BCO Office Guide

BCO BC O GUI UID DE

2000 Best Pra Best ractice ctice in th the e Specification Specificatio n for Offices Offices

C ontents ontents

P resident’s resident’s introdu i ntroduction ction

I am pleased that that this new edition of the Guide has has been issued to coincide with the tenth anniversary of  the founding of the BCO. Over the decade, our members membership hip has grown to some 600 members mem bers representing all elements elements of the supply chain in the procurement of c omm ommercial ercial office space.

President’s introduction Editorial How to use the Guide to Best Practice

1.0 1. 0

2.0 2. 0

3.0 3. 0

4.0

5.0 5. 0

6.0 6. 0

Key Ke y decisio decisions ns before before deciding to build The brief 

1.1

Is a new building necessary?

1.2

Freehold or leasehold?

1.3

Key Ke y vari variables a bles if you decideto build Basisof funding

2.1

Site location

2.2

Town planning

2.3

Planning for sustainability

2.4

Building size

2.5

The objectives objectives of the BC O are:

These objectives have influenced the

• to understand the changing nature

manner in which the guide has been

of work work and the waythat business iness

produced and the eventual content

locates,uses and manages workspace

of the individual sections.

• to understand the investment

Key design design parame parameters ters Site density

3.1

Circulation

3.9

Parking

3.2

Core elements and stairs

3.10

Landscaping

3.3

Use of atria

3.11

Building orientation

3.4

Building section

3.12

The BC O Guide to Best Practice Practice in

anddevelopment issues thataffect

the specification f or offices is currently

the provision of workspace

recognised in the market placea placea s

• to understand the urban system

representing good practicein thep rocurement

within which workplace locations

of commercial office workspace.

feature as prime generators

It is not a presc prescriptiv riptive e specifica specification, tion,

Floor plate efficiency

3.5

Structural systems

3.13

Building plan depth

3.6

Envelope

3.14

Column grid

3.7

Services systems

3.15

Planning grid

3.8

Finishes

3.16

Sustainability

4.1

Capital cost

4.7

so diligentlyto produce theG uide are are

Workstyle

4.2

Embodied energycost

4.8

listed listed at the end of this documen document. t.

Occupancystandards

4.3

Cost in use

4.9

Comfort

4.4

Adaptability/design life

4.10

Amenity

4.5

Safety, security, risk

4.11

Accessibility

4.6

• to understand workplace design and construction i ssues

butrather a documen document of its time that seeks to recognise the key elements in a complex suppl supplychain. ychain. The many members who have worked

Key performan performance ce criteria

I would like to thank them all for their invaluable contribution in, again, establishing a recognised and authoritative yardstick for our industrythat will be of benefit to

Building d ing compl completion e tion Commissioning/handover

5.1

Building logbook and training

5.2

all those involved in the procurement, and the occupation, of commercial offi ce space.

Appen Ap pendix dix The design team

6.1

Comparative table

6.7

Construction strategy

6.2

Materialsguide

Best practice

6.3

Useful websites

6.9

CategoriesA & B

6.4

Tenantsservice charges

6.10

BREEAM 98

6.5

Gross/net internal areas

6.11

Statutoryregulations

6.6

Index

6.12

6.8

Hugh Stebbing President of the British Council for Offices June 2000

Editorial

The Year 2000 Guide to Best Practice The Guide to B est Practice wasf irst published in

Given that buildings are directlyresponsible for approximately50% of CO 2 emissions, and

1994 as a reaction to the constantlyrising levels

indirectlyfor another 25% through transport and

of specification i n the design and procurement of 

materialsmanufacturing, the construction industry

offices experienced in the preceding decade, and which wasrecognised asbeing excessive and wasteful of resources. The G uide quicklybecame a document used by clientsand their professional teamsin deciding the level of specification to be adopted, and to that extent it has achieved itsobjective. The second edition, produced in 1997, reflected

hasa large part to play. The implicationsof sustainabilityare examined in thisGuide and k eyreference sourcesare identified. The B RE and Forum for the Future have reviewed each section and the G uide now includesmany valuable pointers to current best practicesin sustainable design and procurement.

some of the changesthat had tak en place in the awarenessof environmental issuesand their

(2) Recognising the role of the occupier, the end user

influence on the design of the workplace.

In 1998, the B CO adopted the theme ‘Connecting

preceding three years; in particular the growing

This third edition of the Guide coversa broader

• Working with clientsand occupiers to agree whole life cost/value parameters • Educating clients that higher design qualitydoes not necessarilymean greater complexityor cost • Educating investment fundsthat their funding

Productivity staff made a difference to bottom line business

dealing with performance criteria (S ection 4.0).

performance. But with staff costs representing as

When considering, for instance, the appropriate

much as 75-80% of operational costs, it is not

plan depth or mechanical system, a variety of 

surprising that businessis increasingly focusing

performance factorsshould be taken into

on the importance of maximising staff productivity.

consideration.

There are a number of keymoti vators:

propertyto business’ and, in preparing this • The recognition of the impact that the qualityof 

has a greater pool of expertise to draw on in order

comfort, satisfaction and productivity

to decide what represents current best practice.

Representativesof major space occupiers

Of fices, whether located in business parks

contributed to the Guide. T heir aspirationshave been reflected in the text. Inadequate client briefing to the procurement

which have influenced our collective approach:

acrimoniouscontractual relationship, and the

the BCO Guide to Best Practice in the

Guide to Best P ractice now establishes an

Specification of O ffices. With thisrevision comes

(1) Sustainability and sustainable development

obligation on all the parties to establish a clear

the opportunity to addressthese issuesexplicitly

brief at the outset.

and give guidance to those responsible for

made aware of the implicationsof the 1997 K yoto

brief, and to evaluate advice given by their many advisers.

Choice of  Plan Depth

Selected Specification

Choice of  Mechanical System

Selected Specification

Comfort Capital Cost

Cost in Use Adaptability

specifying offices on some of the measuresthat can be taken to enhance office productivity.

Controlability

We have therefore chosen to make productivity Capital Cost

a theme which runs through the document. Where appropriate, under each section you will find a

committed to achieve reductionsin their emissions of greenhouse gasses byan average of 5.2% in

(3) New ideas and new methods

the period 2008 to 2012. The UK Government

In 1998, the Egan Report ‘Rethinking

has a manifesto commitment to reduce CO 2

Construction’ sought to create a new mind set for

emissionsto 20% below 1990 levelsby2010.

the whole industryon what might be a chievable in termsof unit cost, construction time and construction quality.

Energy Use

Specification

adverselyaff ecting staff performance

environments has alwaysbeen an implicit goal of 

that the membership, and a wider audience, is

Design Parameters

Workstyle

• The wish to intensifythe use of space without

all too easily, lead to an unsatisfactoryand

The intention of this document is to help the

Decision Line Performance Criteria

to support effective team work

The realisation of productive working

client make informed decisionsi n establishing a

Selecting a specification

• The wish to provide flexible spacesand settings

team on the desired outcome of the project can,

Global Energy Use

Of ten the performance outcomesof a particular choice of design parameter are multiple, and for this reason the Guide separates the section

the internal environment can have on staff 

Protocol. Under this Protocol, developed countries

appropriat e cross-refere nce to backgr ound and

It is a statement of the obviousthat contented

workspace wit h the end user in mind.

The BC O has been at the forefront in ensuring

manycases presents optional choices, giving

performance.

approach the procurement of commercial

There are four i ssues that we have highlighted

Section 3.0 deals with design specification and in

related information, particularlyconcerning

document, a deliberate effort has been made to

however, these have been clearlyidentified.

the content and location of a development.

dissatisfaction.

It recognisesthat, as an organisation, the B CO

characteristics. Where there are dif ferences,

decisionsabout whether or not to build and about

criteria can lead to over-specification and to user

spectrum of criteria than in the previous editions.

or in urban areas, share many common key

Sections 1.0 and 2.0 are concerned with strategic

:

http://www.construction.detr.gov.uk/cis/rethink/  index.htm

ð

‘Creating the Productive Workplace’ SPON, 2000

Current typical design standards How to use the Guide to Best Practice

Current typical design standardsare available f or

This printed document isan edited version of the

ease of reference in the appendix, section 6.7,

full report. The complete research carried out by

comparativetable.

the Editorial C ommittee and related material can The Guide recognisesthat substantial benefits in procurement time and cost can be achieved by: • Establishing accepted industryperformance criteria for the building fabric and for the engineeringservices • Encouraging the use of standard components,

Cost in Use

discussion of issues relating to productivityand pointersto achieving good practice.

be accessed on www.constructionplus.co.uk Sections will be regularlyupdated and additional information made available on the www copy. The G uide can be used as a conventional

Icons have been used to facilitate ease of  reference in addition to the detailed index, section 6.10.

ð :

Relevant reference section in the text

&

Paper document

www site for an electronic source paper

reference tool, but it is also arranged to enable

standard design solutionsfor repetitive detail

a structured approach to the creation of a

and repeating proven technical solutions

tailored design specification appropriate to a particular development need.

Ti m Batt le

Gr ah am Fr ancis

R ybk a B at tle

S heppa rd R obson

1.0

K ey decisions before deciding to build

The brief sets the performance criteria which will determine the choice of the design parameters. The purpose of the brief is to establish a framework of desired outc omes. 1.1 The brief

1.2 Is a new building necessary?

2.0

K ey variables if you decide to build

This section covers the strategic decisions which w ill affect the choice of office product.

2.1 Basis of Funding (End user/ speculative developer)

2.2 Site location (in-town/out-of-town)

The brief is an essential process bywhich clients

In considering options, the more efficient use of 

communicate their requirements and their

existing buildingsshould alwaysbe evaluated.

Users will need to decide whether to acquire land

In selecting a site for development or occupation,

aspirations. The successof a project relies heavily

Internal reorganisation, or the application of new

and develop a building for their own use, or to

a number of factors need to be considered:

on the quality of briefing. Brief s should not be

working practices, often using new technologies

lease a building constructed bya property

static, but challenged and developed throughout

intensively, can produce verysubstantia l

developer. T he route selected will affect the ability

the life of a project. However, a clear set of 

efficiencies which mayobviate the need for a new

of the end user to influence the design and

strategic objectivesshould be established at the

building. Re-location maylead to staff losses. The

specification. Occupiersand developershave

outset which are not challenged.

decision to develop or refurbish should be driven

much to gain from pre-letting arrangements in

bythe opportunity cost, and the anticipated return,

reducing overall project costs and deliverytimes,

from each alternative.

as well asend user satisfaction.

A f ailure on the part of the design team to be aware of the operational issues during the design processcan lead to buildingsbeing costlyto

Property developers mayadhere to a standard

• Current national and local planning policyis driven bya desire to: reduce private car use; encourage other meansof private (eg. shared  journeys) and public transport; encourage development on previously used sites (particularlyat transport nodes/corridors); and, to encourage mixed use and sustainable development

maintain and operate, sometimesto the detriment

specification, which hashistoricallybecome the

and well-being of the occupants. A ccess to

BC O S pecification. Institutional funding for an

facilities management expertise or an awareness

owner occupier building will only be given on

• Road congestion

of facilities issueswill minimise these impacts.

condition that the building can be returned to the

• Work patterns

Project successwill be reliant on good teamwork; the client should therefore select a

commercial mark et place. A building, either new or refurbished, would

team that will work well together, with roles and

normallybe completed at Practical Completion to

responsibilities clearlydefined. The client’srole

what isk nown as a C ategoryA fit-out. Further

• The availabilityof public transport

Site location isa k eyf actor considered byBREEAM

should be to give clear instructionsbased on good

fitting-out work required bythe incoming occupier

qualityinformation and optionsprovided bythe

of the workspace to meet their particular

design team. Changesmade early will be less

requirementsis known asC ategoryB.

The Town and CountryP lanning Act 1990 is the

costlythan those made later in the project. The

ð

principal legislation for development control.

6.4 Cat A & B

2.3 Town planning

client’songoing i nvolvement should be matched

Where proposalsa ffect listed buildingsor

with sufficient resources to evaluate optionsand

conservation areas, the Planning ( Listed B uildings

make decisionson a timely basis.

and Conservation Areas) Act 1990 comes into play. G overnment guidance, which is intended to

‘Brief ing the Team’ produced bythe

amplify this legislation, is provided in a series of 

Construction IndustryB oard in 1997, provides a

Planning P olicyG uidance Notes, or ‘PP Gs’. M ore

detailed guide.

detailed planning policies are drafted by each local authoritywithin this national framework; these are

BR EEA M providesa meansof specifying

set out in a Unitary Development Plan.

an environmental performance in a simple and flexible manner.

