NBSIR 86-3430

REVISED INTERIM DESIGN GUIDELINES

FOR AUTOMATED OFFICES

August 1986

QC

100

.U56

NO. 86-

3430

1986

Center for Building Technology

National Engineering Laboratory

National Bureau of Standards

Gaithersburg, MD 20899

General Services Administration

Washington, DC 20405

NBSIR 86-3430

REVISED INTERIM DESIGN GUIDELINES FOR

AUTOMATED OFFICES

Arthur Rubin

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Building Technology

Building Physics Division

Gaithersburg, MD 20899

August 1986

Prepared for: General Services Administration

Washington, DC 20405

U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS. Ernest Ambler, Director
ACKNOWLEDGEMENTS

I would like to express my appreciation to Mr. John J. Landers of the

Office of Information Resource Management of the General Services

Administration for his support and advice during the course of the

project. I would also like to thank the following reviewers for their

constructive comments and critiques of the report: Herbert Rosenheck,

Lisa Sauerwein, Vivian Loftness, Dr. Forrest Wilson, Dr. Belinda

Collins, Dr. Tamami Kusuda, and Roger Rensberger.

ii
ABSTRACT

This report presents an update of the first edition of "Interim Design

Guidelines for Automated Offices" , August 1984 (NBSIR 84-2908) . It

is based upon findings obtained by an extensive literature search, a questionnaire survey of design firms, an office automation roundtable,

and interviews with design and other office automation professionals.

The guidelines should still be considered tentative, since the

information is based primarily on judgment, rather than on formal

investigations or on broad consensus from the design community.

Furthermore, many important design issues have not been dealt with,

because they have not yet been appropriately considered, and/or it is

unclear what the design implications of automation are - e.g. will

overall space needs be greater or less?

The introduction of automated systems into offices has changed the

office setting as a place to work. Architects and other design

professionals have responded to this technology by formulating a variety of design strategies. This report identifies design issues

which merit consideration in automated offices, tentative criteria for

environments and systems based on an overview of all resources used to

develop this document, and typical approaches employed to accomplish

design goals. Technological, ergonomic and organizational factors are

considered from the standpoint of their design implications. This

updated report is a major revision of the earlier work, including more

than twice the number of reference documents as the initial study.

Key words: acoustics; design criteria; electrical systems;

ergonomics; lighting; noise; office automation; office design

criteria; office furnishings; safety systems; workstation;

communication systems; LAN's; data centers.

in
PREFACE

This report is the fourth of a report series prepared by NBS as part

of Memoranda of Understanding and Agreement between NBS and the GSA,

dated 1/16/81 and 2/19/85. This work examines the impact of office

automation technologies on interior environments, and provides

guidance for federal office design . The earlier publications,

sponsored by the Public Building Service of GSA are as follows:

1. The Automated Office - An Environment for Productive Work, or an

Information Factory?: A Report on the State-of-the-Art , NBSIR 83-

2784-1 , November 1983.

2. The Automated Office - An Environment for Productive Work, or an

Information Factory?: Executive Summary, NBSIR 83-2784-2, December

1983.

3. Interim Design Guidelines for Automated Offices, NBSIR 84-2908,

August 1984.

This revision, sponsored by the Information Resources Management

Service of GSA, updates the earlier work by a more extensive treatment

of communincat ion and informational issues; e.g. communication

systems, intelligent buildings, and data processing center design. It

is intended to assist in developing functional, economical and humane

environments for federal office buildings. It provides design

information for those charged with the control, administration and

maintenance of office environments with varying degrees of automation.

The document is a compilation and evaluation of design practices,

approaches, tentative criteria, and design factors to be considered in

meeting individual and organizational needs. The information

available is limited and not definitive, since few formal studies have

dealt with this subject and little consensus exists among architects

regarding appropriate practices. Some basic assumptions were made in

preparing this report:

*Office automation is a continuing process, not a discrete event.

*The office environment will consist of electronic and paperbased tasks for the indefinite future.

*Office work will continue to be performed in spaces and

buildings designed for this purpose.

*The "typical office" is as meaningless a concept as the

"average" worker, and the "prototype" organization.

Energy conservation will be of continuing importance.

Consideration of long-term costs are more important than first

costs

.

Office design influences worker productivity; high quality

environments are essential for automated offices.

Better information is needed to formulate performance criteria

for automated offices.

iv
TABLE OF CONTENTS page

1. Introduction 1

1.1 Background 3

1.1.1 General 3

1.1.2 Technology and Design 6

1.1.3 Organizations and Design 7

1.1.4 Ergonomics and Design 8

1.1.5 Security and Design 8

1.1.6 Planning 8

2. Planning and Programming the Automated Office 10

2.1 Function 10

2.2 Criteria 10

2.3 Information Development 10

2.4 Planning Approaches- Programming 13

3. Workstation Systems 19

3.1 Function 19

3.2 Criteria 19

3.3 Furnishings- Flexibility Requirements 23

3.3.1 Checklist — Workstation Flexibility 23

3.4 Environmental Context 23

3.4.1 Checklist for Workstations

Environment/Design Components 23

3.4.2 Checklist Workstation Environment/Design 24

3.4.3. System Panels 24

3. 4. 3.1 Function 24

3. 4. 3. 2 Panel System Criteria 25

3. 4. 3. 3 Checklist for Panel Components 26

3. 4. 3. 4. Interactions with other systems 28

3.5 VDT/Keyboard Systems 28

3.5.1 Checklist- VDT/Keyboard Requirements 29

3.6 Possible Problem Area - VDT Screen Glare 29

3.6.1. Potential Solution - Filters 29

4. Acoustic Environmental Systems 31

4.1 Function 31

4.2 Background 31

4.3 Criteria 32

4.4 Overview of Basic Issues 33

4.4.1 Auditory Privacy 33

4.4.2 Sound 37

4.4.3 Sound Transmission 37

4.4.4 Noise Criteria (NC) Curves 37

4.5 Possible Problem Areas 39

4.6 Typical Solutions 39

4.6.1 Barriers 39

4.6.2 Isolation of Surfaces 39

4.6.3 Sound Absorption 40

4.6.4 Vibration Damping 40

4.6.5 Isolation of Noise Source 40

4.6.6 Masking Sound 40

v
4.6.7 Ceilings 40

4.6.8 Distance 40

4.6.9 Configuration 40

4.6.10 Floors 41

4.7 Acoustical Design Process 41

4.8 Checklist - Acoustical Design 43

5. Lighting Systems 45

5.1 Functions 45

5.2. Background 45

5.3. Criteria 46

5.4 Overview of Basic Issues 48

5.4.1 Artificial Light Sources 48

5. 4. 1.1 Incandescent Lamps 48

5. 4. 1.2 Fluorescent Lamps 50

5. 4. 1.3 High Intensity Discharge (HID) Lamps 50

5.4.2 Ballasts 52

5.4.3. Fixtures 52

5.4.4. Lighting Fixture Rating Schemes 52

5. 4. 4.1 Visual Comfort Probability (VCP) 52

5. 4. 4. 2 Coefficient of Utilization ( CU) 52

5.5. Possible Problem Areas 53

5.6 Typical Lighting Design Approaches 53

5.6.1 Types of Illumination 53

5. 6. 1.1 Ambient (General) Lighting 54

5. 6. 1.2 Task Lighting 54

5. 6. 1.3 Task/Ambient Lighting 54

5. 6. 1.4 Indirect Lighting 54

5.6.2 Controls 56

5.6.3 Maintenance 56

5.7 Environmental Context 56

5.7.1 Checklist for Glare Control 56

6. Environmental Conditioning Systems 58

6.1 Function 58

6.2 Criteria 58

6.3 Design Implications 58

6.4 Typical Design Approaches 60

6.4.1 Existing Buildings 60

6.4.2 New Construction 60

6.5 Interaction with Other Systems 61

6.5.1 Lighting 61

6.5.2 Acoustics 61

6.6 Environmental Context 61

6.6.1 Design Process Issues 61

6.6.2 Interior Design 62

6.6.3 Potential Problem Area - Static Electricity 62

6. 6. 3.1 Common Sources of Static Electricity 62

6. 6. 3. 2 Possible Approaches to Overcome Problem 63

6.7 Air Quality 63

6.7.1 Background 63

6.7.2 Air Contaminants 64

6.7.3 Tight Building Syndrome 65

6.7.4 Control Measures for Indoor Air Pollutants 66

vi
6.7.5

Responsibilities for Healthful Indoor Environments 67

7. Electrical Power Systems 68

7.1 Function 68

7.1.2 Background 68

7.2 Criteria 69

7.3 Possible Problem Areas 70

7.4 Potential Solutions 71

7.4.1 Suppressing Overvoltage Transients 71

7.4.2 Emergency Standby Power 72

7.4.3 Uninter ruptable Power Systems (UPS) 75

7.5 Battery Features 76

7.6 Checklist to Minimize Electrical Disturbances 77

7.7 Environmental Context 79

7.7.1 Specialized Space Needs 79

8. Wiring Systems 80

8.1 Function 80

8.2 Background 80

8.2.1 Problem Areas 82

8.3 Criteria 83

8.3.1 General 83

8.3.2 Specific 83

8.4 Typical Design Approaches 83

8.4.1 Poke-Through System 85

8.4.2 Electrical Cellular Deck 86

8.4.3 Underfloor Duct System 87

8.4.4 Conduit in Slab 87

8.4.5 Raised Access Floor 88

8.4.6 Ceiling-Based Systems/Power Poles 89

8.4.7 Flat Conductor Cable 90

8. 4. 7.1 Flat Conductor Cable Checklist 90

8.4.8 Workstation Distribution 91

8.5 Tradeoffs among Alternative Systems 92

8.6 Additional Design Considerations 94

8.6.1 Retrofits 94

8.6.2 Upgrading of Cabling Systems 94

8.7. Environmental Context 94

8.8 Checklist- Wiring System Design 94

9. Communication Systems 96

9.1 Function 96

9.2 Background 96

9.3 Criteria 96

9.3.1 General 96

9.3.2 Specific 97

9.4 Typical Design Approaches 97

9.4.1 Checklist of Network Features 98

9.4.2 Checklist - Design for Communications Systems 100

9.5 Wiring Closets 101

9.5.1 Advantages of wiring closet 101

9.5.2 Wiring Closet Checklist 101

9.6 Telecommunications Accessories 102

9.6.1 Functions 102

vii
9.6.2 Criteria 102

9.6.3 Checklist of System Requirement Needs .102

9.7 Electrical/communications Linkages 103

9.7.1 Twisted Pair 103

9.7.2 Baseband 104

9.7.3 Broadband 104

9.7.4 Fiber Optics 105

9.7.5 Tradeoffs Among Cable Types 106

9.7.6. LAN or PBX 109

10. Local Area Networks (LAN) 110

10.1 Function 110

10.2 Background 110

10.2.1 Problem Areas 113

10.3 Criteria 113

10.3.1 System Performance 114

10.3.2 Design Issues 114

10.4 Technological Issues 114

10.5 Organizational Issues 116

10.6 Software Issues 117

10.7 Typical Design Approaches 118

10.7.1 Network Configurations 118

10.7.1.1 The Star 118

10.7.1.2 The Ring 119

10.7.1.3 A Bus Network 120

10.7.1.4 Tradeoffs Among Alternative LAN Configurations ..121

10.8 Environmental Context 122

10.8.1 Space Considerations 122

10.8.2 Wiring 122

10.8.3 Signal Amplification 122

11 PBXs 123

11.1 Function 123

11.2 Background 123

11.3 Criteria 123

11.4 Technical Issues 124

11.4.1 Analog vs Digital Systems 124

11.4.2 Integrating Voice and Data 125

11.5 Organizational Issues 126

12. Life Safety Systems 127

12.1 Function 127

12.2 Criteria 128

12.3 Typical Approach 128

12.4 Checklist- Life Safety Systems 130

12.5 Checklist- Central Control 130

12.6 Environmental Context 130

13. Intelligent Buildings- Integration Issues 132

13.1 Background 132

13.2 Criteria 134

13.3 Communications 134

13.4 Wiring Systems 135

13.5 Mechanical Systems 135

viii
13.6 Flooring Systems 136

13.7 Case Study 136

13.8 System Integration Checklist 137

13.9 Management Issues 137

13.10 Design Issues 138

14. Office Materials 141

14.1 Natural and Synthetic Fabrics 141

14.1.1 Function 141

14.1.2 Criteria - Checklist (Fabrics) 141

14.1.3. Carpet Material Characteristics 142

14.2 Carpet Tile 142

14.2.1 Criteria 143

15 Specialized Spaces 145

15.1 Overview 145

15.2 Teleconference Facilities 146

15.2.1 Function 146

15.2.2 Criteria 147

15.2.3 Environmental Context 147

15.2.4 Support System Considerations 147

15.2.4.1 Acoustics 147

15.2.4.2 HVAC Equipment 147

15.2.4.3 Lighting and Color 148

15.3. Data Center 148

15.3.1 Function 148

15.3.2 Background 148

15.3.3 Criteria for Computer Room Design 149

15.3.4 Air Conditioning 149

15.3.5 Electrical Power 150

15.3.5.1 Electrical Power Checklist 151

15.3.6 Fire Detection and Suppression 151

15.3.7 Security 151

15.3.8 Raised Access Floors 152

15.3.9 Lighting 152

16. Summary and Recommendations 153

Bibliography 155

Glossary 159

IX
LIST OF TABLES Page

Table 1. Environment as Support and Catalyst 4

Table 2. Checklist - Design Considerations for

°High Quality' Offices (Criteria) 8

Table 3. Analytic Approach for Relating Technology to

Design 12

Table 4. Checklist for Office Automation Design 13

Table 5. Introduction of Automation into OfficesCritical Factors 15

Table 6. Recommended Workstation Dimensions for VDT's .... 20

Table 7. Minimum federal performance requirements for

panels 27

Table 8. Familiar Background Sound Levels 32

Table 9. Types of Offices Applicable to Articulation Index

Ranges 33

Table 10. Speech Interference Levels (SIL) and Noise

Criteria (NC) Recommended for Rooms 34

Table 11. Conversations and Speech Interference Levels .... 36

Table 12. Lighting Recommendations (IES) 47

Table 13. Lamp Selection Guide 51

Table 14. Static Electricity Issues 62

Table 15. Basic Cause, Effect and Treatment of Power Line

Disturbances 74

Table 16. UPS Guide to Installation and Maintenance 76

Table 17. Comparison of Power Protection Systems 78

Table 18. Cable Characteristics 107

Table 19. Wiring Media Comparisons 108

Table 20. Comparison of LAN and PBX features 109

Table 21. Cost Proportions of LAN's 112

Table 22. LAN Market Share by Type 112

Table 23. Requirements for a LAN 113

Table 24. Typical Throughput Applications for LAN 115

Table 25. Positive and Negative Features of LAN

Configurations 121

Table 26. Smart Building Checklist 138

Table 27. Integration and Telecommunication Systems - Possible Design Impact 140

Table 28. Carpet Materials - Positive and Negative

Features 142

x
LIST OF FIGURES Page

Figure 1. Environment as support and catalyst 1

Figure 2. Office Design Process 16

Figure 3. Conceptual Model for Evaluating Work

Environments 17

Figure 4. Checklist for Facility Evaluation 18

Figure 5. Suggested Parameters for Mockup of a Seated

Operator Console 21

Figure 6. Workstation and Seat Design 22

Figure 7. Approximate relation between AI and Speech

Intelligibility 35

Figure 8. Noise Criteria (NC) Curves 38

Figure 9, Simplified block diagram of OP LAN program 42

Figure 10. Common Types of Lamps 49

Figure 11. Types of Illumination 55

Figure 12. Thermal Comfort Recommendations (ASHRAE) 58

Figure 13. Conventional ceiling air distribution 59

Figure 14. Poke-Through System 85

Figure 15. Cellular Floor System 86

Figure 16. Underfloor Duct System 87

Figure 17. Access Flooring 89

Figure 18. Power Pole 90

Figure 19. Network Applications and Features 98

Figure 20. Star network topology 118

Figure 21. Ring network topology 119

Figure 22. Bus network topology 120

Figure 23. Life Safety Interface Elements 127

Figure 24. ADP Site; Life Safety Elements 129

Figure 25. Control Design for Life Safety System 131

Figure 26. Typical static voltages generated by walking

on common floor materials 144

x 1

1. INTRODUCTION

Office design has a major role to play in the work performance of

the individual, and thereby in the functioning of an organization

as a whole. While the physical setting of an office provides the

direct support for conducting activities in a space, the

environment also serves a catalytic function. It can promote or

inhibit discussions, meetings, and formal or informal

interactions among people. Space characteristics, lighting,

temperature levels, humidity, indoor air quality and other design

features can have positive or negative influences on task

performance and/or satisfaction of the worker (1)

.

Questionnaire surveys consistently have shown the work

environment is an important contributor to satisfaction and

morale of office workers, thereby influencing productivity. The

automation of office functions has further increased its

significance for several reasons.

The characteristics of the office workforce are rapidly changing,

as is the nature of the jobs being performed. Technology has

influenced the way that organizations are structured, and how

decisions are made. The fastest growing segment of the office

population, and the key to increased productivity are knowledge

workers- (professionals and managers) who differ in many respects

from their clerical counterparts. Knowledge workers are highly

educated, have experienced high quality work environments and

expect such settings. They also do not hesitate to express

dissatisfaction with environmental distractions and intrusions on

their privacy. Since their skills are readily transferable from

one organization to another, they are a highly mobile group.

Under these circumstances, the work setting is important in

recruiting and retaining qualified people, because other aspects

of their jobs are often comparable in terms of salary and other

features (2). (See Figure 1.)

Ideas

'''Provide ^

Feedback

Figure 1. Environment as support and catalyst

1
The work performed by knowledge workers using automated equipment

is mentally demanding and requires freedom from distractions such

as glare, noise, and the activities of their colleagues. The tasks

are often intrinsically difficult, as in the case of planning and

problem solving. Personal interactions, which characterize many

management functions, require auditory and visual privacy. The

process required to perform VDT-based activities imposes a further

burden on employees with limited training and/or skills in using

keyboard devices or the specialized programming languages required

to communicate with office automation devices such as

microprocessors. They are also frequently required to access

external sources such as information networks. Employees, often

working at VDT terminals for eight hours a day, are quite

sensitized to their surrounds, and require a respite from high

technology, and an opportunity for social contact in pleasant

settings

.

Management style is an important determinant of the overall

appearance and layout of the traditional office and particularly

the automated one. Decisions concerning the balance between design

uniformity and diversity, within an organization as a whole, among

working groups, for the management hierarchy, and for individuals,

all reflect the organizational culture. A centralized management

approach is characterized by considerable uniformity and little

room for personal expression by the individual. Decentralization

provides the opportunities for working units and individuals to

participate in the design of their environments, and encourage

differentiation among groups and individuals. In this way, a sense

of group cohesiveness can be expressed, as well as a means of

countering the institutionalization of the office. Specialized

spaces such as breakout conference rooms are needed to enhance

communication in this way. In many instances, tradeoffs must be

made between uniformity and the possibility of expressing

diversity

.

A key problem identified in surveys of workers in automated offices

is that of work stress. Among its potential causes are:

* Rigid work procedures

* Oversimplified, repetitive and routine work

* Lost sense of job meaning

* Lack of control

* Heavy workloads

* Pressures for performance; monitoring of performance

* Disrupted social relationships

* Reduced status and self-esteem

* Reduced mobility

* Concern for safety

* Concern for job future

2
1.1 BACKGROUND

1.1.1. General

Productivity in the office has been virtually stagnant for almost

a decade, at a time when white collar work has begun to dominate

our economy. For example, by 1983, 53 percent of the workforce

was engaged in information development and processing activities.

The trend toward more office-based activities, the productivity

figures, the information explosion, technological advances

accompanied by decreased costs, have all combined to create an

intense demand to automate office functions. As a result,

millions of new devices and systems are now in offices, and

countless others are being introduced daily at an ever increasing

rate. Yet the experience with office automation has been

mixed . (3)

While technology is seen by some observers as THE answer to

office productivity problems, considerable evidence exists that

many office workers are less than satisfied with the quality of

the environment in the automated office . Too often, office automation has resulted from the piecemeal

acquisition of new devices and systems placed on available desks

and other work surfaces in environments designed to process

information in paper form. VDT's have been introduced into the

workplace without regard to the differences between them and

paper-based tasks.

A comparison of VDT and paper-based tasks reveals important

differences between the two:

PAPER/HARDCOPY

* Dark characters on a light

background

* Continuous line characters

* Matte surface

* Horizontal plane

* Manual input

* Easy to handle

* Perceptually permanent

* Data stored physically

* Information presented

serially

ELECTRONIC/VDT

* Light characters on a dark

background

* Dot-matrix characters

* Reflective surface

* Vertical plane

* Keyboard input

* Difficult to manipulate

* Perceptually transient

* Electronic data storage

* Information presented

simultaneously

Systematic design planning has been a rarity. Computer

enhancements have been handled as retrofits for furniture

acquisition. This process has resulted in many complaints by

workers about the unsuitability of their offices for performing

VDT-based work. Noise and glare produced by inappropriate

lighting systems lead the list of expressed concerns. Workstation

3
Table 1. Major concerns of building users.

Issue Bottom Line Measures

FURNITURE

Environment Job

Satisfaction

Layout

Comfort

Quality

X

X X

X

AMBIENT CONDITIONS

Temperature/

Air Quality

Lighting X

Noise X

PRIVACY

Control Over Access X

Intrusions/Distractions X

Speech Privacy

Visual Access

COMMUNICATIONS

Ease

Support

FLEXIBILITY

X

X X

X

X X

Job Job

Performance

(Self) (Supervisor)

X

X

X

The increased popularity of open-office designs has contributed to

the problems of office automation because devices such as printers

produce considerable noise, thereby disturbing many people near

them. The fact that automation typically occurs incrementally in

small steps, contributes to the design challenge. Changes are so

gradual that there is little anticipation of the final result, and

its environmental consequences. For example, adding electronic

devices increases a building's heat load, but existing HVAC

systems can usually cope with only minor increases in heat.

However, the presence of many such systems seriously degrades the

quality of the thermal environment, and may require a major HVAC

retrofit for an acceptable work setting.

The first automated systems introduced into offices were word

processors, designed to increase the efficiency of typing by

converting information into an electronically accessible form;

establishing the basis for all other systems. The results from the

word processing experience pointed to advantages and disadvantages

of this approach. While there was some evidence of increased

typing productivity, this was accompanied by a variety of

complaints, which portended many of those later expressed about the

automated office. (5)

4
Word processing activities were organized into a "pool" of workers

performing a centralized function. A typist had little or no

contact with the author of copy, and limited opportunity to carry

through many jobs from beginning to end. This process, derived

from the factory assembly-line system where work was analyzed,

standardized, and simplified to reduce the unit cost of products,

resulted in complaints which echoed those of the production-line

worker. Workers felt they were subordinated to machines, had

limited control over their jobs and little opportunity to interact

cooperatively with colleagues. Finally, working eight hours a day

at a VDT was a source of concern because of the need for

concentration associated with work at terminals . (6)

If the assembly-line system for information processing is

inappropriate for performing clerical functions such as word

processing, it is even less applicable for automating the

activities of knowledge workers. Their tasks are not readily

amenable to analytic and standardized treatment, but are

characterized by dealing with problems of ever-increasing

complexity and a proliferation of information which must be

assimilated and acted upon. Their work depends on using highly

individualized knowledge and experience, limited and uncertain data

in a rather unstructured informational environment. A manager, for

example, is given a set of broad responsibilities and considerable

freedom to formulate ways of carrying them out. The degree of

autonomy associated with this work is one of its principal

attractions, and plays a major role in the satisfaction derived in

pursuing these careers. To the extent that managers are required

to adapt to work methods, technologies and environmental conditions

selected by others, they are likely to be less productive, and less

satisfied with the quality of their working life (7)

.

1.1.2 Technology and Design

Developments in telecommunications, computers, and office

automation systems are changing the office, and the manner in which

functions are performed. Information, traditionally developed,

processed and stored as paper form, now is processed

electronically, while microfiche, magnetic and paper-based systems

are used as storage media. New systems are available to conduct

activities not possible before. For example, video conferencing has

provided an alternative to face-to-face meetings among

geographically dispersed people in the same organization, or among

those in different ones. The informational resources available to

the individual at a workstation are equivalent to those possessed

only by large organizations not many years ago. This has made the

workstation the focal point of the office. It serves as the modular

design unit, requiring considerable attention by designers.

The linking of individual workstations into networks is of special

importance today. It enables individuals to share information and

major hardware systems, such as high quality printers. Since office

and communications technologies are changing so rapidly, it is

virtually impossible to predict how they will evolve in the future.

As a result, a major problem for designers is to provide sufficient

flexibility for change, at a minimum cost and limited disruption of

5
ongoing activities. Among the systems and design strategies

meriting attention are:

* Multi-media presentations

* Network connections to all required systems and services.

* Clean vs. utility power.

* Power and localized cooling to accommodate heat loads from

electrical equipment and backup such as localized exhaust for heat,

heat pump systems to use waste heat, and air-to-air exchange for

improved air quality.

* Mechanical, electrical distribution, lighting, and communications

systems

.

* Workstation design - to accommodate a range of tasks, and

individuals

.

* Standardization of components for workstations - work surfaces,

task lighting, panels, furniture.

* Changes in space use and size.

* Air supply and return, localized and variable in quantity..

* Floor plenum system for air and electrical distribution

* Storage of informational media -reduced redundancy for paper,

disks

.

* Convenience copiers and printers.

* Fire suppression and safety systems.

* Ratio of devices to people.

At the macro level of design, available systems can be automated

and pre-wired into new buildings to accommodate operational,

service, energy conservation, fire safety, communication, and other

systems. However, just because technology exists to automate

functions doesn't mean that it is the most effective approach for

the organization or the individual worker.

Automation is typically based upon uniform requirements, while

individuals and activities often differ from one another in

important ways, and have distinctive needs. The design approach to

the automated office today is directed toward meeting the needs of

the average office worker performing typical tasks in a characteristic organization. This depiction of the automated

office is both widespread and meaningless. There is no such thing

as a typical:

Person

Organization

Task

Office

Office Automation System

Workstation

Office Procedure(s)

Organizations and individuals have unique characteristics which

merit design attention, and it is the function of the design

process to develop the information needed to respond to the

particular of requirements of both of them.

6
1.1.3 Organizations and Design

Architects have an important contribution to make in furthering

organizational and group cohesiveness.

Microcomputer-based workstations have enabled many jobs to be

performed autonomously, isolating the individual from a working

group and from the organization as a whole. Design elements such

as furnishings and panels can serve to distinguish one group from

another one, and the layout of workstation groupings can be

integrated to further organizational functions. Common spaces can

provide the opportunity for members of diverse groups to exchange

ideas, thereby furthering the sense of organizational identity.

Above all, there is a need to provide a high quality environment

for the staff. Table 2 suggests several features which might

contribute to "high quality" design.

Table 2. Checklist - Design Considerations for 'High Quality'

Offices (Criteria)

* Humane and pleasant setting to offset technological

emphasis

.

* Places for visual relief, inside and outside.

* Spaces arranged to make locations and circulation patterns

comprehensible

.

* Places for casual interchange of ideas and unplanned social

contact

.

* Centers of interest to serve as guideposts and informal

meeting places, e.g. works of art, planters.

* Quiet, restful areas, with expanded recreational and

physical exercise spaces.

* Workstations grouped in functional clusters.

* Personalization and individual control of workspace

furnishings and environmental systems.

* Attractively designed public areas.

* Privacy - visual and auditory.

* Secure spaces.

* Individual choice of workspace features; lamps,

furnishings

Organizational issues are closely linked to technological,

ergonomic, and design factors. Technological changes in office

systems have been too rapid for them to be properly assimilated

into most organizations. This has resulted in a gap between what

is technically feasible, and what is needed to further

organizational goals.

7
1.1.4

Ergonomics and Design

Automated technology is neutral with respect to its influences on

the quality of the workplace. It can be used as a means of

standardizing and controlling job characteristics and environmental

features, thereby minimizing the autonomy of the individual worker

and the freedom to make on-the-job decisions. Many of the problems

with the early automated word processing have been attributed to

these factors. On the other hand, automation offers the potential

for the individual worker to exercise considerable control over job

functions and environmental systems, thereby enhancing the quality

and quantity of work performed.

Individual control can take many forms:

* Environment - lighting, heating, cooling

* Information

* Work Procedures

* Task Decisions

* Workspace

* Social Settings

* Furniture - selection, modification

* Personalization of Space

* Planning of Individual Work

* Communications

* Access to information

1.1.5 Security and Design

As communication, information and building technologies become more

dependent on computerized systems, a greater likelihood exists that

when there is a problem, it will be a major one. That is, since

many systems are interdependent, a breakdown in one system often

has widespread and costly effects. This situation makes highly

automated buildings and the activities they house, vulnerable to

people who want to undermine, disrupt and destroy operational

information. Building security is therefore an important design

consideration . The greatest need for security in office-based operations is that

required in a data center, where informational resources are highly

centralized. In chapter 15 of this report, security in data centers

is treated in some detail. The requirements in general offices are

likely to be less stringent and therefore the design requirements

are are not as comprehensive as those in data centers. However, the

methods employed are not apt to be qualitatively different in the

two spaces. Rather, they would differ only in degree.

1.1.6 Planning

Productivity in offices results from the appropriate integration of

people, tools, and places. This integration should be accomplished

by proper planning , including organizational representatives from

human resources, technology, information processing, and design - who often find themselves in competition with one another in

productivity improvement programs. The planning should be under

8
the direction of top management and include extensive involvement

by end-users at all stages of the process (8)

.

