1 0 0 2 / 5 1 N T E T O N L A C I N H C E T
Rules of Thumb
(UK 3rd edition)
Guidelines for assessing building services Edited by Martin Boushear
Contents Space and weight allowances TABLE TABLE TABLE TABLE TABLE TABLE TABLE TABLE
6
1: Floor space allowance for services 2: Space allowances for plant rooms 3: Miscellaneous services 4: Space allowances for on-floor services 5: Space allowances for service ducts and shafts 6: Space allowances for catering facilities 7: Floor space allowance per occupant 8: Plant weight allowances
Equipment and solar loads
14
Acknowledgements The story behind the guide This publication is the third update of the Technical Note TN 17/95: Rules of Thumb last issued in 1995. The rules have been collected from various contemporary sources in the building services industry and can reasonably be held to reflect current design practices. The sources include major design offices, individual engineers and public domain information published by BSRIA and others.
How to use this guide What this guide will do Rules of Thumb has been written to help engineers in the initial stages of designing a building and its services. By gathering many of the most common rules of thumb into one document, BSRIA has provided a powerful source of inital design data that every engineer should find indispensable. Thumb rules (or heuristics as they are more properly known) are extremely useful values for use at various stages of design, such as project
6
When to us e:
Space and weight allowances
During the early stages of design prior to plant selection or system analysis
Where to use: Plant room sizes, riser cupboard locations and plant capacities Watch out for: Poor information that fails to allow for installation, commissioning or maintenance
TABLE 1: Floor space allowance for services (as a percentage of floor area)
R u l e s o f T h u m b B S R I A 2 0 0 1
Design area
Application
All services
Air conditioning (excluding boilers & refrigeration)
Other information
Rule of thumb
Ref
Simple factory Offices and commercial Hi-tech building
4% 6 – 10% 15 – 30%
26 26 26
Fan coil system VAV system
1 5 – 2 5% 3 – 4 5%
26 26
0 3 – 1 5%
26
Electrical services (excluding sub-stations and standby generation sets)
0 5 – 1 5%
26
Lift motor rooms
0 2 – 0 5%
26
Cooling towers and air-cooled condensers
Refrigeration (excluding cooling towers)
Ventilation
Central plant
1 – 2%
26
Toilet extract Supply and extract system All air low velocity system
03 – 1% 3 – 5% 4 – 6%
26 26 26
Your notes and comments
Table 1 continu ed For references see page 32
TABLE 2: Space allowances for plant rooms (floor area) Design area
Application
Air cooled condenser and controls
Air handling units
R u l e s o f T h u m b B S R I A 2 0 0 1
Other information
Rule of thumb
Ref
space for installation and maintenance
25 + kW/200 m 2
29
With extract /recirculation
8 m 2 per m3/s
29
Without extract /recirculation
5 m 2 per m3/s
29
Boilers (percentage floor area)
Boiler plant & calorifiers
Oil tank room
08 – 1 8% 1 – 2%
26 26
Boilers (floor area and height)
Boilers, pumps, piping and space for installation and maintenance
Output: 100 kW Output: 200 kW Output: 1000 kW Output: 4000 kW
15 m2 x 3 m 25 m2 x 3 m 80 m2 x 4 m 30 m2 x 5 m
29 29 29 29
Calorifiers (floor area and height)
Calorifiers, pumps, pipework, controls and space for installation and maintenance
Vertical (1 m3) Vertical (5 m 3) Vertical (10 m3) Ver tical (15 m3)
10 m2 x 3 m 20 m2 x 4 m 25 m2 x 5 m 60 m2 x 3 m
29 29 29 29
25 m2 x 3 m 30 m2 x 3 m 45 m2 x 3 m 60 m2 x 3 m
29 29 29 29
Horizontal Horizontal Horizontal Horizontal
(1 m3) (5 m3) (10 m3) (15 m3)
Your notes and comments
Table 2 continu ed 7
For references see page 32
Space and weight allowances
8
TABLE 2: Space allowances for plant rooms (floor area) Design area
