Rules of thumb (Building services)-3RD EDITION.pdf

TECHNICAL NOTE TN 15/2001

Rules of Thumb (UK 3rd edition) Guidelines for assessing building services Edited by Martin Boushear

Supported by

Contents Space and weight allowances TABLE TABLE TABLE TABLE TABLE TABLE TABLE TABLE

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 TABLE TABLE TABLE TABLE

14

1: Cooling loads 2: Cooling plant 3: Solar gains 4: Heat loads

Comfort factors TABLE TABLE TABLE TABLE TABLE TABLE

6

16

1: External conditions 2: Ventilation and air conditioning 3: Information technology 4: Room air movement 5: Noise levels 6: Comfort data sheet

System features

20

TABLE 1: Sizing and operating characteristics of plant TABLE 2: Water treatment

Energy and carbon issues

24

TABLE 1: Energy conversions TABLE 2: Energy benchmarks (offices) TABLE 3: Lighting benchmarks

Electrical systems

26

TABLE 1: Electrical supplies and loads

Cost data

27

TABLE 1: Capital and maintenance costs TABLE 2: Services costs as a percentage of total costs TABLE 3: System capital and maintenance costs

References Rules of Thumb BSRIA 2001

32 3

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. The industry review team for this project comprised: John Louis Auguste (Bovis Lend-Lease), Dennis Bastow (NHS Estates), Brian Charlesworth (Troup Bywaters & Anders), Laurie Clark (Cundall Johnston & Partners), Michelle Field (Buro Happold), Manus Freeman (SVM Partnership), Nigel Hawkes (Fulcrum Consulting), Glen Irwin (Roberts & Partners), Bob Keenan and Dr Ian Selby (Sheppard Robson, on behalf of the British Council for Offices), Nick Mead (ACDP), Richard Tudor (WSP Group), and Gay Lawrence Race and John Sands (BSRIA). We would also like to thank AMEC Capital Projects, BAA plc, N G Bailey, Bryan Franklin, Building Design Partnership, Foggo Associates, Foremans Ltd, Hoare Lea & Partners, Max Fordham & Partners, Stanhope, and Whitby Bird & Partners for their help. Finally, BSRIA would like to make special acknowedgement to the consulting engineers Foremans Ltd, whose financial support has enabled BSRIA to extend the print run. BSRIA also acknowledges the editing help of Nigel Pavey, author of the second edition of Rules of Thumb and now chief engineer with Foremans Ltd.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means electronic or mechanical including photocopying, recording or otherwise without prior written permission of the publisher. BSRIA TN 15/2001 August 2001

4

Rules of Thumb BSRIA 2001

ISBN 086022 587 9

Printed by The Chameleon Press Ltd

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 inception and outline briefing, feasibility planning, the assessment of global loads and space requirements. They are also useful for getting a initial grasp of costs. Rules of thumb come in handy for carrying out "what if" calculations, and for use by senior engineers when checking the work of junior engineers. The data have been derived from a wide variety of authoratative sources, all of which are referenced. All the figures quoted have also been assessed for usefulness and relevance by a panel of experienced, practising services engineers.

What this guide will not do While every effort has been made to establish current practice, the guide's 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 therefore rests with the engineer. Rules of Thumb has been designed to be your own personal reference document. Use it, add your own data to it, and guard it jealously. And please let us know how it works and where it can be improved.

Roderic Bunn Publisher Rules of Thumb BSRIA 2001

5

6

Space and weight allowances

When to use: 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)

Rules of Thumb BSRIA 2001

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䡠䡠 5 – 2䡠䡠 5% 3 – 4䡠䡠 5%

26 26

0䡠䡠3 – 1䡠䡠5%

26

Electrical services (excluding sub-stations and standby generation sets)

0䡠䡠5 – 1䡠䡠 5%

26

Lift motor rooms

0䡠䡠2 – 0䡠䡠 5%

26

Central plant

1 – 2%

26

Toilet extract Supply and extract system All air low velocity system

0䡠䡠3 – 1% 3 – 5% 4 – 6%

26 26 26

Cooling towers and air-cooled condensers

Refrigeration (excluding cooling towers)