The automation of office functions is a continuous process, not a discrete event, and must be directed to organizational

effectiveness and not the introduction of new technologies because

of their advertised effectiveness. An essential element in such

planning is the preparation and training of the staff to ensure

that automation is viewed as a tool to assist work activities, not

a threat to jobs, or a means to subjugate people to technology. It

is self-evident that the greatest single determinant of office

productivity is the performance of the workforce. Technology as

well as design should contribute positively to the office work

setting (9)

.

9
2. PLANNING AND PROGRAMMING THE AUTOMATED OFFICE

2.1 FUNCTION

Planning is used to promote the orderly transition of office work

from primarily paper-based activities to electronic systems while

maintaining (or improving) the overall quality of the workplace.

This goal can be accomplished by acquiring detailed information

concerning organizational, individual and technological

requirements and then devising appropriate design solutions. The

planning should be accomplished by the close cooperation of a multi-disciplinary design team with the client (10)

.

Designers and office automation experts are in general agreement

that detailed planning is an essential prerequisite for the

automation of office activities. The piecemeal acquisition

equipment has resulted in many complaints by office workers in

the past, because of such factors as the inappropriateness of

furniture and environmental systems (e.g. lighting) for

performing VDT-based activities (11) . A key goal of planning is

to ensure the flexibility required to accommodate future changes.

2.2. CRITERIA

* Planning should be under the auspices and commitment of

top management.

* End-users should be an important source of information.

* Flexibility, and its costs, should be major

considerations

.

* The integration of information and communication systems

is important.

* The analysis of present and proposed office activities as

they meet organizational objectives should precede any

decision about automated equipment and systems.

* Long-term costs should be considered - especially those

associated with the salaries of workers.

* Degree of change forecast.

2.3 INFORMATION DEVELOPMENT

A variety of approaches have been used as planning aids. Some of

these are illustrated in tables 3, 4, and 5.

10
Following (Tables 3 and 4) are two methods which can be used to

develop planning information:

Table 3. a. Analytic Approach for Relating Technology to Design

( 12 )

PRESENT OFFICE AUTOMATED OFFICE POSSIBLE DESIGN IMPACT

INFORMATION/MANAGEMENT

SYSTEMS

Record Storage and

Management

Paper files Limited paper

Electronic files - Less space for file cabinets

Changed layout

Added electronics

Added cooling load

Internal Mail Generation

and Distribution

Paper Electronic Smaller mail room More electronics

Document Distribution Typed copy OCR devices

Electronic mail

Need for physical separation

of noisy machines & activities

Special acoustic treatment

Document Preparation Separated functions;

Manual typing, artwork

graphics

Centralized functions

Electronically based

systems

Larger workstation for

document preparation

Less space for visual arts

Organization of Activities

Specialized

Decentralized

Workstations - clerical

professional, managerial

Change in adjacencies

More electronics

Greater access to data

bases

Expansion of Capabilities

Space set aside More power, wiring, ducting,

to accomodate future needs

Added capacity for electronics

power, plah for local cooling

Planning Activities Minimal necessary Detailed planning essential;

Management, building.

Information, communication, etc

Need for detailed architectural program, CAD system

to keep track of changes, etc.

11
Table 3.b. Analytic Approach for Relating Technology to Design

(Cont'd) (12)

PRESENT OFFICE AUTOMATED OFFICE POSSIBLE DESIGN IMPACT

POWER SYSTEMS

Emergency Power None Batteries, Generator

Support for electrical

equipment during outage

- Added space, special

venting systems, fuel storage, special flooring

for acid, fuel runoff

- Fire protection, security

- Clean power

Wire Distribution Conduits

Under floor systems

In wall outlets

Raised floors

Cellular decks

Flat conductor cable

- New floor systems; carpets

- More space for floor/celling

systems

- Changed power loading factorsless load per local circuit, more cable runs

- More room for wire closets,

risers

- Special protection for cables

OFFICE TECHNOLOGY

BASED ACTIVITIES

Typing Electronic typewriter Word processing systems - Glare free lighting

- Additional workspace for equipment

Communication Telephone, mail, memos Electronic mail - VDT, wiring.

Filing Paper files; individual Electronic data bases

Centralized computer

- Specialized facilityraised floor, clean,

emergency power, less paper storage space

Facsimile

Production

Hands-on duplicating Duplication at a distance, FAX

- Specialized facility for devices; acoustic treated,

separate air conditioning

Reading Paper copy VDT, microfiche - Special lighting, more desktop

room for equipment

12
Table 4. Checklist for Office Automation Design

Not

Yes applicable

1. Are private offices available for personnel who conduct

professional or supervisory counceling or confidential

discussions on a regular basis?

2. Have conference spaces been provided for those times

when employees need to work together?

3. In circumstances where several employees share equipment, are those employees co-located?

4. Are the employees separated from noisy equipment such

as CPUs, copiers, etc?

3. Have office locations been chosen with regard to expected

interactions?

6. Are partitions used to screen traffic?

7. Are all commonly used facilities centrally located?

8. Are frequently interacting functions located on the same

floor?

9. Are the pathways to and from offices straight? (That la, are confusing spirals, curves, or dead-ends avoided)?

10. Vhere an open office concept has been used, is some amount

of pathway continuity present?

11. Are the dimensions of all private offices at least 7.5 x

7.5 ft (2.3 m x 2.3 m)?

12. Are the private offices designated so no one faces a window

while working?

13. Doe6 each private office have a good aource of Illumination?

14. Does each office have independent control of its ventilating

system?

15. Is there adequate apace at the workstation for the equipment

and data (printouts, microfiche, manuals, etc.) that the user needs?

16. Is the work area adjustable so that it can accoamodate

comfortably the 5th to the 95th percentile of the adult

population?

17. If the CRTs, the microfiche readers, etc., are not at the

immediate workstation, are they as close as possible to

that station?

18. Is the workstation adjustable so that the home typing keys

are 2 inches (55 mm) below the elbow height?

19. Are all employees trained to adjust their furniture, or la adjustment provided as requested?

20. Are office noise levels below 45 dB(A), 37 dB PSIL-4, or

38 dB PSIL?

Not Aware

13
2.4 PLANNING APPROACHES-PROGRAMMING

The information developed during the planning phase will serve as

the basis of the architectural program.

Objectives and Philosophy. A clear statement of goals is the

first step. These are based on the history and background of the

organization and its attitudes and expectations towards its

client and staff.

Functional Relationships. An analysis of the interactions and

transactions of individuals and organizational units is needed to

understand traffic flow, communication, information flow and

access. It is also necessary to determine the appropriate

placement of support services such as word processing, mail

reproduction, data storage and communication, etc., with relation

to the location of administrative and organizational units. The

proper location of conference and meeting rooms, libraries,

internal waiting areas, lunchrooms, lounges, all merit particular

attention

.

Facility Spatial Requirements. Spatial needs for individual and

organizational units are based upon a complex of interfacing

factors such as ergonomics, communication requirements, status,

and needs for privacy.

Development of the Program and Program Criteria. The program

should be written in performance language, describing the

functional requirements of a system for example, not the hardware

specifications

.

Post Occupancy Evaluation (POE)

.

Establish at the design stage,

individuals responsible for POE maintenance; as-built drawings

review, training, etc. To prepare for future evaluations, a log

of projects should be kept and preserved, including all plans,

the program, decisions and changes made. Evaluation should be

made on the basis of general staff satisfaction, staff use of

space and facilities, environmental and communications systems,

task performance, and the value and use of staff amenities.

Following (table 5 and figures 2, 3 and 4) are approaches that

have been used to develop and organize programming

act ivities , including post occupancy evaluation (POE).

14
Table 5. Introduction of Automation into Offices- Critical

Factors

1. Collect facts, to document automation approach.

2. Start early to announce and explain system, answer questions

share plans, generate enthusiasm and gain long term commitment.

3. Share information with management, support staff and end

users

.

4. Implement systems gradually? pilot test systems, including

factory tests, mockups; communicate results to staff.

5. Be aware of "grapevine" information; make informal network

work for you.

6. Collect information during entire process; share results.

7. Identify and resolve problems quickly; use experts if needed

8. Use informal meetings to discuss ongoing developments?

maintain staff enthusiasm.

9. Know when to turn operation over to user group? with

documented procedures, and information about available

assistance.

10. Involve management and end-users in process.

11. There should be an information center for on-going training

and help.

12. There should be a ’help' desk to resolve problems.

13. A systematic change control system should be instituted.

14. Information should be solicited and shared with individuals,

not just formal organizational groups.

15
PROGRAMMING - PHASE 1 PLANNING - PHASE 2

STATEMENT OF ORGANIZATIONAL SPACE

PLANNING AND DESIGN GOALS AND OBJECTIVES.

IN TERMS OF FUNCTIONAL. ORGANIZATIONAL, AND AESTHETIC EXPECTATIONS.

IDENTIFICATION OF RELATIONSHIPS AND

TRANSACTIONS BETWEEN AND WITHIN ADMINISTRATIVE, OPERATIONAL ANO PERSONNEL

DEPARTMENTS. ALSO. THE DETERMINATION OF PATTERNS OF ACTIVITIES AS WELL AS INFORMATION AND MATERIAL FLOW.

ASSIGNMENT OF^ZSPATIAL AREA AND

CONFIGURATION REQUIREMENTS FOR: WORK STATIONS. PRIVATE OFFICES. DEPARTMENTS. SUPPORT 8ERVICE8 AND

AMENITIES; BASED ON TA8K FUNCTION. FACE

TO FACE TRANSACTIONS. ANO HIERARCHY.

DEVELOPMENT OFZZ: THE PROGRAM BRIEF AS A DIRECTIVE FOR SPACE PLANNING AND DESIGN IN TERM8 OF CRITERIA. GUIDELINES. AND PERFORMANCE REQUIREMENTS.

TECHNICAL - PHASE 3 EVALUATION - PHASE 4

Figure 2. Office Design Process (14)

16
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Figure 3. Conceptual Model for Evaluating Work Environments (15)

17

that

were

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within

the

case

study

in

this

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Double

lines

denote

characteristics

of

organizations

and

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individual

workers.
OCCUPANT

REQUIREMENT FACILITY RATING COMMENTS

UNIMPORTANT

co

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* «• o *

* •

P •

*

• 9

PRIVACY - Auditory and

Vlaual

SOCIABILITY - Accomodata

Conversations

FORMALITY - Restricted

Activities CHOICE - Control of Environment

COMFORT - Appropriate

Environmental Featurae

-

IMAGERY - Space Depicts

Purpose

EFFICIENCY - Easy to Arrange Workspace

ACTIVITY - Selection of Furnishings, Colors

FLEXIBILITY - Ability to Modify

TASK PERFORMANCE - Space Accomodates Job

TERRITORIALITY - Personalization

LACK OF CROWDING - Not Overoccupied

Figure 4 Checklist for Facility Evaluation (16)
3. WORKSTATION SYSTEMS.

3.1 FUNCTION

The workstation is the basic operating unit of the automated

office. It is here that information and communication

technologies are merged into a powerful system managed by the

worker. Initially confined to secretarial and data processing

tasks electronic devices are increasingly used for managerial

work

.

Organizational, design and personal needs are integrated at the

workstation. It must be designed to meet a variety of

requirements differing from person to person- physical, sensory,

and cognitive. Flexibility is essential for workstation

furnishings and equipment. For example, selecting and placing

objects serving the worker requires considerations of physical

comfort, body movement, and individual preferences and needs.

Employees at workstations must have ready access to the tools and

materials needed to do their jobs. Size of components,

clearances, allowances for free body movement, are integral to

the proper fit of person to workstation. Figures 5 and 6, and

table 6 are examples of recommended designs and dimensions of

workstation components.

3.2 CRITERIA

The workstation should have:

* Flexibility to accommodate the range of tasks performed

and the individuals performing them

* Vertical and horizontal surfaces for materials use and

storage; place for continuous paper supply and output

* Power and communications capabilities consistent with

performing required activities

* Ready access to work materials

* Workstation layout to facilitate performing activities

* Individual controls for equipment and selected

environmental features, e.g. task lighting

* Capability for personalizing workspace

* Easily reached controls; easily read displays

* Sufficient space to facilitate comfortable movement

* Capability for rapid changes and moves

* Appropriate wire management and media for tasks

* Job related space for visitors, paraprof essional; e.g.

meeting areas

* Antistatic materials on work surfaces

19
Table 6.

STD 1472C

Recommended Workstation Dimensions for VDT's (74)

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20
mr BETWEEN aerators

STD LINE Of SI GMT* O*

MIN TO AVOID SEEING TOP- 54 in

STD HORIZ SIGHT LINE -O* MAX TO SEE OVER TOP* 47 m

normal sight line -is*

A- TYPING- TYPEWRITER KEYBOARD

LOWEST LEVEL SHOULD BE 26 m

20*- 50* UPPER ROW NO HIGHER THAN 31 in B-DISPLAY-CONTROL

c-display, set-up control

D-EMERGENCY DISPLAY. SET-UP CONTROL

E -REF DISPLAY. ADJ CONTROL

MOTE • 5th -95th % OPERATORS

Figure 5. Ergonomic Criteria for Workspaces (17)

21
St •commanded Approximate Dfenenaione (in centimeter*)

Adjustment Features of an Ergonomic Wort Seat

enronra

Adjuetment Feature* of an Ergonomic VDU Wort Station

Figure 6. Workstation and Seat Design

22
3.3 FURNISHINGS-FLEXIBILITY REQUIREMENTS

The concept of the 1 average person' has been discarded as a guide

for effective design. Individuals have a wide variety of sizes

and shapes, and have different preferences for equipment and

furnishings. Just as the design of the office must be flexible,

furniture must be adjustable. Seat, keyboard, display, and foot

support are interacting system components in workstation design.

Chairs should be supported on four legs (or a pedestal with a five caster base) , have adjustable seat pans and backrest

heights. The angles of seat pans and backrests should be

adjustable relative to each another. Backrests should also be

modifiable front and back, with respect to the seat pan.

Footrests, adjustable in height, angulation, and front and back

distance are also desirable (18)

.

3.3.1 Checklist — Requirements for Workstation Flexibility

* Capable of change with minimum disruption to staff or

activities

* Adjustments should not require special skills or tools.

* Systems should be simple and made of standardized

components and cost effective.

* Dimensions and heights of work surfaces should be

adjustable and accommodate a range of activity and

individual requirements.

* New component configurations should accommodate changing

requirements

.

* Furnishings should be responsive to individual

differences, e.g., left and right handed people.

* Adjustable seating with firm back and neck support

* Components and design should be cost effective

3.4 ENVIRONMENTAL CONTEXT

3.4.1 Checklist for Workstations Environment/Design Components

* Are components adjustable; fit differences in height,

size, and work habits? Can products be used in a right and

left handed configuration?

* Is the hardware adaptable? Can the system be shifted,

moved on a carpeted floor? Is it readily adjustable with

minimum expertise and simple tools?

* Can the equipment be used in angular configurations?

* Does the system optimize the use of vertical space?

* Do acoustical panels work properly?

* Does the product control, modify, and conceal electrical

and communications systems?

* Are visual privacy needs satisfied?

* Can the worker control the mini-environment?

* Is the product durable, safe, and easy to maintain?

* Is the product standardized; available if additional

components are needed?

23
* Do components relate visually to one another and the other

system elements?

* Is a "family" of products available, e.g., different but

compatible colors?

3.4.2 Checklist - Requirements for Workstation Environment/Design

* Acoustic privacy.

* Freedom from auditory and visual distractions.

* Glare-free lighting.

* Physical separation of unrelated activities.

* Ease of power and communication changes and additions.

* Nondisruptive traffic patterns.

* Clearly defined personal boundaries.

3.4.3. System Panels

System panels in open office settings perform the functions

traditionally served by walls in private offices.

3. 4. 3.1 Function

Systems panels are important in open-office design. They are

used for acoustical and visual privacy, articulating office

layout and facilitating wire system distribution. They help to

implement changes in the office environment. Panel heights vary

from 30 inches to 80 inches (where acoustical and visual privacy

requirements predominate, such as in executive workstations)

.

Lower partition heights produce improved communication and air

circulation at the expense of privacy. Higher partitions aid

acoustical performance, but create difficulties for HVAC and

lighting systems.

An analysis of requirements should precede the selection of panel

systems. For example:

* Will open planning be used for all staff members? What are

the priorities?

* How important is the ability to add units, wire

management?

* Will sophisticated computer equipment have to be

accommodated?

* Does company policy dictate standards for management

levels?

24
Structurally, panels can be placed in one of five categories:

1. Free standing; serves as a space divider.

2. Panel System with End Support; stabilizes work surfaces.

3. Cantilevered; structural element that can support

furniture. Work surfaces and overhead storage cabinets,

which can be raised and lowered are hung from the back

panel, usually on slotted tracks.

4. Post and Panel; supports overhead cabinets and work

surfaces. The posts enable panels to be set in any

configuration

.

5. Full Wall Height; for privacy. They come with

upholstered, wood or glass panels, and full height doors.

Panels are constructed with metal or wood frames, with or without

exposed or integrated supporting posts. Connector systems vary

widely. Panel material composition is fairly standardized. Nonacoustical panels are often made of hardboard or honeycomb cores

sandwiched between layers of laminate, wood veneer or metal.

Acoustical panels may have a hardboard core with layers of

fiberglass or other sound absorbent material on both sized,

covered by a layer of acoustically transparent fabric.

3. 4. 3. 2 Panel System Criteria

The following features of panel systems are desirable:

* Acoustical performance consistent with activities

* Wiring distribution - current and future media

* Capable of being readily disassembled and reconfigured

with unskilled labor

* Sufficiently durable for repeated reuse

* Standardized components to ensure availability of

replacement and expansion

* Appropriate range of sizes, colors, etc to meet

organizational needs and plans

* Adequate stability and impact resistance

25
3. 4. 3. 3 Checklist for Panel Components

* Are components adjustable to fit individual differences in

height, size, and work habits

* Can the product be used in right and left handed

configurations?

* Is the hardware adaptable?

* Can components be moved, shifted on a carpeted floor?

* Can adjustments be made with simple tools and by those

with minimum expertise?

* Are angular configurations possible?

* Is there optimum use of vertical space?

* Do acoustical panels perform as desired?

* Can electrical and communication systems be controlled,

modified and concealed?

* Do they adequately serve visual privacy needs?

* What control does the worker have over the minienvironment; e.g. lighting, cooling ?

* Are the products durable, safe, and easy to maintain?

* Are the products standardized; available if added

components are needed?

* Is there a family of products; e.g. compatible colors,

unit sizes?

* Are there sound or light leaks between connected panels?

* Are there slotted rails along the face edged to hang

storage and workspace components?

* Is there provision for a coat rack?

* See Table 7

26
The following table describes minimum federal performance

requirements for panels: Table 7

MINIMAL FEDERAL

ATTRIBUTE TESTS PERFORMANCE REQUIREMENTS

FLAMMABILITY

FLAME SPREAD ASTM E-84 FLAME SPREAD<25 UNSPRINKLERED

FLAME SPREAD<200 SPRINKLERED

SMOKE NBS 708 SPECIFIC OPTICAL DENSITY* 150

POTENTIAL HEAT BASED ON ASTM

PROCEEDINGS VOL. 61

1961, PP 1337-47

<40,000 BTU

ACOUSTICS

AIRBORNE SOUND PBS-C1

(SUBJECTIVE)

SPP<60 IN OPEN PLAN AREAS

SPP<70 IN ROOMS WITHOUT DOORS

PBS-C2

(OBJECTIVE TEST)

NIC + (NC<40)<60 IN OPEN PLAN

IMPACT SOUND FOOTFALL TEST

1B1-1 1-1965

MASK VERTICAL FOOTFALL SOUNDS

W/NC<40

STABILITY

RESIST HORIZONTAL

LOAD

ASTM 72-74 RESIST LOAD OF 50 LB

SUPPORT 40 LB PER LINEAR FT OF

SHELVING

RESIST TIPPING

RESIST IMPACT ASTM 72-74 RESIST 30-LB IMPACT HORIZONTAL FORCE

OF 100 LB APPLIED 5” ABOVE FLOOR

DURABILITY

ABRASION ASTM 72-74 RESIST ABRASION

COLORFASTNESS FADEOMETER NO COLOR CHANGE AFTER 50 HOURS AT

150°F

CHEMICAL RESISTANCE FTM 141 A

METHOD 6081

RESIST STAINING AND DAMAGE

SOURCE: Specifications for Commercial Interiors, by S.C. Reznikoff, New York,

WHITNEY LIBRARY OF DESIGN, 1979.

27
3. 4. 3. 4. Interactions with other systems

Wiring

The system panel plays an important role in electrical

distribution systems in open offices. Three basic approaches are

used in wire distribution.

* Panel with a raceway that accommodates electrical wires

and communication cables of all kinds, including coaxial,

mixed media.

* Panel which can be equipped with an optional manufacturersupplied power pack, panel-to-panel connectors, and hooks up

to the building's electrical grid.

* The prewired panel, already assembled and plugged into the

electrical grid. (The most expensive option.)

Simple Raceway

This system is assembled before the panels and adds a few inches

to the total system height. Among the specific issues to be

considered are:

* The accessibility of wires and cables

* The durability of base plates and covers concealing the

wires

* Are separate channels available for communications and

electrical wire?

* Availability and accessibility of power feeds from the

floor and ceiling

* Are there optional convenience outlet strips?

* Difficulty in managing wire; replacement, making changes.

Power Pack

Power availability is a major concern for all wiring systems.

Among the factors to be considered are:

* Wiring system retrofitted to non-electrif ied system panels

* Integrated convenience outlets at work surface height

* With systems having integrated ambient lighting, can the

lighting circuit be turned off while task and convenient

lighting are active?

* Pass-through panels for areas not requiring electrified

outlets

* Number of outlets permitted in each circuit

3.5 VDT/KEYBOARD SYSTEMS

The primary working tools at the electronic workstation are the

VDT and associated keyboard. The system should be easy to use

and adaptable to individual requirements, e.g., its ergonomic

features

.

28
3.5.1 Checklist- VDT/Keyboard Requirements:

* Movable and connected keyboards for individual convenience

and/or preference

* Readily adjustable VDT screen- capability to tilt, move

vertically, swivel toward or away from the operator

* Keyboard enabling operator's hands and elbows to be in

comfortable positions

* Work surfaces at preferred height and distance for

individual ease of manipulation, support or forearms, palm

and wrist, and convenience for seeing the task.

3.6 POSSIBLE PROBLEM AREA-VDT SCREEN GLARE

A major complaint by VDT operators has been screen reading

difficulty due to glare. The lighting and design issues related

to this problem are covered in Chap. 5) . A study by the National

Academy of Sciences suggests the use of filters to enhance visual

image quality on the VDT screen. It describes four systems

available for this purpose.

3.6.1. Potential Solution - Filters over VDT screen. (18)

* Circular polarizer with anti-reflective coating, used to

reduce specular and diffuse reflections. The outside

surface is coated with several layers of optically

transparent materials to form an anti-reflective coating to

reduce specular reflections from the filter surface. The

remainder of the filter package is a polarizer to eliminate

reflections from the underlying VDT screen.

* Neutral density filter is the simplest type, consisting of

neutrally tinted plastic allowing a small percentage of

light falling on it to be visible. It reduces diffuse light

reflections from ambient sources.

* Notch or color filters allow transmission of a high

percentage of lights from certain wavelengths (usually

green), and absorption at other wavelengths. It is designed

to be "tuned" to the color of the VDT screen, permitting the

desired light to penetrate, while absorbing the undesirable

ambient light.

* Directional filters employ geometrical means to prevent

ambient light from reaching the screen, thereby preventing

reflections from reaching the user.

29
A summary evaluation of ergonomic features of offices revealed

the following: (20)

GENERAL FEATURES RANK

Comfort 1

Amount of workspace 2

Ability to adjust furniture oneself 3

Amount of storage space 4

Ease of adjustment 4

Amount of light available 6

Privacy 7

Noise control 8

DESK CHARACTERISTICS

Writing surface height adjustment 1

Terminal screen height adjustment 2

Terminal keyboard height adjustment 2

Separate heights; keyboard and screen 2

Terminal screen tilt 5

File drawer storage 6

Shelves 7

Terminal keyboard tilt 8

Terminal viewing distance adjustment 8

Locking storage area for personal items 10

CHAIR CHARACTERISTICS

Seat height adjustment 1

Backrest height adjustment 2

Ability to swivel while seated 3

Back tilt adjustment 4

Arms 5

Seat tilt adjustment 6

Ability to lean back 6

Carpet casters 8

Footrest 9

30
4. ACOUSTIC ENVIRONMENTAL SYSTEMS

4.1 FUNCTION

To provide an acoustical environment appropriate for the

activities performed in automated offices.

The auditory needs of workers depend upon the characteristics of

the work performed. For example, many managerial and

professional functions have stringent acoustical demands and are

performed by people accustomed to a quiet workplace. A manager

is often required to conduct private conversations with staff

members and visitors. Professionals spend considerable time in

planning, creative thinking and report writing. These activities

are susceptible to distraction from noise intrusions. On the

other hand, many office tasks require office machines and systems

inherently noisy, such as copiers and most printers. One design

challenge is to physically separate or isolate activities with

conflicting acoustical properties.

4.2 BACKGROUND

Surveys consistently demonstrate that the acoustical features of

office are extremely important to most employees, especially for

those working in open-space design offices. Studies also

indicate that major sources of complaints are intrusive noises

and the lack of acoustical privacy.

With respect to speech privacy, confidential discussions play an

important role in office activities. The general public is often

served by private and public organizations in open-office

environments. The subjects of many discussions are highly

personal and confidential, and should not be in danger of

compromise

.

Another problem is lack of effective noise isolation from noise

producing equipment. Unlike the situation in a private office

where such noises are largely confined to a specific work area,

in the open-office design these noises frequently intrude to many

work areas where individuals require a quiet environment to

engage in analytical activities. Noise has a detrimental effect

on the ability to concentrate on the job at hand, especially for

management and professional personnel.

The acoustical properties of spaces are influenced by the

thickness and density of enclosing structures, the porosity of

wall and floor covers, insulation, drapes and furnishings. Sound

is affected by room shape, volume, and the characteristics of the

interior surfaces.

31
4.3 CRITERIA

A proper acoustical environment consists of:

1. Adequate acoustical privacy; consistent with the activity

performed

.

2. Freedom from intrusive noise sources.

3. Freedom from distracting vibrations.

4. Ability to conduct conversations at normal speech levels.

5. Isolation of major noise sources from general working

environment

.

6. Special acoustical treatment for sensitive

activities/spaces, e.g. conference, audio-visual rooms.

7. Control of telephone rings; ensure that ring of one phone

is identified and not confused with nearby telephones.

4.4 OVERVIEW OF BASIC ISSUES

Before discussing design approaches to achieve adequate

acoustical performance several basic issues and concepts will be

mentioned. Table 8 indicates background sound levels of familiar

activities and places.

Table 8. Familiar Background Sound Levels

Apparent Loudnos Eumpta Drribrfc DEAFENING Jet aircraft 140

Threshold of feeling DO

VERY LOUD Elevated train Thunder

120

Subway train

Nearby riveter

no

Noisy industrial plant no

Office with ub machines Loud street none

90

Noisy office Vacuum cleaner

ao

LOUD Average street noise 70

Average office Congested department more

to

MODERATE Moderate restaurant clatter Average 2-person conversation

JO

School classroom

Private office

40

FAINT Bedroom 30

Rustling leaves 20 VERY FAINT Normal breathing K> Threshold of audibility 0

32
4.4.1 Auditory Privacy

Two kinds of privacy have been identified. Normal privacy- a condition where speech from adjacent locations can be understood

if one listened intently, but is not loud enough to cause a disturbance. Confidential privacy precludes the understanding of

phrases and/or sentences in adjoining locations.

The preferred method of assessing speech privacy is the

Articulation Index (AI) . This is a measure of the percentage of

sentences that can be understood from a person speaking in a normal conversational tone. The index is based upon signal-tonoise differences in decibels, weighted in terms of the relative

contribution of each one-third octave band, to speech

intelligibility. As the speech level drops toward the noise

level, the AI value approaches zero;as the speech level arises

above the noise, the AI nears 1.0. (See following figure.)

Tables 9 and 10 provide recommendations for acoustical

performance of selected office activities.

Table 9. Types of Offices Applicable to Articulation Index

Ranges (21)

I 00.00- Confidential Privacy. a) Closed offices with

0.05 Speech cannot be followed STC of 40-41.

with understanding. b) Open plan, or office

landscape environment.

II 0.05- Normal Privacy. a) Closed offices with STC

0.20 Speech may be understood with of 35-40.

careful listening attention

but should not interfere with

the ability to concentrate on other work.

b) Open-plan environmental

III 0.20- Marginal Privacy. Open-plan environment

Provides a relatively quiet

office environment when privacy

is not of supreme importance.

IV 0.35- Fair communication, no privacy

0.50 typical, relatively noisy

environment. Does not promote

maximum productivity.

V 0.50- Good to excellent Not normally an office

communication, no privacy. feature. Usually found

only in conference rooms and auditoriums.

