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Equipment and solar loads
Table 1: Cooling loads
Design areaApplicationOther informationRule of thumb
Banks  160 W/m2
Computer suites  400 W/m2 approx
Hotels:  150-300 W/m2
Offices (general)  125 W/m2
 Interior zones more than 7 m from windows 75 W/m2
 Perimeter zones60% glazing120 W/m2
 up to 6 m65% glazing180 W/m2
Restauarants  220 W/m2
Retail buildings  140 W/m2
Table 2: Cooling plant
Design areaApplicationOther informationRule of thumb
Central cooling plant Load/m2 of floor area125 W/m2
  Load/m3 of floor volume 40 W/m3
Distributed cooling plant Load/m2 of floor area140 W/m2
  Load/m3 of floor volume45 W/m3
Electrical power for refrigeration plantkW/kW cooling capacityCentral plant0·5 kW/kW
  Distributed plant0·78 kW/kW
Table 3: Solar gains (floor area)
Design areaApplicationOther informationRule of thumb
Windows with internal blindsJune-SeptemberSouth facing250 W/m2 of glass
 June-SeptemberEast-West facing150 W/m2 of glass
Clear double glazed with internal blindsOut of town buildingsAll data for 6 m deep, 2650 W instant
  1500 mm wide module. U-value 3·3 W/m2K2490 W lag (mass)
As above with flat slabPlus brise soleil 1860 W instant
   1710 lag (mass)
As above with coffered slab Plus brise soleil 1860 W instant
   1680 lag (mass)
Table 4: Heat loads
Design areaApplicationOther informationRule of thumb
General buildings Floor area90 W/m2 (30 W/m2)
Educational buildings  100 W/m2
Industrial buildings  80 W/m2
Offices  70 W/m2
Residential buildings  60 W/m2
Retail buildings  110 W/m2
Heat gainsOfficesMetabolic10 W/m2
  Lighting12 W/m2
 General officesSmall power loads (diversified over minimum of 1000 m2)15 W/m2
Electrical systems
Table 1: Electrical supplies and loads
Design areaApplicationOther informationRule of thumb
Electrical supplyElectrical motorsAbove 3 kW rating3-phase supply
 Electrical motorsUp to and including 3 kW ratingDirect on-line starting
 Electrical motorsAbove 4 kW ratingAssisted start
Electrical services load per m2 of building floor area for offices unless otherwise statedLighting 10-12 W/m2
 Small power diversified over a minimum of 1000 m2 15 W/m2
 Air conditioning 60 W/m2
 Passenger lifts 10 W/m2
 Small computer roomNet area200-400 W/m2
 Bespoke call centresNet area500-1000 W/m2
Total load (kVA) Design allowance for future expansion (percentage)Total building load Total kW/0·8
 Percentage increase in load Add 25% to exisitng capacity
Water consumption
Table 1: Hot water demand, daily
Design areaApplicationOther informationRule of thumb
DwellingsSingle bedroom 115 litres/bedroom
 Two bedrooms 75 litres/bedroom
 More than three bedrooms 55 litres/bedroom
Student accommodation, nurses’, children’s and sheltered home  70 litres/bedroom
Care home  90 litres/bedroom
HotelsBudget 115 litres/bedroom
 Four/five star 135 litres/bedroom
Offices, shops, factoriesWith canteen 15 litres/person
 No canteen 10 litres/person
SchoolsDay school 15 litres/pupil
 Boarding school 114 litres/pupil
HospitalsDistrict general 200 litres/bed
 Surgical and medical wards 110 litres/bed
 Paediatric wards 125 litres/bed
 Geriatric wards 70 litres/bed
Sports changing roomsSports hall and swimming pool20 litres/person 
 Field and all weather pitch 35 litres/person
Places of assemblyArt gallery, bars and library 2 litres/person (excluding staff)
 Museum, theatre, cinema and night club1 litre/person (excluding staff) 
Table 2: Water demand, daily
Design areaApplicationOther informationRule of thumb
DwellingsSingle bedroom 210 litres/bedroom
 Two bedrooms 130 litres/bedroom
 Over three bedrooms 100 litres/bedroom
Student accommodation  90-100 litres/bedroom
Nurses’ homes and sheltered homes  120 litres/bed space
Children’s home, and elderly care home  135 litres/bed space
Prison  150 litres/inmate
HotelsBudget 135-150 litres/bedroom
 Four/five star 200 litres/bedroom
Offices, shops, factoriesWith canteen 45 litres/person
 No canteen 40 litres/person
SchoolsNursery and primary 15 litres/pupil
 Secondary 20 litres/pupil
 Boarding 90 litres/pupil
HospitalsDistrict general 600 litres/bed
 Surgical wards 220 litres/bed
 Medical wards 220 litres/bed
 Paediatric wards 300 litres/bed
 Geriatric 140 litres/bed
Sports changing roomsSports hall and swimming pool20 litres/person 
Field and all weather pitch  35 litres/person
Places of assemblyArt gallery, library and museum6 litres/person (excluding staff) 
 Bars and night club 4 litres/person (excluding staff)