ð

:

6.1 The Design Team, 6.5 BREEAM www.ciboard.org.uk/Procrmnt/briefing.htm

Site location Urban Location

Rural Location

Use of public transport More transport options Less car parking Lower energyand pollution costs Higher capital cost

Reliance on car Fewer transport options More car parking Higher energyand pollution costs Lower capital cost

2.0

Early contact with the relevant local authority to discuss the town planning issueswill prove

3.0

2.5 Building size

beneficial. The length of time taken to determine

The development or tenancybrief will specify total

formal applications can be reduced substantially

space requirements, based on expected

byadopting a f lexible approach to negotiations

occupancy, applying relevant space standards and

prior to submitting proposalsfor planning

having regard to workstyle.

permission.

ð

2.4 Planning for sustainability

1.1 The brief, 4.2 Workstyle, 4.3 Occupancy Standards

For speculative developments, the total quantum of space maybe determined simplyby optimising

The main principlesof sustainable development

the development potential of the site, but aspects

are:

of amenity, accessibilityand planning control will

• economic growth

need to be considered on arriving at an appropriate site density.

• social progress

ð

• environmental protection

There may also be market-driven requirements

• prudent use of natural resourcesand mixed-use

for buildingsand/ or lettingsof a particular size.

developments Theya re being incorporated into planning policy at all levels in the UK . Under Local Agenda 21, local government is obliged to address sustainability issues. BR EEA M can be used as a negotiating tool also.

4.5 Amenity, 4.6 Accessibility

It may be necessaryto provide the total quantum of space in the form of a number of smaller buildingsrather than a single large one; however, this approach will tend to reduce site densityand increase capital cost.

ð

K ey design parameters

This section describes common design parameters and gives background information together with crossreferences to aspects of performance to enable the reader to determine an appropriate specification standard under each subject heading. No two office developments have identical requirements. The developers and users of buildings have their own particular needs and aspirations, and these are rightly reflected in the specifications that are evolved for their buildings. In some cases, typical standards will b e applicable, but in others, selection from a range of possible options will be necessary in order to achieve a specific performance result.

3.1 Site density, 4.7 Capital cost

Where subdivision of larger floor platesto f orm separate tenancies is relied upon to satisfyuser requirements, then the position and number of  coresand escape staircases is critical, and can

Development densityi s affected bybuilding size.

3.1 Site density

Groupings of small buildings result in lower

affect adaptabilityand floor plate efficiency.

ð

3.10 Core elements, 4.10 Adaptability

optimum densitiesthan the provision of larger

45% (gross external area to site area)

buildingsof similar total area, because more space

for business parks

is required for road access to small buildings, and

In general, larger floor plates are more efficient

The key variablesaf fecting site density are car

and more cost-effective. For a given floor plate

parking ratio, design of road network, quantityof 

configuration, cost efficiencyand floor plate

landscaping, and building shape. O ptimising the

efficient. Increasing the number of storeysof 

efficiency will diminish as building height is

because smaller floor plates are lessspace-

right balance between these variables is critical to

buildingsof a given area reduces footprint;

increased or decreased above or below four

the success of a development and will have an

however, plate efficiencyalso reducesand capital

storeys.

effect on value and on perceived amenity.

cost will increase.

ð

ð

3.5 Floor plate efficiency

3.2 Parking, 3.3 Landscaping, 4.5 Amenity

Site density Lower Density

45% (GEA to site area)

Higher Density

smaller buildings more flexible lettings more landscaping

larger buildings less flexible lettings less landscaping

higher energy consumption higher capital cost

lower energy consumption lower capital cost

3.0

3.0

Another useful measure of plate efficiencyis the

3.4 Building orientation

3.2 Parking

Large floor plates of 2,000m 2 or more can be

ratio of floor area to external wall surface area,

veryeff icient and flexible both for single-tenanted

1 space per 25m 2 (of GEA) for business car parks

The orientation of building facadesin relation to

which reflectsthe amount ( and therefore the cost)

and multi-tenanted buildings. O ptimum plate size

Local authoritypoliciesand G overnment

the sun path can have a signifi cant impact on

of envelope required for a given plan shape. If the

is closelyrelated to workstyle.

legislation are together i ncreasinglyrestricting the

running cost. In general, east- and west-facing

floor to wall ratio exceeds0 .4, a value engineering

ð

levelsof car parking that can be provided on both

elevationsare difficult to shade; south-facing

exercise should be considered to test the validity

citycentre and out-of-town sitesbecause of the

elevationscan be provided with effective sun

of the design criteria and value for money.

impact of park ing provision on congestion,

breaks; while north-facing elevationsare

ð

pollution and the use of energy. Accessby private

unconstrained in respect of glazing.

car is still considered desirable, but there is an

&

associated cost to the environment. C ycle and

3.6 Building plan depth

3.14 Envelope, 4.7 Capital cost

13.5m-21m

Plate eff iciencycan be optimised by:

‘Solar Shading of Buildings’ – BR364, Constructi on Research Communications, 1999

• Reducing to a minimum the size and number of 

motorcycle spacesare now required, and

In practice, however, the relative location and

elementsserving the usable space, such as core

standards are applied for the provision of disabled

orientation of buildings is often determined either

areas (stairs, toilets, lifts), duct risersand

spaces.

bythe surrounding urban context, or bythe

enclosed circulation routes

ð

attributesand constraintsof a masterplan, in the

3.1 Site density, 4.6 Accessibility 2

Park ing layoutsof 25m per space are optimum and can be achieved byensuring that aisles serve parking bayson both sides.

are suitable for use with a varietyof mechanial

and converselyby increasing the floor plate in

systems, including conventional air conditioning,

size, where possible, so that maximum travel

mixed-mode. Depths of lessthan 15 metresare

distancesto escape staircasesare achieved

preferred for eff ective natural ventilation, but very

degree of identityand separation theyprovide to

narrow plates (of 13.5 metres or less) are less • Creating square and atrium-based plan shapes

80-85% ( NIA:GIA)

shrub planting, together with hard surface

M easuresof plate efficiencyper floor include:

landscaping, as part of a masterplan strategyi s

• ratio of net internal area to gross internal area

area to wall area, which reducescapital cost. The of good practice in the UK is 21m.

ð

of approximately80-85% (NI A:GI A) maybe

(NIA:GIA)

and ventilation are available to occupiersof 

diagram p.23). In general, smaller platesare less

perimeter space which, depending on the size

efficient because the core elementsbecome

(NIA:GEA)

disproportionatelylarge as plate size isdecreased.

2

• cost per m of net internal area

Floor platesof lessthan 750m 2 are relatively inefficient.

have controlled access. Tree planting adjacent to

Cost per m2 of net internal area isa reliable

glazed elevationsabsorbs solar energyas well as

measure of the cost-efficiencyof providing usable

creating shade and actsas a wind barrier, and can

space, which doesnot relyon interpretations of 

therebycontribute to energyeff iciency.

the basisfor calculation of grossfloor area ( such

3.12 Building section, 4.4 Comfort, 4.9 Cost in use

The relationship between plan depth a nd building section should also be considered. Natura l light

achieved, depending on building shape (see

• ratio of net internal area to gross external area

and location of windows, is a zone approximately 5m-7.5mwide or 2 to 2.5 times the floor-to-ceiling height of the room. C omfort in the space which is not within thisperimeter zone hasto be maintained using artificial light and ventilation, with resulting effectson energyconsumption.

ð

as whether plant areasand escape staircasesare

3.15 Services systems, 4.9 Cost in use

maximum plan depth regarded as within the range

3.10 Core elements, 3.11 Use of atria, 6.6 Statutory regulations

M aximum efficiencyfi guresf or the whole building

a primary contributor to a sense of amenity.

ð

Greater plan depth increasesthe ratio of f loor

minimum practical dimension (when a measure

ð

terms of landscape impact. Structured tree and

open-plan working space.

• Reducing the thickness of the envelope to the of NIA:GEA isused)

O ut-of-town locations are increasinglyassessed in

both implying and/or determining which areas

able to effi cientlyaccommodate mixed cellular and

and cubic rather than linear building shapes

4.5 Amenity

3.5 Floor plate efficiency

Landscape featurescan contribute to securityby

4.2 Workstyle, 4.7 Capital cost

configuration required byS tatutoryRegulations,

3.14 Envelope, 4.9 Cost in use

3.3 Landscaping

ð

ð

ð

Wind-driven generators, Sainsbury’s

3.1 Site density, 4.5 Amenity

Europeansf avour narrow space.

Depths of 15-18 metres are verycommon, and

ð

essential for major businesspark schemes, and is

appropriate to deep-plan space; continental

staircasesfor a given plate size and

of building orientation.

25% (of site area) for business parks

bywork style. American working culture is

case of businesspark locations.

building occupiersi s also a veryimportant aspect

negotiation with the planning authority.

Practice variesacross the world, and isaf fected

• Providing the minimum number of escape

The prominence given to entrancesand the

Park ing levelsin urban areas will be dependent on

4.2 Workstyle, 4.7 Capital cost

included or not).

4.4 Comfort diagram

Site density

Typical multi-storey office buildings efficiency ranges (net grossfloorarea ratios) 40+ storeys 30 to 39 storeys 20 to 29 storeys

Narrow plate

Wide plate

cellular/two zone planning views out individual control natural ventilation natural lighting lower energyc onsumption lower C0 2 emission lower running cost higher capital cost

open plan/multi zone planning internal areas constant conditions mechanical ventilation artificiallighting higher energyconsumption higher C0 2 emission higher running cost lower capital cost

10 to 19 storeys 5 to 9 storeys 2 to 4 storeys

European model 65%

70%

75%

80%

85%

90%

UK model

US model

3.0

3.7 Column grid

3.0

The planning grid is typicallyexpressed on the elevation to facilitate partitioning of perimeter

7.5m-9.0m

offices, and it also operates as the co-ordinating

The column grid dimension should be a multiple of 

grid in plan for the principal componentsof the

the planning grid dimension. The column grid

structure, services, fabric and finishes, including

should be as large as possible taking i nto account

column grid, envelope, ceiling ti le grid and

the characteristicsof the proposed structural

partition grid.

system and having regard to capital cost and

appropriate if workstyle dictatestheir use.

ð

3.8 Planning grid, 3.13 Structural systems, 4.2 Workstyle, 4.7 Capital cost,

Space budgeting isnormally based on an allocation for working footprint area ( derived from standards for occupancy) together with allowancesfor ancillaryspace, and for primaryand

restrict subdivision nor create unusable space.

secondarycirculation.

ð

Common UK standard – 1.5m

and anticipate the maximum occupancy requirement during the life of the building

• be located to promote adaptability and permit flexibility of letting and workstyle • where practical be located to encourage their use for short journeysbetween floors

ð

3.9 Circulation, 4.3 Occupancy, 4.7 Capital cost, 4.10 Adaptability, 6.6 Statutory regulations, See diagram page 10

4.3 Occupancy

Primary circulation space isthe minimum area required to accessand escape from open plan work areas and cellular offices. Secondary

The planning grid is derived primarily from

circulation space is that which isprovided

workstyle and reflectsthe smallest unit of 

between and around personal workspaces.

subdivision of space made available bya particular

• be designed to minimum occupancystandards

largest possible floor plate area

3.9 Circulation

The location of perimeter columns should neither

3.8 Planning grid

Core elements and staircases

• be located to optimise capital cost, and serve the

floor-to-floor constraints. In general, spansof 7.5m to 9m are economic and greater spanswill only be

3.10

Escape staircases should:

Current North A merican, British and Japanese

Goods lifts should: Lavatories should:

• be designed to a standard of one person per 14m2 net area based on 120% of the population (60:6 0 male/female ratio) when male and female toiletsare provided • be designed to a standard of one person per 14m2 net area based on 100% of the population

building system. A mullion grid of 3.0m is not

office developmentstypicallyminimise circulation

uncommon because cellular offi ces are rarely

space to achieve maximum efficiency. Many

narrower; however a 1.5m grid wi ll inevitably

Northern European examples, on the other hand,

Consider whether it is appropriate to install or

provide more layout flexibility. A grid of 1.35m is

demonstrate the importance attached to the

leave space for spare drainage, water risersand

an option used more frequentlyi n Europe. This

function of secondarycirculation areas as

ventilation to provide additional lavatories to meet

grid co-ordinateswith ground floor or basement

when unisex toiletsare provided

interactive and stimulating communal workspaces

increased population, or where sub-letting

parking and brick dimensions, and also permits

which promote a sense of amenity and enhance

requires, the provision of additional services.

slightlysmaller unit offices (2.7m wide) which are

working eff ectiveness and productivity. The

ð

4.3 Occupancy, 4.10 Adaptability

• be provided in buildingsover 10,000m 2, but also consider the need for goods lifts in buildings over 5,000m2 and an associated goodsreceiving area separate from the passenger entrance Kitchens in buildings over 5,000m 2:

• if it would be difficult to adapt the building later, give due consideration to increased fresh air requirementsand position of k itchen exhaust relative to air intakes and adjacent properties

3.11 Use of atria The use of atria i n conjunction with office f loor platesof optimum width can reduce capital cost

regarded asmore efficient in termsof space

imaginative use of atria is a common feature

usage. The lessgenerous standard based on a

of this approach.