33
Table 10. Speech

Criteria (NC) Recommended

Interference Levels

for Rooms (22)

(SIL) and Noise

Maximum permissible laval (measured in vacant rooms)

Type of room 6IL NC

Secretarial offices, typing 60 50-55

Coliseum for sports only (amplification) 55 50

Small private office 45 30-35

Conference room for 20 35 30

Movie theater 35 30

Conference room for 50 30 20-30

Theaters for drama. 500 seats (no amplification) 30 20-25

Homes, sleeping areas 30 20-25

Assembly halls (no amplification) 30

Schoolrooms 30 25

Concert halls (no amplification) 25 15-20

Source: SIL data from Beranek and Newman as modified by Peterson and

Gross to reflect current practice of using octave bands with centers at 500. 1000, and 2000 Hz: NC data from Beranek.

34
Percent

of

Sentences

Fully

Understood

Figure 7. Approximate relation between AI and Speech Intelligibility (21)
Another means of evaluating environmental noise, is the Speech

Interference Level (SIL) . These levels constitute the arithmetic

average of the sound pressure levels of noise in the three octave

bands centered on the frequencies of 500, 1000 and 2000 hertz,

based upon complaints of office workers in conducting speech

communication. Table 11 demonstrates the relationship between

sound level and distance in conducting conversations.

Table 11. Conversations and Speech Interference Levels

Speech-Interference Levels that

Barely Permit Reliable Conversation

Distance between

talker and listener (It) Normal

Speech-Interference level (dB)

Raised Very Loud Shouting

0.5 71 77 S3 69

10 65 71 77 63

2.0 59 65 71 77

3.0 55 61 67 73

4.0 53 59 65 71 5.0 51 57 63 69

6.0 49 55 61 67

12.0 43 49 55 61

36
4.4.2

Sound

Sound is a form of energy produced by minute pressure

fluctuations in the air, generated by vibrating surfaces and

aerodynamic turbulence. Most solid objects can potentially

produce sound, as does air, when it interacts with structures

which change its path, e.g. HVAC ducts.

Sound waves are transmitted directly and indirectly. In direct

sound, waves are neither deflected by reflective surfaces, nor

absorbed by porous ones. The sound pressure levels of direct

sound decreases proportionally with increased distance from the

sound source. Indirect sound occurs when the sound source is

reflected from hard surfaces such as walls, ceilings or floors.

Furnishings, equipment and room features such as light fixtures,

can also create sound reflections. Sound is affected by room

shape, volume, and the characteristics of the interior surfaces.

4.4.3 Sound Transmission

There are two types of sound transmission: airborne and

structure-borne . Airborne sound originates and is transmitted

directly to the person, e.g. conversation, machine noise.

Structure-borne sound is produced when an object impacts against

a structural element of a building, e.g. footsteps. The sound

energy is transmitted in proportion to the mass and rigidity of

the structure. A major acoustical problem in many buildings is

the presence of flanking (indirect) sound paths, which permit

sound to travel throughout many areas of a building. Interior

elements such as HVAC ducts, continuous walls between floors,

uncaulked junctures of ceilings and partitions can all produce

such sound paths.

4.4.4 Noise Criteria (NC) Curves

These curves were also developed from "complaint data" from

questionnaire surveys. They are intended to specify the maximum

noise levels permissible in an environment without eliciting too

many complaints. These curves are an indicator of the ability to

perform assigned work. The survey responses are then correlated

with physical acoustical measurements to specify the acoustical

properties of spaces required to perform given activities. Figure

8 illustrates the NC curves.

37
Old Octave-Band LimHin9 Req..(Hz)

0elo*J 75- 150- 500- 1200- £4<a> 4«C0- 75 750 'boo kOO noo 7AOO 4000 #00

Figure 8. Noise Criteria (NC) Curves

38
4.5 POSSIBLE PROBLEM AREAS

The solutions being employed to cope with several of the design

problems posed by office automation have important implications

for acoustical design. For example:

1. Expanded utility chases are placed above a lowered

ceiling or beneath a raised floor. Chases provide excellent

noise passages, and flanking paths for conversations meant

to be private.

2. Supplementary air conditioning units placed above lowered

ceilings can introduce undesirable noise sources into the

office

.

3. Elevated lightweight floors provide excellent sound and

vibration radiating diaphragms (i.e. sounding boards) for

equipment, machinery and footsteps noises.

4. The mechanization of office tasks results in a proliferation of noisy equipment such as copiers and

printers

.

5. Open-office planning exposes the office workforce to more

noise

.

6. Automation of activities has exposed noise sensitive

tasks such as planning to noise intrusions.

7. Placement of localized air conditioning units to

dissipate heat load of new equipment.

8. Operation of office machines in open environment when

privacy is essential.

9. Planning the introduction of new equipment with minimum

disruption

.

10. Telephone rings not readily identified with particular

phones

.

4.6 TYPICAL SOLUTIONS

4.6.1 Barriers

Sound barriers reduce or eliminate noise by reflecting or

resisting its transmission. The mass of the material used as a barrier determines its effectiveness, the greater the mass, the

better the performance. The performance of a wall, for example,

is measured in decibels (dB) . The measurement is referred to as

the sound transmission loss (STL) . The sound transmission loss

class (STC) is a rating scheme using a single number to rate its

performance. Typical fixed barrier materials in buildings are

sheet rock, gypsum board, concrete, brick or wood. Partitions

used in open-offices are movable barriers.

4.6.2 Isolation of Surfaces

This is a means of preventing vibration transmissions from one

space to an adjoining one. One method of achieving this is to

place rubber, compressed fiberglass or springs between surfaces.

The isolation of a surface receiving impact, such as a floor or

39
ceiling, from the structure, will restrict the transmission of

sound

.

4.6.3 Sound Absorption

The surface treatment of a space is the single most important

determinant of its acoustical properties. Sound is absorbed by

using porous materials to dissipate or absorb acoustical energy,

e.g. fiberglass, cloth. The sound absorption coefficient is a measure of the sound absorbed by a surface; hard materials such

as concrete and steel have low values, while carpeting has a relatively high value (the scale ranges from 0 to 1.0).

Materials used to absorb sound have a low mass, and therefore are

not effective in preventing sound transmission to adjoining

spaces

.

4.6.4 Vibration Damping

This is used to prevent a material or object from resonating to a primary source, thereby acting as a secondary noise source, e.g.

an air conditioning unit mounted in a window frame. Windows,

walls, and machine components are potential problem areas.

Rubber or vinyl is typically laminated to the surface of the

noise producing element to avoid this problem.

4.6.5 Isolation of Noise Source

An effective means of controlling unwanted sound is to isolate

and/or "sound treat" the source of noise. For example,

duplicating and printing equipment should be located remote from

activities requiring quiet. The room should be acoustically

treated if noise-sensitive activities are nearby.

4.6.6 Masking Sound- Background noise is frequently used in

open-space designs as a means of securing speech privacy. This

"white noise" is generally introduced by means of ceiling

speakers. This approach is not recommended because unwanted

sound (noise) is not an optimum design solution.

4.6.7 Ceiling Treatment- Those which reflect sound are apt to

be the major acoustical problem in an open office. If a high

percentage of the ceiling is devoted to light fixtures, major

reflection problems are encountered. Ideally, a flat ceiling in

properly designed spaces should absorb from 90 to 95 percent of

the sound reaching it.

4.6.8 Distance- Individuals and working groups should be

clustered (or separated) based on their needs for quiet, and

their requirement to interact with one another.

4.6.9 Configuration- Panels and screens can be used to cut off

horizontal paths of sound, while providing a degree of acoustic

and visual privacy to individuals and/or working groups.

40
4.6.10 Floors- Carpeting provides an efficient means of

eliminating impact sounds on floors caused by people, equipment

and furniture movement. They also have very desirable sound

absorption properties.

4.7 ACOUSTICAL DESIGN PROCESS

A system has been developed which employs a computer program for

the acoustical design of open-plan offices; it is called OPLAN.

It is intended to provide an estimate of speech privacy for a given workstation. The program takes into account all paths by

which sound travels from one location to another. Data are

collected on the following: "anticipated speech effort,

source/receiver distance, screen locations and dimensions,

materials, background noise levels, and the degree of privacy

required." Figure 9 summarizes the approach developed.

41
Figure 9. Simplified block diagram of OPLAN program (24)

42
4.8 CHECKLIST ACOUSTICAL DESIGN (23)

NOISE CONTROL

1. The outer shell of the building should provide adequate

protection from outdoor noise sources; control of

fenestration is particularly important.

2. HVAC and plumbing equipment should be selected, installed

and operated to minimize noise; ancillary equipment should

not be noisy.

3. Automated equipment should be as quiet as feasible;

vibration isolation from floor and furnishings should be

considered

.

4. Sound absorption properties of ceilings, floors, and

panels are a major design concern.

ACOUSTICAL PRIVACY

1. Spaces for confidential meetings should be available in

open offices.

2. Adequate separation is required between workstations to

ensure proper acoustical comfort.

3. Partitions should be selected and placed in accordance

with noise reduction needs.

4. Flanking paths should be avoided between private spaces

and the general workfloor; special attention should be given

to lowered ceilings, raised floors, and utility chases.

5. Consider using natural sound from HVAC to substitute for

masking noise.

VIBRATION CONTROL

1. Plumbing, HVAC and other mechanical equipment should be

vibration isolated.

2. Noisy automation equipment should be vibration isolated.

3. Raised floors should be designed with high vibration

damping features.

4. Emergency power generators should be located, installed

and used to avoid vibration and noise problems.

43
SPACE DESIGN

1. Individuals and working groups should be clustered in

accordance with acoustical requirements, e.g. privacy,

freedom from noise intrusions.

2. Noise producing equipment should be grouped and separated

from general office activities when feasible.

3. Panels and screens should be used to intercept horizontal

sound paths.

4. Ceilings with a high percentage of light fixture area can

result in noise reflection problems.

44
5. LIGHTING SYSTEMS

5.1 FUNCTIONS

The primary purpose of lighting is to facilitate the performance

of visual office tasks. It provides directional and locational

information and is an integral component of security and safety

systems. Lighting can create an environment with variety, visual

interest and pleasing contrasts, offsetting the institutional

appearance of offices.

Effective lighting requires a consideration of the entire

environment. A balance of contrasts is needed to prevent visual

discomfort and fatigue. The light generated by the VDT, the task

area adjacent to the screen, the keyboard area and the surround

lighting are also important. Visual problems can occur when the

eye must continually adjust to markedly different lighting

characteristics, and a variety of contrasts associated with an

activity such as reading paper copy while monitoring a VDT

screen.

The quality and quantity of light are critical features in

automated office design. Proper lighting also depends upon the

activities performed, the people doing the work, and

organizational requirements. It must take into account

traditional building elements such as ceiling heights, wall and

floor materials and treatments, room area, adjacent spaces,

columns and various equipment and systems. The integration of

lighting with other systems, and flexibility are of special

importance in the automated office. Since lighting systems are a major energy user, this feature merits detailed attention.

Uniform lighting levels for the most visually demanding task are

no longer an acceptable approach to lighting design.

5.2. BACKGROUND

Since most office tasks are predominantly visual, it is not

surprising that lighting conditions are prominently mentioned in

surveys of office workers (25). The use of VDT's in offices has

increased the importance of lighting because most lighting

systems are designed for desktop paper-based activities, with

different visual requirements than those required by VDT tasks.

For the foreseeable future most workstations will have to

accommodate a combination of both types of activities. Individual

control of lighting is an important factor as is the mix of task

and ambient lighting.

Office environments are generally designed under the assumption

that the worker will perform tasks requiring the line-of-sight to

be depressed approximately 20-40 degrees from the horizontal.

The design of many VDT's requires line-of-site to be at or near

horizontal. This elevation brings the operator's fixation point

closer to ceiling luminaires, resulting in a greater possibility

of discomfort glare. Exposure to large luminance differences

45
between the VDT screen and some other part of the visual

surround, such as a window or luminaire, increases the

possibility of discomfort glare. Glare reflected from surfaces

of the VDT and ceiling reflections reduce the visibility of the

display by reducing the physical contrast between the characters

and the screen background.

5.3. CRITERIA

* Lighting should reinforce the architectural intent of the

building, e.g. provide a connection with the outside and

between spaces; create a sense of intimacy and the

delineation of activity spaces.

* The quality and quantity of lighting should support the

visual needs of those performing VDT and/or paper-based

tasks

.

* Levels should be consistent with the tasks performed

* Lighting should not produce glare.

* Extreme brightness contrasts should be avoided.

* Individual control of task and area lighting should be

available

.

* Systems should provide flexibility appropriate for

organizational needs, including expansion.

* Systems should not be wasteful of energy.

* Systems should be properly integrated with other building

systems - e.g. ceiling, wiring, automation, safety.

* Lighting should provide proper margins for safety and

security activities.

* Systems should be designed for ready maintenance.

* Daylight should be appropriately integrated into the

overall lighting system design.

* Two lighting level systems should be considered for

flexibility

.

46
Table 12. Lighting Recommendations- Illuminating Engineering

Society (IES) (26)

Type of Activity Illuminance

Ranges of Illuminances Reference

Work-Plane

Category

Lux Footcandles

Public spaces with

dark surroundings A 20-30-50 2-3-5

Simple orientation for

short temporary visits

B 50-75-100 5-7.5-10

General

lighting

throughout

spaces

Working space where

visual tasks are only

occasionally performed

C 100-150-200 10-15-20

Performance of visual

tasks of high contrast

or large size

D 200-300-500 20-30-50

Performance of visual

tasks of medium

contrast or small size

E 500-750-1000 50-75-100 Illuminance

on task

Performance of visual

tasks of low contrast

or small size

F 1000-1500-2000 100-150-200

Performance of visual

tasks of low contrast

and very small size over

a prolonged period

G 2000-3000-5000 200-300-500

Illuminance

on task.

Performance of very

prolonged and exacting

visual tasks

H 5000-7500-10000 500-750-1000

obtained by

a combination

of general

and local

Performance of very

special visual tasks of extremely low contrast

and small size

I 10000-15000-20000 1000-1500-2000

(supplementary

lighting)

47
5.4 OVERVIEW OF BASIC ISSUES

Office lighting is achieved by a combination of natural and

artificial lighting. Daylight is a varied, changing source of

color and intensity, influenced by atmospheric conditions such as

cloud cover and pollution, the position of the sun, time of day,

reflection of building materials, trees and grass.

The characteristics of the surrounding environment must also be

carefully controlled to ensure the visual comfort of VDT

operators. Walls and other surfaces should have reflectance

values of less than 50 percent to accomplish this . All desk and

work surfaces should be comprised of matte, or low glare nonreflective surfaces, and medium tone colors. They should not be

black or white, or exhibit sharp color contrasts or reflective

surfaces, to minimize visual irritation. VDT's should be

positioned so they are not parallel to each other. This avoids

the possibility of light from screens reflecting on one other. A

test to ensure that the major problems have been eliminated is to

move a mirror across the front surface of the VDT screen. This

will reveal bright sources of light.

5.4.1 Artificial Light Sources

The most common sources are incandescent lamps, gaseous

discharge lamps such as fluorescent, and high intensity discharge

(HID) lamps.

5. 4. 1.1 Incandescent Lamps

Light is produced when a wire of tungsten filament is heated to

intense brightness by the flow of electric current. Although all

spectrum colors are present, the light tends to be strong in the

red, orange and yellow wavelengths. Colors in the "warm"

spectral range are therefore strengthened when illuminated by

incandescent sources, while "cool" colors such as blue and green

are weakened. The efficiency of these lamps is low - i.e. the

amount of light produced by a given amount of energy. Efficiency

is directly related to filament temperature and, for incandescent

lamps, the most efficient ones have the shortest lives. Figure

10 below depicts several types of lamps.

Figure 10 is an illustration of the common types of lamps in use

for lighting offices.

48
A- General service lamp, G- Decorative lamp, S- Decorative lamp, PAR- Lamp used

for directional purposes, e.g. downlight, used with reflective or baffled

fixtures in recessed, surface or track lighting. R- A type of PAR downlight with a wide beam spread. T- A tungsten-halogen lamp, designed for long life

and high intensity output \ used for general lighting in medium—to—high ceiling

areas.

* 400-wan DXownor-coMM nwrcury lamp Lane. 01 o«w mm an conumcmi amiariy

T UN CONTAINS UK CAS CKCTtODf COHD WUh

and NflCWtT VAKHi IHCT>ON-e*ll4S»Vj MATCtlAl

FlUOCISCtNT PMOSmOtS TttU TwM

Cutaway view of fluores- cent lamp* showing typical elec- trodes (a) hot-cathode (filamentary)

rapid-starling or preheat-starling (b) hot-cathode (Mamentary) instant- atartmg. (c) cold-cathode (cylindri- cal) instant-starting

Figure 10. Common Types of Lamps

49
5. 4. 1.2 Fluorescent Lamps

Fluorescent lighting occurs when a phospher powder lining along

the inner tube wall of the lamp, fluoresces or glows. The powder

is activated by ultraviolet radiation emitted from low pressure

mercury vapor in the tube. They are higher in efficiency than

incandescent lamps and produce less heat. Furthermore they last

from 20 to 25 times longer than incandescents , and therefore

require less maintenance. Lamp performance can be overestimated

if measured immediately after installation, because they produce

more light during the first 100 hours of operation than in long

time use. The lamps should therefore be "seasoned" for this

length of time before occupancy. This procedure also identifies

faulty ballasts and lamps because when defective, early problems

are likely. The color rendition properties of fluorescent lamps

depend upon the particular coatings and gases used in design.

5. 4. 1.3 High Intensity Discharge (HID) Lamps

They produce light through the gaseous discharge or vaporization

of atoms of metallic elements contained in arc tubes.

Vaporization causes the atoms to emit large amounts of

electromagnetic energy within the visible range. An arc of

electricity generates heat and pressure much higher than in the

ordinary fluorescent lamp. Mercury, sodium and metal halide

lamps are characterized by wide light distribution, wattage

efficiency and low energy consumption and maintenance costs.

Among the shortcomings of HID lamps are the following:

(1) High light reduction over the life of the lamp (up to

50 percent)

(2) A limited number of colors are available

(3) There are sometimes problems with color stability and

the standardization of particular colors.

50
Table 13 Lamp Selection Guide (28)

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51
5.4.2 Ballasts

A ballast is used to limit the flow of current through

fluorescent and HID lamps. Without it, current increases to a level which will quickly destroy the lamp. The ballast provides

a voltage that is sufficiently height to start and maintain the

arc discharge in the lamps. Special ballasts are now available

which conserve energy and permit the dimming of the lamps.

Ballast hum can be a side effect of HID and fluorescent lamps,

especially as they age.

5.4.3 Fixtures

Incandescent housings are sometimes movable (table, pole, track

or floor lamp), or fixed (recessed, surface-mounted, ceiling

hung) . The quality and distribution of light depend on the type

of bulb used, the diameter of the fixture aperture, the interior

shape and surface finish of the fixture, the distance of the lamp

from the aperture, and the distance of the fixture from the

surface to be illuminated. Interior fixture surfaces are often

coated with a color and/or a special finish to produce given

lighting effects.

Offices today are predominantly lighted by fluorescent lighting

systems. Housings for these systems are ceiling recessed,

surface-mounted, or pendant ceiling-hung. The quantity of light

produced is primarily dependent on the number and wattage of

lamps used in each fixture. The quality of lighting is

influenced by the lens and/or louver system employed to

distribute the light. A major determinant of lighting quality is

the "glare producing" potential of a given system.

5.4.4. Lighting Fixture Rating Schemes

5. 4. 4.1 Visual Comfort Probability (VCP)

This is a rating of the likelihood that people using a given

system would not be bothered by direct glare from a given fixture

design. For example, a VCP of 70 means that 70% of those workers

seated in the worst location in a given space would not be

bothered by direct glare from a lighting system composed of the

type of fixture whose VCP is under evaluation.

5. 4. 4. 2 Coefficient of Utilization (CU)

It is a measure of the efficiency of a fixture in a specified

space, i.e. the percentage of the light produced by a lamp which

ultimately reaches the work area. For example, a fixture with a rating of .50 delivers 50 percent of the lamp's output to the

work plane.

52
The VCP and CU of any given fixture depend upon such factors as

room configuration, reflectivity of surfaces, distance from the

floor, and the spacing between fixtures.

5.5. POSSIBLE PROBLEM AREAS

* Lighting systems at workstations must accommodate VDT and

paper-based tasks

* The line-of-sight of the VDT screen is near the

horizontal, resulting in a greater likelihood of glare from

a fixture in direct view.

* Reflected glare can occur from reflections on the surface

of the VDT, from windows, fixtures, people, and other VDT's.

* Extreme visual contrasts in the visual field, created

from VDT, the workspace, general surrounds, windows, etc

cause visual discomfort.

* The placement of fixtures may be inappropriate for the

tasks being performed - e.g. shadows, glare.

* Indirect HID lighting can produce "hot spots" on the

ceiling; they also might cause surface finish problems..

* Color rendition of HID sources can result in aesthetic

problems, especially when materials and furnishings are not

carefully selected with regard to color characteristics.

* Color stability and uniformity are sometimes a problem

with HID sources.

* Highly reflective materials can be sources of reflected

glare

.

* Black and white "colors" can contribute to undesirable

visual contrasts in the work setting.

* Dirt and dust on fixtures and lamps can substantially

reduce light output; scheduled maintenance is important.

* Fluorescent task lamps can emit electronic noise,

affecting devices nearby.

5.6 TYPICAL APPROACHES USED IN LIGHTING DESIGN

5.6.1 Types of Illumination

Three general approaches are available for office lightinggeneral (ambient), direct, and indirect. Ambient lighting refers

to a uniform pattern of lighting throughout a space. This

approach is being replaced in many offices by task/ambient

systems which are at a relatively low level for movement and

circulation purposes (i.e. less demanding visual tasks), and

direct lighting on the task to be performed. Direct lighting has

the advantage of efficiently using the available light to

accomplish a given purpose, but glare and veiling reflections

must be avoided. Indirect lighting uses wall and/or ceiling

surfaces to reflect light into the workspace, e.g. for ambient

lighting, architectural definition.

53
5. 6. 1.1 Ambient (General) Lighting

An ambient system provides uniform illumination across the entire

space, at the level required to support the most visually

demanding visual task to be performed in the office. The

location of particular tasks do not have to be specified because

the assumption is that if the lighting level is appropriate for

the most demanding task, then it will be sufficient for less

difficult ones. The connected power requirements are a function

of the overall lighting level and the size of the area served.

Ambient lighting can be provided by direct (usually part of the

building system) or indirect means.

Ceiling fluorescent systems are usually employed for ambient

lighting. The first consideration is to avoid lamp reflection on

the face of the VDT . This can be accomplished by using a specular parabolic wedge louver; it has a typical cutoff of 45

degrees, with images from the lamp reflected below the viewing

angle

.

5. 6. 1.2 Task Lighting

Lighting is directed to a specific surface or area to provide

illumination for visual tasks. Typically, light sources are

placed on top of a desk, hung from a panel, placed above a work

surface, or under an overhead bookcase.

5. 6. 1.3 Task/Ambient Lighting

In task/ambient systems, task lighting is treated separately from

the general surround (ambient) , which is usually at a lower

level. Task location must be known in advance to ensure the

adequate space planning density , and the particular needs of

workstations which house different tasks. Power use is variable

because lighting is typically controlled by the user. The

overall space will appear non-uniform because of the lack of a standardized lighting scheme. Task lighting systems can be

furniture mounted, free standing, or depend on suspended

luminaires. The major requirement is to meet the needs of

individual users with diverse performance, habits, and visual

abilities .

5. 6. 1.4 Indirect Lighting

Another method employed to illuminate VDT work is indirect

lighting, the source is mounted below the ceiling, suspended from

the ceiling, or placed in a kiosk. In all instances, the light

must be directed toward the ceiling, which acts as a reflector.

Rays are directed laterally, resulting in shadow-free lighting

with the light source hidden from view, and eliminated as a possible irritant.

54
General Lighting | Indirect Lighting

in mii ,

,

i a . , mmmmmmmmmmmmmmmmmmmmmmmmrn •iiiiiuiiiiuiihiiiiiiiiiiuiiiiiiiiiiiiiiiiiiihiiihIIIIIUIIIIIUIIIIIIIIIIIIIIIIIIIIIIIIIIIIIHIIIUIIIIIIIIIIIIII

Figure 11. Types of Illumination

Checklist for Evaluating Task/Ambient Systems

1. Lighting should be evenly distributed.

2. Veiling reflections should be minimized.

3. A proper brightness relationship between task and

surround is essential. (No more that 3:1 in the immediate

seeing zone, no more than 10:1 in the total zone.

4. Luminaires should be glare free and the light source not

visible

.

5. Ballast noise should be minimized by using properly

mounted, high quality ballasts.

6. Ballast and housing should not radiate excessive heat.

7. Fixtures should be easy to clean and maintain.

Replacement of lamps and ballasts should be an easy task.

8. Fixtures should be properly mounted to prevent

vibration

.

9. Upward light distribution should minimize shadows, while

avoiding "hot spots"

.

10. Downlights should light the rear of the workstation

uniformly

.

55
5.6.2 Controls

Lighting controls provide the operator with the means to adjust

the lighting to suit the activity to be performed. They also

serve an important energy-saving function. Local lighting

controls can activate a small number of fixtures which permit the

lights to be readily turned off when not needed. Dimmers also

provide the opportunity to adjust the lighting conditions as

visual requirements change.

A variety of automated control systems are available; they

frequently are dependent on a combination of manual and automated

features. For example, time switches are employed in areas not

often used. In some configurations, lighting is activated

manually and automatically deactivated after a given time, unless

manual intervention occurs. Some centralized lighting controls

send signals to fixtures over existing circuitry; others use

radio frequencies or require new wiring.

Controls are available which work on the principles of motion

detection (ultrasonics) , body heat (passive infra-red) , noise in

the human activity range (acoustics) , or the interruption of

beams transmitted and detected (active infra-red) . Carbon

dioxide is also used as an occupant sensor. ( Some of these

systems are also used for building security purposes.)

Window lighting should be controlled by curtains and blinds which

also filter and direct sunlight at reasonable cost. Vertical

blinds can be turned and pivoted to redirect sunlight. A fabric

finish is preferable because it diffuses the light, reducing

glare. Mylar and plastic filters and screens can be positioned

in front of windows like sunshades.

5.6.3 Maintenance

Lamps should be replaced before failure because light output

declines with use. Replacing lamps early therefore maintains a greater average light output of the entire system. Relamping

before failure also lengthens ballast life. Group relamping is

best accomplished by changing all lamps at the same time. When

personnel, equipment, and lamps are assembled simultaneously, a lamp change is made in a few minutes. In contrast, single lamp

replacement can take as long as 30 minutes. A further savings is

realized if fixtures are cleaned during scheduled relamping. A

periodic cleaning schedule for fixtures and lamps is a requirement, if designed lighting levels are to be maintained

over the lifetime of the building. Dust and dirt accumulations

can severely limit the efficiency of lighting systems (30)

.

5.7 ENVIRONMENTAL CONTEXT

When a person is operating a VDT, he or she looks not only at the

work materials, but peripherally at the work surface, distant

56
furniture and walls, windows and the general office area. Sharp

contrasts in color and reflective surfaces should be avoided

because they may result in visual distractions and/or difficulty

in performing required tasks.

Brightnesses within the office space should be controlled. Walls

and other surfaces should be diffuse and have a light reflectance

value of less than 50%. Carpeting colors should be muted rather

than saturated in color. Desks and work surfaces should be

matte, or low-glare non-ref lective . The tops of tables and desks

should be made of non-specularly reflective material. Neutral

color tones are preferred for all furnishings.

5.7.1 Checklist for Glare Control (31)

Direct and reflected glare can be limited by means of one or more

of the following methods:

* Drapes, shades, and/or blinds over windows should be

closed or directionally adjusted, especially during sunlight

conditions

.

* Terminals should be properly positioned with respect to

windows and lighting fixtures, e.g. screens facing away from

bright sources.

* Direct lighting fixtures may need to be recessed; baffles

or special covers are used to direct light sources downward.

* Indirect lighting fixtures should have appropriate

lens/louver systems to minimize glare potential.

* Avoid specular surfaces on furnishings and equipment.

57
6. ENVIRONMENTAL CONDITIONING SYSTEMS

6.1 FUNCTION

HVAC systems provide for thermal comfort and well-being of office

occupants and help maintain the proper environment for support

systems operation by regulating (32)

:

* air temperature

* the temperature of surrounding surfaces

* relative humidity and air motion

* air quality- e.g. freedom from unwanted odors and

particulate matter

6.2 CRITERIA (33)

* Air temperatures and humidity must accommodate equipment

and people.

* Flexible air supply and return systems should be designed

to facilitate change and/or expansion.

* Humidity control must accommodate the needs of people and

equipment

.

* Thermal comfort conditions should follow ASHRAE

recommendat ions . (See Figure 12.)

* Energy usage is of major importance.

* Control systems should enable area zoning to accommodate

equipment and activities.

* Static electricity should be minimized.

* Air distribution system should permit change in workstation

locations, maintaining thermal comfort and indoor air quality.

6.3 OFFICE AUTOMATION DESIGN IMPLICATIONS

Automated office have more electronic devices and systems than

traditional ones. This technology produces considerable heat which

substantially increases building cooling loads, resulting in

equipment outages and occupant complaints. Many devices are

humidity sensitive; proper control is essential for the equipment

operation and to minimize the detrimental effects of static

electricity on workers and electrical equipment. A combination of

tight building designs to save energy, and using chemicals in

office activities, such as ink for duplicating machines, cleaning

chemicals, and particle board, degrades office air quality.

58
Figure 12. Thermal Comfort Recommendations ASHRAE) (34)

59
6.4 TYPICAL APPROACHES

Meeting environmental requirements in offices is not easy.

