Rules of thumb | Archive Titles

Table 1 External conditions
Design area	Application	Other information	Rule of thumb
Winter Design temperatures for heating	Without surplus boiler capacity	听	-4掳颁
听	With 20% surplus boiler capacity	Single-storey building	-3掳颁
听	听	Other buildings	-1掳颁
听	Rate of lowering outdoor design temperature with altitude above sea level	听	-0路6掳C/100 m
Summer design temperature for air conditioning	听	Dry bulb temperature	28掳颁
听	听	Wet bulb temperature	19掳颁

Table 2 Ventilation and air conditioning
Design area	Application	Other information	Rule of thumb
Ventilation: recommended maximum temp.	Offices	95% operation/year	25掳颁
Air conditioning: recommended maximum temp	Offices	95% operation/year	24掳颁 (or lower)
IT rooms by classification	Type A IT rooms	Specifically designed and built for IT equipment (ideally, Isolated from office areas)	Dedicated IT room required
听	Type B IT rooms	Designed for intensive use of IT equipment at workstations (where air-conditioning must be used)	Air-conditioned office, room or workspace
听	Type C IT rooms	Room where IT equipment is used at workstations (may use natural or mechanical ventilation)	Non air-conditioned office, room or workspace

Table 3 Room air movement
Design area	Application	Other information	Rule of thumb
Maximum recommended mean air velocities	听	In winter	0路15 m/s
听	听	In summer	0路25 m/s
听	听	At 21掳C	0路15 m/s
听	听	At 22掳颁	0路20 m/s
听	听	At 23掳C	0路25 m/s
听	听	At 24掳颁	0路30 m/s
听	听	On back of neck	0路20 m/s
听	听	Papers will lift at velocities in excess of	0路80 m/s
听	听	Television and broadcasting studios	0路20-0路30 m/s

Table 4 Noise levels
Design area	Application	Other information	Rule of thumb
Recommended maximum background noise levels	Very quiet rooms	Concert halls, sound studios	NR 20
听	Quiet rooms	Bedrooms, theatres, churches	NR 25
听	Private rooms	Small offices, libraries, living rooms	NR 30
听	Public rooms	General offices, classrooms, small shops	NR 35
听	General areas	Reception areas, restaurants	NR 40
听	Work areas	Kitchens, computer rooms, large shops	NR 45
听	Industrial areas	Factories	NR 50 or above
Intelligibility of telephone conversation background noise levels	听	Satisfactory	Up to NR 50
听	听	Slightly difficult	Up to NR 60
听	听	Difficult	Up to NR 60
听	听	Unsatisfactory	Over NR 75
External noise level criteria for new noise (above background noise)	听	If more than 10 dBA	Complaints expected
听	听	If less than 5 dBA	Marginal
Limiting distances for speech intelligibility (background noise level)	听	Up to NR 40	7路0 m
听	听	Up to NR 45	4路0 m
听	听	Up to NR 50	2路2 m
听	听	Up to NR 55	1路2 m
听	听	Over NR 70	Too noisy

Table 5: Comfort data sheet
星空传媒 type	Internal design temperature	Infiltration	Ventilation	Lighting level	Noise level	听
听	Summer	Winter	(ac/h)	fresh air	(Lux)	(NR)
Cinemas (sedentary role)	21-23掳颁	19-21掳颁	0路5 ac/h	8 l/s/person	300 lux	NR25 - NR30
Computer rooms (general)	21-23掳颁	19-21掳颁	1 ac/h	8 l/s/person	300 lux	NR35 - NR45
Education (teaching spaces)	21-23掳颁	19-21掳颁	2 ac/h	8 l/s/person	300 lux	NR25 - NR35
Exhibition hall/conference facilities	21-23掳颁	19-21掳颁	0.25-0.5 ac/h	8 l/s/person	300 lux	NR40
Factory/warehouse	21-23掳颁	11-21掳颁	0.25-2.5 ac/h	8 l/s/person	750-1000 lux	NR45 - NR 65
Fitness/health clubs (equipment rooms)	18掳颁	12-18掳颁	0.75 ac/h	10-12 ac/h	300 lux	NR30 - NR40
Hospitals (ward and patient areas)	23-25掳颁	22-24掳颁	2 ac/h	8 l/s/person	50 - 100 lux	NR30 鈥� NR35
Hotels (bedrooms)	21-23掳颁	19-21掳颁	1 ac/h	8 l/s/person	50 - 100 lux	NR20 鈥� NR30
Libraries (reading rooms)	24-25掳颁	22-23掳颁	0路25-0路75 ac/h	8 l/s/person	300 lux	NR30 鈥� NR35
Museums and galleries (display, storage)	21-23掳颁	19-21掳颁	1 ac/h	8 l/s/person	200 lux	NR30 鈥� NR35
Offices (general, BCO data)	24掳颁	22掳颁	0路25-0路5 ac/h	8-12 l/s/person	300-500 lux	NR25 鈥� NR40
Retail (shops/stores)	21-23掳颁	19-21掳颁	0路5-1 ac/h	8 l/s/person	500-750 lux	NR35 鈥� NR45
Swimming pools (pool halls)	23-26掳颁	23-26掳颁	0路5 ac/h	0-15 l/s/m² (of wetted area)	300 lux	NR40 鈥� NR 50
While every effort has been made to establish current practice, the guide鈥檚 authors are keen to point out that the rules of thumb are merely aids to the design process.
They must not be used in place of detailed design data. The responsibility for the safe and appropriate use of this data rests with the engineer.

星空传媒