Passenger lifts should:

because envelope cost is less, and can reduce

ð

• be designed to a standard of one person

running cost because exposure to external climate

1.2m grid will also co-ordinate with parking.

ð

3.11 Use of atria, 4.2 Workstyle, 4.5 Amenity

3.7 Column Grid, 3.14 Envelope, 3.16 Finishes, 4.2 W orkstyle

per 14m net area 2

• target an average interval of lift departure at the main entrance of 30 secondswith cars assumed

Structural grid/ planning grid

is reduced. Employing building shapesbased on atria also improvesplate effi ciency.

ð

to be loaded at 80% of capacity( for cenic lifts

Plate subdivision/ circulation diagram

reduce car loading to 60% ) • provide a minimum percentage passenger handling capacity in a fi ve-minute interval of  15% • be selected from manufacturers’ standard range

3.5 Floor plate efficiency, 4.7 Capital cost, 4.9 Cost in use,

Apart from the purelytechnical advantages of  atria, they can be used to support a workstyle which is more open and interactive, and when used in conjunction with shared resources, such as meeting areas, catering and retail facilities, can significantlycontribute to the ef fectiveness

(use of standard and pre-engineered

of the office environment and to amenity.

components reducesinitial costs, maintenance

ð

costsand increases reliability) • be located to provide a choice between lift and main stairsf or both occupantsand visitors

ð

4.3 Occupancy

&

“Transportation Systems in Buildings” – Chartered Institution of Building Services Engineers Guide D, 1993

4.2 Workstyle, 4.5 Amenity

In the life of larger buildings, it may be an advantage to be able to create large areas of deep plan space by infilling atria.

ð

4.10 Adaptability

&

“Daylight in Atrium Buildings’ – BRE Information Paper,IP3/98, Construction Research Communications, 1998

3.0

Cross section dimensions diagram

3.12 Building section

3.0

3.13 Structural systems

The overall dimensionsfor servicesand structural

The choice of structural system can be complex.

zoneswill depend on the frame solution and

Itwill be influenced by many factors including site

extent of services to be included. For column grids

location and site constraints, building form, planning

of up to 9m centres, it is usual to keep the

and structural grids, loading requirements and

horizontal servicesi n a separate zone from the

sustainability issues.

The design of longer span and shallower floor

3.14.2

systemsshould be checked to ensure that any

At the earliest opportunity, the designers of the

vibration from footfall (and other sources) is within

structural frame and the designersof the building

acceptable limits.

envelope need to consult on the effects that building frame movement and toleranceswill have on the j ointing between building envelope

3.14 Envelope

structure. For larger span spaces, a different

3 .1 3.1

The space between long-span beamsis the main

Standard allowances for live load:

ð

3.13 Structural systems, 3.15 Services systems, 4.7 Capital cost

Structure and building servicesshould be integrated to achieve a compact zone, but not so tightlyarranged that buildability, accessand flexibility are compromised. Significant savings in overall storeyheight can be obtained bycoordinated overlapsin zones. Ceiling/l ighting zone: 100mm overall

This figure assumessuspended ceiling and

Lo ad in gs

General area 2

• 2.5 kN/m over approx 95% of each potentially sub-lettable floor area High loading area

• 7.5 kN/m 2 over approx 5% of each potentially sub-lettable floor area a nd not in primary

The building envelope provides an interface between

without exception, it is better to provide extra

the controlled internal environment and the

stiffnessto structural framing membersaround

uncontrolled and variable external climate. The

building perimetersto limit movement in the

design of the envelope, therefore, determines how

building envelope elementsrather than design

the climate is moderated while maximising the

frames to minimum code requirementsand then

benefits, such as fresher air and daylight.

have expensive retrofit stiffening done on site.

3.1 4.1

C omponent life

• replaceable elementsshould last lessthan 60 yearsand replacement hasto be considered at

circulationroutes

design stage – double-glazed units (20 to 25 Standard allowances for dead load:

years), sealants (20 to 25 years) • maintainable elements should last a minimum of 

• 1.0 kN/m2

opening windows

natural ventilation is proposed, alternative zones,

• 0.8 5 kN/m 2

• long-life elements will last 60 yearswithout any

connecting the envelope to the f rame to be connected to the top surfaces of floor slabs. At

maintenance, eg. bracketing attaching cladding

least 150mm clear nominal above the target level

designed and marketed with floor loadings

to primary structural frame, cladding framing

of the floor slab should be allowed for these

significantlyhigher than the current British

members

brackets.

The choice of floor-to-ceiling height within these

Standard loading threshold of 2.5 kN/ m .

ð

dimensionswill be influenced bybuilding plan

Research has shown this to be an over-provision.

&

BS 7534: 1992 Amendment – 1998

depth, the form of environmental control system

&

2

selected and daylighting.

Stanhope Position Paper “An Assessment of the Imposed Loading for Current Commercial Office Buildings inGreat Britain”, August 1992

3.14.4

Watertightness

Performance requirementsare defined in the Centre for Wi ndow and Cladding Technology (C WCT ) Standard for Curtain Walling. Testing to

3.6 Building plan depth, 3.15 Services systems, 4.4 Comfort

verifycompliance isdescribed in the CWC T Test

3.13.2

Frame and materials

Raised floor zone: 150mm overall

A steel or reinforced concrete structure is equally

If an underfloor air conditioning or ventilation

acceptable. A comparative table is given below.

system is adopted, thisdimension will increase

inside face of the envelope and the outside edge

Historically, UK off ice buildings have been

4.10 Adaptability

by300 mm to 450mm.

structural frame. When it does, a nominal gap of at

and safetyconsiderations, for bracketing

building services equipment

ð

achieved if the envelope passesoutside the

of the structural frame. It is preferable, from health

Raised floors, ceiling and

technology. Where underfloor air conditioning or

Floor-to-ceiling height: 2600-3000mm

Support system

Generally, better overall envelope performance is

60 years with periodic treatment, eg. opening window ironmongery, weathering gaskets on

considered.

3.1 4.3

least 50mm should be allowed for between the

Demountable partitions

integral fluorescent fittings using T5 lamp

possiblyi ncorporating exposed soffits, can be

elements, and on the connections between the building envelope and the structural frame. A lmost

strategyis needed to avoid large storeyheights. area of services distribution.

Envelope/frame in terfaces

A clear strategyfor flexibility and future adaptabilityof the structure should be developed.

M ethodsfor Curtain Walling.

Steel or reinforced concrete? Steel

Reinforced concrete

Specialised operations

The eff icient and sustainable use of structural

If there is a reasonable expectation that the

materials should be a vital consideration.

relativelylightweight

relatively heavy

ð

greater depths minimumdepth solutionsinefficient

shallower depths for modest spans, flat slabs give minimum depth

good for longer spans but depth requirements imply combined structure and services zone

for longer spans, post-tensioned slabs give

can be effiicient on rectangular and square grids

building mayincorporate dealing operationsor a www internet exchange during its life, the slab-to-

4.7 Capital Cost, 4.8 Embodied Energy Cost, 4.10 Adaptability,

slab height should be increased on relevant floors to accommodate the requirement for greater

3.13.3

raised floor and ceiling void depths. Modern

The overall depth of the structural floor zone

cabling hasreduced the need for very deep floor

should make adequate allowance for dead load

more efficient on rectangular grids than on square grids

voidsi n dealer areas. Consider 200-300mm

deflection of the structure.

inherentlygood for holes and fixings (into soffit)

overall. Major changesin power supplies and

Deflections, tolerances and vibration

The building elements attached to the structure

cooling capacity should be considered.

should be detailed to accommodate both dead

ð

load and live load deflectionsof the structure.

4.10 Adaptability

They should also be detailed to accommodate manufacturing, fabrication and construction tolerancesin the structure.

minimumdepths

holes and fixings can be accommodated but strategy must be considered early.Holes should avoid prestressing tendons concrete soffits give option of chilled beam cooling

3.0

3.0

The following requirementsare appropriate

&

for offices:

“Minimising Air Infiltration in Office Buildings” – Construction Research Communications, BRE Report BR265, 1994

Performance under test

• no leakage onto the internal face of the curtain

Average U-values for building envelopes used

600 P ascalsheld for 5 minuteswhen tested in

for buildingsother than dwellingsare quoted in

accordance with CWC T test methods section 5

Table 5 of the Building RegulationsL1 ,

wall under a dynamic test pressure differential of 

conservation of fuel and power, approved document and are as follows: Roofs

0.25 W/m2k

accordance with CWC T test methodssection 6

Solid sections of exposed walls

0.45 W/m2k

wall under a hose test carried out in accordance with CWC T test methodssection 7, when tested on a test specimen off-site and on the actual wall on-site

3.1 4.5

Windows/personnel doors and roof lights 3.3 W/m2k Vehicle access and similar large doors

0.7 W/m2k

These valuesare used to carryout initial assessmentsof the energyefficiency of a particular building. Adjustmentscan then be made to these valuesto obtain the required aesthetic

Air tig htness

Performance requirements for curtain wallsare

occupancy, lighting and office equipment power. should preferablynot exceed 60-90W/ m2 of  perimeter office f loor area. O ccupancyshould be based typicallyon one person per 12m 2, but diversified, where possible, to one per 14m 2 at the central plant. Lig hting should be designed to ensure no more than 12W/ m 2 heat gain to the

600 P ascalsheld for 15 minuteswhen tested in

• no leakage onto the internal face of the curtain

Mechanical systems

Solar gai ns, which depend on facade orientations,

Thermal insulation

wall under a static test pressure differential of 

• no leakage onto the internal face of the curtain

without compromising the overall requirementsof  the Regulations.

central cooling plant. Cooling loads due to power consumption for office equipment in general office areas rarely exceed 15W/ m2 when diversified and measured over an area of 1,000m 2 or more, but with an abilityto upgrade to 25W/ m 2. Local work station loadsare typically20-25W/ m 2. Where possible provide space for additional cooling plant.

&

“Stanhope BCO Occupancy and Small Power Position Paper”, June 2000

• Adaptability4.10

Air tightnesstesting,

• Capital cost 4.7

DoxfordInternational,Sunderland © R ybka Battle

defined in the Centre for Windowsand C ladding

Zoning

• Controllability4.4.7

Technology(C WCT) Standard for C urtain

Zoning of air conditioning should segregate the

• Energyand maintenance costs4.9

perimeter and internal zonesand be selected to

• Workstyle 4.2

take account of likely partitioning, occupancyand

• Noise 4.4.6

use of the space.

• Spacerequirements 4.3

Walling. Testing to verifycompliance of curtain wallsis described in the CWCT Test Methodsfor Ionica building, Cambridgeshire

3.14.6

3.15.2

Cooling requirementsare dictated bysolar gains,

Curtain Walling. Performance requirementsand test procedures for the whole completed building envelope are described in BSR IA T echnical M emorandum TN8/ 95 Air Leakage of O ffice Buildings. The following requirementsare appropriate for offices:

3.15 Services systems 3.15.1

Electrical systems

Small power consumption

When diversified over an area of 1,000m2 or more, power consumption for equipment in offices rarely exceeds15W/m 2. Ri sers/busbars should be sized for 25W/m2 overall asa minimum. Provide a sufficient number of spare ways, typically15-25% , at each riser distribution board

Performance under test

and at the central mainspanel.