Ventilation

For references see page 32

Your notes and comments

TABLE 2: Space allowances for plant rooms (floor area) Design area

Application

Air cooled condenser and controls

Air handling units

Other information

Rule of thumb

Ref

space for installation and maintenance

25 + kW/200 m2

29

With extract /recirculation

8 m2 per m3/s

29

Without extract /recirculation

5 m2 per m3/s

29

Rules of Thumb BSRIA 2001

Boilers (percentage floor area)

Boiler plant & calorifiers

Oil tank room

0䡠䡠 8 – 1䡠䡠 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 140 m2 x 5 m

29 29 29 29

Calorifiers (floor area and height)

Calorifiers, pumps, pipework, controls and space for installation and maintenance

Vertical Vertical Vertical Vertical

(1 m3) (5 m3) (10 m3) (15 m3)

Horizontal Horizontal Horizontal Horizontal

(1 m3) (5 m3) (10 m3) (15 m3)

10 20 25 60

m2 m2 m2 m2

x x x x

3 4 5 3

m m m m

29 29 29 29

25 30 45 60

m2 m2 m2 m2

x x x x

3 3 3 3

m m m m

29 29 29 29

Your notes and comments

Table 2 continued 佡 7

For references see page 32

8

Space and weight allowances TABLE 2: Space allowances for plant rooms (floor area)

Rules of Thumb BSRIA 2001

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䡠䡠 5 m 108 m2 x 4 m

29 29 29 29

Chillers (air cooled)

Located outside. Includes space for installation and maintenance

Output: 200 kW Output: 400 kW Output: 600 kW Output: 800 kW Output: 1000 kW Output: 1200 kW

39 m2 53 m2 75 m2 84 m2 98 m2 116 m2

29 29 29 29 29 29

Cold water storage

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 m3 1 m high 2 m high 3 m high

FA: 10 + V/0䡠䡠75 m2 FA: 10 + V/1䡠䡠 6 m2 FA: 10 + V/2䡠䡠 4 m2

29 29 29

Minimum for hot and cold outlets

Offices

10-20 litres/person

4

Cold water storage

Hotels, children’s home, residential nursery, convalescent home 135 litres/bed space

Your notes and comments

4

Table 2 continued 佡 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 m2

29

HV switchgear HV + LV switchgear

47 m2 14 m2 27 m2

29 29 29

Standby sets and accessories

FA: Floor area

FA:15 + kVA/30 m2

29

Single module system (add space for batteries)

FA: Floor area

FA: (2 + kW/200) x 2 m2

29

Other information

Rule of thumb

Ref

1200 – 1800 mm

18

Tank contents + 10%

19

Cooling towers

Sub-station

Rules of Thumb BSRIA 2001

Standby generation

Uninterruptible power supply

2000 kVA transformers Switchgear

Your notes and comments

TABLE 3: Miscellaneous services 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

9

For references see page 32

If tank fails, walls and doors treated to contain spillage

Your notes and comments

10

Space and weight allowances TABLE 4: Space allowances for services (depth of clear space in ceiling/floor void) Design area

Application

Air conditioning

Rules of Thumb BSRIA 2001

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 (Ⳮ access) 16 150 – 300 mm 16

Power and communications

Multi-core cables and lighting cables

100 – 200 mm

16

Power and data (heavy line)

200 – 250 mm

16

Computer rooms

300 mm

16

For references see page 32

Other information

Your notes and comments

TABLE 5: Space allowances for service ducts and shafts Design area

Application

Air ducting

Lift shafts

Mechanical service riser

Simple pipework riser

Rules of Thumb BSRIA 2001

Three-sided riser

11

For references see page 32

Rule of thumb

Ref

Typical ducting size

0䡠䡠2 m2/m3/s

30

3+A(N-4)/250 m2

30

Between 4 – 18 floors Internal shaft area in office-type buildings A: floor area/ storey (250 m2 min), N: Floors