Conditions in a space served by a central system may vary markedly,

depending on the distribution of people and electronic equipment.

The conventional system of ceiling air distribution consists of a main trunk and a grid of either flexible or rigid auxiliary feeder

ducts. Adequate clearance is needed between the ceiling and

structure above the ductwork and access to mechanical equipment in

the plenum space. Supply and return air grills in the ceilings must

conform to the module of the ceiling system. Newer and proposed

systems employ supply and return air through the floor and some

deliver air through workstation units with localized control. See

following figure.

Figure 13 Conventional ceiling air distribution

6.4.1 Existing Buildings

For spaces with clusters of computer equipment, modular ceiling

mounted HVAC units can be used to supplement the central system.

Localized controls should be available for this equipment so that

they can be turned off when not used. Heat-recovery systems from

clustered workspaces are applicable in high heat load areas.

Packaged air conditioning and humidity control systems can

supplement central building systems.

6.4.2 New Construction

* Variable air volume systems are used to maintain desired

temperature levels by controlling air volume instead of supply

air temperature, for energy savings. If air movement is

insufficient, fan-power is added. (However, some problems have

occurred with regard to air motion and ventilation in occupied

spaces with these systems.)

* Thermostats must be carefully positioned in open spaces; out

of the path of the return air supply, and at a height

representative of office activities. Separate units are needed

in each zone.

* Floor plenums should be considered for HVAC/elect r ical

distribution

.

60
* Zoning, using individual HVAC systems, can be used to

service core areas subjected to concentrated heat loads. They

require year round cooling even in northern climates.

* Portions of the building might be occupied on a 24 hour per

day basis and merit separate treatment.

* Computer rooms should have localized air conditioning units,

which often require backup power supply.

*Ceiling-mounted air cooled systems operating independently of

central systems are available. However, installation cost and

difficulty in moving them are shortcomings.

6.5 INTERACTION WITH OTHER SYSTEMS

6.5.1 Lighting

Heat removal and air handling lighting fixtures extract heat before

it enters the air conditioning system, thereby reducing the overall

heating load. Furniture-integrated lighting systems emit heat

directly into the air. Lighting and HVAC system design must be

integrated to optimize lighting efficacy and useful heat

generation; e.g. systems which recover and/or remove heat from

lighting and other devices, thereby saving energy.

6.5.2 Acoustics

Air distribution systems can be designed to produce relatively

uniform sound, thereby eliminating the need for the introduction of

white noise into office spaces as an aid to privacy. Inconsistency

in acoustic quality results from variable air volume and other

systems which repeatedly switch from on to off.

6.6 ENVIRONMENTAL CONTEXT

6.6.1 Design Process Issues

Better planning and coordination is needed for implementing office

automation systems. Improved coordination is required among the

user, the A/E, and the consultants involved in designing the office

systems

.

Among the issues that require detailed architectural programming

attention are:

* Means of achieving proper air distribution with provision

for future changes at minimum cost.

* Determining tradeoffs among automation, energy conservation,

and thermal comfort requirements at each design stage.

* Responding to a strategic automation plan by the building

user

.

* Integrating HVAC effectively with other building systems.

* Providing control systems responsive to specific needs of

equipment and people, e.g. older workers often require warmer

temperatures than younger ones; requirements differ with the

physical demands of tasks.

61
6.6.2 Interior Design

* Window coverings, wall fabrics, floor coverings and

adjustment of air flow patterns all influence the thermal

comfort of a space. The proper placement and adjustment of

diffusers and radiators also contribute to environmental

satisfaction

.

* Window exposures affects the thermal environment in

significant ways. For example, in the winter months, southern

exposure can contribute to the heat needed.

* Functions that require similar environmental conditions can

be grouped together, focusing mechanical demands

appropriately.

6.6.3 Potential Problem Area - Static Electricity (35)

Electrostatic discharge is often a major problem in automated

offices. Static electricity occurs in two ways, induction charging

and contact charging. In induction charging, electrical fields

radiate from the surfaces of materials such as styrofoam and cloth.

For example, an electrostatic discharge from a shirt sleeve can

generate power to destroy the read only memory (ROM) of a computer.

In contact charging, two materials make contact with one another

and then separate. This action causes one material to strip

electrons from the other. This occurs when one walks across a carpet and is shocked when touching a doorknob. The size of a charge depends on the speed, degree of friction, and

characteristics of materials into contacting one an other. The

higher the electron density of the material, the greater its

charge. While voltages of 3,000 are sometimes sufficient to

disturb computer circuits, it is not until voltages are in the

10,000 to 15,000 range that people become aware of unpleasant or

painful sensations. Table 14 summarizes some effects of static

electricity

.

6. 6. 3.1 Common Sources of Static Electricity

* Waxed, painted or varnished surfaces

* Vinyl tile flooring

* Polystyrene (Styrofoam)

* Finished wood or plastic covered desks, chairs

* Electrostatic copiers

* Insufficient humidification

62
TABLE 14. Static Electricity Issues

ACTIVITY VOLTAGE

10-20% RH 65-90% RH

Walking on carpet

Walking on vinyl floor

Picking up polyethelene bag

Sliding on foam padded chair

35.000

12.000

20,000

18,000

1,500

250

1,200

1,500

ENDANGERED COMPONENTS

Precision voltage regulator circuits

Transistor logic devices

Silicon power transistors

Small signal diodes

1 - 1,000

1.000-

4,000

4.000-

15,000

4,000-15,000

6. 6. 3. 2 Possible Approaches to Overcome Problem

* Power Grounding

* Humidity control. Humidity in the 40 - 60 percent range

is recommended by manufacturers of office automation

equipment

.

* Carpeting materials should be selected for low static

electricity properties.

* Chairs and movable furnishings should have metal, conducting

rubber or plastic wheels.

* Conductive anti-static floor mats can be used to bleed

static charges to ground, through a wire. The mat must be

free of dirt and wax; operators must wear conductive footwear.

* Anti-static agents can be sprayed directly on carpet or

tile. This increases the rate at which air ions recombine

with surface charges by maintaining a thin moisture layer over

the area applied.

* An ionizer can be used; it emits both positive and negative

electrons which combine with opposite charges on the surfaces

of non-conductive materials such as cloth and plastics.

6.7 AIR QUALITY

6.7.1 Background

Air quality traditionally refers to outdoor air, and is related to

levels of specific pollutants designated by the Environmental

Protection Agency (EPA) as acceptable for good health. No formal

guidelines govern the quality of indoor air. Another difficulty is

that air quality is not limited to health issues; odors and

humidity levels are important, especially indoors.

For many pollutants, indoor concentrations are four to ten times

more than outdoor ones. In computer rooms, printout paper has a high concentration of dust. Microscopic particles are in the air

and when humidity is low, the particles often cause itching.

63
Pollutants include gases given off from combustion processes,

airborne particles resulting from activities such as smoking, and

gaseous emissions from materials.

Energy conservation has led to buildings designed to reduce air

leakage through cracks and around doors, windows, and other

openings. Potential air pathways are blocked and/or minimized by

caulking and weather stripping. Added insulation reduces

temperature loss through the structure by adding thermal resistance

to walls, ceilings and floors. (36)

As buildings are designed for energy efficiency, they are less

forgiving environmentally. The capacities of mechanical equipment

more closely match the thermal loads imposed on the system, and are

less capable of responding to changes not contemplated in original

designs. Energy efficient buildings have unopenable windows,

keeping contaminants generated within, inside the building. Most

buildings recirculate up to 90% of conditioned air, and up to 50%

of heating air. This situation causes a gradual buildup of

pollutants because of lack of fresh air to dilute them.

Summary of causes of reduced air quality in buildings: ( 37)

* Sealed building envelopes

* Reduced ventilation rates, mechanical and natural.

* Dependence on mechanical HVAC systems

* Introduction of unstable synthetic materials, maintenance

products, and finishes that off-gas toxic contaminants and

respirable particles, or leave dust residues.

* Dependence on fluorescent and other gas vapor lighting

that emit non-iodizing radiation

* Photocopiers and VDT's emit radiation and airborne

contaminants and may require special environments for safe

use

.

* Methods of identifying and measuring concentrations of

pollutants have improved.

To alleviate these problems, improved air distribution, humidity

and temperature control is required, together with source, dilution

and removal control of contaminants.

6.7.2 Air Contaminants

Air contaminants can be characterized as particulates (solids or

liquids) and gases. Some are merely annoying, others are

potentially harmful. (38)

Particulates are described in terms of mass concentrations,

expressed as micrograms per cubic meter. These include all particle

sizes or total suspended concentration. Large particles are more

of an annoyance than a health hazard since they lodge in nasal

passages. Respirable suspended particulates (ranging up to 3 micrometers in size) are important for health, because they can

lodge in the lung. Among the major sources of contamination are:

64
* Radon- a radioactive gas which decays into solid alpha

emitters which can attach to dust particles and surfaces

.

Sealing of foundations, ventilation of basement areas and an

increased outdoor air supply lower levels can alleviate this

problem.

* Formaldehyde- from tobacco smoke, insulation, resins in

paneling, furniture, cloth, carpets and adhesives.

* Carbon Monoxide- from tobacco smoke, furnaces

* Particles- from asbestos, fiberglass, fire retardents

* Radon Particles- from ground, cement, bricks

* Organic Chemicals- from copiers and paints

* Nitrogen Oxides- from heaters

* Micro-organisms- from people, plants; incubated in

furnishings, ducts, cooling towers

* Allergens- from dust, insects

* Carbon Dioxide- from human breathing, combustion .( 39)

6.7.3 Tight Building Syndrome

Tight building syndrome refers to epidemic complaints of illness or

discomfort including headache, burning eyes, irritation of the

respiratory system, drowsiness and fatigue. The symptoms are

generally experienced for an extended time and occur in sealed

buildings. The cause is difficult to determine, but often suspected

to be related to building components or the air supply system. (40)

In 1979, a survey of 1100 office workers from 9 buildings in New

York City was undertaken. The purpose was to investigate "tight

building syndrome" complaints. Among the major complaints were:

* Too little air movement (75%)

* Unpleasant odors (54%)

* Temperature too hot or too cold (70%)

* Air too dry (65%)

* Air too stuffy (77%)

Among the health related symptoms noted were:

* Headaches (37%)

* Fatigue (51%)

* Sleepiness (59%)

* Nasal Irritation (31%)

* Eye Irritation (34%)

A consistent association was found for all relevant symptoms with

the ability to control ventilation. A potential problem is also the

production of photo-chemical smog. All the necessary conditions

exist in offices to produce this smog- ultraviolet radiation from

photocopiers and fluorescent lamps, formaldehyde (off-gassing from

particle board, insulation), hydrocarbon vapors (off-gassing from

paints, plastics), chemicals from solvents, cleaners, copiers.

Nine features common to building problems were identified:

1. A sealed building envelope. Insufficient fresh air drawn

into building to conserve energy.

65
2. HVAC systems disperse irritants throughout buildings.

3. Location of vents and exhausts can introduce outdoor

contaminants into building. Poor placement of supply and

exhaust vents can prevent exhaust from escaping, or

reintroduce exhaust air into air supply.

4. Location of ventilation diffusers. Inlets and outlets are

often in ceiling, sometimes short circuiting supply air,

resulting in pockets of dead air and poor circulation.

5. Lack of individual control of environment contributes to

stressful conditions.

6. Use of new furniture materials and cleaning agents.

7. Fluorescent lamps may provide energy for photochemical

reactions among pollutants, creating indoor smog.

8. Parking garages, restaurants within office developments may

add substantial amounts of combustion products to air.

9. Reduction of fresh air supply; lowered velocity of

ventilation, which also reduces effectiveness of filters.

6.7.4 Control Measures for Indoor Air Pollutants; Responsibilities

(41)

Concrol Measure Description Pollutant Example

Ventilation: dilution of Indoor air

with fre6h outdoor air or recirculated

filtered air, using mechanical or natural methods to promote localized,

zonal, or general ventilation

Radon and radon progeny;

combustion by-products; tobacco

smoke; biological agents

(particles)

Local exhaust of gas stove emissions; air-to- air heat exchangers; building ventilation

codes

Source removal or substitution: removal

of Indoor emission sources of substitution of less hazardous materials or products

Organic substances; asbestlform

minerals; tobacco smoke

Restrictions on smoking in public places; removal of asbestos

Some modification: reduction of emission rates through changes in design or processes; containment of emissions by barriers or sealants

Radon and radon progeny; organic substances; asbestlform

minerals; combustion by-products

Plastic barriers to reduce radon lavals;

containment of asbestos; design of buildings

without basements to avoid radon; catalytic

oxidation of CO to CO 2 in karoesna burners

Air cleaning: purification of indoor

air by gas adsorbers, air filters,

and electrostatic precipitators

Particulate matter; combustion

by-products; biological agents

(particles)

Residential air cleaners to control tobacco

smoke or wood smoke; ultraviolet irradiation

to decontaminate ventilation air; formaldehyde sorbent filters

Behavioral adjustments: reduction in human exposure through modification of behavior patterns; facilitated by consumer education, product labeling,

building design, warning devices, and legal liability

Organic substances; combustion

by-products; tobacco smoke

Smoke-free zones; architectural design of interior space; certification of formaldehyde concentrations for boms products

66
6.7.5 Responsibilities for Healthful Indoor Environments (41)

INDIVIDUALS

* Maintain and properly use products and appliances.

* Exercise direct control of ventilation

* Restrict smoking in common areas

* Report incidents of degraded air quality

* Do not unnecessarily introduce contaminants in workplace

BUILDING OWNERS OR MANAGERS

* Operate and maintain a balanced ventilation system in

compliance with codes.

* Use zone ventilation or local exhaust for indoor

contaminant sources.

* Properly use cleaning solvents, paints, varnishes,

herbicides, furnishings and insulation.

* Train staff in the limited use of potential contaminants,

and their application in proper concentrations.

* Limit smoking where feasible.

ARCHITECTS, DEVELOPERS, CONTRACTORS

* Identify protection of indoor air quality as a design

objective

.

* Design ventilation systems to comply with ASHRAE standard

62-1981.

* Provide for separation of occupants from indoor pollutant

sources

.

* Specify materials and systems that minimize pollution

risks, e.g. copiers.

* Provide containment systems for unavoidable pollutants.

* Provide exhaust fans for specialized "dirty" areas.

67
7. ELECTRICAL POWER SYSTEMS

7.1 FUNCTION

Provide an electrical environment for the safe, reliable

operation of office automation equipment and other electrical

systems. This is the most critical system for office automation.

The value of the information to be protected is a major factor in

determining power protection needs. The other key elements are

the dependability of the power source and the susceptibility of

equipment to power changes.

The electrical environment for computers includes their power

sources, grounding and electrical interfaces with communications

lines, air conditioning, and life-safety systems. It also

includes lighting and other electrically operated equipment. The

electrical environment in which office equipment operates must

also be considered, since electrical disturbances propagate

through conductors, pipes, metal ducts and conductive structural

members, or by radiation as radio waves. External sources of

electrical fluctuations range from lighting to electrical loads

generating electrical noise when operated or switched on and off.

Internal sources of electrical changes can be caused by the

office automation equipment itself. (42)

If absolute protection is needed, an on-line UPS is probably

needed. This system regulates and conditions power fluctuations

in addition to maintaining power during temporary outages. For

organizations concerned with power outages, a standby UPS might

be sufficient. This system costs from one-third to one-half of

an on-line system. Standard switching times - the interval from

the time that power fails until the UPS is initiated- are in the

2-8 millisecond range? within the 10-15 millisecond buffer

storage of most microcomputers . (43)

Other power protection options include a variety of line

conditioners and monitors. These provide varying degrees of

protection in regulating electrical noise, surges, transients,

and sags. Line monitors measure the current on electrical lines,

permitting users to determine the effect of fluctuations on

computer performance. Some monitors also keep track of

temperature and humidity levels, which can cause operational

errors and even failures.

7.1.2 Background

The quality of electrical power varies considerably from place to

place. The power received at an unprotected workstation is

likely to be susceptible to fluctuations which can result in

problems ranging from lost data, to disabling a microcomputer.

Consistency of power also depends upon location. For example, a company located in a multi-tenant office building is likely to be

affected by other electrical usage in the building; e.g. motors

cause fluctuations.

68
Equipment characteristics determine susceptibility to power

fluctuations. Mainframe computers are engineered to be tolerant

of power changes, while microprocessors do not contain similar

safeguards; they would add too much cost to the system. They are

available as add-ons.

No equipment is immune to electrical disturbances but sensitivity

to such changes varies from device to device and from one type of

disturbance to another. Disturbances of high energy content can

result in catastrophic failure of impairment of circuit

components. Smaller disruptions may not damage components but

may disturb logic signals and cause intermittent errors in data

or control functions. Significant improvements in logic design

and circuit integration ironically has made office systems more

susceptible to disruption by electronic noise. These circuits

need less power than their predecessors, and the quality of

commercial power hasn't kept pace with these requirements. The

faster response times of newer, high performance logic circuits

makes them susceptible to fast noise pulses which have always

existed, but failed to disturb the older, slower logic circuits.

This implies that electrical environments suitable for older

generation office machines may need improvement to accommodate

newer systems. Power and electrical system requirements should

be carefully reviewed prior to installing new systems. Separated

clean power outlets are often needed for computer equipment.

7.2 CRITERIA

* Power sources should be relatively free of major

fluctuations

.

* The means to reduce or eliminate sources of electrical

disturbances is needed.

* Circuits should reduce the coupling of electrical noise

and transients from all sources into low power level

circuits

.

* The office equipment purchased should not be readily

disturbed by power abnormalities.

* Software and operating procedures should readily detect,

correct and recover from errors and power outages.

* Spare capacity is needed in electrical bus risers to

handle future needs, e.g. to main and distribution panels.

*Power panels are required for station-to-station

distribution

.

* Use power distribution modules for isolation.

* Segregate power usage ("clean" vs. "dirty" power), e.g.

coffee maker should not be on same circuit as an office

device

.

* Consider using uninterruptable power systems for

critical operations.

* Properly ground equipment for safety and operational

purposes, e.g. lightning protection.

* Equipment rooms should be large enough to provide

equipment with proper clearances and have proper HVAC.

69
7.3 POSSIBLE PROBLEM AREAS

Problems originate in all parts of the power subsystem: (44)

* Primary Energy Source - public utility

* Converter to Electric Power - from steam power to rotary

mechanical energy of the generator - to electrical power

* Distribution System- wiring

* AC-DC Converter - convert from delivered power to DC,

needed by computers

* DC Distribution System -

* AC Distribution System - needed to run motors, relays,

lamps, etc. These components are tolerant of dirty power,

but in the network there are many generators of noise and

disruption and constantly varying loads, separated from the

power company's delivered power. All can be disruptive to

digital systems.

Power line pollution can be divided into three basic categories:

overvoltage, undervoltage, and noise. Devices and systems are

available to deal with each of these problems. The most severe

problems in the electrical environment of an office are caused by

overvoltage, which typically occurs in short bursts as surges or

spikes. (45)

A power surge is an increase of voltage levels from 10 to 20

percent (or more) above normal, usually lasting from one half

cycle to several seconds. A surge can be induced by static

discharges, lightning, or inductive switching produced by

starting or stopping a major electrical motor on another circuit,

e.g. an elevator or air conditioner motor. A third, less

frequent cause is power restoration after an outage. Surges

generally do not affect the performance of traditional motor

driven machines, but computers and microprocessors have critical

threshold operating voltages, and power fluctuations can

seriously impair their performance.

Spikes, which are sudden but brief disturbances reaching

thousands of volts with frequencies reaching to the megaherz

level, are also a danger to the operations of electronic office

equipment

.

Lightning does its damage directly and indirectly. A direct

"hit" is possible, but very unlikely. However, when a bolt of

lighting contacts a transmission line, or even comes close to the

line (thereby inducing large voltages) , the effect can be

devastating to a computer.

In the case of man-made activities, spikes in the range of

thousands of volts are commonly caused by a variety of

circumstances; for example, when a large motor or transformer is

switched off, or when utility companies reroute feed lines to

adjust for changing consumer demand.

70
Undervoltage occurs when the voltage drops below 120, the nominal

value used for most equipment. They can range from sags of a few

volts, to complete outages. Most microprocessors are designed to

handle voltage dips of 15 to 20%; however greater amounts can

result in the loss of data.

Electrical noise is probably the most universal a.c. line

problem. It is broadly defined as high voltage, high frequency

interference. There are two types- common mode, interference

between a line and ground and transverse mode, interference

across lines. The most common noise source is electromagnetic

interference (EMI), often referred to as radio interference.

Other common causes of interference are electrical motors and

power lines that act as antennas for signals, and electronic

ballasts in fluorescent lamp fixtures.

7.4 POSSIBLE SOLUTIONS (36)

7.4.1 Suppressing Overvoltage Transients (46)

Several methods are available to suppress overvoltage transients:

1. Dedicated power lines are used primarily for computer

installations. The power is obtained from an inverter fed by an

uninterrupted power source (UPS) . This is an expensive method

and therefore limited to critical instruments and controls that

must be maintained on-line during power outages.

2. Isolation transformers installed between the ac power line and

the equipment serviced are helpful for some voltage transients,

but are not effective against high frequencies; secondary

windings in the transformers can compound the problem. The

addition of regulators, separating the primary and secondary

windings of the transformer can overcome this difficulty.

3. Surge suppressors- The only way to guard against the effects

of spikes and surges is to prevent them from from reaching

sensitive equipment. This is accomplished by surge suppressors,

which limit them to a size which protects data and devices. They

employ sophisticated semiconductor devices to detect, limit, and

dissipate spikes very rapidly. The best location for the surge

suppression device is at the power input of the equipment being

protected

.

4. Voltage Regulators - supplies constant voltage to equipment;

sometimes called constant voltage transformers or voltage

conditioning equipment. Voltage regulators protect against

"brownouts", and increased voltage levels. They control the power

supplied to equipment, keeping the level within the required

operating range. However, when there is a power failure, standby

power supplies and UPS are needed to ensure that data are not

lost

.

71
5. Power Distribution Equipment - Multiple plugs to distribute

power to PC and peripherals. Can utilize features for short

circuit prevention and circuit switching.

6. Monitors provide accurate diagnosis of power line quality by

detecting and identifying all common a.c. line disturbances.

Some can record ambient room temperatures also. In the simplest

models, indicators light up and sound an audible alarm. More

advanced models provide printouts of interruptions; summary

reports of what went wrong, when, etc. They can be positioned

upstream, nearer the power source, to document the status of

incoming power; or downstream, from the power conditioner to

record the power characteristics reaching computers or other

devices . (47)

7. Power line filters are used to eliminate the undesired

signals. They are designed to block out all frequencies except

the desired 60 Hz of the power line. These filters do not

eliminate surges and spikes.

8. Electromagnetic Interference (EMI) SuppressionElect romagnectic interference may be conducted along power lines

or radiated through space. Power line EMI filters at the

equipment input, and proper grounding of lamp ballasts and metal

lamp fixtures will reduce both forms of EMI.

7.4.2 Emergency Standby Power

The UPS and standby power supply are designed to overcome the

problems of power outages. Their goal is to provide required

power to ensure against loss of data and interruption of normal

operations of electronic equipment. Both devices get the energy

needed for generating AC from the same source- batteries. Before

the computer can make use of battery power, direct current of low

voltage, it must be converted to AC and then increased to

standard line voltage using a transformer. The device that makes

this conversion is an inverter, which converts DC battery power

into AC.

Standby power is normally off and does not start manually or

automatically until the public utility power fails. The power is

provided by a bank of batteries and/or diesel generators, which

can be started within ten to thirty seconds, if their rapid

starting condition has been maintained. However, this length of

interruption would shut down electronic office equipment not

served by an uninter ruptable power system. Power surges should

be controlled when this source is activated.

Standby and UPS are limited by the capacity of the inverter

(maximum power available) and the battery capacity (duration of

backup available) . A few minutes of backup is usually sufficient

to take actions to save the data by placing it in a permanent

storage medium, e.g. a disk. (48)

72
Speed is a critical factor in backup systems; they must act

almost instantaneously if data are not to be lost. A standby

power supply combines battery power and an inverter with a fast

switch. The UPS uses a large battery charger with an inverter

inside it. It is connected to the microprocessor and constantly

draws power from batteries, thereby being isolated from the power

line and the problems associated with "dirty" power.

The batteries supplying the inverter can only supply a limited

amount of power, and standby backup consists of rechargeable

batteries and a recharger, which keeps the batteries fully

charged. The standby system is activated by a switch when the

main power fails. The power outage must first be sensed, and then

the switch activated. These operations, while fast, take some

time, and can cause problems with ongoing activities.

73
Table 15. Basic Cause, Effect and Treatment of Power Line

Disturbances

Condition %

rfOMOHIXj Causes Effect Daatment

Line voltages too high

or low 11-12% Neighboring increases in demand, loading down

supply.

Improper equipment

operation. Possible damage if sustained. Overheating.

Constant Voltage

Regulator (CVR)

Severe power drops or outages of short duration (20 mllleseconds

(thousandths] to a few

seconds)

3-1% Electrical storms, power

equipment fault. Addition

of heavy equipment to

load.

Total disruption of computer operations.

Danube to equip- ment when power Is restored abruptly.

Uninterruptible Power Sources. Reserve supply

equipment,

Inverters Motor

Generators. Power surges and sags

of short durations (typi- cally a few milliseconds

or a single power cycle)

40-47% Abruptly adding or removing loads to the power line by users. Faulty or arcing

switches.

False computer output, misregistration

of logic circuits, possible hardware damage

Surge suppression

devices or isolation transformers optionally with surge sup- pression devices High voltage impulses

of extremely short duration (a few microseconds

to a short nanosecond)

30-40% Inductive load switching, contact arcs, start/stop

equipment operation,

static discharge, electri- cal storms.

Premature component failure misregistration of logic

circuitry, equipment

down time

Surge suppression devices

High frequency RFI /EMI N/A

%

Other computers, radio and communication

devices, small motors,

and commutators.

Little effect on

digital equipment.

Low pass filters
7.4.3 Uninterruptable Power Systems (UPS)

The UPS is continuously connected to the electrical system

through its inverter, always supplying power independent of the

AC electrical line. Battery power is constantly maintained by a charger. All power is twice transformed; from AC to DC and back

again to AC, a wasteful procedure in terms of energy. The

advantage of such a system is that power dips and surges never

reach equipment, because the UPS system is between commercial AC

power and the equipment at all times.

UPS have become a virtual necessity for powering electronic

systems where the application serves a critical need, e.g. a life

safety system. These systems, unlike the emergency standby power

systems, are always in operation (except for planned maintenance,

or outages) . UPS systems are typically supplied with sufficient

battery capacity to carry a data processing load for periods

ranging from five minutes or less, to several hours. The success

of a UPS system depends on its ability to permit operations to

continue without interruption; requiring power switching to be

performed in less than one half cycle without substantial

transient noise during the switching.

The most important feature of the UPS is its capacity, in voltamperes (VA) , which must be sufficient to run all of the

equipment that the UPS or backup power is connected to. Another

key to selecting equipment is how long the system can run. The

object of backup systems is not to function indefinitely, but

provide sufficient time for an orderly shutdown when necessary,

preserving all data, closing active files, etc. This can usually

be accomplished within 5-10 minutes. Other important

characteristics are the time required for recharging, and the

waveform shape; sinusoidal is the best for most equipment.

75
Table 16. UPS GUIDE TO INSTALLATION, MAINTENANCE (49)

INSTALLATION

* Have wiring, protection systems and disconnects been

specified by the supplier?

* Has proper cabling been specified to prevent excessive

voltage drop between UPS and critical load; UPS and battery

supply?

* Is the building power adequate?

* Are the computers adequately grounded?

* Is the load protection coordinated with UPS protective

devices?

* Is bypass power fed from a separate circuit breaker?

* Is air handling equipment adequate for UPS heat load and

temperature limits?

* Who will install the equipment; should the supplier

supervise?

* How will equipment be tested; is a formal procedure

available?

MAINTENANCE

* Is there a monitoring system for UPS status?

* Is there a plan for responding to a UPS alarm?

* Is special test equipment needed; is it available?

* Are spare parts needed?

* Does the supplier offer preventative maintenance?

* Does the supplier offer training programs?

7.5 Battery Features: (50)

The older wet cell batteries are typically mounted in open-frame,

two to three tier racks. They are shipped wet and charged for

full-capacity startup. Conventional lead-calcium, wet batteries

offer high reliability and require little maintenance and are

easy to install. They do generate hydrogen when charged so

ventilation is important.

Lead-antimony batteries or lead-acid stationary batteries are

functionally equivalent to the lead-calcium type, but they have

only half the life span, require more maintenance and monthly

charging to maintain cell capacity.

Nickel cadmium batteries are the most expensive, are compact and

light and have excellent temperature maintenance features; they

perform well at both high and low temperature extremes. They also

require monthly recharging and if maintained properly will last

as long as lead-calcium batteries.

76
7.6 Checklist to Minimize Electrical Disturbances (42)

* Use separate feeders and branch circuits for office

automation systems so that no sudden common voltage drop

will be created by non computer equipment sharing the same

circuits ("clean" power)

.

* Large motors which drive air conditioning compressors,

regularly started and stopped should not be powered from the

same feeders or isolating transformers which supply the OA

power

.

* The operation of OA equipment from high impedance power

sources such as diesel or gas turbine driven engines can

result in large transient voltage variations; low internal

impedance and/or larger kVA sizes can minimize this risk.