• the permissible air leakage rate through the

&

curtain wall should not be more than

“Stanhope BCO Occupancy and Small Power Position Paper”, June 2000

1.5cu.m 3/hour/m2 of wall for fixed areas, and not

Standby generation

more than 2.0cu.m 3/hour/ linear metre of joint

The base building design may provide for standby

At the perimeter, provide one control device to

• Special user requirements5.9

perimeter office depth of 4.5m. Zoning of 

An appropriate system may be, amongst others,

mechanical equipment should be consistent with

anyof the following:

the planning grid to take into account future partitioning. Internal zones do not attract solar gainsand

• Variable refrigerant volume

ð

ð

3.15.3

Choice of mechanical system

generator plant for essential servicesto maintain the use of the building during power failure (when

available, each of which has particular

not operating in fire mode) . Provision should be

performance characteristicsand is therefore

methodssection 4

made for occupiers’ standbyplant, i ncluding

suitable for differing locations or building forms

space, for fuel storage and exhaust flue.

and for specific applications.

There are many mechanical-air cooling systems

and opening areas for static test pressure

Information technology

differentials of between 50 and 600 Pascals

Consideration should be given to diverse routes

account the particular circumstancesof the

should not be more than the values given in

for links to external telecommunications

building, and the following factors:

figure 1 of the CWC T Standard for Curtain

infrastructure. Each i ntake position should make

Walling

provision for several service providers. Whenever possible the intake roomsshould be at the building perimeter and have incoming ducts

5.0m /hr/m at 50 P ascalstest pressure

directlyfrom outside.

3

2

differential, and with anyair leak age paths evenlydistributed about the envelope

&

“Air leakage Testing of Buildings” – Chartered Institution of Building Services Engineers, TM23, 2000

• Fan coils • Variable air volume

4.3 Occupancy

when tested in accordance with CWC T test

completed envelope should not be more than

• Displacement ventilation

zonesof 50-80m 2 to be accommodated.

differential of 600 P ascalsheld for 5 minutes

• the permissible air leakage rate for the whole

• Chilled ceiling/beams

have more stable conditions. This allowslarger

for opening areas under a static test pressure

• the permissible air leakage ratesf or fixed areas

• Comfort 4.4

not more than 6m of perimeter space assuming a

The selecti on of system type should take into

4.9 Cost in use

Regardlessof which system is selected, installationsshould be designed to take maximum advantage of natural or renewable energy. This should include “free cooling”, where advantage is taken of uncooled ambient air in mid-season conditions, when economic. Occupantsshould be able to run their systems in a simple but effective manner, regardlessof  other occupants.

ð

4.4 Comfort

Where refrigerantsare to be used, theyshould have an ozone depletion potential of zero.

&

Refrigeration and air-conditioning gases – March 1993, DETR

3.0

3.1 5.4

3.0

C ontrols /BMS

flushes, having spraytaps for wash hand basins,

Procedures for preventative measuresagai nst the

Office space

Controls should be designed to operate the

the use of low flush WCs and of greywater

sludge-generating effectsin pipework of the

The use of emulsion paint on plasterboard walls

mechanical system in line with each anticipated

systems.

aerobi c bacteria, Pseudomona s, should be

is acceptable. For suspended ceilings, use either

incorporated into the commissioning

mineral fibre or metal ceilings that are easily

documentation.

demountable and allow the incorporation and

&

interchangeability of recessed light fittings.

occupancy. The system should be capable of  operation on a part-floor basiswhere large f loor platesare proposed. Controls should enable occupants to make limited adjustments locally to the heating/air-conditioning systems.

ð

4.4.7 Comfort control, 4.10 Adaptability

A Building Management System (B M S) should be

Rainwater

Evaluat e siphonic systems which can reduce the number of roof outlets and enable horizontal pipework to be used.

BSRIA Pre-commissioning and cleaning of water systems Guide AG 8-91 with report of BSRIA Seminar, 12th February 1999

C ommis sioning

Efficient and effective operation of building

cubiclesand vanityunits provide a perfectly

3.16 Finishes

satisfactoryand functional level of finish.

considered a standard requirement to co-ordinate

servicessystems is reliant on successful

Too often, elaborate and individual designs,

the control of building engineering systemsand to

commissioning of the i nstallationsand their

using expensive and unique materials, have been

monitor their performance. The system

subsequent maintenance; provision for

evolved in areasof the building where theyare

architecture should be based on intelligent plant

commissioning must be considered during the

not warranted, with the result that occupiershave

controllers networked to a PC supervisory

design of the services.

been faced with high costsof maintenance and

terminal. Provision should be made to allow integration of future tenant billing of heating, cooling and power.

Consideration should be given to employing an independent commissioning engineer. Adequate time must be programmed during the

3 .1 5.5

construction processto allow all commissioning

Wa te r

replacement during the life of a building. The use of standardised productsand proprietarysystems increasesreliability and the availability of  replacement parts.

20 litres per person per dayto k eep turnover high

monitored under operating conditions. Full records

and it isa ccepted that richer materials maybe

to minimise the risk of LegionnairesD isease.

of the installed systems, together with clear and

used in the public areasof the building, in

complete maintenance recommendations, must be

particular the entrance hall.

Natural ventilation Capital cost

Staircases in modern buildingsare generallyused for escape purposesrather than inter-floor communication. A functional and utilitarian standard of finish, such as painted plaster wall finishes, painted concrete floors and painted metal handrails, istherefore appropriate. Where interfloor communication isanticipated, then a higher standard of finish could be appropriate.

activities to be completed. Systemsshould be

PI R control with sequenced flushing of all urinal

Core/staircase area

This doesnot seek to limit the qualityof design

If required, provide water storage at a rate of 10-

To minimise water usage, consider the use of 

Lavatories

Ceramic tiles to floorsand walls with laminate

3.15.6

provided.

Mixed mode

Energy-efficient airconditioning

Low

C apital cost

M edium

Capital cost

R unning cost

Low

R unning cost

M edium

Small power capaci ty

L ow

Small power capacity

M edi um

S i mp il ci ty o f c on st ru ct io n Fe l xi bi li ty/ ad ap ta bi li ty

S i mp e l M o de ra te

S i mp li ci ty o f c on st ru ct io n Fe l xi bi li ty/ ad ap ta bi li ty

M o de ra te M o de ra te

S i mp li ci t y of c on st ru ct i on Fe l xi bi li ty/ ad ap ta bi li ty

Conventional airconditioning H igh

Capital cost

Running cost

M edium

R unning cost

High

S mall power capaci ty

H igh

S mall power capaci ty

H igh H igh

C o mp e l x H i gh

S i mp li ci t y of c on st ru ct i on Fe l xi bi li ty/ ad ap ta bi li ty

C o mp e l x H i gh

High-level windowsallow passive cooling at night.

Displacement mechanicalventilationunderfloorplenum.Integral

Fancoil unitsin ceiling void.

Shading andblindsreduce solargain.

Shadingand blindsreducesolargain.

Buildingstructurescanbeexposedfor masscooling. Perimeter heating offsetsheat losses.

Building structurescanbe exposedfor masscooling. Maximum temperature 25°C for95% of year.

blindsreduce solargain. Maximum temperature 24°C for95% of yearor lower.

Blindsreducesolargain. Maximum temperature 24°C orlower.

TypicalannualC O 2 emissions: 60-90 kg/ m 2

TypicalannualC O 2 emissions: 80-140 kg/ m2

High-levelwindowsallowpassivecoolingat night.

Maximum temperature 25°C for95% of year. TypicalannualC O 2 emissions: 30-80 kg/ m

2

TypicalannualC O 2 emissions: 40-80 kg/ m 2

3.0

4.0

Lift car interiors

The building shell-and-core should be offered

The lift car interior isgenerally seen asan integral

to the occupier completed to the following

part of the design of the entrance hall and, as

specification:

such, the quality of f inishesshould be compatible. However, unique designsfor the functional

Fully finished areas:

aspectsof the li ft car, such as call buttons, etc.,

• Entrance hall, staircases, common parts, toilets,

should be avoided. The use of manufacturers’ standard car finishes is more economic and allows for easier mai ntenance.

3.1 6.1

Shell and core

lifts and core Shell finish areas:

• Of fice space excluding suspended ceiling, lighting, raised floor, wiring, air conditioning ductwork and terminal boxes, decoration

There are advantages to both owner and occupier in completing the building to shell-and-core standard. These are: • Shorter construction period for owner and earlier possession byoccupier for fitting out

• Base servicesplant and equipment terminated at breakout to floors When completing a building to shell-and-core, a portion of the space maybe fitted out to the developers standard into which a marketing suite

• Savings in coststo occupier asdevelopers’

can be incorporated.

standard itemsdo not need to be removed or protected during fitting out • Flexibility for the occupier to varyfi nishes specification without cost of removing and discarding materials alreadyinstalled byowner • Reducing waste caused by stripping out base

3.1 6.2

Fully -fitted

identified prior to completion of the building. The landlord undertakes to complete the building to a standard readyfor occupation bythe occupier and to a specification agreed between

out requirement

the parties.

6.4 Categories A & B

Users and owners of buildings are interested in the way in which their workplace p erforms; whether the buildings and spaces support their working p atterns and corporate aspirations, and whether they provide a safe, comfortable and productive environment. The location and accessibility of a development, its function and appearance, and its whole-life costs (including both c apital and running costs) are all aspects of performance, but not as important as the performance of  the workforce. All of t hese features should be understood and measured.

This option applies where an occupier hasbeen

building works to accommodate tenant fitting-

ð

K ey performance criteria

The cost of bringing the building up to notional developer’s standard will be borne bythe landlord but the extent to which the landlord will contribute to the additional cost of fitting out beyond that point will be subject to negotiation.

4.1 Sustainability and building performance

4.2 Workstyle Trendsin workstyle are evolving and vary

Buildings alone are directlyresponsible for

considerablybetween business processes and

approximately50% of all energyconsumption, and

cultures. The traditi onal practice of allocating

much more if the effects of road traffic generation

space bygrade or statusis being replaced bya

are taken into account. Buildings are also

new pattern in which space standards are related

responsible for half of the UK ’sC O 2 emissions,

to specific activities with specific footprint and

double that caused byindustryor transport.

environmenta l requirements. Group-based,

M anyof the choicesmade by the developers and designers of buildings have a direct and inevitable impact on sustainable performance. These include choicesassociated with, the reuse of existing buildings; site location; building orientation; building shape; heating and cooling methods; and the selection of materials. Standardsf or sustainable design will

interactive working is becoming more prevalent than isolated, cellularised working. As work becomesmore project-oriented and less processdriven, the interaction between people becomes more fluid and more dynamic. Developments in IT have made possible a variety of mobile, timeflexible working practices, and these have an impact on the variable use of space. At peak occupancymany spaces( in addition to cellular

increasingly be set bylegislation. Theywill also be

offices and open workstations) are occupied

used byprogressive businessesas criteria for the

dynamicallyas short stay work settings.

selection of suitable premises. Improved environmental performance and sustainabilityin a building can result in significant benefits in running costs, staff satisfaction and productivity. The BR EE AM 98 environmental assessment method is the current industrystandard for measuring environmental performance; it establishes levelsof performance that represent industrybestpractice.

ð

:

6.5 BREEAM, p3 Productivity www.products.bre.co.uk/breeam

O rganisationscan be characterised bythe degree to which these new workstyleshave been embraced or are appropriate, and solutionscan be tailored to their specific corporate requirements. H owever, when buildingsare developed speculatively,and when design life i s an overriding concern, the most versatile solutions anticipating the widest application of innovative work ing practice should be sought. In general, change of space planning from open to closed

4.0

4.0

and vice versa hasto be anticipated, as doesthe

Good U K practice for conventional occupancyis

4.4.2 Temperature

flexible insertion of distributed support faciliti es

currentlybetween 1 2m2 and 17m2 per person of 

Recommended standards for offices are:

such asmeeting rooms, project spaces, rest and

net internal area. Space standardsf or specific

catering spaces and local centres for

individual task-based activities range from a 4m 2

copier/printer/post and office suppliesdistribution.

to 6m2 footprint for trading desks or call-centre

This degree of flexibility can be facilitated by

workstations, and up to 15m or more for

creating wider floor platesand bymak ing

enclosed offices.

provision (in section and in plan) for future

ð

changesto building services.