Pipework

Service ducts

Other information

Vertical service duct

Depth needed to open 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

Minimum depth 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

12

Space and weight allowances TABLE 6: Space allowances for catering facilities

Rules of Thumb BSRIA 2001

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䡠䡠4 m2/meal 0䡠䡠 25 m2/meal

31 31

For single sittings

Ratio of kitchen space to dining space

0䡠䡠33:1 to 0䡠䡠 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 m2/person

4

Trading desks, call centre, work stations

4 – 6 m2/person

4

15 m2 (or more) per person

4

Enclosed offices

For references see page 32

Application

Other information

Your notes and comments

TABLE 8: Plant weight allowances Design area

Application

Single boiler

Rules of Thumb BSRIA 2001

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

13

For references see page 32

Other information

Your notes and comments

14

When to use: How to use: Watch out for:

Equipment and solar loads

For estimates of thermal loads used to assess plant and terminal equipment sizes To determine total solar and internal gains, multiply the loads by total floor area Solar gains depend on glazing and shading, and contribution of thermal mass

TABLE 1: Cooling loads Design area

Application

Other information

Rules Of Thumb BSRIA 2001

Rule of thumb

Ref

Banks

160 W/m2

34

Computer suites

400 W/m2 approx

34

Hotels

150 – 300 W/m2

34

Offices (general)

125 W/m2

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/m2 40 W/m3

36 36

Distributed cooling plant

Load/m2 of floor area Load/m3 of floor vol.

140 W/m2 45 W/m3

36 36

Central plant Distributed plant

0䡠䡠5 kW/kW 0䡠䡠 78 kW/kW

36 36

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

Your notes and comments

TABLE 3: Solar gains (over floor area)

Rules Of Thumb BSRIA 2001

Design area

Application

Other information

Rule of thumb

Ref

Windows with internal blinds

(June-Sept) (June-Sept)

South facing East-West facing

250 W/m2 of glass 150 W/m2 of glass

34 34

Clear double-glazed with internal blinds

Out-of-town building

All data for 6 m deep, 1500 mm wide module. U-value 3䡠3 W/m2K.

2650 W instant 2490 W lag (mass)

39 39

As above with flat slab

Plus brise soleil

1860 W instant 1710 W lag (mass)

39 39

As above with coffered slab

Plus brise soleil

1860 W instant 1680 W lag (mass)

39 39

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䡠䡠 5 W/m3

34

Retail buildings

110 W/m2

34

10 W/m2 12 W/m2 15 – 25 W/m2

16 16 16

Your notes and comments

TABLE 4: Heat loads Design area

Application

General buildings

Other heat gains

Offices General offices

15

For references see page 32

Metabolic Lighting Office equipment

Your notes and comments

16

When to use: Where to use: Watch out for:

Comfort factors

During the early stages of design When setting inernal environmental conditons based on known or assumed loads Specific client requirements, and contexts that allow greater latitude in design settings

TABLE 1: External conditions Design area

Application

Winter design temperatures for heating

Without surplus boiler capacity With 20% surplus boiler capacity

Other information

Single-storey building Other buildings

Rules of Thumb BSRIA 2001

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䡠䡠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 office areas) Dedicated IT room required

For references see page 32

38

Your notes and comments

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)

Type C IT rooms

Rules of Thumb BSRIA 2001

Rule of thumb

Ref

Air-conditioned office, room or workspace

38

Non air-conditioned office, room or workspace

38

Other information

Rule of thumb

Ref

In Winter In Summer At 21⬚C At 22⬚C At 23⬚C At 24⬚C On back of neck

0䡠䡠15 m/s 0䡠䡠 25 m/s 0䡠䡠 15 m/s 0䡠䡠 2 m/s 0䡠䡠 25 m/s 0䡠䡠 3 m/s 0䡠䡠 2 m/s

37 37 37 37 37 37 37

Papers will lift at velocities in excess of

0䡠䡠8 m/s

37

0䡠䡠2 – 0䡠䡠 3 m/s

2

Your notes and comments

Room where IT equipment is used at workstations (may use natural or mechanical ventilation)