* Avoid apparatus with regulators susceptible to overheating

or to oscillatory interaction with loads containing their

own regulators.

* The input power to equipment should be filtered to ensure

proper performance.

77
Table

17.

Comparison

of

Power

Protection

Systems

(10)

CO2

CO o wQ 25 M M Pi > H ft) o 25 3 CO Pi O O <u Pm CJ CM

COw >h o 0c5 Ph M W 23 > H w o CJ CO Pi <c < 0) Pm pp CP >H w w

CO CO

CO PiH

EH

w o T3 T3 2 > 2 CD 0) w CO U 4J > £2 w •H H w 2 Q a a CO CO Pi PC o •H •H <u CD CM H 2 2 2 >H >H W

CO 2

eh 1 T) 2 2 CD WOW U > 2 CO •H W § w to CO CO a CO CO 2 o O a) CD CD •H 0) CD CM O 2 >H >H >H 2 >i >H

CO

cj<

CO

CO CO H W M o s Pi H 2 2 CO

CD CO CO CD CD CD >H >H >*

COHM

CO CO

Pm 2 w 2 CO CO CO CO CO

CO H

CD CD B X) 2 2 CD CD CD CD 0) O O

CJ

H >-l >-l >H >H CO 2

COw

EH

W < cj 2 < 2 H

cj 2 CO CO CO W O CD 0) ID 2 > >H f>H fH

Pi

W o 2 CJ

Pi CO

O < w CO M H pi Pi EH w EH 2 w 3 2 w < 04 oi O 05 H 5 w pH 2 Ed CJ w > M 2 o w Pm O Z 2 CJ s Ph Pi Ph 2 CO 2 2 2 Eh 2 2 O w CO w o O § z o O H >1

w > 1 Pi 2 <2

O < PP

w

CJ

w

W < CO Eh CJH CO

O 2 a cj

H CO

O 2 z CJ CO z Pi 2 2 Pi > CO Pi H 2 W Ph 2 CJ CJ <2 2 w <d 2 2 2 2 < O 2 M W Eh O o Ph CO 2 H W Eh CJ H 2 2 CO CO

78

UPS

Yes

Yes

Yes

Yes

Yes

Yes

Yes
7.7 ENVIRONMENTAL CONTEXT

7.7.1 Specialized Space Needs

UPS systems and barriers should be in protected utility areas.

Batteries represent potential danger from shock hazards, acid

spills, flash heat and sparks from high-energy short circuits, or

even explosions. They should be installed in dedicated battery

rooms with controlled access, with temperature maintained between

70 and 80 degrees F, to ensure long life and capacity. The UPS

hardware should be placed close to the batteries to avoid

unnecessary loss in the dc bus and excessive electrical noise or

possible shock hazards. Typically, the UPS is placed in a basement utility room or utility corridor area where the

equipment can be properly ventilated and kept at the appropriate

temperatures. The space should be secured and locked to prevent

unauthorized entry. Appropriate warning signs should be

strategically located. A shower is needed if batteries are of

the lead-acid type. Finally, rooms should be shielded from

potential sources of electromagnetic and/or radio interference.

Telecommunications and PBX rooms might have to be secured because

of the sensitivity or criticality of information. Keylock,

security card or manned systems can all accomplish this purpose.

79
8. WIRING SYSTEMS

8.1 FUNCTION

Wiring systems provide power and communications services wherever

needed to facilitate organizational performance in offices. To

provide flexibility to cope with changing requirements.

8.2 BACKGROUND

Wiring systems in offices have remained the same for years, but

within the past decade this situation has profoundly changed.

Manufacturers now offer new systems, designed to provide

flexibility in delivering power and communications to work areas

and running wires to, and in switching lighting fixtures. They

also provide for greater capacities and security for

communications wiring. The central role of individual

workstations in automated offices has accelerated improvements

ranging in complexity and sophistication from "intelligent

buildings" to flat conductor cable. The impetus for these changes

stem from:

1) the growth of the open-plan;

2) the advent of the electronic office;

3) energy conservation;

4) labor savings in running wiring and connecting it to lights

and outlets.

Providing power and communication services anywhere requires a wire conductor within a conduit (sheath, raceway, plane under

carpet squares, raised floors, etc.) connected to a terminal

within the room and/or above the ceiling. Flexibility varies

among systems - and initial costs vary accordingly. Under carpet

cable can go anywhere. Wiring below access floors is possible

anywhere there is an "electrified" panel. With cellular flooring

and underfloor ducts, flexibility is governed by the spacing of

electrical cells, but can be enhanced by the addition of under

carpet systems.

The wiring approach taken depends on the likelihood and frequency

of change in workstation location and/or configuration. For

example the number and spacing of service fittings in an

electrical grid configuration can dictate the degree of

flexibility available (assuming no flat-conductor cable system)

.

Every underfloor system shares the requirement to penetrate the

actual floor surface, but the particular method used can be as

simple as a lid, or as complex as a hole drilled through a concrete slab.

80
In wiring several factors must be kept in mind:

* Flexibility. Examining needs for 5 to 10 years in the

future. LANs, voice/data communications and PBXs all have

special needs to be considered. Twisted pair technology is

employed typically for PBX switches; if high speed data

transmission is contemplated, proper insulating media is

needed to accommodate this function. Many LANs today use

twisted pair and coaxial cable; the latter serves as a main

trunk. Other uses for coaxial cable are for broadband and

baseband systems for interconnections to mainframe computers

and high density communications networks.

* Transmission clarity. All wires differ in performance,

depending on the materials used in construction and their

capability in transmitting clear signals. Three problems

encountered with wiring are capacitance, attenuation, and

crosstalk

.

* High capacitance is a particular problem; it refers to the

wire's dielectric slowing of the signal resulting in loss of

data or the distortion of information.

* Attenuation. This is a reduction in the amplitude of a transmitted signal and can result loss of data or the

introduction of system errors.

* Crosstalk. This refers to the crossing of information

from one circuit to another. (52)

* Media choices for present use and flexibility for future

changes and/or installation are critical.

* The gauge of the wire and the permissible number of twists

permissible per foot are important features.

* A wire survey of existing installed wire should be made,

and updated when changes are made.

* Information concerning conduit sizing and space

availability for current and future needs are required.

* Wire sheathing requirements for current and future needs

should be specified.

81
Great flexibility is needed for general purpose office buildings

where tenant activities often exhibit high workstation density

and medium-to-heavy communications needs with frequent tenant

changes and rearrangement of offices. (53)

In planning for network growth, there are three primary factors

to be considered:

* Expanded network utilization by the original users.

* Extension of the network to new users.

* Physical plant or campus modifications.

8.2.1 SOME PROBLEM AREAS

A major problem for the designer of the intelligent building is

the wire distribution system; especially for open space planning

which eliminates the walls that have traditionally housed wiring.

The movement of advanced technologies into offices is

evolutionary

.

Installing and operating many different types of cable is to be

avoided. It is not unusual for almost 50% of terminals and

telephones in place to be moved within one year. Proper planning

of wiring space must accommodate long and short term

communications needs. The cost of wiring in existing buildings

goes up with the height of the ceiling. A popular approach is

prewiring; installing cables and raceways (cable conduit) during

construction. This reduces installation costs and permits

careful labeling and recording of cable runs and circuits, making

changes easier.

A critical decision is selecting the types of cables and wires

linking advanced data processing and telecommunications systems.

The quality and dependability of these systems will determine the

performance capabilities of other systems. Proper selection of

wires and insulation materials can overcome most problems. For

example, teflon fluorocarbon resin has superior dielectric

properties and desirable thermal and chemical features. It can

transmit information over long distances without distortion very

quickly. It also has lower installation costs because it can be

installed without conduit, since it has low smoke and flame

spread characteristics.

82
8.3 CRITERIA

8.3.1 GENERAL

* Capacity. Sufficient physical space to accommodate

cabling, connectors, and advanced equipment such as LAN's.

* Convenience. Flexibility and ease of initial workstation

installation and future changes.

* Cosmetics. The appearance at distribution and delivery

points, and special treatment required.

* Credibility. Code acceptance, single system

responsibility, reputation of manufacturer.

* Cost. Complete distribution and delivery cost; first cost

to building shell, move-in; and ongoing costs. (54)

8.3.2 SPECIFIC

* Optimized flexibility is needed to accommodate future

changes; tradeoffs must be made between frequency of

changes, initial and long-term costs.

* Wiring and communications systems should be integrated

when feasible, e.g. information and energy management;

proper shielding is also required.

* Systems should be aesthetically acceptable.

* Wiring changes should not disrupt ongoing activities.

* Dedicated circuits should be used to maintain critical

operations such as security, safety, and highly critical

information services.

* When laying cable, future needs for communications and

office automation systems must be considered.

* Complete wiring diagrams and records are needed, updated

to reflect all changes automatically by CAD system if

possible

.

* Cabling should be identified everywhere it enters or exits

a room.

8.4 TYPICAL APPROACHES

The building architect traditionally addresses structural and

architectural matters having direct impact on in-building

communications networks. Horizontal signal distribution on the

building floor is largely dictated by the floor structure.

The architect and developer want to minimize space for

communication because it is not revenue producing. Minimal space

is provided for telephone closets and communications equipment;

tenant space is used instead. The basic office structure is

expected to have a lifetime of 50 years, but technological and

organizational changes occur about every 5-7 years. Network

changes are costly in terms of dollars and disrupt iveness .( 51)

83
Providing power and communications requires a wire or fiber

conductor within a conduit (e.g. sheath, raceway, raised floor)

connected to a terminal within a room and/or above the ceiling.

The flexibility provided varies from system to system, as do the

initial and long term costs. However, power and communications

signal lines require sufficient separation to prevent

interference, e.g. magnetic coupling.

Open office systems has led to the popularity of underfloor

systems for electrical distribution and communication. The

replacement of permanent walls with partitions and dividers and

the movement of desks from exterior walls have decreased the use

of walls for power distribution purposes.

The work support system exists under the floor in one of five

different horizontal planes. It can run along the underside of

the slab (as in a poke-through system) , within the body of the

slab (in a concrete underfloor system), just under the top

surface of the slab (fill and finish) , or above the structural

slab and below the walking surface (raised or access floor)

.

Underfloor systems require the penetration of the floor surface.

The penetration can be as simple as raising a hatch lid, or

require drilling through the concrete slab. The location and

appearance of the service fitting are important design

considerations, as is the appearance of the floor after

relocation. Some designs treat service fittings as a necessary

functional element to be clearly exposed and detailed, while

others attempt to conceal them.

Equipment types, densities, and locations are frequently changed

in a building's lifetime; power and communications systems must

be designed to move and adapt. The options for distributing

power, lighting, electronics and communications services consist

of five basic approaches, often used in combination:

1. Poke-Through System.

2. Electrical Cellular Deck.

3. Underfloor Duct System.

4. Conduit in slab.

5. Raised Access Floor.

6. Ceiling-Based Systems/Power Poles.

7. Flat Conductor Cable.

84
8.4.1 Poke-Through System

This system does not require any underfloor raceway. When a hole

is drilled, a sleeve is forced into place and the service

fittings is then installed from above. A fire-rated fitting is

inserted into the hole, connecting either conduit or flexible

plug-in wiring to it from the ceiling below. The conduit runs

from its connection to the slab service fittings, to the

currently spaced junction box. A sleeve may be preset during

construction or after. The initial investment is low and outlets

can be readily moved and the hole plugged. Too many holes can

weaken the structure however.

Figure 14. Poke-Through System

85
8.4.2 Electrical Cellular Deck

The cellular deck is based on a corrugated steel deck containing

electrified cells, with reinforced concrete on top. Cells run

the entire length of the floor and provide services at

predetermined locations through a short vertical outlet to flushmounted floor outlets. They share many of the features of the

underfloor system; high first cost, flexibility and ultimate

limitations for placement of outlets based on grid size - 6 or 8

ft intervals.

It consists of closely-spaced cellular raceways that connect at

regular intervals to a main and header duct. A matrix of preset

service fittings is spaced just below the surface floor in a trench. Service is obtained by punching a hole through a thin

panel and bringing the appropriate cables through the opening.

Physically, the wiring must penetrate the floor, and with carpet

tiles, the carpet might have to be cut out or peeled back.

Cellular decks, like ducted systems, have trench headers that

feed cables to parallel chases in the slab. The cellular deck

contains the power, data and telephone cables within the enclosed

cells of the floor deck itself. They also have a much greater

capacity than ducts, which have outlets spaced about every 5

feet

.

The system provides great flexibility with a minimal change in

required floor depth to accommodate the system. Service fittings

are sometimes flush with the floor, but frequently they project

through the floor, causing an unsightly appearance and a potential tripping hazard. (See Figure 15.)

Raceway for Electrical Wiring

Figure 15. Cellular Floor System
8.4.3 Underfloor Duct System

Underfloor ducts have been used in buildings since the 1930s;

they usually contain raceways for power and space for telephone

cabling. The system consists of metal ducts, between five to

eight feet on centers, buried in the floor slab and connected by

means of a vertical trench header duct, to electrical risers.

The top of the trench header is flush with the finish floor and

has electrical plates for wire access. The ducts are divided to

separate power, data and communications channels. The ducts are

non-structural , standing on top of the structural deck. Most

ducts are now made of metal. The system has preset access points

which allow minimal floor slab disruption, thus eliminating the

need for fire safety precautions.

An underfloor raceway can run within the structural depth of the

floor or be placed on the completed floor slab. Once the main

trench duct has been placed, the branch ducts can be spaced at

virtually any interval. Preset fittings poke up from the duct

desired. Perhaps because of this inherent freedom, and the

success of this approach that underfloor duct systems have been

so little altered over the years. (See Figure 16.)

Figure 16. Underfloor Duct System

8.4.4 Conduit in slab.

Conduit is run from a power closet to a workstation. The conduit

is suspended from hangars attached to concrete form, then is bent

and brought up above the finished floor level. The floor is then

poured and the wire pulled through the conduit. The system has

little flexibility; outlet locations must be known in advance.

The design usually consists of a crisscrossing of raceways

installed in a reinforced concrete floor. Junction boxes are

needed at every grid intersection. Access is through risers in

the duct to access boxes in the floor.

87
8.4.5 Raised Access Floor

Total access flooring is a system of interconnecting floor panels

raised sufficiently above the structural slab to allow

installation of electrical, mechanical, and air distribution

systems. Access is possible anywhere on the floor by means of

modular cabling systems. It is more expensive to install than

other systems and requires considerable space. This approach is

frequently used for the design of major computer facilities.

Cabling may have to be plenum-rated if the underfloor area is a plenum.

This approach was originally taken to accommodate the special

requirements of major computer facilities. Since many types of

spaces require the use of conventional floors (bathrooms and

washrooms) , ramps, steps, or sunken floors have to be

accommodated in some locations.

An access floor system has three major components: the panels,

which form the working surface; the understructure supporting the

floor panels from underneath; and the floor covering.

Selecting the proper support system is critically important. Two

basic types exist. The rigid grid, snap-on, and stringerless

systems are all kept in place by gravity. These systems are

appropriate for computer floors but not for offices.

Bolted panels, secured to the pedestal and bolted to one another

at the panel edge are appropriate in offices. They approximate

the sound and feel of customary floors. A good structural

connection between panel edges allows adjacent panels to share

dynamic and rolling loads.

Three major types of panels are available. A woodcore panel

consists of a one inch plywood or particle board core sandwiched

between steel sheets. A potential problem is water absorption by

the core, and it is not used in offices. The most commonly used

panel is made of fabricated steel. This panel has a flat steel

top sheet and a formed structural bottom sheet in a welded

construction. A modification of this system features a steel

panel with the interior cavity filled with a cementitious

material; not concrete, because it contains no aggregate. This

approach improves the acoustical characteristics of the floor.

The third type of panel consists of a concrete mixture; it is

susceptible to impact loads and failure if overloaded.

The last part of the system is the floor covering. Carpeting can

be laminated to the panel or tiles can be placed over the floor

after installation. A good grade of commercial carpet will

absorb the impact sound of foot traffic.

88
Mockups of systems are an effective method of evaluating

subjective features such as the "sound" and "feel" of the floor.

These tests are best conducted with side by side comparisons of

the systems being considered; it is difficult to make such

comparative judgments in any other way. (55) (See Figure 17.)

Figure 17. Raised Access Floor

8.4.6 Ceiling-Based Systems/Power Poles

These systems are an alternative to underfloor systems. Power

poles are used as a direct means of distribution by vertical

poles or flexible hoses located at workstations.

For the past 20 years, ceiling systems have been popular; they

are inexpensive to install and easy to access. They are often

used in conjunction with other systems to add more capacity; e.g.

computer cables. The poles are metal columns which deliver wiring

and cabling from a ceiling plenum to the floor, usually through

enclosed ducts; outlets for power, data and communication are

within the pole. Relocation of outlets requires unplugging and

moving poles. They offer security to data lines since they run

within the offices' ceiling plenums. They can be used together

with partitions in open planning. A raceway at the bottom of a panel can bring lines to several workstations. The wiring

capacity of raceways in panels and that of poles, is limited.

(See Figure 18.)

89
Figure 18. Power Pole

8.4.7 Flat Conductor Cable

This is a rather new approach receiving considerable attention

today. It offers an option for wiring design in buildings where

underfloor ducting cannot be used and conduit combined with

exposed ceilings is not desired. Flat cable delivers power and

communications services to floor pedestals (power outlets) that

serve electric appliances and telephones. Good coaxial flat

conductor cables are often difficult to find. (Pedestals should

not be placed until workstations are assembled and last minute

adjustments made.) Cables can be mounted directly on the floor

(with a protective metal shield) under existing carpet tiles.

Locational changes and/or new systems are installed by raising

carpet tiles in the desired path, and redirecting existing flat

cable runs or by tapping into a run. Connections between flat

and round cables are made at transition boxes, usually located in

walls or columns. A major consideration in the use of flat cable

systems is to ensure that they are shielded against puncture or

other contact. (56).

The following are benefits of these systems:

(1) Short installation time.

(2) Simplified specification of branch circuit wiring

(e.g., no drilling).

(3) Maintained structural integrity of the floor system.

(4) Elimination of slab height increase needed with floor

ducts

.

8. 4. 7.1 Flat Conductor Cable Checklist

* Expect to see cable-caused ridges in the carpet tile

initially; the problem is often a temporary one.

* The cable cover should not be reused; it will be distorted

when pulled up, causing an uneven carpet tile.

* Consider keeping excess material for replacement purposes.

* Plan beyond the pedestal itself.

90
* Determine the kinds of wire management needed between the

pedestal and the using appliance.

* Determine the number of outlets needed for each

workstation

.

* Close coordination is required among the following

systems: electrical, communications, floor (carpet tiles),

and workstations.

* Use undercarpet telephone cable where appropriate.

* Breaks in the wire are difficult to locate.

* Turning radius may be a problem.

8.4.8 Workstation Distribution

This consists of pre-wired interconnecting panels, which

eliminate the need for individual wiring. Many furniture systems

have power in raceways, but power must be clustered at some point

from floor, wall or column; planning of clusters for future

expansion is important.

91
8.5 TRADEOFFS AMONG ALTERNATIVE WIRING SYSTEMS

SYSTEM

POKE THROUGH

ELECTRICAL

CELLULAR DECK

UNDERFLOOR

DUCT

POSITIVE FEATURES

* Low first cost

* No raceway

* Delayed installation

until rental

* Cables readily

accessed

* Minimal visual

intrusion

* Relatively flexible

* Changes are easy

* Minimal visual

impact

* Integration of cells

reduces costs, labor

* Large cable capacity

and great flexibility

* Preset outlets easily

relocated

* Simplified wiring

organization

* Accessible

* Fire safe

* Minimum visual impact

* Preset outlets easily

relocated

* Can be used with

flat wire

* Simplified wire

organization

* Cables protected

from damage; secure

NEGATIVE FEATURES

* Expensive to change

* Disrupts activities

* Fire safety concerns

* Outlet relocation

disrupts floor below

* Possible data

security problem

* Limits on outlet

spacing; total

outlets

* Need to maintain

fire and structural

integrity

* Expensive

* Service fittings may

protrude; hazards

* Added fire

protection needed

under activated

cells

* Lengthy cable

runs if flat cable

not used

* Expensive

* Planning flexibility is

difficult

* Less capacity than

cellular deck

* Sheetmetal work

required

* Nonstructural

ducts need added

slab in concrete

buildings

* Wide duct spacing

* Long cable runs if

flat wire not used

92
TRADEOFFS AMONG ALTERNATIVE WIRING SYSTEMS (Continued)

SYSTEM

RAISED ACCESS

FLOOR

CEILING-BASED

SYSTEMS

FLAT CONDUCTOR

CABLE

POSITIVE FEATURES

* System integration

facilitated

* Flexible

* Almost unlimited

cable capacity and

routing

* Outlets easily

relocated

* HVAC systems

accommodated

* Easy to integrate

with furniture systems

* Flexible

* Short installation

time

* Floor integrity kept

* Used under carpets

* Readily moved

* No limits to spacing

or routine cables

* Outlets quickly

relocated

* Installation can be

delayed to rental

NEGATIVE FEATURES

* Installation expensive

* Changes sometimes

disruptive

* Some spaces need

conventional floors

* May require teflon

treatment- air plenum

* High initial cost

* Some systems can't

accommodate heavy

loads

* Some systems have

hollow sound when

walked on

* High first cost

* Planning critical

* Aesthetics

* Cable must be protected

* Careful installation

needed to avoid ridges

* Expensive

* Turning radius needed

* Carpet tiles

required

* Floor slab must be

smooth

* Overlapping cables

can create carpet

lumps

* Damage from heavy

loads

* Cable length

limited to 50 feet

* Not allowed in

some places

93
8.6 ADDITIONAL DESIGN CONSIDERATIONS

8.6.1 Retrofits

Providing adequate methods for concealing and running cables from

mainframe computers to peripheral equipment is often difficult in

existing facilities. Standard solutions include running cables up

inside walls and over ceilings, flat conductor cable systems,

power poles, or raised flooring systems.

8.6.2 Upgrading of Cabling Systems

Substituting new technologies for old ones depends on the ability

to remove obsolete systems because of limited capacity of

horizontal and riser space. Cable runs should be visible and

accessible over their entire run, and must meet fire safety

requirements .

8.7. ENVIRONMENTAL CONTEXT

* Hung ceilings with greater than average depth below the

structural member, for coaxial cable, fiber optics, and

future air conditioning ductwork. This can sometimes result

in aesthetic problems because of incorrectly repositioned

ceiling tiles or tiles chipped from repeated access for

maintenance and/or changes.

* Floor to ceiling utility chases can be placed on a regular

module. It is readily accessible, but reduces flexibility

and limits room dimension and total space arrangement

options available.

* Movable walls, floors and/or ceilings are available, with

vertical and horizontal chases to accommodate future wiring

needs

.

* Plug-in cables can be used to connect above ceiling

runways to power poles; these systems have been used

traditionally for installing lighting fixtures. For

enclosed offices, the plug-in cables can be nested in

floor/ceiling assemblies.

* Underfloor soft wiring systems with plug-in boxes and

harnesses of various lengths can be used to connect with

pre-slotted outlets in raised floors.

8.8 CHECKLIST WIRING SYSTEM DESIGN

* With cellular flooring and underfloor ducts, system

flexibility is governed by the spacing of electrical cells,

but can be augmented by undercarpet systems.

* Maintenance areas must be designed with sufficient space

for distribution boxes and panels for changes and planned

expansion

.

* Expansion space is needed in the building core to install

additional bus risers for communications and power.

94
* Extra sleeves are required for future power and

communication cables.

* Additional riser space might be needed on each floor for

office automation systems and networking, including

mainframe and minicomputer linkages.

* Ceiling heights of rooms must accommodate raised floors

and/or ceiling plenums must be deep enough to accommodate

present and future needs.

* Sufficient capacity is needed for feed conduit, vertical

risers, telephone closets, and conduit to individual

tenants

.

* Specific needs of building users should be considered,

such as industry specified requirements for medical groups,

stockbrokers

.

* Plenum space requires plenum rated cable approved by local

fire regulation agency.

* Electrical needs for telephone/wiring closets.

95
9. COMMUNICATION SYSTEMS

9.1 FUNCTION

Communications systems provide the means to transmit voice,

image, and data information within an office or campus, and to

outside services or mainframe computers.

9.2 BACKGROUND

Several types of communications and/or computer applications

occur in offices. Soon, all workstations will likely have a terminal and at least one telephone. The computer may be

serviced by dedicated hard-wired connections to desktop

terminals, or by the same wires serving the telephone, possibly

in a local area network. Other possible workstation services are

electronic and/or voice mail, electronic filing, and facsimile

transmission. The telecommunication system can have a major

impact on the services for office workers. It will also have

important implications for the design of buildings and systems,

e.g. cable distribution, wiring closets, riser systems, main

telephone room and service entrance. There is also a need to

plan for future expansion of these services. The percent probable

expansion in five year increments should be estimated. A useful

strategy in planning such systems is to identify the known

requirements and those which are not yet specified, and provide

for the flexibility and/or adaptability to make changes in the

future

.

9.3 CRITERIA

9.3.1 GENERAL

* Ubiquity. Access must be comparable to a telephone

system, and terminal hardware should be inexpensive.

* Simplicity. Sending a message should be as simple as

typing a letter or using a telephone.

* Flexibility. The system should be capable of transmitting

texts of any length in any format, and be able to send

graphic information.

* Reliability. It must be available for use virtually all of

the time.

* Privacy and Authentication. Messages should be protected

from inspection by unauthorized people. Positive

identification of the sender to the recipient should be

available. Most systems employ passwords for this purpose.

96
9.3.2 SPECIFIC

* Voice and data information should be readily transmitted

at an acceptable rate of speed.

* Error rates of systems should conform to organizational

requirements

.

* Systems should be sufficiently flexible to facilitate

future changes and/or expansion.

* System features, e.g. capacity, flexibility, bandwidth,

should respond to office activities.

* Sufficient power is needed to meet emergency conditions,

e.g. UPS.

* Systems should handle analog and digital information.

* Adequate protection is needed from electromagnetic and

radio frequency interference.

* Systems should provide the means to integrate building

support (e.g. energy management) and operational data.

* Systems should be designed to facilitate maintenance.

* A single organization should be responsible for system

operation, and problem reporting; a "help" desk is useful.

* A diagnostic capability is needed to locate problem - what

and where. This should be located in a network control

center

.

* Voice and data communications channels should be

separated, unless digitized.

* Video signals may be digital or analog; part of a local

area network or separate. It may be installed with video

conferencing, video text, CATV, security, etc. 97

* Systems should be designed to facilitate security in

information handling and transfer.

* Voice and data closets should be provided; more room is

required if security is of primary importance.

9.4 TYPICAL APPROACHES

The telephone lines or cables cross the property line at the

telephone service entrance, where they enter the building. These

lines interconnect with the building cable system at the main

telephone terminal equipment room, the "heart" of the building's

communication system. (In multi-storied buildings, more than one

main terminal room may be needed.) From the main terminal

room(s) , riser systems distribute the lines to each building

floor. The particular riser system design used depends on the

type and layout of the building and the systems installed. There

are two basic types of systems - closed shaft and open shaft.

The closed system consists of vertically aligned closets on each

floor, connected by pipe sleeves, slots, or conduit through

floors. In the open shaft design, the riser cables pass from

floor to floor, without being enclosed in closets. Early

coordination with the local telephone company is essential during

initial planning.

97
9.4.1 Checklist of Network Features (57)

NETWORK CHARACTERISTICS

NETWORK

APPLICATIONS

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Figure 19. Network Applications and Features

98
The framework for defining a communications network is based on a highly layered series of protocols developed by the International

Standards Organization (ISO) , called the Open System

Interconnection (OSI) , consisting of seven communication

layers: (58)

1. Physical- defines the electrical and mechanical network

interfaces. It specifies the signaling means, e.g. baseband,

the modulation technique used, station identification

addresses, etc.

2. Data Link- where the actual packet formats are

established, with particular access control mechanisms used

to regulate physical network use. Data are encapsulated in

packets containing physical addressing information, error

detection, etc.

3. Network- determines how messages are transmitted from one

network to others, since many paths may exist. It may use

several intermediate steps to move information to its

ultimate destination.

4. Transport- provides another level of connections between

network entities. It manages the connections and segments

messages into pieces that the network can support. It may

also be involved in error and flow control.

5. Session- used to set up and break communications paths

across the network and manage the exchange of data. It is

responsible for multiplexing and demultiplexing messages,

managing the sequencing and priority of messages and

providing needed buffers.

6. Presentation- responsible for making data available to

the Application layer in a meaningful fashion. It takes

care of protocol conversion, data unpacking, translation, or

encryption

.

7. Application- provides for the identification of users and

services; responsible for initiation and reliability of data

transfers, general network access, flow control and

recovery. Utility programs may perform network file

transfers, terminal to network support, etc.

99
9.4.2 Checklist - Design for Communications Systems

* Telephone Service Entrance

* Size is determined by the number of lines needed, present

and future. (Except for fiber optic systems)

* Main Telephone Terminal Room

* Location should be close to the center of the riser cable

distribution network.

* It should be convenient to the service entrance.

* Environmental conditions should be appropriate for the

equipment supported.

* The size should house existing equipment, accommodate

necessary activities and planned expansion.

* If a non-sealed battery powered or battery backup for non

sealed PBX is installed, separate space should be available

for the batteries.

* Cabling

* It must be housed in conduits where required, and riser

ducts separated from power conductors.

* It should be protected from sources of electromagnetic

interference.

* Networking

* Internal systems should be linked with external ones, e.g

public, private, LAN's, telephone, microwave, satellite.