Application
Other information
Rule of thumb
Ref
Chillers (water cooled) Floor area times height
With pumps, pressurisation, pipework and control panels
Output: 1000 kW Output: 2000 kW Output: 3000 kW Output: 4000 kW
50 m2 x 3 m 63 m2 x 3 m 83 m2 x 3 5 m 108 m2 x 4 m
29 29 29 29
Located outside . I nc lu de s sp ac e for installation and maintenance
Output: 20 0 kW O ut pu t: 40 0 k W Output: 600 kW Output: 800 kW Output: 1000 kW Output: 1200 kW
39 m 2 53 m 2 75 m 2 84 m 2 98 m 2 116 m2
29 29 29 29 29 29
Single cold water tank Includes space for installation and maintenance but add space for pressurisation plant or circulation pumps
FA: Floor area V: gross storage m 3 1 m high 2 m high 3 m high
FA: 10 + V/0 75 m 2 FA: 10 + V/1 6 m 2 FA: 10 + V/2 4 m 2
29 29 29
Minimum for hot and cold outlets
Offices
10-20 litres/person
4
R Chillers (air cooled) u l e s o f T h u m b B S R Cold water storage I A 2 0 0 1
Cold water storage
Hotels, children’s home, residential nursery, 135 litres/bed space convalescent home
Your notes and comments
4
Table 2 continu ed For references see page 32
Design area
Application
Other information
Rule of thumb
Ref
Cold water storage (domestic) continued
Minimum for hot and cold outlets
Restaurant Day school Hostel
7 litres/meal 15-20 litres/pupil 90 litres/bed space
20 20 20
FA: Floor area (kW: heat rejection)
FA: 50 + kW/66 m 2
29
HV switchgear HV + MV switchgear
47 m 2 14 m 2 27 m 2
29 29 29
Standby sets and accessories
FA: Floor area
FA:15 + kVA/30 m 2
29
Single module system (add space for batteries)
FA: Floor area
FA: (2 + kW/200) x 2 m 2
29
Other information
Rule of thumb
Cooling towers
Sub-station
R u l e s o f T Standby generation h u m b B S Uninterruptible power supply R I A 2 0 0 1
2000 kVA transformers Switchgear
Your notes and comments
TABLE 3: Miscellaneous services
9
Design area
Application
Control panels & distribution boards
Front panel controls, Fixing height range wall-mounted or floor (above finished floor standing or operating platform level)
LTHW boiler plant component criteria for leakage containment
Oil storage tanks, distillate & residual fuel oils
For references see page 32
If tank fails, walls and doors treated to contain spillage
1200 – 1800 mm
Tank contents + 10%
Ref 18
19
Your notes and comments
Space and weight allowances
1 0
TABLE 4: Space allowances for services (depth of clear space in ceiling/floor void)
R u l e s o f T h u m b B S R I A 2 0 0 1
Design area
Application
Air conditioning
Rule of thumb
Ref
VAV VRV Recessed chilled beams Surface chilled beams Chilled ceilings Fan coils Ducted air system
350 – 750 mm 450 mm 350 – 450 mm 250 mm 250 mm 450 mm 450 mm
16 16 16 16 16 27 27
Drainage Soil and waste
100 mm dia. 150 mm dia.
10 – 25 mm per m run 7 – 16 mm per m run
27 27
Lighting
Fluorescent Downlighter
100 – 150 mm ( access) 16
Power and communications
For references see page 32
Other information
150 – 300 mm
16
100 – 200 mm
16
Power and data (heavy line)
200 – 250 mm
16
Computer rooms
300 mm
16
Multi-core cables and lighting cables
Your notes and comments
TABLE 5: Space allowances for service ducts and shafts Design area
Application
Air ducting
Lift shafts
Mechanical service riser
R u l e s o f T h u m b Pipework B S R I A 2 0 0 1
Service ducts
1 1
For references see page 32
Other information
Rule of thumb
Ref
Typical ducting size
02 m 2/m3/s
30
3+A(N-4)/250 m 2
30
Between 4 –18 floors Internal shaft area in office-type buildings A: floor area/ storey (250 m2 min), N: Floors
S imp le pi pewor k riser
T hr ee -si de d r is er
Vertical service duct
D ep th ne ed ed to op en access door/pane when width of door varies with size/type of pipe or depth of service/duct 690 mm
17
Pipe: 20 mm dia. Pipe: 25 mm dia. Pipe: 32 mm dia.