TABLE 4: Room air movement Design area Maximum recommended mean air velocities

Application

Television and broadcasting studios

17

For references see page 32

Your notes and comments

18

Comfort factors TABLE 5: Noise levels Design area

Application

Other information

Rule of thumb

Ref

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

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䡠䡠 2 m 1䡠䡠 2 m Too noisy

37 37 37 37 37

Quiet rooms Private rooms Public rooms

Rules of Thumb BSRIA 2001

General areas Work areas Industrial areas

For references see page 32

Your notes and comments

TABLE 6: Comfort data sheet Building Type

Internal design temperature Summer Winter

Humidity (% RH)

Infiltration (ac/h)

Ventilation fresh air

Ventilation air change

Lighting level (Lux)

Noise level (NR)

Cinemas (sedentary role)

21-23⬚C

19-21⬚C

50Ⳳ10% RH

0䡠5 ac/h

8 l/s/person

6-10 ac/h

300 lux

NR25-NR30

Computer rooms (general)

21-23⬚C

19-21⬚C

50Ⳳ5% RH

1 ac/h

8 l/s/person

4-15 ac/h

300 lux

NR35-NR45

Education (teaching spaces)

21-23⬚C

19-21⬚C

50Ⳳ5% RH

2 ac/h

8 l/s/person

6-10 ac/h

300 lux

NR25-NR35

Exhibition hall/conference facilities

21-23⬚C

19-21⬚C

50-55% RH

0䡠25-0䡠5 ac/h

8 l/s/person

1 ac/h

300 lux

NR40

Factory/warehouse

21-23⬚C

11-21⬚C

50Ⳳ10% RH

0䡠25-2䡠5 ac/h

8 l/s/person

6 ac/h

750-1000 lux

NR45-NR65

Fitness/health clubs (equipment rooms)

>18⬚C

12-18⬚C

40-70% RH

0䡠75 ac/h

8 l/s/person

4 ac/h

300 lux

NR30-NR40

Hospitals (ward and patient areas)

23-25⬚C

22-24⬚C

50-60% RH

2 ac/h

8 l/s/person

3 ac/h

50-100 lux

NR30-NR35

Hotels (bedrooms)

21-23⬚C

19-21⬚C

50Ⳳ10% RH

1 ac/h

8 l/s/person

6-10 ac/h

50-100 lux

NR20-NR30

Rules of Thumb BSRIA 2001

Libraries (reading rooms)

24-25⬚C

22-23⬚C

50Ⳳ5% RH

0䡠25-0䡠75 ac/h

8 l/s/person

3-4 ac/h

300 lux

NR30-NR35

Museums and galleries (display, storage)

21-23⬚C

19-21⬚C

50-55% RH

1 ac/h

8 l/s/person

3-4 ac/h

200 lux

NR30-NR35

Offices (general, BCO data)

24⬚C

22⬚C

35-40% RH

0䡠25-0䡠5 ac/h

8-12 l/s/person

4-6 ac/h

300-500 lux

NR25-NR40

Retail (shops/stores)

21-23⬚C

19-21⬚C

45Ⳳ5% RH

0䡠5-1 ac/h

8 l/s/person

3-8 ac/h

500-750 lux

NR35-NR45

300 lux

NR 40-NR50

19

For references see page 32

Swimming pools (pool halls) Your notes and comments

23-26⬚C

23-26⬚C

40-70% RH

0䡠5 ac/h

2

0-15 l/s/m (of wetted area)

20

When to use: Where to use: Watch out for:

System features

During outline design before the architect has finalised space planning For determining the spatial and operational characteristics of main plant The rules for boiler and cooling plant are based on unit floor area or unit volume

TABLE 1: Sizing and operating characteristics of plant Design area Air handling units Air face velocity

Application

Other information

Rules of Thumb BSRIA 2001

Coil water velocity

36 16

Heating mode Cooling mode

30⬚C (max) 13⬚C (min)

16 16

Air discharge

0䡠䡠6 – 2 m/s

36

10 – 40 kPa 0䡠䡠 33 – 1䡠䡠 72 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䡠䡠3 m width