2

&

3.15 Services systems “Stanhope BCO Occupancy and Small Power Position Paper”, June 2000

How hot is too hot/ design criteria

24ºC for summer design

Inland Revenue,Nott ingham

22ºC for winter design The range of temperatures achieved in the space will depend on the selected control band

other comfort criteria such asradiant effects and

reinterpretation of the use and value of secondary circulation space, and use of atria.

Set point

Maximum

ISO 7730 @10% PPD BCOSpecification

chilled ceilings, achieve equal comfort at higher

CIBSEGuide A.1

workplace productivity. B uilding services

design temperatures.

18

19

20

21

22

23

24

25

26

27

28

Predicted thermal comfort in naturallyventilated

ð

3.6 Plan depth, 3.9 Circulation, 3.11 Use of atria, 4.3 Occupancy, 4.10 Adaptability

(pa ssive measures) should be designed together

buildings can be assessed based on the

to help ensure a healthywork ing environment.

percentage of occupied hoursfor which particular

&

“The New Office” – Francis Duffy, ISBN 85029 8912

&

internal temperaturesare expected to be

can permit dimming. The high f requency

exceeded. An appropriate design target might be

eliminates stroboscopic effects, so reducing the

to limit the time when air temperaturesexceed

feeling of nausea and headachessometimes

25°C f or 5% of occupied hours.

associated with fluorescent lighting. I nstalled

&

efficiencyshould be at least 75lm/W.

4.3 Occupancy standards

&

“Sick Building Syndrome: A Review of the Evidence onCauses and Solutions” – The Health and Safety Executive, 1992 Creating the protective workplace, SPON 2000

In recent years the norm hasbeen 10m 2 per

4.4.1 Visual Comfort

person of net floor area. R esearch hasshown that

Daylight and sunlight playan essential part i n the

veryfew buildings are occupied to a density that is

physiological well-being of occupantsand have an

General Information Report 30 – “A Performance Specification for the Energy Efficient Office of the Future”.

Uplighting, or a combination of up and downlighting, can avoid dull ceilingsbut the

this high. However, it is essential to ensure that

effect on productivityin the workplace. Evolving

If wider bands of tolerance can be set for

the maximum number of people occupying a

glasstechnologycan provide improved solar

temperature rangeswithin general offi ce space,

building is not artificiallylimited, particularlysince

characteristicswhile allowing good daylight

then there isan opportunityto consider ventilation

4.4.4 Fresh air

new workstyles can involve variable levelsof 

penetration. Provision should be made for user-

systemswith reduced cooling capacityor without

General offi ce areasshould be provided with fresh

occupancy.

controlled blinds to prevent glare and resulting eye

mechanical cooling.B RE EAM requires adequate

air at a minimum rate of 8-12 litres per second

ð

strain.

thermal modelling to ascertain that these criteria

per person, and thisshould take into a ccount

are achieved.

desired indoor air quality and the quality of  proposed and i ts ventilation effectiveness.

3.9 Circulation, 3.10 Core elements, 4.2 Workstyle, 6.6 Statutory regulations

O ptimum standardsfor the off ice workplace are:

power consumption maybe greater.

outdoor air. C onsider the type of system being

M i ni mu m d ayl ig ht fa ct or

> 0 .5 %

4.4.3 Lighting

A ve ra ge da yl ig ht f ac to r

>2%-5%

Design for a maintai ned illuminance level of 300-

ð

4.3 Occupancy

500 lux (open plan) with a uniformityrati o of 0.8

&

“Minimising Pollution at Air Intakes” – Chartered Institution of Building Services Engineers, TM21, 1999

(D aylight factor: lux inside/ lux outside x 100% )

Daylight penetration/di stribution and natural ventilation depth Note should be taken of Health & Safety (Display Screen Equipment) Regulations 1992

ð & &

Ionica Cambridge

air movement . Radia nt cooling systems, such as

Occupants’ perception of comfort influences (active measures) and the fabric of the building

3.6 Plan depth, 3.11 Use of atria, 3.12 Building section, 3.14 Envelope, 3.15 Services systems “Desktop Guide to Daylighting for Architects” – GoodPractice Guide 245, Department of the Environment, Transport and the Regions, 1998 “Daylighting and Window Design” – Chartered Institution of Building Services Engineers, LG10, 19 99

over the designated task area, with 12W/ m

2

maximum power consumption. Lighting is a significant cause of energyuse in

The system should be designed as a non-smoking environment, but if smoking areas are required the

office buildings, and the use of photoelectric or

system should be augmented locally to provide

presence switching devices should be considered.

increased ventilation extraction rates and to

The lighting control system should allow

discharge externally. Provision should be made for

reconfiguration to Part L of the Building

additional fresh air to meeting rooms.

Regulations without the need to modifythe wiring. In V DT environments, where bright uncontrolled

4.4.5 Humidity

The provision of daylighting will eff ect decisions

light sources can cause glare and eye strain,

Humidity control should not be i nstalled within the

with regard to overall plan depth, floor-to-ceiling

compliance with CIB SE L ighting Guide 3 must be

base office scheme unless a particularlyhigh rate

heights, shading solutions and glass type.

sought. Unless specific occupant activities are

of fresh air per occupant is required, (2.0 litres per

ð

known, base the lighting design on luminaires

second per m 2), in which case it should be

incorporating reflectorswith Category 2

controlled to give a minimum of 35-40% RH

performance suitable for regular use with VD T’s.

(relative humidity). Humidification is rarelyneeded

3.6 Plan depth, 3.15 Services systems

BRE

when summer design conditionsare exceeded.

interaction leadsto the need to accommodate a

4.4 Comfort

Actual

typicallybe ± 2°C. Internal temperatureswill rise Design air temperaturesneed to be reviewed with

as well asplanned meetings. One outcome isa

Minimum

which can varyfor dif ferent system typesbut will

The importance to working effectivenessof  varietyof spacesand facilities for spontaneous,

Medium acceptable

Satisfactory Intermediate

Use high frequency control gear on fluorescent

for general office use but space should be

luminairesas it haslower energyconsumption and

allowed for a steam-based system to be added at a later date.

29

30

°C

4.0

4.0

4.4.6 Acoustics

ventilated buildings, designed to a broader

The acoustic environment inside a building is

temperature band, tend to be perceived as

dependent on noise from the following:

relativelycomfortable both because theyare

The accessibilityof a development bymore than

to construct on site.

easier to manage, and because theyafford more

one meansof transport, and the qualityof 

ð

personal control.

interconnection between the available means of 

• Building servicesplant and equipment

ð

3.6 Plan depth, 3.15 Services systems

transport, are now veryimportant selection criteria

• O ccupiers’ use of the space,

&

Probe Reports (Post-Occupancy Review of Buildings and their Engineering)

• External sources, such as traffic or aircraft noise

includingequipment • The level of sound insulation of walls and floors

:

www.usable buildings.co.uk/Probe/ProbeIndex.html

4.6 Accessibility

the building structure, but also the finisheslik ely to be used bythe building’s occupants. Acoustic privacybetween offices is a performance requirement. Residual external noise, after attenuation bythe

4.5 Amenity Workstyle, occupancylevelsand comfort are

design will make the building easier and faster 3.5 Floor plate efficiency, 3.6 Plan depth, 3.7 Column grid, 3.12 Building section, 3.13 Structural systems, 3.14 Envelope, 3.15 Service systems, 3.16 Finishes

applied bydevelopersand end users in assessing

The optimisation of capital cost, once the level of 

desirability. For endusers, location in relation to an

specification or qualityof product hasbeen fi xed,

established workforce will also be critical.

is assisted bythe use of techniques such as Cost

ð

Planning, Value M anagement, Value Engineering,

2.2 Site location, 3.2 Parking, 6.5 BREEAM

The design of anynoise control measuresin occupier areasshould take account not onlyof 

of envelope and finishes. Simple and effective

Developmentsthat relyexclusivelyon accessby car not onlylimit choice, but also contribute to environmental and lifestyle costs(i ncluding

performance measuresconcerned with the nature

pollution, energyconsumption and wasted ti me).

and qualityof the workspace itself. The additional

In general, there isan emphasison reduction in

featuresand characteristicsthat contribute to the

car parking and support for proposalswhich

Risk A nalysis/C ontrol and Whole Lif e Costing. The latter is used to optimise the cost of  construction together with maintenance and running costs– Cost in Use.

ð

4.9 Cost in use, 5.3.6 Value engineering

The efficiencyand effectivenessof the

creation of an agreeable and pleasant general

building facade, should meet the following criteria

contribute to a mixed-use urban environment

procurement method used will also impact on

working environment are also important. T hese are

within the relevant space:

encompassing employment, housing and social

capital cost. Integrated design and construction

referred to as ‘amenity’ and are those thingsthat

facilities, so that people can live and work in the

processes help to reduce waste, both in the

• Open plan offices

45-50 LAeq

usersfeel add qualityto their working liveswhen

same area without having to travel far. The term

finished product and during construction.

• Cellular offices

40-45 LAeq

theyare ‘away from their desks’. From a user and

‘accessibility’ can be used in the context of access

Benchmarking and the rigorous measurement

• Conference rooms

30-40 LAeq

an investment perspective, there is a clear

for the disabled.

of resultsin the context of a rolling development

relationship between amenityand value.

ð

programme can also be an effective technique

In the case of naturallyventilated buildings, it may be appropriate to accept higher values. Building Services noise should be controlled to meet the following criteria:

qualityof landscaping, relationship of entrances, positioning of buildingscreating framed viewsand

NR40

vistas, and the relationships with surrounding and

NR38

adjoining developmentsneed to be determined

• Cellular offices

NR35

with great care.

• Conference rooms

NR 25-35

ð

2.2 Site location, 3.1 Site density, 3.3 Landscaping 4.6 Accessibility,

Reverberation time should be in the range of 0 .4 seconds for small rooms of 50m3 to 0.7 seconds

Proximity to local high street services providing

for a 500m3 room. BR EEA Mrequiresthe lower

restaurants and cafés, shopping, hairdressing,

end of these scalesin all office areasas a

sportsand other leisure facilitiesi s desirable.

reflection of best practice.

When town centre facilities are remote, these

&

servicescan be i ntegrated into a development

Research showsa causal relationship between the ease of control of services systemsand the

ð

significantlycontribute to a sense of amenity. The

• Open plan offices

4.4.7 Control

for optimising expenditure.

The character of the external environment can

• Entrance hallsand lavatories

BS 823-1999

6.6.3 Access and facilities for disabled people

and can be particularlyeff ective when provided as part of a workstyle concept operating asthe focus of an interactive worki ng community.

ð

4.7

Capital cost is defined as the expenditure incurred in the construction of new buildings and the extension or refurbishment of exi sting buildings. It includesthe cost of construction works and

• Maximum lettable m2 floor area per m 2 site

purchase and letting costs.

• Mi nimum building cost per m2 lettable floor area

Variableswhich aff ect capital cost include:

• Reduce amount of most expensive item per m2 of lettable

• location of site, including regional variationsi n materials and wage costs, remoteness and weather conditions

contours,exi sting vegetation, a rchaeological interest and accessibility

3.11 Use of atria, 4.2 Workstyle

• building control requirements, town planning

M ore difficult to measure, but neverthelessof  great importance, are the image and the

capable of delivering precise and constant

aestheticsof a new office development. Buildings

conditions, but which are poorlymaintained and/ or

impose compulsoryviewing on their owners and

poorlymanaged, are perceived as uncomfortable.

usersover many years. Insufficient attention, time,

Buildings whose servicesare well-managed are

talent and financial investment applied to the

perceived asrelativelycomfortable.

design of the building envelope can yield results

Capital cost is a performance issue in the sense

which fail to represent occupiers’ aspirations.

that design choices, made after the above

are regarded asmore comfortable. Naturally

ð

floor area = cladding in quantity • The most efficient geometrywould be the sphere or cube

• nature of site, including ground conditions,

Buildings which relyon sophisticated systems

individual occupantsover their local circumstances

Ideal building diagram from commercial points of view

associated professional fees, but excludessite

perceived comfort of buildingsby their occupiers.