100 mm x 100 mm 120 mm x 120 mm 130 mm x 130 mm
30 30 30
M in imu m d ep th from services to (open) access door/panel
690 mm
17
Floor space served by vertical service (radius)
15 – 23 m
30
Aspect ratio of vertical service duct
2:1 – 4:1
30
Total duct area as % of gross floor area
2%
30
Your notes and comments
Space and weight allowances
1 2
TABLE 6: Space allowances for catering facilities
R u l e s o f T h u m b B S R I A 2 0 0 1
Design area
Application
Other information
Rule of thumb
Ref
Kitchen and dining facilities
Kitchens including preparation and storage
Min. requirements: Up to 100 meals Up to 500 meals
0 4 m 2/meal 0 25 m 2/meal
31 31
For single sittings
Ratio of kitchen space to dining space
0 33:1 to 0 5:1
31
Ratio of kitchen space to dining space
1:1
31
For multiple sittings
Your notes and comments
TABLE 7: Floor space allowance per occupant (net internal area) Design area
Rule of thumb
Ref
General offices
12 – 17 m 2/person
4
Trading desks, call centre, work stations
4 – 6 m 2/person
4
15 m 2 (or more) per person
4
Enclosed offices
For references see page 32
Application
Other information
Your notes and comments
TABLE 8: Plant weight allowances
R u l e s o f T h u m b B S R I A 2 0 0 1
Design area
Application
Single boiler
Rule of thumb
Ref
500 kW 1500 kW 2500 kW
1500 kg 4250 kg 6500 kg
39 39 39
Single storage steel calorifier
4 m3 8 m3 12 m3
1250 kg 2500 kg 3300 kg
39 39 39
Single non-storage mild-steel heating calorifier
500 kW 1000 kW 1500 kW 2000 kW
150 225 275 325
kg kg kg kg
39 39 39 39
1500 kW 3000 kW 4500 kW
10 000 kg 20 000 kg 30 000 kg
39 39 39
Single air-cooled liquid chiller
500 kW 1000 kW 1500 kW
6 000 kg 11 000 kg 14 000 kg
39 39 39
Single generator
500 kVa 1000 kVa 1500 kVa
5000 kg 8000 kg 11 000 kg
39 39 39
100 kVa 300 kVa 500 kVa
1250 kg 2750 kg 4250 kg
39 39 39
Single water-cooled liquid chiller
Single UPS system
1 3
For references see page 32
Other information
Your notes and comments
1 4
When to use:
For estimates of thermal loads used to assess plant and terminal equipment sizes
How to use:
To determine total solar and internal gains, multiply the loads by total floor area
Watch out for:
Solar gains depend on glazing and shading, and contribution of thermal mass
Equipment and solar loads
TABLE 1: Cooling loads Design area
R u l e s O f T h u m b B S R I A 2 0 0 1
Application
Other information
Rule of thumb
Ref
Banks
160 W/m2
34
Computer suites
400 W/m 2 approx
34
Hotels
150 – 300 W/m 2
34
125 W/m 2
34
75 W/m2
34
120 W/m2 180 W/m2
34 34
Restaurants
220 W/m2
34
Retail buildings
140 W/m2
34
Other information
Rule of thumb
Ref
Central cooling plant
Load/m2 of floor area Load/m3 of floor vol.
125 W/m 2 40 W/m3
36 36
Distributed cooling plant
Load/m2 of floor area Load/m3 of floor vol.
140 W/m 2 45 W/m3
36 36
Offices (general)
Interior zones more than 7 m from windows Perimeter zones up to 6 m
60% glazing 65% glazing
Your notes and comments
TABLE 2: Cooling plant Design area
Electrical power for refrigeration plant
For references see page 32
Application
kW/kW cooling capacity
Central plant Distributed plant
0 5 kW/kW 0 78 kW/kW
36 36
Your notes and comments
TABLE 3: Solar gains (over floor area) Design area
Application
Other information
Rule of thumb
Ref
(June-Sept) (June-Sept)
South facing East-West facing
250 W/m 2 of glass 150 W/m 2 of glass
34 34
Clear double-glazed with internal blinds
Out-of-town building
U-value 3 3 W/m 2K
2650 W/m2 instant 2490 W/m2 lag (mass)
40 40
As above with flat slab
Plus brise soleil
1860 W/m2 instant 1710 W/m2 lag (mass)
40 40
As above with coffered slab
Plus brise soleil
1860 W/m2 instant 1680 W/m2 lag (mass)
40 40
Other information
Rule of thumb
Ref
Floor area
90 W/m2 (30 W/m3)
34
Educational buildings
100 W/m2
34
Industrial buildings
80 W/m2
34
Offices
70 W/m2
34
Residential buildings
60 W/m2
34
Infiltration: air heating load
7 5 W/m3
34
Retail buildings
110 W/m2
34
10 W/m2 12 W/m2 15 – 25 W/m 2
16 16 16
Windows with internal blinds
R u l e s O f T h u m b B S R I A 2 0 0 1
TABLE 4: Heat loads Design area
Application
General buildings
Other heat gains
Offices Ge ne ral of fi ce s
1 5
Your notes and comments
For references see page 32
Metabolic Lighting O ff ic e e qu ip me nt
Your notes and comments
1 6
When to us e:
During the early stages of design prior to plant selection or system analysis
Where to use:
Plant room sizes, riser cupboard locations and plant capacities
Watch out for:
Poor information that fails to allow for installation, commissioning or maintenance
Comfort factors
TABLE 1: External conditions Design area
Application
Winter design temperatures for heating
Without surplus boiler capacity With 20% surplus boiler capacity
R u l e s o f T h u m b B S R I A 2 0 0 1
Other information
Single-storey building Other buildings
Rate of lowering outdoor design temp. with altitude above sea level
Rule of thumb
Ref
-4 C
37
-3 C -1 C
37 37
-0 6 C/100 m
37
Summer design temperature
Dry bulb temp.
28 C
37
for air conditioning
Wet bulb temp.