36

120 W/m2 floor area 40 W/m3 volume

36 36

Water pressure drop Steam pressure drop

Air distribution From source

Ceiling diffusers

Non-zoning partitions Sill diffusers

Boiler plant capacity

Power per unit area

Ref

2䡠䡠5 – 4 m/s 1䡠䡠 0 – 2䡠䡠 5 m/s

Heating coil Cooling coil Air supply temperatures

Rule of thumb

Limit of throw Surface projections

Your notes and comments

36

Table 1 continued 佡 For references see page 32

Design area

Application

Other information

Rule of thumb

Ref

Boiler plant efficiency

Boiler efficiency Efficiency losses

Typical efficiency Blowdown (steam) 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

Modern high efficiency 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䡠䡠 5 – 15 m/s

36 36

Boiler plant Typical seasonal efficiencies

Rules of Thumb BSRIA 2001

Non-condensing boilers

Chiller plant capacity

Fuel storage

Ductwork Typical duct velocities

Class D oil

Your notes and comments

Table 1 continued 佡 21

For references see page 32

22

System features Design area

Application

Other information Rule of thumb

Ductwork

Inlet louvres

(through free area)

Maximum pressure drop rates (per m run)

Ref

Rules of Thumb BSRIA 2001

2䡠䡠5 m/s

36

Low velocity systems High velocity systems

1 Pa/m 8 Pa/m

36 36

Typical system resistances (including air handling plant)

Low velocity supply Low velocity extract High velocity supply

900 Pa 400 Pa 1䡠䡠 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䡠䡠6 x total fan pressure (kPa) x volume flow rate (m3/s)

36

1⬚C per kPa

36

Offices Restaurants Retail stores, halls, theatres

1䡠䡠4 litres/s per m3 3䡠䡠 5 litres/s per m3 2䡠䡠 1 litres/s per m3

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/m2

36

Capacity per unit of power produced (boilers, radiators)

Boilers Aluminium, cast radiator

1䡠䡠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 佡 For references see page 32

Design area

Pipework Capacity per unit length of of steel pipe

Application

Rule of thumb

Ref

E xtruded aluminium Steel panel radiators

1䡠䡠2 litres/kW 5 litres/kW

36 36

15 mm diameter pipe 20 mm diameter pipe 25 mm diameter pipe 32 mm diameter pipe 40 mm diameter pipe

0䡠䡠25 litres/m 0䡠䡠 4 litres/m 0䡠䡠 6 litres/m 1䡠䡠 2 litres/m 1䡠䡠 5 litres/m

36 36 36 36 36

15 – 50 mm pipe dia. Over 50 mm pipe dia.

0䡠䡠75 – 1䡠䡠 5 m/s 1䡠䡠 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䡠䡠 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䡠䡠9 litres/m2

36

Pressure (in kPa), length (m)

0䡠䡠36 x circuit length

36

Copper pipework

With steel pipework

Add 10% to water

36

Frost protection

Glycol concentration

30% of system vol.

16

Water velocity Conventional systems

Rules of Thumb BSRIA 2001

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

23

For references see page 32

Other information

Your notes and comments

24

When to use: Where to use: Watch out for:

Energy and carbon issues

When determining total building energy consumption From briefing onwards through to design and operation (See also CIBSE TM22) Change to the carbon conversion ratios which are continually being updated

TABLE 1: Energy conversions Design area Carbon dioxide emission (Kg CO2/kWh delivery) by fuel

Application

Natural Gas Oil Electricity Coal

Other information

Average

CO2 to Carbon

Rule of thumb

Ref

0䡠䡠19 0䡠䡠 25 0䡠䡠 46 0䡠䡠 30

1 1 1 1

kg kg kg kg

CO2/kWh CO2/kWh CO2/kWh CO2/kWh

Divide by 3䡠䡠 67

1

Your notes and comments

Rules of Thumb BSRIA 2001

TABLE 2: Energy benchmarks (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

Energy costs over treated floor area (tfa)

