Table 2.

Comfort levels recommended by the Chartered Institution of Building Services Engineers (CIBSE 1986)

Parameter	Recommended level
Temperature (dry bulb)	19-23°C
Relative humidity (RH)	40-70%
	More than 55% RH is needed in carpeted buildings with under floor heating to avoid electrostatic shocks
Ventilation
Delivery of fresh air	8 l/s/person (minimum)
	16 l/s/person where some smoking
	25 l/s/person where heavy smoking
Total air supply	4–6 air changes/h
Air speed	0.1–0.3 m/s. Less than 0.1 m/s causes stuffiness. More than 0.3 m/s causes draughts. For air speeds higher than 0.1 m/s, CIBSE recommends an increase in air temperature to take account of air movement
Sound	46 dBA is the upper limit for general office work
Lighting	500 lux for general office work, 750 lux for deep-plan offices and work at drawing boards, proofreading, etc.