19 C
37
Your notes and comments
TABLE 2: Ventilation and air conditioning Design area
Application
Other information
Rule of thumb
Ref
Ventilation: recommended maximum temperature
Offices
95% operation/year
25 C
4
Air conditioning: recommended maximum temperature
Offices
95% operation/year
24 C (or lower)
4
IT rooms by classification
Type A IT rooms
Specifically designed and built for IT equipment (ideally, isolated from Dedicated IT room office areas) required
Your notes and comments
38
Table 2 continu ed For references see page 32
TABLE 3: Information technology Design area
Application
Other information
IT rooms by classification (continued)
Type B IT rooms
Designed for intensive use of IT equipment at workstations (where air-conditioning must be used)
Ty pe C I T ro oms
R u l e s o f T h u m b B S R I A 2 0 0 1
Ref
Air-conditioned office, room or workspace
38
Your notes and comments
R oom w he re I T equipment is used at workstations (may use natural or mechanical ventilation)
Non air-conditioned office, room or workspace
38
Other information
Rule of thumb
Ref
In Winter In Summer At 21C At 22C At 23C At 24C On back of neck
0 15 m/s 0 25 m/s 0 15 m/s 0 2 m/s 0 25 m/s 0 3 m/s 0 2 m/s
37 37 37 37 37 37 37
Papers will lift at velocities in excess of
0 8 m/s
37
0 2 – 0 3 m/s
2
TABLE 4: Room air movement Design area Maximum recommended mean air velocities
Application
Television and broadcasting studios
1 7
Rule of thumb
For references see page 32
Your notes and comments
Comfort factors
1 8
TABLE 5: Noise levels Design area
Application
Other information
Recommended maximum background noise levels
Very quiet rooms
Concert halls, sound studios Bedrooms, theatres, churches Small offices, libraries, living rooms General offices, classrooms, small shops Reception areas, restaurants Kitchens, computer rooms, large shops Factories
Quiet rooms Private r ooms
R u l e s o f T h u m b B S R I A 2 0 0 1
Public rooms General areas Work areas Industrial areas
Rule of thumb
Ref
NR 20
37
NR 25
37
NR 30
37
NR 35
37
NR 40
37
NR 45 NR 50 or above
37 37
Intelligibility of telephone conversation at background noise levels
Satisfactory Slightly difficult Difficult Unsatisfactory
Up to NR 50 Up to NR 60 Up to NR 75 Over NR 75
37 37 37 37
External noise level criteria for new noise (above background noise)
If more than 10 dBA If less than 5 dBA
Complaints expected Marginal
37 37
Limiting distances for speech intelligibility (background noise level)
Up to NR 40 Up to NR 45 Up to NR 50 Up to NR 55 Over NR 70
7m 4m 2 2 m 1 2 m Too noisy
37 37 37 37 37
For references see page 32
Your notes and comments
TABLE 6: Comfort data sheet Building Type
R u l e s o f T h u m b B S R I A 2 0 0 1
1 9
Summer
Winter
Humidity (% RH)
Infiltration (ac/h)
Ventilation fresh air
Ventilation air change
Lighting level (Lux)
Noise level (NR)
Cinemas (sedentary role)
21-23C
19-21C
5010% RH
05 ac/h
8 l/s/person
6-10 ac/h
300 lux
NR25-NR30
Computer rooms (general)
21-23C
19-21C
505% RH
1 ac/h
8 l/s/person
4-15 ac/h
300 lux
NR35-NR45
Education (teaching spaces)
21-23C
19-21C
505% RH
2 ac/h
8 l/s/person
6-10 ac/h
300 lux
NR25-NR35
Exhibition hall/conference facilities
21-23C
19-21C
50-55% RH
025-05 ac/h
8 l/s/person
1 ac/h
300 lux
NR40
Factory/warehouse
21-23C
11-21C
5010% RH
025-25 ac/h
8 l/s/person
6 ac/h
750-1000 lux
NR45-NR65
Fitness/health clubs (e qu ip me nt r ooms )
> 18C
12-18C
40-70% RH
075 ac/h
8 l/s/person
4 ac/h
300 lux
NR30-NR40
Hospitals (ward and patient areas)
23-25C
22-24C
50-60% RH
2 ac/h
8 l/s/person
3 ac/h
50-100 lux
NR30-NR35
Hotels (bedrooms)
21-23C
19-21C
5010% RH
1 ac/h
8 l/s/person
6-10 ac/h
50-100 lux
NR20-NR30
Libraries (reading rooms)
24-25C
22-23C
505% RH
025-075 ac/h
8 l/s/person
3-4 ac/h
300 lux
NR30-NR35
Museums and galleries (display, storage)
21-23C
19-21C
50-55% RH
1 ac/h
8 l/s/person
3-4 ac/h
200 lux
NR30-NR35
Offices (general, BCO data)
24C
22C
35-40% RH
025-05 ac/h
8-12 l/s/person
4-6 ac/h
300-500 lux
NR25-NR40
Retail (shops/stores)
21-23C
19-21C
455% RH
05-1 ac/h
8 l/s/person
3-8 ac/h
