Indoor environment

Pol is the unit of perceived air quality in a space with a sensory load of 1 olf ventilated by 1 L/s.

It is the unwanted cooling sensation caused by the movement of indoor air. DR is the

draught rate, the percentage of people dissatisfied because of the draught. It is a function of air

temperature, air velocity, and turbulence intensity.

Predicted Mean Vote

• Index using a scale (psychophysics 7-point scale) from +3 (Hot) to -3 (Cold), where 0 corresponds to thermal neutral

• PMV-values can be calculated for a given situation on the basis of air temperature, mean radiant temperature, air velocity, humidity, activity, and clothing level

Predicted Percentage of Dissatisfied can be derived from PMV and this relates to the temperature range.

PPD = 100 – 95·exp(-0.03353·PMV4 – 0.2179·PMV2)

PPD is the predicted percent of dissatisfied people at each PMV. As PMV changes away from zero in

either the positive or negative directions, PPD increases.

Optimum operative temperature: ‘…where a maximum number of the occupants can be expected to feel the indoor temperature acceptable’

A unit used to describe the energy generated inside the body due to metabolic activity. It is defined as = 58 W/m2 body surface, which is equal to the energy produced per unit surface of an average person (relaxed).

Isolation of clothing: It expresses the thermal resistance between the surface of the skin and the outer surface of the clothing. Expressed in: m2K/W, or clo (relative unit). Unit of clo:1 clo = 0.155 m2K/W. Corresponds to insulation required to maintain a sedentary person (activity level of one met) comfortable at 21 °C, 50% RF and 0.1 m/s air velocity.