In general, buildingswhich off er greater control by

5.2 Construction strategy, 5.3.5 Benchmarking

Capital cost

3.14 Envelope

constraints • availabilityof mains servicesand diversion works

Ratio of cladding to floor area

P lan

Section

• market conditions • level of specification or quality of product

variableshave been established for a specific project, will directlyaff ect building cost. These choicesinclude building size, floor plate design, structural and services systemsand the design

© Foster& Partners

Cladding area100

Cladding area 100

Floorarea

Floorarea

100

60

4.0

4.8 Embodied energy cost

4.0

The reduction of embodied energycan be achieved through applying the four R s: Rethink, Reduce, Recycle and Reuse.

Cost in use isalso referred to asT otal Occupancy

of the building occupants. Accordi ngly, careful

procuring raw materials, manufacture, transport,

ð

Cost, and is the sum of costsassociated with:

selection of componentsand systems that have

amount of energy needed can be high, typically accounting for 20% of the building’senergy useduring a 50-year life cycle, the equivalent of  10 to 20 times the annual energyuse. Reducing embodied energycan reduce the overall environmental burden of a building, and provide

3.13 Structural Systems, 3.16 Finishes, 5.1 Procurement

• propertyoccupation (rent, propertytax)

• design for flexibilityand adaptability( longer

• adaptation (fit-out, furniture, equipment)

cooling, ventilation, control and the selection of 

• building operation (insurance, maintenance,

furniture) is the most important issue.

spans, higher ceilings, ease of maintenance • design for durabilityconsidering the extended design life of permanent partsof the building (foundations, structure, service core, drainage)

plasticsand rubber, can easilybe stripped out

Note: excludesoccupants’ staff costs

and replaced • minimise transport of materials to site

ð

3.15 Services systems, 4.4 Comfort, 4.5 Amenity

sewage, energy)

&

“Whole Life Costing – A Client’s Guide” – Construction Clients Forum, 19 99

&

Investment property data-bank. www.ipindex.co.uk

post room) • management (FM and estate management)

consumption, production of greenhouse gases and

While rent and local propertytax will often

other pollutants, and transportation costsresulting

account for half of the total cost in use, adaptation

from site location and accessibility.

durabilityand mechanical properties are still

and building operation costscan also be very

acceptable ( eg. aggregates, bricks, steel

ð

significant, typicallyaccounting for a further 30% .

2.2 Site location, 3.6 Plandepth, 3.11 Use of atria, 3.14 Envelope, 3.15 Services systems

sections)

Building design solutions mayhave a direct impact

&

The Long Term Cost of Owning & Using Buildings, Royal Academy of Engineering www.raeng.org.uk

• use materials alreadypresent on site, provided

• advertise (with BR E’s construction materials

on cost in use, particularlyon maintenance and

information exchange) anymaterials which are

running costs, and the performance of design

7.5% Furnishingsand furniture

present on site but cannot be used, and search

choicesshould therefore be understood and

for local supplies of potential recycled materials

tested. A buildi ng with low cost in use should

7% Land

• specifywaste minimisation and productivity 6% Building – maintenance 5.5% Cleaning

3.5% Furnishingsandfurniture – maintenance and depreciation

have a lower rate of rental depreciation.

Typical and good practice standards for energy consumption and C O 2 emission are contrasted below.

enhancement measuresto be implemented during construction • utilise, where possible, formsof renewable

5.5% M& E services– depreciation

Cost in use in the context of sustainability includesthe coststo societyof energy

• IT/ technology

andmaintenance – capitalcost

the building occupants( such asfi nishes, heating,

security,cleaning, wastedisposal, water,

• business support (telephones, reception services,

• ensure that less durable materials, such as

Total investment in office building discount ed to present value

an influence on the productivity and comfort of

In general:

pointersto reducing capital cost.

24% M& E services– running

with commercial office buildingsare the salaries

Embodied energyi s the energyneeded for construction, maintenance and repair. T he total

41% Buildi ng – constructioncost

By far the greatest whole life costsassociated

4.9 Cost in use

2 Energy (kwh/ m  / yr)

energy

Naturally Ventilated Office

• minimise the use of high energymaterials

Gas

(eg. plastics)

ð

4.10 Adaptability

&

Energy Consumption Guide 19 – ‘Energy Use inOffices’, Department of the Environment, Transportand Regions, January 2000

&

‘Building for Energy Efficiency – TheClients’Briefing Guide – CIC, 1997

&

‘Environmentally Smart Buildings – A Quantity Surveyor’s Guide to the Cost Effectiveness of Energy Efficient Offices’ – Department of Environment, Transport and Regions, November 199 9

&

‘What will Energy Efficiency do for Your Business – A Business Manager’s Guide to Environmentally Smart Buildings’ – Department of Environment, Transport and Regions (due to be available April2000)

&

‘A Developers Guide to Environmentally Smart Buildings’. Department of the Environment, Transportand Regions, September 1999

Electricity Total

Airconditioned

Typical pra cti ce

Good practice

151

79

Gas

178

97

54

33

Electricity

Typical practic e 226

128

205

112

Total

404

228

(45% improvement)

Good practice

(44% improvement)

CO2 emission (kg/m2 /yr) Naturally Ventilated Office

Typical practic e Total

58.7

Airconditioned

Good practic e 33.0

Typical practice

Good practic e

144.8

86.2

Total

(44% improvement)

(40%improvement)

Comparison of Whole Life Costs for Alternative Mechanical Systems (at year 2000) Capital cost Installation £/ m 2

Annual Maintenance Cost £/m 2

Annual Energy Cost £/m 2

2 pipe fan coil

155

8

16

Displacement ventilation

140

4

13

1 Both systemsbasedon the use of electricheating 2

All figuresassume a notionaloffice building of 10,000m2 gross( 8,000m2 net)

3 All figuresare expressedin termsof grossinternal area

4.0

4.10 Adaptability/design life

4.0

4.11 Safety, security and risk

Current businessculture and work style require

The key to good safety, security and risk

office buildingsto accommodate high levels of 

management is early identification of the issues

both transience (in terms of tenant turnover) and

involved.

distinction is therefore made between the

4.11.1

optimum life span of the physical elements of the

The site

office environment:

• Location of building in relation to site boundary

• site (indefinite)

• skin or envelope (50-75 years) • services(15 years) • space planning elements (5 years) • work settings( constantlychanging) In practice, servicesand space planning elements( in particular) mayhave to be adapted on a much more frequent basis, and IT (which drivesmuch of the change in workstyle) is obsolescent within 3 yearsor less. In general, long-life features (eg. structure, plate shape, access points, location) should allow as manyservicing and layout optionsas possible to accommodate transience and volatility. This approach accordswith the need to create generic solutionswhen buildingsare developed speculatively. Consi deratio n should also be given to the inclusion of features designed to deliver high levelsof future flexibility. These include the provision of additional space capacityin vertical service risers, plant areasand building section. The additional construction cost of these features

• Single point of secure accessto building. • The number of recessesand re-entrant corners to be minimised or covered byC CT V cameras • Conduit to be installed to allow tenant to install

volatility( in termsof work setting change). A

• structure (75 yearsor more)

The building

Risk management

and the provision of external wall or fence to provide the principle of ‘defensible space’ • Single, monitored/manned point of accessto site • External C CT V coverage to entryroad/building approach • Car parki ng areasare to be well lit, covered by

4.11.4

The following should be considered:

changed

provision of blast shelter • Incorporate design features to minimise effects of bomb blast

4.1 1.2

Fir e protection

to the business, to manage any business interruption. Functionsthat require consideration

people to leave a building more quickly, theyare

include: a central manager, accommodation,

• Securitypatrols to external and internal areas • All vulnerable external spacesto be well lit, including access doors, external doorsand windows • Access to car park/goodsentrancesto be monitored bycentral securityroom

ð

2.2 Site location, 4.5 Amenity

&

BCO ManagementGuidanceSecurity ISBN 0952 413 132

essential for phased evacuation but should be considered f or all installations.

&

Building Regulations Part L

Current advice is that hose reelsshould not be installed, although this should be agreed with individual Building Control officers at the outset.

ð

5.9 Statutory regulations

Consideration should be given to the relationship between active and passive fire protection systemswhen formulating the design of a building. The combination of all aspects of life safetyshould be considered as a whole as opposed to element byelement.

enhancement measures, and can include the

Supportfacil ities

following:

BPG Building Fabric Component Life Manual ISBN 0-419-26000-5

manage an interruption • Formation of a core team, of a size appropriate

detection and alarms. Voice alarms motivate

The performance in use of supplied building

&

key contactswith work/customers/suppliers, meansof testing the plansto allow them to

L2 covera ge should be provided in respect of 

probabilityof more compact, lower energy-use

ð

identification of critical components, names of 

controlled

products in the future.

3.12 Building section, 3.14 Envelope, 3.15 Services systems, 4.8 Embodiedenergycost

business includingbusinessimpact analysis,

CC TV cameras and have accessri gorously

availabilityof M & E systemsmay be part of tenant

components under consideration will meet the

Disaster recovery planning

• Production of detailed action plansby the

• Robust construction of building, including

Standard practice in the diversification and

specific requirements of designers and users.

3.15 Services systems

required 30 days. Video cassettesto be regularly

4.11.3

should be undertak en to determine whether

maintenancecyclesetc

ð

recorded in securityroom and stored for

looser fit and longer design life and against the

maintainability is extremelyvariable, and research

planned testsand inspections • Install control systemsthat can measure energy,

CC TV coverage to all common areas. Film to be

must be weighed against value attached to a

components in terms of durability and

• Provide a regular maintenance regime of 

• Providing alternative and well separated sources of supplyfor utilityservices • Assess the reliabilityand qualityof the electrical supply • Caref ul and selective oversizing of main plant and running them at a percentage of full load but be aware of the possible adverse impact on energyconsumption • Specifying high qualityequipment • Siting of normal and standbyplant in different fire compartments, floors and aspects of the building • Provide suitable maintenance facilitiesand design of plant for ease of maintenance and repair

personnel, communications, IT and insurance • Identifying and, if necessary, procuring recovery options: these mayi nclude doing nothing, working f rom home, switching operation, using off-site backed up faciliti es, using alternative accommodation • Ongoing programme to maintain, and validate, recoveryplans

5.0

5.0

B uilding C ompletion

The construction of new, or refurbished building is only satisfactorily concluded when the end user has been adequately briefed in how t o occupy the workspace

5.1 Commissioning/handover Commissioning/ handover should be regarded as the successful transition from a construction project to an occupied, operational and defect-free building.

This process can be broken down into distinct elementsdependent upon timing of occupation. Construction: pre-practical completion

FacilitiesM anagement Familiarisation/P rePlanning Stage comprising: • Development of proposed operational strategies

Post practical completion to occupation

• Preparation of an occupational operation guide covering fitti ng-out procedures, cleaning, security, operation and maintenance • Planned maintenance contracts put into operation • Confi rmation of occupier acceptance following Construction Team issue of Practical Completion Certification • Identification of facilitiesmanagement space and equipment needsas a result of agreed

5.2 Building log book and training

• Progressive consideration of all the information which will be in the Building Log Book

• Guidance for tenantsf or fitting-out works and re-commissioning procedures

• Attendance at Construction Team inspections prior to Practical Completion Certifi cation • Preparation of standard Planned Maintenance Contract T ender documentation • Set up of requisite facilities management

systemsthat have been incorporated within the

• Building register recording all maintenance activities, breakdownsand defects • Compliance procedures

• Early rectification of identified building defects

building structure and to give guidance to the user

• Environmental management, B RE EAM

of the best way in which theyshould be

• Building warranties, including construction

cost efficiency The commissioning/handover processrepresents

security, cleaning and operation/maintenance

a total concept of qualitycontrol covering the

generally

inter-relationship of building componentsand

3.15 Services systems, 5.2 Building log book

The aim of the building log book is to provide a

• Ensuring building’soperational energyand

proceduresand documentation covering staffing,

ð

5.2.1 Building log book proper record of the components, materialsand

12 months post practical completion

In addition, provisionsare made for: • Recording system for all occupier requests

operational strategies

maintained. It is also to provide a working

team’s termsof engagement, statutoryapprovals

document that can be updated when changes

and consentsand building contracts

occur in the building. The building log book should comprise a

operation to anticipate the future ‘impact’ upon

number of volumes, each covering a particular

building use.

subject. The information within each volume

Commissioning/handover of the building has the habit of bringing up the unexpected. It is

should be presented in a structured and logical format.

essential to have the facilities management

Contents to include:

experience and expertise to cope with all

• Fabric and data

situationsthat might arise.