Swimming pools (pool halls)
23-26C
23-26C
40-70% RH
05 ac/h
0-15 l/s/m2 (of wetted area)
Your notes and comments
For references see page 32
Internal design temperature
500-750 lux
NR35-NR45
300 lux
NR 40-NR50
2 0
When to use:
During outline design before the architect has finalised space planning
Where to use:
For determining the spatial and operational characteristics of main plant
Watch out for:
The rules for boiler and cooling plant are based on unit floor area or unit volume
System features
TABLE 1: Sizing and operating characteristics of plant Design area Air handling units Air face velocity
Application
Rule of thumb
Ref
2 5 – 4 m/s 1 0 – 2 5 m/s
36 16
Heating mode Cooling mode
30C (max) 13C (min)
16 16
Air discharge
0 6 – 2 m/s
36
10 – 40 kPa 0 33 – 172 bar
16 36
8m Not to exceed 50 mm within 1m of diffuser outlet
36
Maximum height
66% of ceiling height
36
Allowance for grille
Allow 0 3 m width
36
120 W/m2 floor area 40 W/m3 volume
36 36
Heating coil Cooling coil Air supply temperatures
R u l e s o f T h u m b B S R I A 2 0 0 1
Other information
Coil water velocity Water pressure drop Steam pressure drop
Air distribution From source
Ceiling diffusers
Non-zoning partitions Sill diffusers
Boiler plant capacity
Power per unit area
Limit of throw Surface projections
Your notes and comments
36
Table 1 continu ed For references see page 32
Design area
Application
Other information
Rule of thumb
Ref
Boiler plant efficiency
B oi le r e ff ic ie nc y E ff ic ie nc y l os se s
Ty pic al ef fic ie nc y B low dow n (s te am) Casing Flue
75% 2% 3% 15 – 20 %
36 36 36 36
Condensing boilers
Underfloor or warm water system
90%
22
Standard size radiators, variable temp circuit (weather compensation)
87%
22
Standard fixedtemperature emitters (83/72 C flow/return)
85%
22
M ode rn h ig h ef fi ci en cy boilers
80 – 82%
22
Good modern boiler design closely matched to demand
75%
22
Typical good boiler
70%
22
1 kW/person
36
Volume per kW
40 litres/kW
36
Low velocity systems High velocity systems
3 – 5 m/s 7 5 – 15 m/s
36 36
Boiler plant Typical seasonal efficiencies
R u l e s o f T h u m b B S R I A 2 0 0 1
No n- co nd en sin g boilers
Chiller plant capacity
Fuel storage
Ductwork Typical duct velocities
Class D oil
Your notes and comments
Table 1 continu ed 2 1
For references see page 32
System features
2 2
R u l e s o f T h u m b B S R I A 2 0 0 1
Design area
Application
Other information Rule of thumb
Ductwork
Inlet louvres
(through free area)
Maximum pressure drop rates (per m run)
Ref
2 5 m/s
36
Low velocity systems High velocity systems
1 Pa/m 8 Pa/m
36 36
Typical system resistances ( in cl udi ng air ha ndl in g p la nt )
Low velocity supply Low ve loc it y e xt ra ct High velocity supply
900 Pa 400 Pa 1 5 – 2 kPa
36 36 36
Air leakage system loss (%)
Low pressure systems Med. pressure systems High pressure systems
6% 3% 2%
15 15 15
Fans
Electrical input (kW)
1 6 x total fan pressure (kPa) x volume flow rate (m 3/s)
36
1C per kPa
36
Offices Restaurants Retail stores, halls, theatres
1 4 litres/s per m 3 3 5 litres/s per m 3 2 1 litres/s per m 3
23 23 23
Total system volume (system size, in litres)
Domestic systems Commercial systems
6 x boiler size (kW)+10% 3 10 x boiler size (kW)+10% 3
Capacity per unit area of radiator surface
Conventional system
1 litre/m 2
36
Capacity per unit of power produced (boilers, radiators)
Boilers Aluminium, cast radiator
1 5 litres/kW 3 litres/kW
36 36
Temperature rise of air Fan capacity of ventilated space
Class A Class B Class C
Total fan pressure
Your notes and comments
Heating systems
Approx. value Approx. value
Table 1 continued For references see page 32
Design area
Pipework Capacity per u nit lengt h of of steel pipe
Application
Rule of thumb
Ref
E xtruded aluminium Steel panel radiators
1 2 litres/kW 5 litres/kW
36 36
15 mm diamete r pipe 20 mm diameter pipe 25 mm diameter pipe 32 mm diameter pipe 40 mm diameter pipe
0 25 litres/m 0 4 litres/m 0 6 litres/m 1 2 litres/m 1 5 litres/m
36 36 36 36 36
15 –50 mm pipe dia. Over 50 mm pipe dia.