* Security impacts

100
9.5 WIRING CLOSETS (53)

Wiring is run into central distribution points, and individual

connections made there. They are used to distribute voice and

data to and from terminals and devices. They can also facilitate

wiring circuits, house power supplies and control devices

The floor area served by any given closet is limited by the space

available for cables to enter and leave the closet. This is

usually about 10,000 sq ft, but may reach upward of 50,000 sq ft.

Having multiple closets on each floor helps reduce cable-drop

lengths, facilitates the addition of more drops, and makes

rearrangement of cables easier.

Cabling between wiring closets, workstations, and other devices

is achieved by several means. Underfloor raceways should be

accessible during initial construction and later expansion. An

underfloor is usually assembled and installed using feeder and

distribution ducts, junction boxes and other modular components.

This design can put constraints on the structural design needed

to accommodate the ducts. The cellular floor is an integral part

of the building support structure, with distribution cells made

of steel or concrete. A trench header is a specially

manufactured metallic trough (maximum depth of 2.5 inches) with a cover that fits flush with the finished floor; it is normally

used as a feeder duct for cellular or underfloor configurations.

9.5.1 Advantages of wiring closet:

* It allows communication network installation, alteration,

and maintenance with minimum disruption of ongoing work.

* Noise generated by communications equipment or workers can

be contained and controlled.

* The internal environment of the wiring closet area can be

readily managed and controlled.

* Network security can be ensured by locking closets.

* During initial building construction, wiring closets can

be located in areas to provide optimal cable distribution.

9.5.2 Wiring Closet Checklist:

* The wiring closet should be located at the point offering

the best access to the cabling distribution.

* Access is needed without disrupting normal office

operations

.

* Doorways should be at least 36 inches wide, 80 inches

high, and without doorsills.

* All doors should open outward and be equipped with locks.

Data communications closets usually have standard 19 inch

racks with universal hole spacings.

* Walk-in and shallow (if they open into circulation areas)

types are both used. They should be at least three feet deep

unless they open into a circulation area.

* Floor space should be open, without center posts.

101
* Within the closet, carpeting or uncovered concrete should

be avoided. Carpets create static electricity while concrete

is a source of dust.

* Walls of three quarter inch plywood for mounting telephone

punch-down blocks and strain-relief cabling should be

installed

.

* The racks are usually bolted to the floor, but can be wall

mounted. A minimum sized closet provides one rack for each

100 drops, and space for one additional rack for future

expansion

.

* Closets for data systems should contain patch panels to

cross connect data devices.

* Easy access to risers is needed.

* Sufficient power should be provided for equipment and

systems

.

* Closets should be protected from sources of

electromagnetic interference.

* Environmental conditions should support equipment.

* Lighting should be from incandescent sources. The light

source should be overhead and distribute a shadowless light.

9.6 TELECOMMUNICATIONS ACCESSORIES (59)

9.6.1 Functions

There are self-contained, plug-compatible devices for word

processors, small computers, terminals, and other types of office

automation equipment. Once connected they provide direct and

automatic access to one or more domestic and international

networks

.

9.6.2 Criteria

Desirable features are as follows:

* Capability to support multiple private and public

networks

.

* Access to a text editor.

* Call dialing, connect, disconnect, and reentry features.

* Capability to address commonly called locations.

* Communications port options allowing for selection of one,

two, or all business networks.

* Compatibility with dissimilar types of equipment through

standard accessory ports.

9.6.3 Checklist of System Requirement Needs

* Appropriate protocols, speed conversions and signaling

must be perfectly matched with those of the networks

accessed

* A careful maintenance capability

* An integral battery back-up system to protect the memory

from momentary power outages

102
* User-friendly programming features, with instructions in

jargon free language

* Multiple user capability, connecting dissimilar systems.

* Low power requirements, lightweight, and low heat output

* Modular, expandable and capable of upgrading

* Capability to perform simultaneous operations - e.g.

receiving and pending messages, information status, etc.

* Good record bf customer service, preferably through local

dealers and users

9.7 ELECTRICAL/COMMUNICATIONS LINKAGES

Four approaches are available - twisted pair, coaxial cablebaseband and broadband, fiber optics. Considerations for their

selection depend upon a number of factors: (51)

* The capacity required

* The distances between proposed stations

* The importance of data speed

* The requirements to interfere with other systems

* Acceptable error rates

* Proposed expansion requirements

* Maintenance requirements and constraints

* Cost considerations - first and long-term

* Availability

* Existing conditions

* Manufacturer or supplier

9.7.1 Twisted Pair

This is the oldest technology and consists of two or more wires

connecting devices to one another, sometimes employing a PBX for central switching. Limited bandwidth makes it

inappropriate for high speed data and television. Lack of

shielding makes it susceptible to interference from sources such

as AC power lines and mechanical equipment. They need large,

expensive ducts to carry the many required wires; trouble

shooting and fault isolation is difficult because of the number

of wires.

It consists of paired copper conductors in a sheath; used for

vertical and horizontal signal distribution within a building.

It is used with PBX equipment to switch to the terminal

equipment. Twisted pairs can produce crosstalk between wires and

can pick up unwanted signals from external sources such as

telephone cables in an electrical closet. (It is a dispersive

medium.) Shields are provided to minimize such problems (between

pairs and for groupings of pairs.) The greater the effectiveness

of the shield however, the greater the mutual capacitance of the

cable, resulting in poorer data transmission characteristics.

Also, the more pairs within a common shield, the greater the

difficulty to bend and place cable and the higher the cost. Large

shielded cables are both heavy and stiff.

103
The major benefit of twisted-pair technology is its reasonable

performance at a low cost per foot at maximum data rates of 1-4

kilobits per second. With proper design rings and bus topologies

are accommodated.

9.7.2 Baseband

These systems are especially useful within a building or a campus. They avoid the need for dedicated lines; communication is

transmitted on separate channels. They offer plug-in

installation, are relatively trouble free and easy to repair when

difficulties arise. Taps must be made at specified locations

along the cable. Connecting baseband with other systems requires

interfaces

.

The system is placed on one channel of a coaxial cable or a TWX

cable and users must take turns sending and receiving. They send

one signal at a time at 1-10 megabits per second. The signals

can be sent via time division multiplex, thereby enabling several

users to use the system simultaneously. It is a nondispersive

medium, the signal being confined within the shield placed around

the central conductor. Baseband doesn't require the dedicated

wires associated with twisted pairs.

Baseband systems can connect computers, word processors and other

office automation devices on a single floor or limited area. They

can support high data rates but are not generic; many different

types are available with widely different electrical

characteristics. They cost about $4 a square foot, which minimize

their usefulness in serving individual workstations. Wiring

dimensions are large, presenting problems for cable runs in small

plenum spaces favored in new buildings.

Among other shortcomings are susceptibility to electromagnetic

and RF interference; also cabling cannot extend more than a few

thousand feet without expensive digital repeaters. Unlike twisted

pair technology, baseband systems do not permit ready cross

connections. Taps are used to connect devices to networks

sometimes and are prone to noise interference.

9.7.3 Broadband

Broadband systems work best over large geographic areas (many

kilometers), using inexpensive amplifiers. Information is

carried up to distances of more than 40 miles by several hundred

channels on a cable television type of coaxial cable. The

channel bandwidth can accommodate voice, video and data channels

at high transmission speeds.

This is an excellent vehicle for a generic telecommunications

utility. Many signals can be sent concurrently; each on a different frequency at 1-5 megabits per second. Transmissions

require radio frequency (RF) modems to convert digital to analog

signals, and then back to its original digital form. It allows

104
each workstation universal access to a common signal

transportation utility. A user can communicate anywhere there is

physical connection to the cable; cross connections with twisted

pairs is not needed. Connections between workstations are

changed by allocating different frequencies; analogous to the

switching function performed by PBXs through common time slots.

Broadband systems have high maintenance costs since they require

a staff of trained RF technicians for design, daily maintenance

and careful tuning of components to proper frequencies. Both the

cable and the broadband hardware are extremely sensitive to

temperature and humidity changes.

9.7.4 Fiber Optics

Fiber optic systems use light beams traveling through glass

threads. Each fiber can carry many channels, and many channels

can be packed into a relatively slender cable. The bandwidth is

considerable, as is the capacity to accommodate network system

terminals

.

This technology employs light signals, pulsed in fine glass

strands (about 0.005 inches in diameter) to carry a stream of

data at extremely high rates. Light can be modulated in shorter

duration and lower power pulses than electrical signals (light

has shorter wave lengths) . Receivers can also detect signals

containing less energy than is required for telephone modems.

The principal advantages are its sturdiness and its inherent

security. Fiber optic systems are immune to physical and

electrical influences and apparently are almost impossible to

tap. They are difficult to use for local networks for the same

reason; precise alignment of thousands of fibers is needed to

ensure a continuous connection.

Table 18 presents the cable characteristics of various media.

105
9.7.5 Tradeoffs Among Cable Types (60)

POSITIVE FEATURES NEGATIVE FEATURES

TWISTED PAIR

* System compatibility through

the telephone system

* Availability of wiring

* Inexpensive

BASEBAND

* High speed data transmission

* Relatively trouble free

BROADBAND

* High speed data transmission

* Doesn't require conduits or

protective ductwork, when special

cable used

* Can be fastened directly to

walls or ceilings

FIBER OPTICS

* High transmission speed

* Very high bandwidth

* Secure transmissions

* Limited capacity

* Slow transmission speed

* Lack of shielding;

susceptible to interference

* Large ducts needed for wire

* Problem detection difficult

* Connecting to other networks

requires interface devices

* Requires ducting, conduit or

fireproofing to meet codes

* Limited range; repeaters

needed

* Cable pulling required

* Interface needed to link to

other networks

* Requires ducting, conduit or

fireproofing to meet codes

* Taps must be made at

specified locations

* Relatively expensive

* Limited to point-to-point

* Maintenance difficult

* New technology; operational

data limited

106
Table 18 CABLE CHARACTERISTICS

FEATURE TWISTED

PAIR

SHIELDED

TWISTED

PAIR

COAXIAL FIBER

OPTICS

TRANSMISSION

SPEED (Mbps) 1 10 400 50

EASE OF

INSTALLATION *** *** ** ***

COST * ** *** **

POTENTIAL FOR

INTERFERENCE

** * * *

SKILL NEEDED

TO INSTALL * * * ***

MAINTENANCE

DIFFICULTY ** * *

SUPPORTED

CONFIGURATIONS R,S,B,T B,R,T B/R/T S f R f T

KEYS

*** HIGH

** MODERATE

* LOW

R= RING

T= TREE

B= BUS

S= STAR

faDie 19 presents LAN media comparisons or various wiring approaches.

Table 20 compares features of LANs and PBXs from a functional standpoint.

107
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108
9.7.6. LAN OR PBX (61)

Questions that a manager should ask when choosing between a LAN a PBX are:

* How many users are expected to be on the network?

* Will the users need switched access to multiple hosts?

* Can you cost-justify additional cable needs?

* Are people expected to move frequently within space?

* Does the PBX have the capacity for long data transfers in

addition to normal telephone traffic?

* Do you need remote access to distant data bases?

For PC and terminal users to send limited amounts of data at

speeds below 2400 baud, the PBX is sufficient.

The wiring for both PBX's and LAN's is from workstations to

wiring closets. In the PBX, the wire is then physically

concentrated into trunks before being brought to the PBX. In

LAN's, the network interface units are in the closets, and then

connected into the major network cable.

Table 20. Comparison of LAN and PBX features

LANs advantages:

* when large amounts of data are transferred at high speeds

* when data protocol conversions are needed

* local work groups exchange data; less expensive

PBXs advantages:

* many users communicate with shared resource; high speed

not critical

* combined voice and data possible

* existing wire can be used

* changes made readily without new wire needed

* permits ready billing for telephone usage

109
10. LOCAL AREA NETWORKS (LAN)

10.1 FUNCTION

LANs provide the means for office technologies to communicate

with one another. They are characterized by single organization

ownership, within a building or among a small set of buildings,

distances not more than a few miles, and switching capability

which permits messages to be transmitted and received.

Establishing a LAN requires an understanding of how to best serve

organizational needs. Typically such needs might include

monitoring and control of building systems, data processing,

security alarms, and the generation, transmission and

reproduction of written documents. The selection of a particular

system depends on how many of these elements are to be integrated

into one coherent communication system. (62)

10.2 BACKGROUND

One way to think about LANs is a complete computer system,

connecting small computers and peripherals together. A processor

is dedicated to each user and a network is used for sharing data,

or to access peripheral equipment.

A LAN is an electronic communication linkage which may not

require public communications facilities to operate. It is

designed to establish a "highway" to optimize network traffic

and trouble shooting capabilities for linking different machines,

languages, and operating techniques into a coherent system. A

network can provide of advanced technology capabilities to every

worker at every location. It also enables coordination of

diverse activities, consistent with overall organizational

objectives, e.g. management information systems, security and

safety requirements, energy management, and centralized data

bases (62)

.

LANs must have enough communications capacity to transfer

documents without extensive delay or the need to coordinate such

actions with network users. Flexibility is very important; the

more system design is tailored for specific types of equipment

and/or physical locations, the less useful it is.

LANs should be easy to install and maintain and be user-friendly

for laymen. Its should be as easy to use as a telephone. For

example, users should not have to learn many screen formats or

instructions. LANs should support the maximum data transfer rate

between any pair of communications devices and any communication

between devices operating at different speeds.

There is no single LAN networking approach that can meet all

telecommunications requirements. A network should allow equipment

from different vendors to communicate at varying speeds using

110
different protocols. It should provide easy access without

considerable rewiring.

The simplest LAN is one which links components from a single

vendor. The highest level of sophistication are those systems

which provide:

* Local processing capability of a personal computer network

* Intercomputer communications of a universal network

* Powerful data management capabilities

* High speed and sophisticated software, essential for

handling voice and document image as well as data

communication (63)

Networks can be divided into three general categories: (64)

1. Vendor specific; developed by computer manufacturers to

support the end-to-end needs of their equipment. Their main

function is to provide single vendor host-to-host and terminalto-host connectivity.

2. All purpose LANs have little affiliation to host vendors.

They are broadband and baseband systems to provide connectivity

and protocol support to a variety of vendor equipment.

3. New PBX's allow RS-232 and coaxial connection of

workstations, support moderate to high data rates, and provide

protocol conversion and device emulation. They offer the

advantage of a single wiring approach to data and voice

communication; many users can use existing twisted pairs.

In choosing a LAN, two issues are of prime importance: Will the

network fit into the existing environment, e.g. is the wiring

appropriate? Does it meet the functional requirements of the

organization?

Among other important LAN factors to be considered are:

* Connectivity. It should provide physical connectivity

equivalent to the vendor's standard approach; transparent to

the user, devices should appear to be attached to standard

coaxial, twin-axial, or twisted pair connections. It should

be protocol transparent.

* Network speed. Flexibility in speed should be provided to

accommodate device growth and increases in transaction

volume. A common mistake is to demand too much speed and pay

for unneeded capacity. Terminals and other devices must be

able to utilize the speeds provided.

* Capacity. How much added capacity should be built in

during initial installation? Provision for modular

expansion at reasonable cost is essential.

Ill
* Cabling. The cabling architecture should place as few

restrictions as possible on cable type and length. Cables

should provide easy access throughout site, and flexible

enough to accommodate a variety of interfaces.

* Gateways. LANs must be able to communicate with external

hosts, networks, users and other devices.

* Multivendor communication. The system should permit access

to databases and equipment from many vendors. Protocol

translation, device emulation and code conversion

capabilities are needed.

The following tables provide information concerning the economics

and market shares of LAN's.

Table 21. Cost Proportions of

DESCRIPTION

DETAILED PLANNING

DETAILED INSTALLATION

DESIGN

HARDWARE COMPONENTS

INSTALLATION

Typical LAN's

PERCENTAGE OF TOTAL

28

8

34

32

Table 22. Market Share by Type (A.D. Little)- Percentage (65)

TYPE 1987 1992

BASEBAND BUS 20 15

BROADBAND BUS 15 10

TOKEN RING 10 10 (WITH PBX)

CENTRALIZED LAN 20 25

THIRD GENERATION PBX 15 25 (WITH LAN)

PBX WITH INTEGRATED LAN 10

112
10.2.1 PROBLEM AREAS

The products of one vendor for accomplishing a function, e.g.

electronic mail, are incompatible with those of other vendors.

Furthermore, the software that runs one computer, commanding a printer or a disk, is often unique to a vendor, and cannot be

used for a different system, even when sharing a cable. To help

solve this problem, the Institute of Electrical and Electronic

Engineers (IEEE) created project 802 to establish standards for

hardware and software components of networks.

Careful system installation is needed for good performance.

Places where the cable is cut should be marked and sufficient

room provided where cable runs negotiate tight spaces and turns.

If not mounted securely the cable can be twisted, which can lead

to a cable break. A 360 degree cable loop is required where

connected with a component, to permit reconnection if a break

occurs. A weather tight shrink tubing seal should be used to

protect the junction to the equipment housing.

10.3 CRITERIA

Two types of criteria are important for LAN, those associated

with system performance, and those which address design issues.

10.3.1 System Performance

Table 23. Requirements for a LAN (62)

* Relatively high data transmission rates (typically 1 to 10

or higher megabits per second) . * Geographic distance spanning at 1 kilometer or more

* Should support at least several hundred independent

devices

.

* Simplicity, or providing the simplest possible mechanisms

for the required functionality and performance.

* Good error characteristics, good reliability, and minimal

dependence upon any centralized components or control.

* Efficient use of shared resources.

* Stability under high load.

* Fair access to the system by all devices.

* Easy installation of a small system, with gradual growth

as the system evolves.

* Ability to optimize and report status of system elements.

* Ease of re-configuration and maintenance.

* High reliability of devices on network.

* Low cost.

* Easy maintainability.

* Maintenance service contract at low cost.

Tables 23 and 24 indicate technical requirements and

throughput applications of LANs, respectively.

113
10.3.2 Design Issues

* LANs should operate under typical environmental conditions

of buildings in which they are located, with normal exposure

to dust, humidity and temperature change.

* Equipment may be required to operate within given

electrical constraints, e.g. power, voltage, phase, and/or

frequency characteristics.

* Space is needed to accommodate specialized equipment and

cabling requirements.

* Flexibility to accommodate changes and additions with

minimal disruption to ongoing activities.

10.4 TECHNOLOGICAL ISSUES

First generation systems were designed to serve asynchronous

terminals, not synchronous systems or PCs. They were designed for

baseband transmission. Some present broadband systems support

comprehensive network-measurement, performance and control

facilities. These facilities simplify the installation and

support of the broadband-based networking systems.

The Ethernet system, the first commercial one, employed CSMA/CD

applications; the most widely used method today. This system

requires that before transmitting data, each network interface

listens to the media to determine whether any messages are being

sent; if so, transmission is not made. The later systems employ

token passing, where any station that has the token can transmit

a message. (66)

The newer methods, coaxial cable and CATV technology are both

designed to operate in harsh environments and share cost benefits

from high-volume manufacturing processes. The price difference

between baseband and broadband wiring is narrowing.

More than one local network is often needed to support the

company wide mix of equipment and uses, requiring a linking of

networks. Two devices are used to accomplish this, a bridge or a gateway

.

A bridge is a simple device to link networks using the same

protocols. It reads information packets transmitted on a network, and routes them accordingly to each network addressee.

It doesn't modify the content or format. It provides a simple

and efficient way to interconnect devices remote from one

another. It is also used locally to guard against failure of an

entire network when a problem occurs; it partitions an large

system into smaller self-contained units. A bridge can also be

used to maintain security; preventing distribution of sensitive

data

.

114
Gateways are used to enable LAN's with different features to

communicate with one another. Among the differences are:

* Addressing schemes

* Maximum packet size

* Protocols

* Time delays for data transmission

* Error recovery schemes

* Status and performance information

* Routing schemes

* User access controls

One type of gateway is a protocol converter, which entails

developing connection schemes for each network pair. It accepts

a packet from one network, strips off the control information and

retransmits the data using protocols for the receiving network.

At the other extreme is the use of standardized protocols usable

by all networks. Unfortunately this standardization has not yet

occurred. (67)

Table 24. Typical Throughput Applications of a LAN

APPLICATION DESCRIPTION APPROXIMATE THROUGHPUT

(bps)

TELEX 55

COMPUTER TERMINAL

PHONE-LINE 2400-4800

MAXIMUM DATA RATEPRIVATE LINE WITH

CONDITIONING 9600

DATA PHONE DIGITAL SERVICE 9600-56000

SATELLITE DIGITAL VOICE 24000-32000

TELEPHONE SPEECH 64000

COMPRESSED DIGITAL VIDEO 1.5-3 MILLION

BROADCAST COLOR VIDEO 92 MILLION

115
10.5 ORGANIZATIONAL ISSUES

Network management can be complicated by LANs. Most management

tools do not work on local networks. The evaluation of LANs is

made on a cost per node basis. This must account for cable,

interface devices, active and passive network components,

interface boards, and software. Future costs should be estimated

to determine the effects of expansion on the initial estimate.

Support for most networks requires that operators be trained in

the use of configuration software. The complexity of the

software varies from system to system as does the mode of change.

Some changes must be performed at individual workstations; in

other instances, they can be made centrally.

A company has three installation options: (68)

* It can install the network itself

* It can use third-party vendors and hire contractors and

consultants for certain aspects of installation

* It can have the network designed and installed by a vendor

that offers turnkey service.

The first option is the least popular one because it requires a high degree of expertise and involvement by the user

organization. It is likely that the installation will take longer

and is more apt to result in problems than the other two

approaches. Normal activities will have to be modified while

personnel learn how to design and implement the system. However,

they will be well trained to use the final system as a result of

on-the-job experience.

The second option works best when at least one staff member is

knowledgeable enough to develop design and performance

specifications as well as acceptance criteria. A major problem is

that a variety of vendors will be involved in putting the system

together and coordination is likely to be a major task.

Furthermore, overall system responsibility rests with the user,

and when difficulties arise, it is difficult to determine which

particular vendor should correct the problem. This lack of

system responsibility by hardware, design and systems contractors

is a major shortcoming of this approach.

The turnkey system is one which is now receiving considerable

attention by users. The turnkey vendor develops the needed

planning information, develops a workable design, installs the

network and trains the staff in its use and then is responsible

for maintaining the system. The one vendor approach simplifies

equipment procurement and processing time, and therefore is the

most timely method. A problem area is that the vendor might not

be as responsive as in-house personnel when system malfunctions

occur; response times to solve problems should be addressed in

contract negotiations for such systems.

116
Obtain technical documentation on features such as specific

frequencies used for each service, frequencies available for

expansion and maximum the maximum distance terminal equipment can

be located from trunk terminal. Also important are trunkinterface-device specifications, including number of ports, speed

processor chips employed, and number of interface devices

planned. The precise protocol for data transmission, the actual

throughput expected and the services supported are also vital to

know.

Services requiring special care should be noted, and the services

critical to organizational needs to be optimized during the

design process. The physical location of trunk taps should be

identified, to ensure that planned expansion is facilitated.

Planning should include using organizations, e.g. data processing

and communications, and be coordinated with long range plans.

The actual layout (topology) of wiring and its mounting, should

be carefully planned and documented; vertical and horizontal

distribution systems. The characteristics of the cable medium

must be carefully considered during these plans, e.g. attenuation

loss, amplification, accessibility for servicing, etc.

The growth limits of the networks should be clearly understood

from the outset. If a branch is near its capacity, early

redesign is preferable to the needs for major repair after

installation

.

The cable should be tested throughout its bandwidth, before

installation. Finally, the installed cable must conform to

building codes. (69)

10.6 SOFTWARE ISSUES

PC networks link computers operating under MS-DOS, a single user

operating system. Performing network functions such as

coordinating simultaneous updating of data files requires

additional capabilities that must be added to MS-DOS. Every

implementation requires a unique approach.

Network software consists of a set of programs designed to

control the input and output of all the hardware in the system.

These programs are needed at each network station and at the

central server to take care of network functions. The first task

of any LAN operating system is to allow multiple systems to share

a large central hard disk, a server.

The server can be divided in many ways. The simplest one,

allocates a portion of the disk to each user, who are the only

ones permitted to access it. This system is not a true network

since it does not permit sharing of data.

A network needs a system to assign and monitor read and write

access privileges. Typically, this consists of files designated

117
as private and public or shared. Private files are accessible by

the owner only; public ones have read access to everyone, but not

write access; shared files have read and write access.

With shared files, controls are needed to ensure file integrity.

For example, when two users simultaneously are updating files,

the last one to make modifications will overwrite the data added

by the first user; thereby losing these data. (70)

10.7 TYPICAL APPROACHES

10.7.1 Network Configurations

Most local networks are designed to accommodate several hundred

stations (nodes) , separated from one another by various

distances, sometimes as much as a mile. Each node operates as a device (terminal, computer port, printer, etc.) and a communication system, enabling data from diverse organizational

elements tobe used by an individual working on a given problem or

office function. Three types of configurations exemplify the

structure of most networks.

10.7.1.1 The Star

This is the oldest arrangement, with a multiplexing device

serving at the head of the network. Devices connect directly to

the hub by coaxial cable, or a voice/data telephone, or by using

some type of modem. The net is centrally controlled - resulting

in a breakdown of the entire system when the hub encounters

problems. (See Figure 20.)

Figure 20. Star network topology

118
10.7.1.2 The Ring

This configuration eliminates the need for a central hub

switcher. A signal repeater is located at each node of the

network, enabling signals to travel great distances. The ring

permits the use of fiber-optic cable for transmissions,

permitting very high performance. A major problem is that if one

node goes down, the entire network is out of operation. Also,

when a station is added, the network is down. (See Figure 21.)

Figure 2.1. Ring network topology

119
10.7.1.3 A Bus Network

This is the most common form of network, consisting of a length

of coaxial cable (bus) , to which microcomputer stations are

attached by means of simple cable taps. There is no centralized

control hub and signals from one station move along the bus in

both directions to all stations tapped into the cable. This

system is suited to a business environment because installation

is relatively easy and cheap, without requiring system shutdown

when changes are made. Also, it is reliable because there are no

active components along the transmission cable. It does not

accommodate fiber-optic cables. (See Figure 22.)

Figure 22. Bus network topology

120
10.7.1.4 Tradeoffs Among Alternative Configurations of LAN

Table 25 indicates some important positive and negative features

of each approach.

Table 25. Positive and Negative Features of LAN Configurations

POSITIVE FEATURES NEGATIVE FEATURES

STAR

* Multiple access possible

* Memory may reside in central

and peripheral locations

* Ideal for monitoring system

and individual performance

* Accommodates fiber optics

RING

* High overall performance

* All terminals can communicate

with one another

* Supports distributed systems

* Repeaters used for greater

distance possibilities

* Fault detection and diagnosis

from any terminal

BUS

* All terminals communicate with

one another

* Control may be decentralized

* Widely used? good results

* Few maintenance problems

* Easy to add peripherals

* CPU malfunction affects

entire system

* CPU limitations influence

system capability

* High load operations

require careful access plans

* Easy to access; security

problem

* Bandwidth limits data

transmission

* On-line access control

strategy needed

* System doesn't operate if

one node goes down; redundancy

and logic unit needed.

* A broken bus cripples all

down-line communications

* Relatively easy to access;

security problem

* Bus bandwidth limits data

transmission capability

* Controlled access needed

* Hard to use fiber optics

121
10.8 ENVIRONMENTAL CONTEXT

10.8.1 Space Considerations.

Among the considerations are:

* Room for the interconnection of units colocated with

support units.

* Available wall and floor space for taps/transceivers.

* Areas within or outside of walls, ceilings, and floors for

cabling, and repeaters/amplifiers.

* Dedicated rooms or floor space for network control units

placed centrally or distributed appropriately.

* Floor loading.

* Adequate space for working on equipment; maintenance and

service support.

* Availability of proper power, for normal and emergency

operations

.

10.8.2 Wiring (71)

Several types of wiring schemes are available for LANs; in making

an appropriate selection, several factors must be considered:

* Is network intelligence needed?

* How much capacity is required?

* Are there long distances between the various stations in

the proposed network?

* How important is data speed?

* Will the proposed network interface with other systems?

* What data error rate is acceptable?

* What are the projections for future expansion, relocation?

10.8.3 Signal Amplification

To ensure the quality of signals, amplifiers are often required.

They are sizable units, and their placement should be planned for

ease of access and aesthetic acceptability. There are two types

of devices used for improving signals, the trunk amplifier and

the line extender. The trunk amplifier is a sophisticated

electronic device incorporating automatic gain control, automatic

equalization, and noise suppression circuits. It can also serve

up to four branch feeder points. A line extender has little

sophisticated electronics and cannot serve feeders.

122
11 PBXs

11.1 FUNCTION

The primary purpose of the PBX is to provide basic telephone

service, divided into essential services and desirable options.

Current systems are either based on centralized or decentralized

architectures. Most systems are non-blocking (they are certain

to acquire a path through the switch between two unoccupied

ports) . Traffic loading and holding time features of users do not

limit the switch's internal capacity in the non blocking

configuration

.

