposes, the values of view coefficients may be taken from the last column of the following table.
The table indicates the formula applicable to each type of emitter, and suitable values for the correction factors appearing in that formula. The values in the last column have been calculated for a room of dimensions 5m x 5m, and in the cases dealing with ceiling and floor heating, the value of e (distance between observer and emitting plane) is taken to be 1.3m.
Conditions under which these values may not be valid include the following:
Large rooms (dimensions much greater than 5m).
Ceiling emitters or other overhead emitters where the value of e is significantly different from 1.3m.
In such cases the formulae should be used (see below).
When applying the formulae, it should be understood that the dimensions referred to are those of a typical room, not those of the Tas zone.
If the room contains emitters of different types within a given emitter category, (for example, ceiling lighting and task lighting), the view coefficient can be calculated as an average of the view coefficients appropriate to each emitter, weighted in proportion to emitter power.
Default value for emitter category.
Notes:
1) From equation 6.4-4a with h/d = 5.5
2) From equation 6.4-3a.