Good practice 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

Good practice 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) Energy costs over Type 2, purpose-built, sometimes treated floor area converted industrial space, 500 m2 – 4000 m2 Gas or oil (delivered) Electricity (delivered)

Your notes and comments

Table 2 continued 佡 For references see page 32

Rules of Thumb BSRIA 2001

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 m2 tfa £14.00 m2 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 m2 tfa £20.00 m2 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/m2 15 W/m2

1 1

Type 2

Good practice Typical

12 W/m2 18 W/m2

1 1

Type 3

Good practice Typical

12 W/m2 20 W/m2

1 1

Type 4

Good practice Typical

12 W/m2 20 W/m2

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 m2

Your notes and comments

TABLE 2: Lighting systems

25

For references see page 32

Your notes and comments

26

When to use: Where to use: Watch out for:

Electrical systems

To determine electrical supply requirements in buildings When assessing the connected capacity in terms of unit floor area Allowances for expansion, particularly for on-floor communications rooms

TABLE 1: Electrical supplies and loads Design area

Application

Other information

Rule of thumb

Ref

Electrical supply

Electrical motors Electrical motors

Above 3 kW rating Up to and including 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

Electrical motors

Rules of Thumb BSRIA 2001

Electrical services load (per m2 of building floor area)

Total load (kVA) Design allowance for future expansion (%)

For references see page 32

Above 4 kW rating

Small computer room

Net area

200 – 400 W/m2

16

Bespoke call centre

Net area

500 – 1000 W/m2

16

Total building load

Total kW/0䡠䡠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 use: Where to use: Watch out for:

Cost data

As a general guide to the outline services costs of specific building types At the briefing stage onwards and during assessment of m&e tenders Additions or amendments to the generic building type which might alter costs

TABLE 1: Capital and maintenance costs in £/m2 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

Rules of Thumb BSRIA 2001

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 佡 27

For references see page 32

28

Cost data TABLE 2: Services costs per square metre as a percentage of total cost

Rules of Thumb BSRIA 2001

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 佡 For references see page 32

Rules of Thumb BSRIA 2001

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)

30% 61% Not included 9% 91% 100%

14 14 14 14 14 14

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 (m2 gifa)

Offices: urban commercial (category A standard fit-out)

Mechanical and public health Electrical Total cost

1999 data (per m2 nia)

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

Your notes and comments

Table 2 continued 佡 29

For references see page 32

30

Cost data

Rules of Thumb BSRIA 2001

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 Ⳳ 25%

£67 – £113 £71 – £119

33 33

For references see page 32

Your notes and comments

TABLE 3: System capital and maintenance costs (£/m2) 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 Ⳳ 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 Ⳳ 25%

£14 – £22 £14 – £22 £14 – £22

33 33 33

1995 figure + 10% (2001 adjustment) then Ⳳ 25%

£148 – £248

33

Air conditioning (average capital costs)

31

Application

Rules of Thumb BSRIA 2001

Design area

For references see page 32

Your notes and comments

32

References

Rules of Thumb BSRIA 2001

Ref

Title

Publication

Year

Publisher

ISBN

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Energy use in offices Television studios, Section B2, page B2-14 Fry Technology (Fernox Manufacturers) Best Practice in the specification for offices Cost model: Conference Centres Cost model: City Offices Cost model: Indoor arenas Cost model: Call Centres Cost model: Health & fitness centres Cost model: Supermarkets Cost model: Out-of-town commercial offices Cost model: Urban commercial offices Cost data: Multiplex Cinemas Cost model: Data/computer centres DW/144 Specification for sheet metal ductwork. Part 8, Appendix A: Air leakage from ductwork, system leakage loss Industry Review - Rules of Thumb publication, May 2001 Space requirements for plant access, operation and maintenance: Defence Works Functional Standard, Design and Maintenance Guide 08 - Section 4, Figure D4 Mechanical surface risers Space requirements for plant access, operation and maintenance: Defence Works Functional Standard, Design and Maintenance Guide 08 - Section 4, Figure D10 Control Panels and Distribution Boards Space requirements for plant access, operation and maintenance: Defence Works Functional Standard, Design and Maintenance Guide 08 - Section 5, Section 5.1 Central station plant, 5.1.1 LTHW boilers Public health engineering, extract from Table 2.3 Recommended minimum storage of cold water for domestic purposes for hot and cold outlets Public health engineering, Extract from Table 2.11 Measured daily hot water consumption in various types of commercial buildings Energy efficiency in buildings,Table 9.1 Seasonal (boiler) efficiencies