11.2 BACKGROUND

About 60 % of an organizations communication take place within

one building or campus; another 22% is within 50 miles. The

trend is toward digital data; which can be accommodated by a digital PBX. (72)

A PBX system has four basic parts; a switching matrix, control

and user terminals and trunks. The PBX itself is comprised of

the matrix and controls as well as line, trunk and service

circuits that connect to telephones or other switches . (73)

)

While current systems are complex, their functions are almost

identical to the manual switchboard where wires were connected to

boards by means of jacks, to complete circuits. Lamps provided

feedback information to indicate when service was needed,

connections made, etc. The cords performed the same function

that a switching matrix does in a PBX, while the modern dial tone

serves as a surrogate for the operator asking for a telephone

number. In both instances, a test is made to determine whether

the connection can be made; i.e. if the line is busy, and if not,

the call is completed. In both instances a feedback signal is

transmitted when there is a problem and when the conversation is

over. In the latter instance, the lines are disconnected in

preparation for future service.

The trend in PBX's is toward distributed architectures, where

switching is performed by an interconnected set of modules, which

can be widely distributed; e.g. in different cities.

Maintenance and service support should be major factors in

selecting a PBX.

11.3 CRITERIA FOR PBX SYSTEMS (74)

* System diagnostics

* Least cost routing

* Call-detail routing

* A non-blocking digital switch matrix for heavy data

traffic where holding times are long and eliminating switch

load balancing over time.

123
* Remote modules for multi-premise use

* Multiple processors to allow for system growth with

expanded requirements.

* Speed/format/protocol conversion to house environments

with different equipment and software needs.

* A high level programming language to facilitate customer

control over system.

* Conformance with ISO network standards to avoid the need

for tailored systems for particular applications and

hardware

.

* Integrated voice/data terminals.

* PBX/LAN wideband communications channels between nodes and

modules

.

* Integrated advanced features; e.g. electronic mail

* Packetized data switching

11.4 TECHNICAL ISSUES

PBX's switch data in one of two modes; synchronous and

asynchronous. Most can switch data asynchronously at speeds up

to 19.2 kilobits per second, generally the limit of ASCII and

PC's. In the synchronous mode they can switch up to the limit of

the internal switching speed, 2 or 3 megabits per second.

Organizations with low data terminal usage; less than 30% per day

can use asynchronous communication with a PBX; others with more

intense data requirements require other solut ions . (75)

The advantage of a PBX for switching data is in the inherent

design of the system. It is a concentrator; i.e. terminal

devices contend for paths (time slots) through the PBX, which can

support such usage because in the voice world, all terminals do

not need paths simultaneously. Designs are most effective when

voice and data traffic occur in short, bursty, low-speed data

streams; requiring short holding times.

11.4.1 Analog vs Digital Systems

Analog transmission is a system whereby the pressure changes on a microphone or transmitter are translated into electrical currents

proportional to the input signals. Signal amplification is

critical because it is attenuated by cables. Unfortunately

noises are amplified together with signals, until ultimately the

message is lost. (73)

A digital system overcomes this problem because signals are

recreated along the line with noise being eliminated each time

they are regenerated. Voice signals can be transmitted digitally

by means of pulses in successive time intervals which define the

amplitude of the signal at any given instant. While many pulses

are required, all the system has to do is detect whether or not a pulse is present, a simpler task than transmitting a complex

analog signal.

124
A digital switch enables data to be transmitted together with

voice communications in an all digital network without the

requirement for modems. However, most trunk systems are analog

and transmission media such as coaxial cable can handle more

analog than digital circuits simultaneously. Also, protocols

among various systems and hardware are not standardized, and

therefore data communications are made quite difficult.

11.4.2 Integrating Voice and Data (76)

Despite widespread advertising, integration of voice and data

communications is still quite limited. For the most part they

have been used to link ASCII terminals, transmitting

asynchronously at 19.2 kilobits per second. (Synchronous methods

are also used occasionally.)

A digital PBX is costly; up to $1000 per user to line a special

digital telephone into a 100-line digital PBX. (The cost is being

lowered rapidly, and is dependent on the mix of voice and data

requirements.) The cost includes telephone line cards with data

transfer modules, telephones to link and format data for the PBX.

This system is needed for simultaneous transmission of voice and

data over the same twisted pair. (Some manufacturers use separate

wire pairs for data and voice.) (77)

The popularity of personal computers provides a logical and

economic use of PBX's, since microcomputers typically communicate

asynchronously, in ASCII, at speeds under 9600 bit/sec through an

RS-232-C Port. All voice/data PBX's support this connection

easily, and there is the option of plugging the computer into the

telephone line. Furthermore, personal computer users often use

communication services for local processing, but the volume of

use is light. The PBX is basically a switching system. Sharing

lines among many users requiring periodic service, forms the

basis for its design. Finally, the telephone, like the personal

computer is likely to be on most desks in offices. It is

available for use immediately, without added wiring or equipment

required

.

Each PBX system has a unique approach to integrating voice and

data communications. Some digitize the voice at the telephone

set and multiplex the voice and data together onto a single

digital path into the PBX. Others use separate paths for voice

and data from the telephone; voice traffic remaining in analog

form, with digital data sent on a separate wire pair. The wires

are then physically multiplexed within a single three or four

twisted-pair jacket. (78)

The foundation of linking voice and data is the integrated

digital telephone, with a RS-232C interface. The combined

information is sent to and from the instrument in digital form,

multiplexed on either one or two wire pairs. Each vendor has a unique proprietary architecture to handle communication between

the telephone and PBX. In a typical multiplexed signal system.

125
the instrument supports 64 kilobits per second of voice as 8000

samples of 8 bits each, and 64 kilobits per second of data in a synchronous mode, or 19.2 kilobits per second asynchronously, and

16 kilobit per second for control functions. Some PBX's can

handle up to 2 megabits per second of data at the instrument by

means of appropriate interfaces.

11.5 ORGANIZATIONAL ISSUES

One reason for the lack of progress in integrating voice and data

communications is organizational separation of voice and data

communications functions. Organizational barriers between the

two are very strong, because of training, historical separation

of activities, disciplines, etc. This separation is reinforced

by the vendor community, who have few people equally

knowledgeable about the two.

Voice traffic is generally of low call duration, with busy

telephones used between 8-16% of the time. Thus, a PBX switch

with 500 connected instruments probably requires only 100

pathways. Data traffic tends to be longer (several hours is not

unusual), especially when terminals are linked to hosts.

Network management functions for the PBX are:

* Accounting. Detailed records of usage.

* Restriction and Authorization. Class of service can be

restricted to users.

* Maintenance. Monitoring and diagnosing of system

operations minimizes system downtime and facilitates

maintenance

.

* Security. Information can be controlled; accessed only by

authorized users.

An alternative to the self contained and operated PBX, is a system provided by the telephone company, supplied from a central

office - Centrex. It lacks some user control, integral to the PBX

such as voice forwarding and data switching.

If communication is central to the major function of a large

organization, then a PBX is called for. When less than 50 users

are involved, Centrex service offers many advantages. Smaller

companies are often unsure of their future needs, and systems can

be rented and running in less time than it takes to plan,

purchase and install a PBX. Centrex also provides the

opportunity to add an unlimited number of lines without major

capital expenditures . (79)

126
12. LIFE SAFETY SYSTEMS (36)

12.1 FUNCTION

To prevent life and property from harm or loss caused by

accidents and natural or man-made events. Life safety systems

include fire protection equipment and systems such as sensors and

alarms, extinguishing systems, exit lights, control of emergency

exits, emergency lighting, control of fire dampers, smoke exhaust

and ventilating fans, and some aspects of site security.

(See Figure 23.)

i 0-

EPO$

AJEPO

CWatran Law*

Figure 23. Life Safety Interface Elements

127
12.2 CRITERIA

* Ensure safety of building occupants.

* Minimize equipment and data loss during emergencies.

* Minimize "downtime" of operations after emergencies.

* Establish adequate safeguards against system activation

when not required.

* Systems should be easy to operate and monitor.

* Power should be independent of main system.

* System design should facilitate future expansion and/or

changes

.

12.3 TYPICAL APPROACH

The design of a life safety system can be accomplished by the

following steps:

* Develop a list of life-safety subsystems, individual

devices and controls, then list the operating modes of each

one

.

* Develop a strategy for linking and prioritizing

operations, showing which systems trigger, or prevent others

from operating.

* Resolve time delays, inhibitions, and sequences necessary

to eliminate logical conflicts and establish priorities.

If these systems can be placed in a single, readily accessible

cabinet, and the circuits clearly documented for installation,

maintenance and future additions, many potential problems can be

avoided. A possible system configuration appears on the next

page:

128
ADP site basic life-safety elements to be coordinated include: Athe halon fire suppression control system cabinet; B—the smoke,

fire and sprinkler alarm and arming system cabinet, C —

a

"console" to monitor other environmental parameters such as room

temperature, humidity, water under the floor, status of power

sources, HVAC equipment, etc. (See Figure 24.)

Unk. » Unknown Voltage. F«pu««cv and/or Load Currant Requnement.

Ptobiama Aria* in Custom Wiring Intarconnactiona Which wars Dasignad Without Fu* Data* on Working Vottagaa and Currant Raquiremanta of Sanaora and Intarfaca Connactiona. it Wirad at tha Oiacration of Inetattara, a Trua Diagram May

Nawar ba Created Documentation of Oavicaa and

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©Warren law*

Figure 24. ADP Site; Life Safety Elements

129
12.4 CHECKLIST-LIFE SAFETY SYSTEMS

Systems should have the following features:

* Smoke detectors based on optical or ionization designs.

* Temperature and rate of heat rise detectors.

* Flame detectors.

* Halon discharge control units accepting inputs from

sensing alarms. They supervise systems, produce audible

alarms, provide manual activation and manual override, time

delays and equipment shutdown; finally, they suppress fires

using halogen gas.

* "Panic" button for turning off power.

* Automatic shutdown of: central computer, HVAC system.

* Automatic startup of smoke removal fans.

* Automatic control of fire dampers, blocking air

ventilation passages.

* Controlled personal access to central computer and life

safety control system.

* Manual and automatic initiation of alarm systems.

* Fire related circuits should run separately in conduit

containing only those conductors.

* A data logging system identifying significant changes in

systems; the ability to access information concerning status

of system components.

* A schedule for testing primary and backup life safety

power systems.

* Continuous monitoring of on-off condition of major

equipment and systems.

12.5 CHECKLIST-CENTRAL CONTROL OF LIFE SAFETY SYSTEMS

* Location convenient to personnel expected to respond to

them.

* Controls and displays grouped according to major

functions, e.g. fire, HVAC, power.

* Consistent grouping of system elements, e.g. locations of

displays, controls.

* Clearly labeled indicators and controls.

* Schematic diagram should be available, including "as

wired" and "as installed" corrections for all devices and

interconnections

.

* Formal acceptance tests should be conducted; scheduled

maintenance and testing to verify system performance - typically annually or semi-annually

12.6 ENVIRONMENTAL CONTEXT

The design of life safety system must be integrated with the

other power, electrical and information systems in a building.

For example in a building containing energy management and

advanced telecommunications systems, monitoring and control

activities might be centralized with life safety systems.

130
Following is an illustration of a life safety system control

configuration:

A well-organized, convenient, and coordinated arrangement of lifesafety indicators and controls: An emergency telephone with separate

line (not via PBX or switchboard) is needed near the exit and the

life-safety indicators and controls. The audible alarm should not

be so close to the telephone as to defeat attempts to communicate.

Figure 25. Life Safety Control System

131
13. INTELLIGENT BUILDINGS- INTEGRATION OF COMMUNICATIONS AND

AUTOMATION SYSTEMS (80)

One definition of intelligent buildings is: "communication

between people to people, people to computer, and computer to

computer". Another commonly employed characterization is where

building services consist of several integrated and interactive

systems- e.g. building control, information management, and

telecommunications. The systems are served by a single wiring

system. (81) For example:

* The information management system can automatically route

data to a workstation.

* The building management system can detect a fault in an

air conditioning unit and direct the telecommunication

system to send an electronic message to the maintenance

supervisor

.

* An identity card can admit a person to a building, turn on

lights, and activate the HVAC system.

* During a fire, systems can pinpoint its location and alert

building and fire station personnel.

* Buildings can be monitored for around the clock security

by sensors and/or or closed circuit tv.

* Microprocessor controlled elevators can be programmed to

take coordinated action, thereby responding to peak load

conditions by reducing waiting time for occupants.

Very few, if any, buildings can claim this level of integration.

The basic premise of the intelligent building is that it will

provide a better environment to conduct business by integrating

building and office systems by advanced communications. The major

benefits of such integration are greater functionality to the

tenants, lower installation and operating costs, and potential

benefits through the resale of services. (82)

Intelligent buildings are often designed with the aid of computer

aided design (CAD) systems. The workplace now has a combination

of terminals, telephones and cables with responsibilities for

systems scattered throughout the organization. Barely controlled

chaos is the result when rearrangements of workstations are

needed

.

13.1 BACKGROUND

An integrated system may be less costly to install, operate and

maintain than separate systems due to the elimination of

redundant communications networks. It will provide one

communication path for voice and data signals. Also, since one

contractor will develop the system there will be less

coordination needed and fewer individual maintenance contracts.

Integrated systems are built around a stand alone microprocessor

that monitors and controls various functions. Microelectronics

132
makes it possible to create a unified, centrally managed system.

A voice/data network can connect all the systems, while linking

the building to the outside world. Central computers and

microprocessors tie every part of the building together. The

network has electronic monitors and direct digital controls for

all of the building equipment. All building functions can be

monitored on computer terminals from a central location.

Building can operate automatically but remain under the control

of a human operator.

Economic viability of such systems has been demonstrated for

buildings of 300,000 square feet or more. Greater functionality

occurs as a result of greater tenant control over comfort and

safety and additional services. Among the potential benefits of

such systems are:

1. A single cabling system can reduce wiring costs by 30%

over traditional methods.

2. The number of support processors can be cut by 25%.

3. Operating costs can be cut through reduced manpower,

space and energy, with savings up to 20%.

4. Maintenance savings of up to 20% are possible because of

less equipment.

5. Energy savings. The telephone system can be used to

control lighting and HVAC during off hours. Tenants can be

billed for actual costs.

6. Security monitoring. Controlled access and intrusion

detection systems can be monitored centrally.

7. Critical equipment such as data processors can be

monitored on a 24 hour a day basis.

8. Automatic fire and smoke detection and control.

There are various levels of system integration, based on the

design elements combined:

* Non-integrated . Each system has a stand alone processor

and dedicated cabling.

* Shared cabling. The minimum level of integration involves

separate processors and sensors or terminals with shared

conduit and/or cable.

* Interfaced sub-systems. Separate, stand alone processors,

actively interfaced can share data and communicate with one

another. Cabling may or may not be shared.

* Total integration. Shared processor (s) and cable

highways

.

Several functional levels of integration have also been

defined: (83)

1. Energy management, life/safety, and security systems

2. Conference/meeting room space; photocopying, word

processing centers.

133
3. Telecommunications, services including long distance

voice and some data; telephone service using a building core

cabling system.

4. Sophisticated office automation and high speed

communication and data processing; wideband communication

for video conferencing.

13.2 CRITERIA FOR INTEGRATED SYSTEMS

* Integration of energy management, HVAC system operations

and maintenance, data acquisition and management, fire and

smoke management, and system alarms.

* Air handling system, fans, duct smoke dampers, outside

air, and exhaust dampers integrated with fire and smoke

controls

.

* State-of-the-art sensors.

* Distributed building automation system with stand-alone

field interface devices.

* Direct digital controls, as appropriate.

* Conventional/adaptive algorithms for HVAC system controls.

* Fire system overrides other systems when necessary; it is

always operational and secure from interference.

13.3 COMMUNICATIONS

With the breakup of AT&T, end users have many choices and are ill

prepared to make them in a cost beneficial manner; e.g. countless

systems are available and hundreds of vendors are selling

products for telephone service.

The telecommunication system switches and routes all voice and

data within the integrated building. It also connects internal

sources with the outside world. The PBX is used to route signals

originating in any of the building systems; e.g. a control signal

from the CPU of the management system to a fan motor; data

between a PC and the CPU. Telephone systems can provide speed

dialing, the ability to serve as an intercom, display messages

and conduct conference calls. For long distance calls, the PBX

can automatically select the least expensive routing path.

The capability of integrating communication, monitoring and

control systems reflect newly emerging technology which has only

been tested in a few applications. Each major function is likely

to have its own stand-alone processor with individual function

multiplexers connected to them. Subsystems which should be

considered for inclusion in an integrated network include:

* Voice and data communications.

* Office automation (and networking)

.

* HVAC, security, fire safety.

* Elevators.

* Lighting.

134
13.4 WIRING SYSTEMS

The problem of distributing signals within buildings still is

unresolved; i.e. how should signals be brought from the building

boundary to and from end-users through common areas. Often

signals must be transmitted over wires with different

characteristics. In order to cope with this new situation,

several design and construction issues require attention: (84)

1. The capacity of feed conduit, vertical risers, telephone

closets, telephone switching rooms, and tenant conduit.

2. Electricity. Is there sufficient power for the

installed and planned automated equipment and standalone

environmental systems; e.g. local HVAC units. Is the

quality and reliability of power appropriate?

3. The roof. Is it sufficiently strong to accommodate

antennas. Do risers extend to the roof?

4. Ceiling heights. Will the plenums accommodate cabling

and ducting needs? Is there space for raised floor designs?

5. HVAC systems. Are they sized for the new equipment?

Are there spaces for the standalone systems?

6. Are wiring diagrams updated to reflect changes?

7. Is it applicable to the widest possible array of tenant

needs?

8. Modularity. Is the design a modular, cost-effective

means of implementation to minimize cost and disruption of

ongoing work?

9. Can the system adapt to changing technologies readily

and at minimum cost.

13.5 MECHANICAL SYSTEMS

Energy management systems are designed to maintain a comfortable

and safe environment with efficient energy usage. Sensors

monitor temperatures throughout a building, with information

being transmitted to local microprocessors, which adjust fans and

dampers. Each area of the building can have the local

temperatures adjusted to the occupant's desires. The system can

account for usage by curtailing heating and air conditioning when

spaces are not occupied. During peak power usage periods, when

energy prices are higher, building temperatures can be lowered in

the winter and raised in the summer, yet kept within comfortable

levels. Sensors can be used to turn off lights when rooms are

unoccupied. Energy management systems to control light and HVAC

are important elements of intelligent buildings, but they must be

manned by people who fully understand how to operate them

efficiently

.

The major impact on mechanical systems has been a move away from

constant air volume (CAV) systems to variable volume (VAV)

systems. The reason for the change is to increase flexibility

and control. Conventional (CAV) multi-zoned systems are usually

limited to 10 to 12 zones per flow; with variable volume systems,

135
the number is unlimited. Air conditioning flexibility is also

important especially when limited data are available concerning

how many new computers will be provided for an organization. One

design approach to accommodate new equipment is to allow room for

additional cooling capacity when the load requires it. (85)

HVAC systems can adjust to changing environmental conditions and

to different internal requirements. For example, an office being

warmed by sunlight will be conditioned differently than an

interior office. Systems can keep track of exterior and interior

air temperatures and use outside air for cooling when conditions

warrant this approach.

13.6 FLOORING SYSTEMS

Other design approaches have been increased plenum depth from

four to at least five feet and pedestal flooring anywhere from 6

to 24 inches. The larger plenums accommodate overhead cable

trays that typically run above corridors and serve computers,

peripherals and telephone systems. The pedestal floors were

originally used for mainframe computers but are now employed for

general cabling requirements in many buildings because of their

easy accessibility.

13.7 CASE STUDY

The intelligent building is part of an evolutionary trend that in

the 1970's focused on energy management systems. One such

approach is the use of shared tenant services. The primary market

for the shared tenant services are tenants occupying less than

100,000 sq ft of space; three floors or less of a major office

building . (86)

The service provider owns the common equipment, processors and

terminals; tenants subscribe by paying a monthly fee for

services, include voice and telecommunications systems, work

station networking, PCs, electronic mail and filing, customer

training, consulting, on-site repair, operations .( 87)

City Place in Hartford, Connecticut exemplifies this approach. It

has an optical fiber cable used throughout the 38 story building.

* It is equipped with infra-red sensors which are used to detect

the presence of people; when spaces are unoccupied for 12

minutes, the lights are automatically turned off.

* Fire sensors ring an alarm, notify the fire department,

pressurizes the floors above and below the fire floor and

exhausts the smoke from the fire floor.

* A Lexar digital telephone system is used to transmit data and

voice information simultaneously. It can be used to transmit

reports from one workstation to another and uses a least cost

routing scheme for long distance telephone conversations; lines

are bought by United Technologies from major carriers and the

service is resold to tenants.

136
* Tenants can lease computer hardware and software.

Merrill Lynch, a major tenant in City Place, has its own system

because it couldn't take the chance of sharing telephone service;

most of its business is transacted by telephone and availability

of lines is essential to its operations. Internal control of its

own network is paramount.

13.8 CHECKLIST FOR SYSTEMS INTEGRATION

* Which functions are integrated/controlled?

* Which functions can or must be controlled separately?

* For each major integrated function, what operations are

controllable, and what features of control, programmability,

input/output, display, etc. are available?

* What is system architecture, i.e. central/distributed;

redundancy, sensor types, conductor media?

* How does the system assure reliability?

* What is done to protect functions, zones, the entire

system?

* What manual backup systems are available?

* Who provides emergency repairs; how long will it take?

* What are initial and operating costs of system (including

maintenance and repairs)?

* Does the system require dedicated staff to monitor and

operate it? If so, what training and experience is needed?

* What are special physical requirements of the system, e.g.

size of central and distributed processors, control panels,

HVAC and power, cable runs?

13.9 INTELLIGENT BUILDING MANAGEMENT DECISIONS

Among the questions to be answered by tenants and facility

managers are:

* How much growth is anticipated in the next 5, 10 years?

* What are the initial and long term costs of technology

and design implementation?

* How reliable are the technologies and systems?

* What are the cabling system requirements for voice, data,

video?

* What is the viability of shared tenant services? e.g.

what are costs/benefits; what support personnel are needed;

should it be done in house or managed externally?

137
13.10 DESIGN ISSUES FOR INTELLIGENT BUILDINGS (88)

* The integration of technologies in existing organizations and

their assimilation by users in their daily work.

* How to include technological factors in the design process.

* Office design based on system concepts rather than focusing on

micro issues such as individual hardware components.

* More new and small firms are being formed; they often are more

innovative than larger ones and more likely to employ the latest

technologies

.

* Larger organizations are delegating more decision making to

subordinate groups; technology is fostering decentralization.

They are also providing less technical and service support.

* Building designers are being asked to provide support such as

health and athletic center, day care facilities, etc.

* The ratio of professional and staff members is changing; fewer

support personnel are employed.

* Advanced telecommunications has enabled companies to disperse

operations geographically; small suburban centers are becoming

popular in contrast to large centralized operations.

Table 26. SMART BUILDING CHECKLIST (89)

I. PROJECT BACKGROUND

1. Who is considering enhancing the structure? Why?

2. Are the structure and tenants good candidates for

building enhancements? If so, what criteria used to

determine?

3. What support services are currently available to be

shared?

II. BUILDING STRUCTURE

1. What wiring technologies are used within building?

2. What provisions are made for future enhancements?

3. How will technology changes affect the support systems,

e.g. HVAC

.

4. What flexibility is available to tenants who move or

require added space?

5. How would the cost and design of the following support

systems be affected by proposed enhancements?

* Electric power, air conditioning, fire protection

* Direct design and materials costs; e.g. space,

ceiling heights, vertical risers, floor ducting, space

for equipment, floor loading.

* Wiring system specifications, e.g. conduit, cable

* Security and alarm systems.

6. What are design and coordination tradeoffs between

retrofit and new design?

7. What provisions are there for tenant service expansion?

8. What specific design aspects of the building (other than

wiring) are affected, e.g. satellite dish?

138
III. EQUIPMENT TECHNOLOGY

1. What are technical specifications of the PBX switch, e.g.

maximum capacities of trunk groups, consoles, class of

service?

2. Is the existing tenant equipment compatible with the

proposed system?

3. How were the tenants' communications needs determined?

4. What voice and data features are available with the PBX?

5. What types of data and word processing equipment will be

used? What other systems will be employed?

6. What communications systems will be used; local area

networks, microwave, satellite, etc?

7. What specialized common carrier services are offered? How

are they accessed?

8. Does the building owner have the option of specifying and

owning cabling systems and control, if the vendor's products

do not perform properly.

9. How is the PBX upgraded to access new technologies?

10. What is signal distribution system; how does it handle

multiple local area networks, different data processing

protocols? Will the tenants require a separate cable plant

to handle voice and data systems?

IV. SYSTEM MANAGEMENT

1. Is there a detailed plan for systems maintenance?

2. How can tenants subscribe to partial services, to

complement equipment and services already owned.

3. What are the backup services available to deal with

system malfunctions?

4. What centralized monitoring and control functions are

available? Who performs functions? Provide details.

Table 27 describes the possible design impacts of

integration and telecommunication systems.

139
Table 27. Integration and Telecommunications Systems- Possible

Design Impacts (43)

ISSUES

INTEGRATION SYSTEMS

* Voice/data interface

• Security

• Electrical

• Fire-safety

Environmental

* Telecoamunlcatlons

- Telephone Systems

- Local area networks

- Point-to-point

and external

communications

systems

- Facsimile (FAX)

Systems

- Types of Cable

PRESENT OFFICE AUTOMATED OFFICE POSSIBLE IMPACT

Separated Integrated using

state-of-the-art

equipment

- Less space

- Power cables

- Raised., flooring

- overhead ceilings

with plenum

Patch panels

- Distribution systems

- Data highways

Stand-alone Integrated - Electronic sensors

- Fewer personnel

- Less space

- Maintaining devices

Decentralized Centralized and

Integrated

- Automated

- Cabling

- Lighting control

- Monitoring system

Separate system Integrated with

"Central nervous

Systems

- Sensors

- Automated

- Alarms

- Wiring

Separate heating and

A/C systems

Energy management

system

- Automatic control

- Wiring

- Less space

- Central control

Stand-alone voice Combine voice/data

(Digital PBX's)

- Different cabling requirement

- Less equipment room space - Less equipment

- Network Implications

Decentralized, standaloneCentralized, integrated - Combined with other equipment

systems

- Cabling requirements

- Interface

- Interoperability

- Equipment definition

- Structure requirements

Dedicated Telephone

lines

Hybrid (satellite,

microwave fiberoptic, and telephone

lines)

- koof antennas - Cabling

- Site surveys

- Space for concentrators

- multiplexors, etc.

Stand-alone A network Integrated

with other systems

- Interfaces

- Cabling

- Environment consideration

Multipair (3+) twisted

copper, coaxial cable

Large capacity fiber

trlaxlal

Radio and/or Infrared

Multimedia in single

jacket

Twisted fiber; coax replacement

- Increased sice, protection

of equipment In closet

- More space needed for closets, vertical

cable distribution

140
14. OFFICE MATERIALS (90)

14.1 NATURAL AND SYNTHETIC FABRICS (27)

14.1.1 Function

Aside from its other practical and aesthetic features, a major

purpose for the use of fabrics is to contribute to the desired

acoustical performance of the automated office. Fabrics are used

extensively for floor coverings, furniture and panel systems, as

a means of controlling noise and enhancing auditory privacy.

14.1.2 Criteria - Checklist (Fabrics)

* Permanency. Will the fiber content fade in the sunlight

or disintegrate with age?

* Moisture and mildew resistance. Does the weave allow

dimensional stability for dry and humid conditions? Will

dampness promote mildew or outgassing of chemicals?

* Maintenance. Is it resistant to abrasion? Can it be

washed, dry-cleaned or refinished?

* Fire resistance. Is it flameproof? Will it melt and

produce dangerous flames and/or fumes?

* Installation. Is it easy to work with? Can it be easily

replaced?

* Thermal resistance. Will it expand or contract with

thermal absorption?

* Weight. How heavy is the material? Can it be easily

handled?

* Sound absorption. What are its characteristics with

respect to absorbing, dampening, reflecting sound?

* Appropriateness. Is it consistent with the uses of the

space?

* Availability. Can the material be obtained for

replacement and expansion purposes; for how long?

* Decorative palette. How varied are the colors and

textures?

* Price. Is it cost effective?

* Aesthetics. Is it attractive?

* Electrostatic buildup. What are electrostatic features?

Table 28 presents the positive and negative carpet materials. features of

141
14.1.3. Carpet Material Characteristics

MATERIAL TYPE POSITIVE FEATURES NEGATIVE FEATURES

WOOL * Warm, soft, resilient * Supports static

* Fire and mildew * Expensive

resistant

* Doesn't attract dirt

* Resistant to aging

and abrasions

* Good color fastness

to sunlight exposure

NYLON * Very tough material * Melts on contact with

* Good static control flames

* Resistant to mildew * Attracts dirt

* Resistant to aging

and abrasions

* Blends with other

fibers

POLYESTER * Water resistant, soft * Loses strength with

* Resistant to mildew sun exposure

* Resistant to wear

and abrasions

ACRYLIC * Good wearing * Poor soiling and

properties cleaning properties

* Resistant to sunlight

* Abrasion resistant

* Low static electricity

POLYPROPYLENE

(OLEFIN)

* Resistant to acid, * Low heat resistance

chemicals

* Resistant to mildew,

water

Table 28. Carpet Materials - Positive and Negative Features

142
14.2 CARPET TILE

Office automation has led to the increased use of carpet tiles

for floor coverings. Their modular design provides underfloor

accessibility, easy maintenance and replacement consistent with

the need for flexibility.

14.2.1 Criteria

The following performance features are important when carpet

tiles are employed:

* Abrasion resistance and wearability.

* Appearance retention; the ability to withstand crushing,

fading, soiling and maintenance.

* Proper maintenance.

* Appropriate combustion and smoke performance

characteristics

.