0 75 – 1 5 m/s 1 25 – 3 m/s
36 36
Initial pressure per 100 m pipe run
6%
36
Over 50 mm pipe dia.
100 – 300 Pa/m
16
Corrosive water
1 m/s 1 2 m/s 2 m/s max
36 36 36
Superheated steam Saturated steam Exhaust
40 – 60 m/s 30 – 40 m/s 20 – 30 m/s
36 36 36
4 9 litres/m 2
36
0 36 x circuit length
36
Water velocity Conventional systems
R u l e s o f T h u m b B S R I A 2 0 0 1
Steam pressure drop
Water pressure
Conventional systems
Water velocity (system)
Small bore Microbore
Steam velocity
Capacity per unit of finned area
Finned tube coils
Pumps Head pressure (pump head) Water treatment Additives required
Pressure (in kPa), length (m) Copper pipework Fr ost prot ection
2 3
For references see page 32
Other information
With steel pipework Add 10% to water Glycol concen trat ion
30% of system vol.
36 16
Your notes and comments
2 4
When to us e:
When determining total building energy consumption
Where to use:
From briefing onwards through to design and operation (See also CIBSE TM22)
Watch out for :
Change to the carbon conversion ratios which are continually being updated
Energy and carbon issues
TABLE 1: Energy conversions Design area Carbon dioxide emission (Kg CO2/ kWh de li ver y) by fu el
Application
N at ur al Ga s Oil Electricity Coal
Other information
Average
Carbon to CO2
R u l e s o f T h u m b B S R I A 2 0 0 1
Rule of thumb
Ref
019 025 046 030
1 1 1 1
kg kg kg kg
CO2/kWh CO2/kWh CO2/kWh CO2/kWh
Divide by 3 67
1
Your notes and comments
TABLE 2: Energy benc hmarks (offices) Design area
Application
Other information
Rule of thumb
Ref
Naturally ventilated (cellular) Type 1, simple relatively small building, sometimes converted residential, 100 – 3000 m2
E ne rg y c ost s ov er treated floor area (tfa)
G oo d p ra ct ic e Typical
£3.50 m2 tfa £6.00 m2 tfa
1 1
Gas or oil (delivered)
Good practice Typical
79 kWh/m2 151 kWh/m2
1 1
Electricity (delivered)
Good practice Typical
33 kWh/m2 54 kWh/m2
1 1
G oo d p ra ct ic e Typical
£4.50 m2 tfa £7.00 m2 tfa
1 1
Good practice Typical
79 kWh/m2 151 kWh/m2
1 1
Good practice Typical
54 kWh/m2 85 kWh/m2
1 1
Naturally ventilated (open plan) E ne rg y c ost s ov er Type 2, purpose-built, sometimes treated floor area converted industrial space, 500 m 2 – 4000 m 2 Gas or oil (delivered)
Electricity (delivered)
Your notes and comments
Table 2 continu ed For references see page 32
R u l e s o f T h u m b B S R I A 2 0 0 1
2 5
Design area
Application
Other information
Rule of thumb
Ref
Air conditioned (standard) Type 3, purpose-built, speculative often intensively used, 2000 – 8000 m2
Energy costs
Good practice Typical
£8.00 m 2 tfa £14.00 m 2 tfa
1 1
Gas or oil (delivered)
Good practice Typical
97 kWh/m2 178 kWh/m2
1 1
Electricity (delivered)
Good practice Typical
128 kWh/m2 226 kWh/m2
1 1
Energy costs
Good practice Typical
£13.00 m 2 tfa £20.00 m 2 tfa
1 1
Gas or oil (delivered)
Good practice Typical
114 kWh/m2 210 kWh/m2
1 1
Electricity (delivered)
Good practice Typical
234 kWh/m2 358 kWh/m2
1 1
Design area
Application
Other information
Rule of thumb
Ref
Lighting benchmarks
Type 1
Good practice Typical
12 W/m 2 15 W/m 2
1 1
Type 2
Good practice Typical
12 W/m 2 18 W/m 2
1 1
Type 3
Good practice Typical
12 W/m 2 20 W/m 2
1 1
Type 4
Good practice Typical
12 W/m 2 20 W/m 2
1 1
Air conditioned (prestige) Type 4, national or regional head office, purpose-built to high standards, intensively used and extensive storage, parking and leisure facilities, 4000 – 20 000 m 2
Your notes and comments
TABLE 2: Lighting systems
For references see page 32
Your notes and comments
2 6
When t o use:
To determine electrical supply requirements in buildings
Where to use:
When assessing the connected capacity in terms of unit floor area
Watch out for:
Allowances for expansion, particularly for on-floor communications rooms
Electrical systems
TABLE 1: Electrical supplies and loads
R u l e s o f T h u m b B S R I A 2 0 0 1
Design area
Application
Other information
Rule of thumb
Ref
Electrical supply
E le ct ri cal mot or s E le ct ri cal mot or s
A bove 3 k W r at in g U p t o an d i nc lu din g 3 kW rating
3-phase supply
16