ð

3.15.6 Commissioning

• Building services

• M ethodologyfor regular audit procedures The building log book is to be made available in paper form and computer disk a t the completion of the project.

5.2.2 Training The componentsof a modern office building are complex and varied. The building owner must ensure that the building user/maintainer is given clear training and has the necessary

• Specialist elements

understanding so that the building can be run

• M anufacturers’ literature

efficiently and economically, and above all else, safely.

• Commissioning and testing data • Record drawings • Information produced during construction (CD M regulations)

:

www.hse.gov.uk

6.0

6.0

A ppendix

The procurement of construction projects can follow a number of routes, each with advantages and disa dvantages. A successful outcome or a potential failure, commences with the selection and briefing of the design team by the client.

trade contractors. Unlike T raditional Lump Sum

Construction Best Practice Programme, the

and Design and B uild, there are no standard

M ovement for Innovation, the Reading

contractsfor the appointment of a construction

Construction Forum, the Design + B uild

manager or the trade contractors. All of the trade

Foundation and the Construction Round Table.

contractors are appointed directlybythe client, not

: : : :

the construction manager.

6.2.5 Management Contracting

6.1 The design team

Standard forms of building contract published by the Joint ContractsT ribunal are commonlyused

There are two alternativesf or the formsof 

and three versionsare available for projects of 

appointment for the design team, either a

varying size. For the construction of an of fice

standard form produced bythe professional

building, the ‘Private with Q uantities’ version will

bodies( RI BA, AC E, RIC S) or bespoke forms

normallybe used. An alternative to requesting

drafted bysolicitors.

tenderson the basis of completed designs, which

The selection will be influenced bythe experience of the client, the complexityand size of  the project and the choice of construction strategy.

is becoming increasinglypopular, is known as‘two stage tendering’. With this approach, the contractor is selected much earlier, either bynegotiation or

preliminaries and perhapssome elementsof the

6.1.1 Warranties

6.2.3 ‘Design and Build’

Warrantieswill usuallybe required where a

A design team, or perhapsa single consultant, is appointed bythe client to work with him to agree

party. The purpose of the warrantyis to provide

and document his brief for the construction of the

the tenant or purchaser with direct contractual

office building. O nce this brief hasbeen

rightsto the design team member.

developed in conjunction with the design team, a set of employer’s requirements is prepared and

6.1.2 Professional Indemnity Insurance

issued to, typically, three or four contractors who

Professional IndemnityInsurance (PI ) cover should

have previously been assessed to have the

be provided byeach member of the design team

competence, resourcesand f inancial strength to

to a level that reflects their risk profile in the

design and construct the project. The contracto r

project.

designsas well asconstructs the new building.

6.3.2 Partnering

benefits of the Construction M anagement as it

The essential principle of partnering is the ability to develop long-term relationshipswith the supply

for the delivery of the building. The disadvantage

chain and to create a project environment within

is that the main contractor doesnot have an

which the objectivesof the customer and those of 

obligation to complete on time and to cost, but

the variousparticipants can be aligned as closely

aims to complete the project within a target cost

as possible.

(the Prime Cost).

There are four principal ways in which contracts for the construction of offi ce buildingsare arranged.

opportunityf or developing objectives.

6.3 Best Practice

6.3.3 Selection on quality and price 6.3.1 Background

It is imperative that all appointmentsof contractors

In 1994, Sir M ichael Latham’sreport ‘Constructing

and consultantsproperlyref lect the quality of the

the Team’ was published which identified failings

service aswell asits price. The C IB guide

of the U K construction industry and proposed

‘Selecting Consultantsfor the Team – B alancing

measuresto develop effective, profitable and

Quality& Price’ providesa basis for a project- or

customer-focused approaches. Tak ing their lead

client-specific approach.

from the work of Sir Mi chael, the CI B and the

ð

1.1 The brief 

Construction Task Force developments include the

Principal criteria in selecting forms of contract/procurement rout es Tr ad ti o i na l L um pS um fixed price

Ac ce e l rat ed /2 Sa t ge Tr ad ti o i na l methods

Co ns rt uc it on M an ag em en t

Price certaintybefore commitment to build

5

2

1

1

5

Lowestconstruction cost

4

3

2

2

5

5

Programme commitment fromContractor before entering Contract

5

4

1

1

5

5

confirm the acceptability of the ‘C ontractor’s Proposals’ for the design and construction of the

Shortest overall programme (inception to completion)

2

4

5

5

4

3

Control over designand materials

5

5

5

5

2

4

Control over choice of TradeContractors and Sub-contractors

3

4

5

5

1

1

Input (during design) from Contractoron programming and buildability

1

4

5

5

5

3

bythe Joint ContractsT ribunal, namelythe ‘With Contractor’s Design’ version, 1998. The design team, or single consultant, will

project received from the tendering contractors. A contract is then placed solely with the contractor

These fall under the generic headingsof :

for the delivery of the building, an Employer’s

• Traditional Lump Sum

Agent being retained by the client to represent his

• Design and Build

Partnering can have significant benefits in termsof sustainability as it allowsa greater

The form of building contract is that published

6.2.1 The options

www.crtp.org.uk

Management C ontract is created. This hasmany

Sel ec it on cr ti er a i

6.2 Construction strategy

www.m4i.org.uk

enablesthe client to contract with a single unity

work, for example).

development will be f inanced, let or sold to a third

www.ciboard.org.uk

the main contractor rather than the client, a

byinviting competitive proposalson certain aspectsof the project ( the cost of staff and

Bespoke forms can lead to misinterpretation by the partiesi nvolved.

If the individual trade contractors are contracted to

www.cbpp.org.uk

interests.

Mana gem ent C on tr ac ti ng

De si gn a nd B ui d l

De ve o l pa nd C on st ru ct

5

• Construction M anagement

6.2.4 Construction Management

Control over programming/planning on site

2

2

5

5

1

1

• M anagement contracting

A design team, usuallyled bythe architect, is

Single point of responsibilityfor design and construction

1

1

1

1

5

5

3

appointed bythe client to develop designsfor the

6.2.2 Traditional Lump Sum

new office building. A construction manager is

Direct contractual relationshipbetween employer and designers

5

5

5

5

1

5

5

1

1

5

5

will then be tendered to i ndividual specialist trade

Liquidated damages recoverable fromContractor if he completes late

requested from, typically, four contractors who

contractors, eg. f oundations, steelwork, air

Ability to introduce and accommodate changes

4

4

5

5

2

2

have been assessed to have the competence,

conditioning, etc. The construction manager will

Suitability for complex design

4

3

5

5

2

3

A design team, usuallyled bythe architect, is

also appointed who will direct the preparation and

appointed bythe client to develop designsfor the

completion of the designs into ‘packages’ which

new office building. Competitive tenders are

6.0

6.3.4 Standardisation and pre-assembly C IR IA 1997 offer the following definitions:

6.0

6.4 Categories A&B

‘The extensive use of components, methodsor

6.4.1 Category ‘A’ works (Background fitting out)

processesi n which there is regularity, repetition

• These worksgenerally follow completion of the

Standardisation

and a background of successful practice. M ore generally, an agreed shared framework for project decisions, such ascommon interfaces or a dimensionalgrid.’

base building structural works • Category A is the definition used to describe the level of f itting out between the shell and core building option, and a point at which internal

Pre-assembly

components must be designed to a specification

‘The organisation and completion of a substantial

for the particular end user, which isk nown as

proportion of final assembly work before

Category B, bespoke fitting out works.

installation in itsf inal position. It includes many forms of sub-assembly. It can take place on site, but more usuallyoff-site, and of ten involves standardisation from project to project.’

‘K eyP erformance Indicators’, published in 1999 bythe C onstruction Best Practice Programme, are a good first step towards introducing objective performance benchmarking standards. CAL IB RE has been developed bythe B RE to assess, and

teams’ responsesto that brief, by the application of structured processesand work shops.

: &

http://helios.bre.co.uk/valman ‘Value Management in Construction – A Client’s Guide’, Ciria Special Publication 129

property developers and occupiers in 1990 and has been revised twice since then. The current scheme is neither prescriptive nor biased against any particular situation and so provides a fair

etc.) • Basic lighting, heating, ventilation and cooling control system • Raised flooring system or other cable distribution systemsinstalled

• Basic safety signage system installed.

6.4.2 Category ‘B’ works (Bespoke fitting out) These works generallyfollow completion of  Category ‘A’ works, but maysometimes be incorporated into the Category ‘A’ construction programme to reduce construction time and avoid duplication of materials and handling.

• Suspended ceiling upgrade/modifications

BS RI A have developed tools to improve

• Installation of internal partitioning

productivity and efficiency on construction sites.

There are a number of proprietary ED M S systems available that enable information to be exchanged electronicallyvia telephone linesand a central ‘hub’.

:

www.team-work.org.uk

requirements. A second scale, the Environmental Performance Index or EP I, is also calculated. This providesa di rect comparison of performance between buildings of all ages.

:

www.bre.co.uk

comparison of the environmental impacts of one building with those of others.

6.6

Statutoryregulations

• Floor finishes

powersgranted in the Building Act 1984. A

• Management policyand procedural issuesi ncluding commissioning

designer is at libertyto demonstrate compliance with the requirementsof the Regulations using parametersother than those contained in the

• Health and well-being

Approved D ocuments.

indoor and external factors

O f principal importance are the Regulations

• Operatio nal energy including C O 2 emissionsand controllability

governing escape, energyconservation and accessfor the disabled.

• Transport including C O 2 emissionsfor commuting

meansof escape. Standardsfor off ice buildings

consumption and leak age

include, but are not limited to, the following:

• Materials environmental implicationsof materialsselection

Limitations on travel distance:

• M aximum travel distance in one direction only:

• Land use

18m

Greenfield and Brownfield sites

• M aximum travel distance in more than one

• Site ecology

direction: 45m

Ecological Value of the site

• Pollution

Limitations on direct distance:

air and water pollution

&

6.6.1 Means of escape Regulation and Approved Document B1 deal with

• Water

• M aximum travel distance in one direction only:

‘Looking for a New Investment Angle – A Developer’s Guide to Environmentally Smart Buildings’ – Good Practice Guide 258, Department of Environment, Transport and Regions, September 19 99

• Acoustic upgrades

6.3.8 Electronic Document Management Systems

a significant i mprovement on regulatory

Secretaryof State for the Environment under

6.3.7 Site productivity

:

in collaboration with ECD and a number of major

These are asf ollows:

• Basic mechanical and electrical services

Fitting out elements will include :

www.bsria.co.uk

The scheme was originally launched by BRE

The UK Building Regulations are issued bythe

• Fullyfitted out WC’s

VE and VM are methods to eliminate waste from

calculate the final B RE EA M rati ng on a scale of  Pass; Good; Very Good or Excellent. All represent

Buildings.

which performance criteria are defined.

:

the client brief, and the design and construction

consensus-based weightings. These are used to

BR EEA M 98 establishesa set of issuesfor

• Finishesto cores

6.3.6 Value Engineering and Value Management

BRE’s Environmental Assessment Method for

• Suspended ceilings

benchmark, site performance. www.CALIBRE2000.com

is taken into account through the application of 

BREEAM 98 for Offices is the latest version of the

Fitting out elements will include :

(lighting, heating, ventilation and cooling systems

6.3.5 Benchmarking

The relative importance of these different issues

6.5 BREEAM 98

12m • M aximum travel distance in more than one direction: 30m

• M echanical and electrical servicesupgrades (lighting, heating, ventilation and cooling systemsetc.) • Tailoring/upgrading lighting, heating, ventilation and cooling control systems

BREEAMrating for commercial offices by location

• Adaptation of raised flooring system or other cabledistribution systemsinstalled • Reconfiguration of below-floor cabling and floor/ceiling outlets • Upgradesto coresfinishes • Executive WC’s • Basic safetysignage system installed

Building location

Medium sustainability target rating

High sustainability target rating

City Centre a/c

Good

Excellent

City Centre n/v

Very good

Excellent

Town Centre

Good

Excellent

Out of Town

Pass

Excellent

6.0

Occupancy factors for means of escape calculations:

• Open plan officesexceeding 60m 2: 6m2 per person • Other offices: 7m2 per person

6.0

6.6.3 Access and facilities for disabled people

6.7 Comparative table

Regulation and Approved Document M deal with accessand facilities for disabled people.