Energy Consumption Guide 19 CIBSE Guide B Fry Technology UK Ltd BCO Guide 2000 Building 3 November 2000 Building 24th March 2000 Building 10th September 1999 Building 16th July 1999 Building 11th September 1998 Building Services Journal April 2000 Building Services Journal April 1999 Building Services Journal February 1999 Davis Langdon & Everest Building Services Journal January 2001

2000 1986 2000 2000 2000 2000 1999 1999 1998 2000 1999 1999 2000 2001

BRECSU CIBSE Fry Technology British Council of Offices The Builder Group The Builder Group The Builder Group The Builder Group The Builder Group The Builder Group The Builder Group The Builder Group Davis Langdon & Everest The Builder Group

0-9524131-2-4 0007-3318 0007-3318 ISSN 1365-5671 ISSN 1365-5671 ISSN 1365-5671 ISSN 1365-5671 ISSN 1365-5671 ISSN 1365-5671 Website ISSN 1365-5671

Heating and Ventilating Contractors Association Rules of Thumb Industry Review Committee

1998 2001

HVCA BSRIA

0-903783-27-4 Not published

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

CIBSE Guide G CIBSE Guide F

1999 1998

CIBSE CIBSE

0-900953-87-X 0-900953-861

16 17

18

19

20

21 22

Rules of Thumb BSRIA 2001

Ref

Title

Publication

Year

Publisher

ISBN

23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38

Energy efficiency in buildings,Table 6.2 Basic fan capacity benchmarks Energy efficiency in buildings,Table 7.1 Chiller plant capacity Spon’s Mechanical and Electrical Services Price Book 2001 Space allocation for services,Table 2: floor space Space allocation for services,Table 3: depth of ceiling space Space allocation for services, Table 4: depth of floor space Space allocation for plant rooms,Table 6: floor area Space allocation for service ducts and shafts,Table 7 Space allocation for catering facilities, Table 9 Cost of M&E services by type of building and service, Table 10 System capital and maintenance costs,Table 11 Thermal Loads, Table 12 Electrical loads by type of load, Table 14 Sizing and operating characteristics of air system plant,Table 16 Design requirements or rules of thumb for air systems, Table 17 Guide to the accommodation and operating environment for Information technology (IT) equipment “Facade Engineering: Fun with Facades”

CIBSE Guide F CIBSE Guide F Rules of Thumb, 2nd Edition Rules of Thumb, 2nd Edition Rules of Thumb, 2nd Edition Rules of Thumb, 2nd Edition Rules of Thumb, 2nd Edition Rules of Thumb, 2nd Edition Rules of Thumb, 2nd Edition Rules of Thumb, 2nd Edition Rules of Thumb, 2nd Edition Rules of Thumb, 2nd Edition Rules of Thumb, 2nd Edition Rules of Thumb, 2nd Edition

1998 1998 2001 1995 1995 1995 1995 1995 1995 1995 1995 1995 1995 1995 1995

CIBSE CIBSE Spon Press BSRIA BSRIA BSRIA BSRIA BSRIA BSRIA BSRIA BSRIA BSRIA BSRIA BSRIA BSRIA

0-900953-861 0-900953-861 0-415-24280-0 0-86022-4198 0-86022-4198 0-86022-4198 0-86022-4198 0-86022-4198 0-86022-4198 0-86022-4198 0-86022-4198 0-86022-4198 0-86022-4198 0-86022-4198 0-86022-4198

BS 7083, 1996 Building Services Journal, August 1997

1996 1997

BSI The Builder Group

0-580-26705-9 ISSN 1365-5671

39

33

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