Direct on-line starting
16
Assisted start
16
Lighting
10 – 12 W/m2
16
Small power
15 – 45 W/m2
16
Air conditioning
60 W/m2
35
Passenger lifts
10 W/m2
35
E le ct ri cal mot or s
Electrical services load (per m2 of building floor area)
Total load (kVA) Design allowance for future expansion (%)
For references see page 32
A bove 4 k W r at in g
Small computer room
Net area
200 – 400 W/m2
16
B esp oke cal l c en tr e
Ne t a re a
500 – 1000 W/m2
16
Total building load
Total kW/0 8
35
% increase in load
Add 25% to existing capacity
35
Your notes and comments
Cost of m&e services by building type When to us e:
As a general guide to the outline services costs of specific building types
Where to use:
At the briefing stage onwards and during assessment of m&e tenders
Watch out for:
Additions or amendments to the generic building type which might alter costs
Cost data
TABLE 1: Capital and maintenance costs in £/m2
R u l e s o f T h u m b B S R I A 2 0 0 1
Design area
Application
Factories
Owner occupied For letting
Other information
1995 figure + 10% (2001 adjustment)
Rule of thumb
Ref
£64 – £161 £34 – £78
25 32
Hospitals
District general Private
£393 – £556 £415 – £654
25 25
Offices
For letting Non air-conditioned (Category A standard) Fully air-conditioned
£170 – £190 £280 – £410
25 25
Offices
Owner occupied)
Non air-conditioned Fully air-conditioned
£210 – £280 £310 – £500
25 25
Civic
Fully air-conditioned
£350 – £500
25
Residential housing
Local authority
Two-storey houses Medium rise flats
£71 – £97 £96 – £126
25 25
Schools
Secondary /middle schools
£163 – £241
25
Universities
Arts buildings Science buildings
£212 – £268 £213 – £395
25 25
Shopping centre
Department store
£223 – £347
32
Warehouses
High bay
£86 – £171
25
1995 figure + 10% 2001 adjustment)
Your notes and comments
Table 1 continued 2 7
For references see page 32
2 8
Cost data TABLE 2: Services costs per square metre as a percentage of total cost
R u l e s o f T h u m b B S R I A 2 0 0 1
Design area
Application
Other information
Rule of thumb
Ref
Arenas (indoor)
Mechanical Electrical Total m&e Lift installations Other Total cost
1999 data, gross internal floor area
9% 12% 21% 1% 78% 100%
7 7 7 7 7 7
Call centres
Mechanical Electrical Total m&e Lift installations Other Total cost
1999 data (gifa)
10% 17% 27% 1% 72% 100%
8 8 8 8 8 8
Cinemas: multiplex (shell construction)
Mechanical Electrical Lift installations Total m&e Other Total cost
2000 data (gifa)
1% 8% 6% 9% 85% 100%
13 13 13 13 13 13
Cinemas: multiplex (cinema fit-out)
Mechanical Electrical Total m&e Lift installations Other Total cost
2000 data (gifa)
19% 13% 32% 0% 68% 100%
13 13 13 13 13 13
Your notes and comments
Table 2 continued For references see page 32
R u l e s o f T h u m b B S R I A 2 0 0 1
Design area
Application
Other information
Rule of thumb
Ref
Conference centres
Mechanical Electrical Lift installations Other Total m&e Total cost
2000 data (m2 gifa)
8% 11% 3% 78% 19% 100%
5 5 5 5 5 5
Data/computer centres
Mechanical Electrical Lift installations Other Total m&e Total cost
2001 data (per m2)
Health & fitness centres
Mechanical Electrical Lift installations Other Total m&e Total cost
1998 data (m2 gifa)
Offices: city (shell & core only)
Mechanical Electrical Total m&e Lift installations Other Total cost
2000 data (m 2 gifa)
Offices: urban commercial (category A standard fit-out)
Mechanical and public health Electrical Total cost
1999 data (per m2 nia)
30% 61% Not included 9% 91% 100%
Your notes and comments
14 14 14 14 14 14
13% 11% 1% 75% 24%
9 9 9 9 9
100%
9
46% 37% 83% Not included 17% 100%
6 6 6 6 6 6
66% 34% 100%
12 12 12
Table 2 continued 2 9
For references see page 32
Cost data
3 0
R u l e s o f T h u m b B S R I A 2 0 0 1
Design area
Application
Other information
Rule of thumb
Ref
Offices: out-of-town commercial (shell & core)
Mechanical Electrical Total m&e Other
1999 data (per m2 gifa)
57% 30% 87% 13%
11 11 11 11
Offices: out-of-town commercial (category A standard fit-out)
Mechanical & public health Electrical
1999 data (per m2 nia)
78%
11
22%
11
Offices: urban commercial (shell & core)