Current typical design standards

For offices, the A pproved Document covers Minimum widths of escape routes:

accessto and into a building, accesswithin the

• Maximum number of persons– 50:750mm

building and sanitaryconveniences within the

• Maximum number of persons – 110:850mm

building. Standardsinclude, but are not limited to:

• Maximum number of persons – 220:1050mm

Ramped approach

• M aximum number of persons– greater than

Length of ramp:

220:5mm per person. Stair widths:

Section 5 of Regulation B1 deals with numbers and widthsof stairs and describestwo methods of width calculation based upon total or phased evacuation. The numbers of stairs provided and their widths must be assessed byreference to varioustables and to other British Standards. These stairs mayalso be fire-fighting stairs if  the building comes within the requirements laid out in Part B5: Access and facilitiesfor the fire service.

10m for 1:15 to 1:20 slope 5m for 1:12 to 1:15 slope Width of ramp: 1200mm surface width / 1000mm unobstructed width Landing length: 1200mm minimum Entrance doorways minimum clear opening:

Occupancy: Net area/perso n

Germany

14m2

15m2

6m2

Occupancy: minimum workspace

5m2

Plan efficiency: NIA: GIA Plan depth:

USA

Ref 4.3

Occupancy: Net area/person escape

3.10 100ft 2 /10m2 4.3 5m2 3.5 85%

80%

15m to 18m

13.5m to 15m

60ft/18.2m

3.6

7.5m or 9m or 8.1m

7.2m or 7.5m

32ft/9.8m

3.7

1.5m or 1.35m

1.2m or 1.5m

4ft/1.2m

3.8

Floor to ceiling clear height

2.7m

3m

9ft/2.7m

3.12

Lifts: standards

80% loading 30 sec.inte rval

60% loading 30-40 sec. in terval

5.5 sec. per floor in terval

3.10

Column grid:

Planning grid:

800mm Internal doorwaysminimum clear opening:

UK (BCO)

750mm

6.6.2 Energy conservation Regulation and Approved Document L deal with

Lift cars

conservation of fuel and power. T hese documents

M inimum internal dimensions:

are undergoing a full review and a radicallyrevised version, targeting the reduction of C O 2 emissions, is due for release during 2000. C urrently, however, the Approved Document permits three methods of  calculating the heat lossthrough a building f abric. Theyare:

Raised floors

150mm 300/450mm (subfloorA/C)

150mm

2 inches 50mm

3.12

Structural loading live

General:2.5kN/m2 High: 7.5kN/m2

General: 5.0kN/m2

100psf

3.13

Structural loadingdead

General: 2.0kN/m2 High: 4.0kN/m2

30psf

3.13

Small power loading

15W/m2 – 25W/m2

10-35W/m 2

1.57W/ft2 17W/m2

3.15

300-450 lux open plan

400-500 lux

500 lux

4.4.3

1100mm wide x 1400mm deep Height of controlsfrom F FL: 900mm minimum 1200mm maximum Wheelchair WC compartment: 1500mm wide x 2000mm deep

The elemental method:

Where the thermal performances of building

6.6.4 Health and safety

elementsare required to conform with stated

Other relevant regulations governing health

‘U’ Values.

and safetyin the UK include:

The calculation method:

Where the heat loss through the whole envelope

The Construction

(Design & Management) R egulations1994

of a building is compared with, and shown to be better than, that for a notional building of the

Management of Health & Safety at Work

same size and shape calculated bythe element al

Regulations1992

method. The energy use method:

Where the calculated annual energyuse of a building is shown to be lessthan that for a similar building calculated bythe elemental method. Guidance for the design of energy-efficient space-heating controls, hot-water storage systems and lighting within offices is also given in Approved Document L.

ð

Workplace

(Health Safety& Welfare) R egulations1992 Provision and Use of Work Equipment

Regulations1992 Health & Safety (Display Screen Equipment)

Regulations1992 Manual Handling Operations

Regulations1992

3.14 Envelope, 3.15 Services systems

Personal Protective Equipment at Work

Regulations1992

Lighting standard Temperature standard Fresh air standard Air conditioning Systems

22ºC+ –2ºC

4.4.2

8-12l/s/person

23ºC

20ft3 /person

4.4.4

VA V/ fa nc oi l/ di sp lac eme nt ch il led c ei li ng

O pe ni ng wi nd ow s s imp le s ys te ms

VAV/ fan co il

3 .1 5. 3

Energy: 2 A/C (kwh/m  /yr)

Typical: 404 Good: 225

Energy: 2 N/V (kwh/m  /yr)

Typical: 205 Good: 112

CO2 emission: 2 A/C (kg/m  /yr)

Typical:120-14 0 Good: 86

CO2 emission: 2 N/V (kg/m  /yr)

Typical: 40-50 Good: 33

Noise criteria

75ºF/23ºC

LAeg

4.9

4.4.6

6.0

6.8 Materials guide

6.0

6.10 Tenants’ Services Charge s

Certain materials should not be specified, or used,

Tenantsshould require their landlords to follow the

in the construction of a building to avoid hazards

Briti sh Property Federation Code of Practice for

to the health and safety of the occupants, and to

Service Chargesi n Commercial Properties. This

ensure long-term structural integrity.

requireslandlordsto produce annual budgets, to

The G uide to Good Practice in the selection of 

seek regular competitive tendersfor services, not

construction materials, produced by a steering

to make a profit out of service charges, to bear

group representing the B CO and the British

themselves the share of cost attributable to vacant

PropertyF ederation, the Guide to Good Practice

unitsand to be open in providing information.

coversthe following categories of materials:

GrossExternal Area (GEA) is the area of a

• Admixtures for use in concrete and mortar

building measured externallyat each floor level. It

• Aggregates for use in reinforced concrete • Asbestosproducts • Brick slips

includeswall thicknessesand external projections, the area of internal walls and partitions, atria measured at base level only, and covered plant rooms. It excludes open balconies and open fire escapes.

• Calcium silicate bricks • High alumina cement in structural elements • Lead or materials containing lead • Man-made with mineral fibres(M M M F)

6.11 Internal gross/ net areas GrossInternal Area (GIA ) is the area of a building measured to the internal face of the perimeter

• Urea formaldehyde (UH ) foam

wall at each floor level. It includes areas occupied

• Vermiculite products

byi nternal walls and partitions, columns, piersand

• Wood preservatives • Wood wool cement slabs

&

‘Good Practice in the Selection of Construction Materials’. Tony Sheeham (Lead author). Ove Arup and Partners, R&D, 1997

other internal projections, internal balconies, stairwells, toilets, lif t lobbies, fire corridors, atria measured at base level only, and covered plant rooms. It excludesthe perimeter wall thickness and external projections, external balconiesand external fire escapes. Net Internal Area (NIA ) i s the usable area

6.9 Useful websites Useful web sites and references

within a building measured to the internal face of  the perimeter wallsat each floor level. It includes kitchens and cleanerscupboards. (A tria and

BRE www.bre.co.uk British Institute of Facilities Management www.bifm.org.uk BSRIA www.bsria.co.uk CIBSE www.cibse.org DETR www.detr.gov.uk HSE www.hse.gov.uk Reading Construction Forum www.ref.org.uk RIBA www.riba.org RICS www.rics.org.uk

entrance hallsshould be measured separately.) It excludestoilets, stairwells, plant rooms, fire corridors, and internal structural walls, columns, internal projectionsand vertical ducts.

&

Code of Measuring Practice, Fourth Edition, RICS Books, ISBN 0 85406 610 1.

6.11 Index

Quantity surveying

Editor Ti mo th y B at tl e

Ry bk a B at tl e

Deputy Editor G ra ha m Fr an ci s

S he pp ar d Ro bs on

Nick Rowe

G&T

M ichael C harley

M DA G roup

R B rodi e-C ooper

G leeds

R ichard H arr g i an

E C Ha rri s

Editorial Reviewing Panel

James C larke

D L& E

A lastai rM ellon

S tanhope

C li ve A rdi ng

I nsi gni a R ichard E li s

B arry Nugent

M ott G reen Wall

P et er F r ac ko wi ec z

L a nd S e cu ri ti es

A ndrew L ett

A uk ett A ssociates

N eal P ennell

L and Securi ti es

Sm i on Wilk es

L egal & G eneral

G eoff Wright

H ammersons

Planning Pe te r Re es

Ci ty of Lo nd on Co rp or at io n

Productivity W O R K I N G P A R T I ES

Architecture

David Warriner

B RE

Ja me sP i ck ar d

C ar tw ri gh tP i ck ar d

Paul Ruyssevelt

Energyfor Sustainable Development

Ro b er t D al z ie l

G eo f fr ey Re i d A s so c ia te s

D avi dN elson

Foster & P tnrs

P aul Stansall

Tectus

Nigel P ittam

BA A

D enice Jaunzens

BRE

R ob K night

D L& E

M indy H adi

BRE

S te ph en B r ad le y

D E G W & Sp ac ef or B u si ne ss

B ob K eenan

Sheppard Robson

J oh n D og ga rt

E C D E ne rg y& En vi ro nm en t

Risk Management Mark Di l on

Sheppard Robs on

D avi d Hadden

O ve Arup and P art ners

John H addon

O ve A rup a nd P art ner s

B R E E AM

Alan Yates

BRE

B ill Gloyne

A ON Risk Services

I nsp ec to r R oo ke

N a ti on al T e rr or is t C r im e PreventionU nit

Construction P ru d en ti al P or t fo l io Ma na ge rs

R ichard J ones

A bbey N at o i nal

R ichard H uxster

K va erner

R o ge r P ar so ns

W at es C i ty o f L on do n D ev el op me nt s

G raham Jelly

Bovis

M artin Davis

D rak e& Scull

Paul Warner

G eoffrey Reid

N ig el Wo ol c oc k

Development Ju l ia n B ar wi c k

D ev el o pm e nt S ec ur i ti e s M an ag er s

M B ur ge ss -A sh to n

R a il tr ac k

Jonat hanWeymout h

Prudent a i lPortfo li oManagers

D avid Easson

M A B UK

Legal

Services Tr ev or F ar nf i el d

R og er P re st o n & P ar t ne rs

G uy Battle

Battle M cCarthy

D avid Warriner

BR E

R on German

Stanhope

K evi nR eed

R oger P reston & P artners

Structures Ri ch ar d Te rr y

O ve Ar up an d P ar tn er s

Jim M athys

Waterman

S ta n G ni ad ow sk i

Wi ld e Sa pt e

Paul Clark

D J Freeman

Evelyn Murray

WSP

D avi d Sa und er s

C am er on M cK e nn a

H anif K ara

A dams Kara T aylor

R icha rd W hi te

O ve A rup and P art ners

Occupiers Tony Bones

JLW

Accountants P au l H ar ri ng to n John M ason

Envelope D av id A nd er so n

Faro

Sustainability G eo rg e M ar ti n

Corporate Ted P earce

B T plc

Financial

Price £50

A ru p Fa ca de

P ri ce Wa te rh ou se

Fo ru m f or th e F ut ur e

ProfessorDavidCadman

Forumforthe Future

A lan Y ates

BRE

Electronic and Web Advisor

G reville B ar

A bbey National

Nigel Waring

HSB C

Pa ul S ti mp so n

Ry bk a B at tl e

Editing and Production Wordsearch

ISBN 0 9524131 2 4 Copiesof this report are available from

The British Council for Offices Shinfield Grange Cutbush Lane Shinfield Reading RG2 9AF Tel: 0118 988 5505 www.constructionplus.co.uk

First published: May 1994 Secondedition: 1997 Thisedition: June2000 The British Councilfor Officesand the membersof the working partycommittee which producedthis specificationhave endeavouredto ensure the accuracyof its contents.However, the guidance and recommendationsgiven in thisspecificationshouldalwaysbe reviewedby those using it in the light of their particularcase andshouldnot be relied onwithout obtaining specialist advice asnecessary. No liabilityf or negligence orotherwise inrelationto this specificationand itscontentsis acceptedby the BritishCouncilfor Offices, the membersof the working partycommittee, itsservantsor agents. © 2000 BritishC ouncil forO ffices