Mechanical Electrical Total m&e Other
1999 data (per m2 gifa)
47% 32% 79% 21%
12 12 12 12
Supermarkets (services fit-out)
Mechanical Electrical Total m&e Other
2000 data (per m2 gifa)
15% 31% 46% 54%
10 10 10 10
Ventilation (capital costs)
Low velocity High velocity
1995 figure + 10% (2001 adjustment) then 25%
£67 – £113 £71 – £119
33 33
For references see page 32
Your notes and comments
TABLE 3: System capital and m aintenance costs (£/m2)
R u l e s o f T h u m b B S R I A 2 0 0 1
3 1
Design area
Application
Other information
Rule of thumb
Ref
Air conditioning (capital costs)
Unit air conditioners All-air systems Air/water system
1995 figure + 10% (2001 adjustment) then 25%
£67 – £113 £82 – £136 £109 – £181 £91 – £151
33 33 33 33
Air conditioning (maintenance costs)
Unit air conditioners All-air systems Air/water system
1995 figure + 10% (2001 adjustment) then 25%
£14 – £22 £14 – £22 £14 – £22
33 33 33
Air conditioning (average capital costs)
For references see page 32
1995 figure + 10% (2001 adjustment) then 25%
£148 – £248
33
Your notes and comments
References
3 2
R u l e s o f T h u m b B S R I A 2 0 0 1
Ref
Title
Publication
Year
Publisher
1
Energy use in offices
Energy Consumption Guide 19
2000
BRECSU
2
Television studios, Section B2, page B2-14
CIBSE Guide B
1986
CIBSE
3
Fry Technology (Fernox Manufacturers)
Fry Technology UK Ltd
2000
Fry Technology
4
Best Practice in the specification for offices
BCO Guide 2000
2000
British Council of Offices
0-9524131-2-4
5
Cost model: Conference Centres
Building 3 November 2000
2000
The Builder Group
0007-3318
6
Cost model: City Offices
Building 24th March 2000
2000
The Builder Group
0007-3318
7
Cost model :Indoor arenas
Building 10th September 1999
1999
The Builder Group
ISSN 1365-5671
8
Cost model: Ca ll Cent res
Building 16th July 1999
1999
The Builder Group
ISSN 1365-5671
9
Cost model: Health & fitness centres
Building 11th September 1998
1998
The Builder Group
ISSN 1365-5671
10
Cost model: Supermarkets
Building Services Journal April 2000
2000
The Builder Group
ISSN 1365-5671
11
Cost model:Out-of-town commercial offices
Building Services Journal April 1999
1999
The Builder Group
ISSN 1365-5671
12
Cost model: Urban commercial offices
Building Services Journal February 1999
1999
The Builder Group
ISSN 1365-5671
13
Cost data: Multiplex Cinemas
Davis Langdon & Everest
2000
Davis Langdon & Everest
Website
14
Cost model: Data/computer centres
Building Services Journal January 2001
2001
The Builder Group
ISSN 1365-5671
15
DW/144 Specification for sheet metal ductwork . Part 8, Appen dix A: Air leakage from ductwork, system leakage loss
Heating and Ventilating Contractors Association
1998
HVCA
0-903783-27-4
16
Industry Review - Rules of Thumb publication, May 2001
Rules of Thumb Industry Review Committee
2001
BSRIA
Not published
17
Space requirements for plant access, operation and maintenance: Defence Estate Organisation (Works), Mo D
1996
HMSO
0-11-772785-7
Defence Estate Organisation (Works), Mo D
1996
HMSO
0-11-772785-7
Defence Estate Organisation (Works), MoD
1996
HMSO
0-11-772785-7
CIBSE Guide G
1999
CIBSE
0-900953-87-X
CIBSE Guide G
1999
CIBSE
0-900953-87-X
Defence Works Functional St andard, Design and Maintenance Guide 08
ISBN
- Section 4, Figure D4 Mechanical surface risers 18
Space requirements for plant access, operation and maintenance: Defence Works Functional St andard, Design and Maintenance Guide 08 - Section 4, Figure D10 Control Panels and Distribution Boards
19
Space requirements for plant access, operation and maintenance: Defence Works Functional St andard, Design and Maintenance Guide 08 - Section 5, Section 5.1 Central station plant, 5.1.1 LTHW boilers
20
Public health engineering, extract from Table 2.3 Recommended minimum storage of cold water for domestic purposes for hot and cold outlets
21
Public health engineering, Extract from Table 2.11 Measured daily hot water consumption in various types of commercial buildings
CIBSE Guide G
1999
CIBSE
0-900953-87-X
22
Energy efficiency in buildings,Table 9.1 Seasonal (boiler) efficiencies
CIBSE Guide F
1998
CIBSE
0-900953-861