* Inhibiting the accumulation of static electricity through

built-in special fibers, wires or coatings.

* Cost-effectiveness as compared with the materials and

maintenance cost of alternative choices.

* Maintenance of critical performance features after initial

installation, e.g. loss of adhesion.

Figure 26 shows typical static

on common floor surfaces. voltages generated by walking

143
Figure 26. Typical static voltages generated by walking on common

floor materials (18)

.

144
15 SPECIALIZED SPACES

15.1 OVERVIEW

A comprehensive literature search, a questionnaire survey and a roundtable meeting formed the basis for the information in the

present document. These activities, augmented by interviews with

architects and other professionals, resulted in identifying

specialized spaces which merit consideration in designing for

office automation (91)

.

* An atrium. This can be used to offset the technological

emphasis of automated offices by providing a connection with

the outside, a change in scale, and a place for social

contact

.

* Training and media presentation rooms. Organizational and

technological changes occur so rapidly that a continuing

need exists to upgrade personal skills and transmit

information to staff members.

* Meeting rooms. With the popularity of open-space design,

fewer spaces are available for private meetings of small

groups. Such spaces, and those accommodating more people

are required to facilitate staff interactions, and offset

the isolation inherent in many VDT-based activities.

* Centralized reproduction facilities. New and

sophisticated systems provide the capability to produce

documents with the quality formerly available only from

printers. The cost of such systems can only be

justified by organization-wide use. These systems are

usually quite noisy and should be acoustically isolated from

the general work floor. Merging of computerized printing,

image processing and reproduction facilities is a recent

development

.

* Centralized information storage. For the foreseeable

future, paper will continue to be an important media for

storing information. In addition, microfiche, magnetic tape

and disks must be stored. The latter two types of storage

require careful environmental control.

* Centralized communications and information processing.

More offices are likely to contain CPUs and systems such as

telex and facsimile reproduction. Such equipment require

specialized spaces and facilities for occasional users.

* Decentralized computer/controller facilities must be

located throughout the building to satisfy future cluster

controller and/or standalone CPU requirements.

* Equipment areas. As more technology is moved into the

office, more spare parts, cables , replacement systems and

1^5
facilities for maintenance and checking are all needed. The

demand for these resources will accelerate as office

activities depend more on automation, equipment outages

being very costly to productivity.

* Equipment staging areas are required.

* Clusters of offices, grouped according to similar

activities

.

* Furnishing storage. With the popularity of open-office

design, the increased acceptance of ergonomically responsive

furnishings (tailored to individual needs) , and the need to

respond rapidly to change, there is a substantial need to

maintain an inventory of furniture, panels, etc.

* Convenience rooms for copiers, printers, etc.

* Magnetic media storage. Careful environmental control is

required to ensure that information is preserved. Warping

and stretching occurs in hot environments. Low humidity can

cause problems due to static buildup, allowing dust and dirt

to accumulate. Variable environmental conditions can affect

the longevity and reliability of media performance. Among

other potential problems are:

- Magnetic fields. Media should be kept away from

transformers or large motors that generate magnetic

fields. (This might influence the placement of UPS

systems .

)

- Shock and vibration. These conditions can cause

discs to lose information.

- Chemical solvents. Volatile chemicals can degrade

media, and should not be stored nearby.

15.2 TELECONFERENCE FACILITIES

15.2.1 Function

The high cost of travel and the proliferation of organizational

meetings has increased the demand for the capability to conduct

meetings remotely. The technology required to accomplish this

has been available for some time, with costs being the major

obstacle. Technological advances have resulted in substantial

economies and increased communications capabilities, and it is

anticipated that teleconferencing facilities will become more

commonplace in the near future. Special presentation skills and

meeting formats are required for successful teleconferencing.

A teleconference is a meeting involving two or more people at two

or more different locations, with discussions being transmitted

through audio, digital, and/or video techniques. Video

teleconferencing offers the greatest potential for substituting

146
for meetings because of the availability of powerful technologies

to simulate a live meeting.

15.2.2 Criteria

* The room should facilitate the communication of verbal and

visual information and reflect the design needs of the

system vendor.

* The space should be free from visual and noise

distractions

.

* Required support equipment should be readily accommodated

without impairing communications.

* Room decor should be consistent with normal work areas

major users.

15.2.3 Environmental Context

* The room location should be suitable for the expected

users. It should not be part of an executive suite, unless

top management are its primary users. Middle managers often

make the most effective use of these facilities.

* The room should be located away from mechanical devices

such as elevators, central air conditioning and heating,

major systems such as PBX's and computer rooms, and from

street and office sounds.

15.2.4 Support System Considerations

15.2.4.1 Acoustics

* Existing rooms are often converted to teleconference

facilities, creating acoustical problems in some instances.

Most such rooms are constructed of standard building

materials that are 4 feet by 8 feet rectangles. These

dimensions often lead to a room designed with a ratio of

length of width to height of 3:3:1, which reinforces many

negative acoustic properties such as reverberation. A ratio

of 5:3:2 is more preferable. A still more effective way

of reducing acoustical problems is to use non-parallel walls

and/or having large pieces of furniture in the space to

scatter sound.

* Careful acoustical treatment of all surfaces, walls,

ceiling, and floors is required in such facilities.

* The noise from the support equipment can be minimized by

locating HVAC equipment required for teleconferencing in

acoustically isolated adjacent spaces.

15.2.4.2 HVAC Equipment

In a fully equipped room containing facsimile systems and VDT

equipment, provisions must be made for proper ventilation and for

the air conditioning equipment.
15.2.4.3 Lighting and Color (92)

* Because of the need to see people and visual displays

clearly, lighting and color selection for the room are of

critical importance.

* Room surfaces should be non-specularly-ref lective . The

colors selected, including those of carpets and furnishings

should have neutral tones.

* The system vendor should participate in the decision

process for making lighting and color selections.

15.3. DATA CENTER

15.3.1 Function

The data or computer center houses the mainframe computer and

supporting equipment in large organizations.

15.3.2 Background

A controlled environment is the major goal in planning and

designing data centers; rooms must be dust free, cool and antistatic. Fluctuations in power, temperature, humidity, or air

distribution can cause severe problems. The room should have

compartmentalization of functions when possible; e.g. printers in

separate rooms because they do not have same environmental needs.

The center must have adequate and reliable power sources; the

site should accommodate a flexible communications network,

including land lines, line-of-sight microwave, and satellite

facilities. Construction activities near the site can be

disruptive; e.g. severed power lines, power fluctuations,

disruptions of power as well as dust and broken water lines.

The computer room is the heart of the center. Its size depends on

the system employed. The design must have adequate space for

current needs and provisions for growth and expansion. This can

be accomplished by locating staff lounges, maintenance, repair

and storage spaces nearby. These facilities can be relocated when

systems are upgraded and two systems must be colocated to avoid

shutdown of operations. (93)

The computer room should have a raised access floor from 15-18"

in height to accommodate cabling and air plenum for direct

cooling of equipment. Electronic storage is usually adjacent to

the computer room. If the data center relies heavily on phone

lines for data transmission, a separate telecommunications space

is required to house equipment. If data are generated in-house,

a data entry space must be provided.
General Checklist: (94)

* What is the age and general condition of the building?

* What is the occupancy schedule?

* What will be located above and below the data center?

* Will the building be owned or leased by the organization?

* Is there a freight or service elevator; is it large enough

to carry needed equipment and supplies?

* Is the clearance between floors adequate?

* Are the load-bearing columns adequately spaced for center?

15.3.3 Criteria for Computer Room Design (95)

* Visual security from main streets

* Controlled access to CPU

* Windowless for security and to minimize moisture infiltration

and exfiltration

* Closely regulated temperatures, humidity and air quality

* Process cooling to accommodate equipment

* Vapor sealing on ceilings, walls and floors to maintain proper

humidification

* Served by two independent electrical power sources

* Located away from major microwave transmissions

* Backup and/or UPS

* Circulation corridors around manned and unmanned machine rooms

for added security

* Unobstructed flexible open area with expansion capabilities

* Floor-to-ceiling height sufficient for raised access floor

* Support systems located apart, acoustically isolated when

needed

* Floor drains

* Fire detection and suppression system

15.3.4 Air Conditioning

Clean, warm, moderately moist air is needed in data processing

centers to assure optimal computer, peripheral and memory

performance and longevity. Air conditioning accomplishes two

purposes:

* Provides cool air mainly by removing heat:

- produced by electronic hardware

- transmitted across room boundaries

- produced by people

- brought in with ventilated air

* Provides latent cooling, which condenses water vapor from

the humid ventilating and infiltrating air, and moisture

generated by occupants.

Computer room air conditioning systems are primarily "process

cooling" type systems; human comfort is not the primary concern.

Considerably more air must be circulated through cooling coils

149
than in traditional systems. Special humidity requirements make

the introduction of outside air undesirable. (96)

Process cooling systems maintain humidity, temperature and air

cleanliness control. Most such systems are direct feed types,

pumping air directly into the computer room through the cavity

beneath the pedestal floor, which provide space for the cooling

units, processed air, and cabling. Vapor sealing of floors, walls

and ceilings minimizes moisture migration from outside and inside

computer areas, ensuring proper humidity control.

Computer equipment requires year round cooling with close

humidity and temperature control. Prepackaged downflow air

conditioning units with integral automatic controls should be

used to maintain uniform temperatures (72 degrees F, + or - 2

degrees) with relative humidity of 50 % (+ or - 5 percent)

.

Domestic cold water is needed to each air conditioner for

humidification. Redundant air conditioning units should be

available as backup for working units.

15.3.5 Electrical Power

Electrical power can seem to be an uncontrollable resource; the

power quality delivered to a site must be used, whether supplied

by a private or public utility or self generated. Riding along

on the electrical wave are noise spikes, surges, caused by

lightning, switching transients, or other equipment working

nearby. Brownouts and total loss of power are other dangers.

Clean electrical power is essential and backup power and UPS

systems are both used to guard against outages and fluctuations.

The best design is to have dedicated power to the center. When

backup power and/or UPS systems are used, space is required to

house equipment. A 3- phase, 5-wire power distribution should be

provided. Average power loads range from 25 watts/sq ft to 50

watts/sq ft. Power requirements differ significantly from system

to system; varying from 50% to 100%, depending on the

manufacturer. "Less expensive" computers often cost far more in

the long run, when taking energy usage into account.

15.3.5.1 Electrical Power Checklist (97)

1. Importance of trouble free operations of center.

* How much down time is tolerated; length of each,

frequency?

* What can interrupt ADP power; e.g. HVAC plant?

* Are operations dependent on communications lines requiring

continuity of power?

150
2. Site location problems- is site subject to:

* Natural hazards- storm damage, winds, snow

* Man-made hazards- vandalism, sabotage, vehicular

collisions

* Offsite damage to communications and power

* Are building and/or electrical codes overly restrictive?

* Are there backup distribution lines in case of failure of

main one?

3. Quality of power.

* Review power outage and disturbance records of utility.

* Ask other major users about power quality.

* Plan to have HVAC equipment power separated from ADP

power

.

15.3.6 Fire Detection and Suppression

The data files should be properly protected with the latest fire

and security systems. Speed is critical and state-of-the-art

detection and suppression devices are worthwhile. Ionization or

photoelectric detectors in the ceilings and underfloors are

preferred because of their sensitivity to fire conditions and the

capability to automatically trigger fire suppressants and alarm

signals. Halon based systems are very effective because of their

speed and minimal damage and disruption to computer systems. The

alarm systems should be interconnected to a central system.

Fire extinguishing agents such as water and chemicals can cause

extensive damage to sensitive electronics and magnetic storage

media. Irreplaceable program documentation and business can be

destroyed. To reduce these risks, the computer room should not

be located near external fire hazards, and combustible materials

should not be stored nearby. Early warning fire detection

equipment is necessary, and air circulation and ventilation fans

should be connected to the fire detection system.

15.3.7 Security

Security depends on the building location, the surrounding areas,

the interior layout, and the location of the computer room.

Security precautions start at the street level and work toward

the computer room. It should be zoned; e.g. separate entrances

for employees and visitors, card-readers based on need-to-enter

,

alarm doors to limit passage. Sound, motion, and heat sensing

devices as well as close circuit television systems are all

useful in monitoring access to sensitive areas.

Entry to the room is monitored by a guard, a code operated

electric door, or both. Placing the room in an enclosed

inconspicuous location provides additional protection.

151
Once admitted to a computer room, access to specific memory

tapes, disks, control terminals and operating consoles may

require added identification.

A central security console should be employed to monitor all

systems and components. The console should be the termination

point for all protection and monitoring systems and devices.

Trained personnel should be employed for this function.

15.3.8 Raised Access Floors

This is the most convenient method of ensuring that equipment and

systems can be readily updated and moved with minimum disruption

to normal work activities. It provides ready access to

ventilation, communications, power, and other building systems.

Raised floors are subdivided into portable panels, permitting the

exchange of plain panels with those with ventilation registers or

cable exits.

The loading rating of the should be between 100-150 lbs per sq

ft; with floors for UPS and backup power requiring more capacity.

The walls should have 2 hour fire resistant ratings. Access

floors should have at least 12 inches of clearance to house all

of the necessary cabling; with 18 inches preferred if possible.

15.3.9 Lighting

The recommended approach is a combination of task lighting and

indirect or parabolic lens ceiling lighting at a reduced level.

Adjustable swivel arm task lighting is especially appropriate

because it facilitates personal control.

152
16. SUMMARY AND RECOMMENDATIONS

Developing appropriate designs for new office technologies poses

a major challenge to the design and engineering professions.

Since office automation is a relatively recent phenomenon, and

not yet subject to systematic study, it is premature to formulate

performance criteria for office settings. However, designers

have coped with new technologies for more than a decade using a variety of design practices. These practices, together with

published material in design and research publications, form the

basis for this report. Since developments in this field have been

rapid, a mechanism should be developed to acquire current

information - perhaps by means of conferences or workshops,

jointly sponsored by federal agencies and the private sector.

Office automation has profoundly affected the office as a place

to work in ways not well understood. General agreement exists

among office automation experts however that a diversity of

interdependent issues merit consideration when planning to

automate office functions. These issues include:

management , informat ion processing, human resources (ergonomics),

telecommunications, technology, and design.

The differences between traditional and automated offices has

increased the importance of office design as a contributing

factor to organizational effectiveness. In traditional offices

considerable opportunity exists for personal interaction among

employees. For example, since most information is in paper form,

it must be handled and transmitted manually from person to

person. Exchanging information and report writing therefore

provides the opportunity for conversation and social exchanges.

There is also a one-on-one relationship between the person

initiating a document and the one responsible for putting it in

final form, e.g. typing it.

With the advent of electronic based information systems, a person

at a workstation often communicates only with a VDT-based

terminal during an eight hour workday. Little need exists in

many activities to work personally with office colleagues. As a result, office workers have complained about a sense of

isolation, and being subservient to technology (1) . Office

design can be used to alleviate these problems by providing

places for informal conversations and a general appearance which

provides visual relief from technology.

Technology has influenced the composition of the office

workforce. More professionals and managers are in the workforce,

as a greater percentage of people engage in white collar work.

These knowledge workers want a "high quality" work setting,

responsive to the mental and physical demands of their jobs.

Questionnaire surveys have identified a desire for visual and

auditory privacy, glare-free lighting, and control of the

immediate environment as important design issues for knowledge

workers (4)

.

153
Unfortunately, as the quality of the work environment has become

more important, introducing technologies into offices has

frequently resulted in deteriorated environmental quality, e.g.

machines producing noise and heat placed on desks designed to

support paper-based activities. This has occurred because office

automation has been largely hardware-driven, i.e. machines and

systems being purchased because they purportedly increase office

productivity. All too often insufficient planning typifies the

automation of office functions, especially with respect to design

consequences (9)

.

Looking toward the development of design criteria for office

automation, improved information is needed in the following

areas

:

* Determining the effectiveness of design practices used to

date. Considerable experience has been gained by the

federal government and the private sector, but few

systematic findings are available in the public domain.

Evaluations of approaches that "work" or don't "work" would

result in considerable dollar savings.

* In recent years, office design has employed open-space

planning for traditional and automated office functions.

Yet, surveys of office workers indicate many problems with

such designs. Post occupancy evaluations of these designs

should be conducted.

* Technological advancements have permitted the automation

of many building systems, operational, service and

environmental. However, tradeoffs associated with

automation are not well understood and require

investigation. For example, studies have shown that workers

want more, not less control of their workspaces and

environments (5)

.

* The integration of operational systems with other building

service systems is receiving considerable attention by

designers, but little consensus exists as to how to achieve

this result. Field studies are required to develop the data

needed for design criteria to accomplish this important

function

.

* In response to the need for better office automation

planning, an improved architectural programming process is

needed. It should facilitate the incorporation of

technologies into offices while minimizing the disruption of

ongoing activities, and do so in a cost effective manner.

154
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GLOSSARY

ACCESS TIME- The time interval between data request and delivery.

ACOUSTIC COUPLER- A modem enabling a remote device to be

connected to devices or data bases using a conventional

telephone, dialed over a leased public line.

AMBIENT LIGHTING- Lighting throughout an area that produces

general illumination.

ANALOG COMPUTER- A calculating machine that operates with numbers

represented by directly measurable quantities (as voltages,

resistances, or rotations).

ANTHROPOMETRY- The study of human body measurements, especially

on a comparative basis.

AI- Articulation Index

ARPANET- A set of autonomous, interconnected, and independent

computer centers which use a standard transmission method to

permit interactive resource sharing among all participants —set

up by ARPA (Advanced Research Project Agency)

.

ARTICULATION INDEX- A numerically calculated measure of the

intelligibility of transmitted or processed speech. It takes

into account the limitation of the transmission path and the

background noise.

ASCII- American Standard Code for Information Exchange. A coding

system for characters of seven bits plus one parity bit, for

transmission over a data network.

ASHRAE- American Society of Heating, Refrigerating, and Air

Conditioning Engineers, Inc.

ASYNCHRONOUS- A transmission sequence where the intervals between

characters are not equal; start and stop bits are added for

coordination

.

ASYNCHRONOUS MODEM- A communications channel capable of

transmitting data but not able to time the information.

AUXILIARY STORAGE- Any peripheral device where data may be

stored, e.g. disk, tape.

BASEBAND- The band of frequencies occupied by all transmitted

signals used to modulate the radio wave produced by the

transmitter in the absence of a signal.

BATCH PROCESSING- A technique that uses a single program loading

to process many individual jobs, tasks or signals for service.

BAUD- A measure of the transmission speed capability of a communications line or system. In a sequence of binary signals,

1 baud =1 bit/sec.

BINARY CODE- A coding system employing the binary digits one and

zero to represent letters, digits, or other characters in a computer

.

BIT- The smallest entity in the memory of a computer

BITS PER SECOND (BPS)- A measure of data transmission speed,

equal to the number of changes per second.

BPS- Bits per second.

BRIDGE- Circuitry used to connect networks with a common set of

high-level protocols.

BROADBAND - A band with a wide range of frequencies.

BUFFER- A small storage space, used for temporary storage of data

before processing.

159
BUS- A length of coaxial cable, to which microcomputer stations

are attached.

BYTE- A term used to describe the storage in a computer; it may

contain 8, 16 or 32 BITS, depending on the computer design.

CENTRAL PROCESSING UNIT- The computer at the center of an on-line

system which performs the processing according to the

applications package.

CIS- Computer based information system.

CLUSTER- A data network in which two or more terminals are

connected to a line or data channel at a single point.

CMBS- Computer based information system.

COAXIAL CABLE- A transmission line in which one conductor is

contained inside and insulated from an outer metal tube that

serves as a second conductor; used for networks and connecting

terminals to mainframe computers.

COEFFICIENT OF UTILIZATION- The ratio of luminous flux (lumens)

from a luminaire calculated as received on the work-plane to the

luminous flux emitted by the luminaire's lamp alone.

COM- Computer output microfilm

COMMAND LANGUAGE- A type of dialogue in which the user formulates

control entries with minimal prompting by the computer.

COMPUTER MAIL- The transmission of messages using computer

systems. CPU - Central processing unit

CONTRAST RENDITION FACTOR- The ratio of visual task contrast with

a given lighting environment to the contrast with sphere

(uniform) lighting.

CORE STORAGE- The memory or internal storage of a computer.

CPU- Central Processing Unit.

CRITICAL SUCCESS FACTORS (CSF) - Those activities most important

in performing major job functions.

CU- Coefficient of Utilization.

DATA BASE MANAGEMENT SYSTEM- General purpose programs that accept

data in a format determined by the user, process, the data, the

output it in a desired format.

dB- Decibel.

DBMS- Data base management system

DDP- Distributed data processing

DECIBEL- The unit of sound intensity.

DECISION SUPPORT SYSTEM- A computer information system designed

for managers and professionals, using simplified interactive

programming with access to one or more data bases.

DIALOGUE- A structured series of interchanges between a user and

a terminal. They can be computer-initiated (question and

answer) or user controlled by a command language.

DIFFUSER- A device to redirect or scatter the light from a source, primarily by diffuse transmission.

DIGITAL SWITCH - Interconnecting data, word processing, and

telephone equipment by a digital PBX

.

DISABILITY GLARE- Glare resulting in reduced visual performance

and visibility.

DISCOMFORT GLARE- Glare producing discomfort; not necessarily

interfering with performance

DISTRIBUTED DATA PROCESSING- Sharing of computing among several

computers at different locations.

160
DP- Data processing

DSS- Decision support systems

DUPLEX- The ability to simultaneously transmit and receive signals

over a network.

DYNAMIC DISPLAY- A display that changes automatically as a result of

system action.

EDP- Electronic data processing.

EFFECTIVE TEMPERATURE- A combination of air temperature, air velocity,

and relative humidity, used to define a thermal comfort zone for people

in buildings,

ELECTRONIC MAIL- An electronic system using communications lines,

computers, CRT and hard copy terminals to transmit documents and

messages to individual addresses.

ERGONOMICS- A subject are which deals with the interaction of

person/machine and person/environment issues.

ET- Effective Temperature.

ETHERNET- An baseband local network, with several microcomputers,

based upon workstations performing a given function, with data

processing capability.

FACSIMILE- Analog or digital transmission of page images.

FDM- Frequency division multiplexing

FEEDBACK- A response from the system which informs the user of the

status of current requests or commands.

FIBER OPTICS- Very thin strands of glass, used to transmit information

by means of light pulses.

FILE- A collection of related records, usually arranged sequentially

according to a directory key contained in each record.

FIRMWARE- Routines wired into the computer as part of the circuitry.

FLANKING PATH- Noise transmission by an indirect path, e.g.

structural element.

FLOPPY DISC- A small mylar data storage device, resembling a phonograph record.

FRONTEND SYSTEM- The part of the computer system that interprets what

the user specifies, and interacts with the "background" of the system,

which performs the detailed operations desired.

FULL DUPLEX- The simultaneous independent transmission of data in both

directions over a communications line.

GATEWAY- System and software permitting networks using different

protocols to communicate with one another.

HABITABILITY- The impact of the environment on the behavior of

building users with respect to their welfare, task performance, and

job satisfaction.

HALF-DUPLEX- Users can transmit data in one direction at a time, with

each user signaling a completed transmission before the next one can

begin

.

HERTZ- Cycles per second

HID- High intensity discharge

HIGH INTENSITY DISCHARGE- A general group of lamps consisting of

mercury, metal halide, and high pressure sodium sources.

HOST COMPUTER- A system in a network performing data processing

operations and with which network nodes communicate.

IBD- Institute of Business Designers

IEEE- Institute of Electrical and Electronic Engineers

IES- Illuminating Engineering Society

161
IEEE- Institute of Electrical and Electronic Engineers

IES- Illuminating Engineering Society

IESNA- Illuminating Engineering Society of North America.

INTELLIGENT TERMINAL- Terminal with limited programming

capabilities such as format creation and parameter definition.

INTERFACE- An electronic device enabling one item of equipment to

communicate with or control another one.

INVERTER- A device that converts low-voltage DC to high-voltage

AC.

IS, I/S- Information system

ISO- International Standards Organization

JOYSTICK- Manual input device for graphic display consoles, which

allows the user to specify 2 dimensional or 3 dimensional

coordinates

.

KBITS- Kilobits

KHZ- Kilohertz

KILOBITS- Thousands of bits.

KNOWLEDGE WORKER- A person with a major responsibility for

developing, analyzing and/or acquiring information, e.g.,

professional, manager.

LAMP LUMEN DEPRECIATION FACTOR- The multiplier used in lighting

calculations to relate initial rated output of light sources to

the anticipated minimum output based on the relamping program to

be used.

LAN- Local area network

LOCAL AREA NETWORK- Systems of computers and peripheral devices

linked together in adjacent offices or buildings.

LUMINANCE CONTRAST- The relationship between the luminance of an

object and that of its immediate background.

MAINFRAME- The central processing unit of a large computer

system.

MANAGEMENT INFORMATION SYSTEM - A computerized procedure for

providing managers with immediate knowledge, information, and

data needed to make decisions , direct people, and regulate

operations to better attain organizational goals.

MANUAL PROCESSING- Any data processing operation performed by

hand

.

MBITS- Megabits

MEGABITS- Millions of bits

MENU- A type of dialogue in which the user selects from a number

of displayed alternatives.

META LANGUAGE- A set of symbols and words used to describe

another language (in which these symbols do not appear)

.

MHZ- Megaherts

MICROCOMPUTER- A term describing the small physical size of a computer

.

MICROGRAPHICS- The capture, retrieval, and display of

miniaturized, high-resolution photographic images containing

either textural or graphic information.

MINICOMPUTER- A computer whose physical size is between a microcomputer and a full size computer.

MIS- Management information system

MICROCOMPUTER- Used to described the small physical size of a computer

.

162
MODEM- A device the converts analog signals to digital ones and

visa versa (MOdulator/DEModulator)

.

MULTI -DROP-LINE- A circuit dedicated to communications among

multiple terminals and peripherals on the same circuit.

MULTIPLEX- to interleave or simultaneously transmit two or more

messages on a single channel.

NC CURVES- Noise Criteria Curves.

NODE- A single station in a local area network

NOISE CRITERIA CURVES- Criteria to rate the acceptability of

continuous noise levels for performing given activities.

0A- Office automation

OCR- Optical character reader

OFF-LINE SYSTEM- A system configuration in which the input/output

devices, such as terminals, are not in direct communication with

a central processor.

ON-LINE-SYSTEM- A systems configuration where input/output

devices, such as terminals are in direct communication with a central processor.

OPEN SYSTEM INTERCONNECTION- A model developed by the

International Standards Organization (OSI) to describe a network

open to equipment from different manufacturers.

OPERATING SYSTEM- Software routines for interfacing activities of

system components (e.g. disks, CRT's, printers), tailored to each

device

.

OPTICAL CHARACTER READER- The reading and identification of

characters optically, under computer control.

OSI- Open system interconnection

PABX- Private automatic branch exchange

PACKET SWITCHING- A transmission method in which data are

assembled in small packets before being transmitted from node to

node across the network.

PARITY- The condition of the number of items in a group, e.g.

bits in a byte, being odd or even; to check for errors.

PARITY CHECK- The automatic transmission of additional parity

bits to enable the receiving device to check the accuracy of

transmitted data.

PBX- Private branch exchange

POINT-TO-POINT- Dedicated transmission between two devices.

POLARIZATION FILTER- A type of screen filter reducing the

reflection of the incident light on the screen.

POWER SURGE- An increase of voltage levels 10% or more above

normal, lasting from one half cycle to several seconds.

PROTOCOL- A set of rules governing the format, timing and error

control of messages, to ensure compatibility of data transmitted

over a network

.

PROTOCOL CONVERTER- Enables ASCII terminals and microprocessors

to function in various mainframe and other environments.

QWL- Quality of working life

RAM- Random access memory

RANDOM ACCESS MEMORY- Solid state machine memory, independent

from external storage.

READ ONLY MEMORY- Routines and languages wired into a plug-in

circuit card.

163
REFLECTED GLARE- Glare from specular reflections of high

luminances on polished or glossy surfaces in the field of view.

RF- Radio frequency.

RH- Relative humidity.

RING- A network topology in which stations are arranged in a circle

.

ROM- Read only memory

RS-232-C- An electrical standard used for serial ports.

SCIENTIFIC MANAGEMENT- Analysis of tasks into smallest possible

standard components; "time-and-motion" studies to increase

productivity

.

SEMANTICS- The meaning of language intended by the originator of

a message.

SERIAL DATA TRANSMISSION- A method of data transmission whereby

characters or bytes are sent one bit at a time over a single

path

.

SERIAL PORT- An input/output port that transmits data one bit at

a time.

SIGNAL TO NOISE RATIO- The ratio of signal intensity to noise

intensity, usually expressed as the decibel difference between

the signal and noise levels.

SIL- Speech Interference Level.

SNA- Systems Network Architecture

SOFTWARE- Computer programs, rules, procedures, and associated

documentation concerned with the operation of a computer-based

system.

SOUND ABSORPTION - The change of sound energy into another form,

usually heat, in passing through a medium or striking a surface.

SOUND TRANSMISSION CLASS- The preferred single figure rating

scheme giving an estimate of the sound insulation properties of a partition. Used when speech and office noise constitutes a major

problem.

SOUND TRANSMISSION LOSS- A measure of sound insulation. The

amount of incident sound passing through a partition.

SPEECH INTERFERENCE LEVEL- The arithmetic average of the sound

pressure levels of noise in the three octave bands centered at

500, 1000, and 2000 herz.

SPIKE- A sudden but brief electrical disturbance, reaching

thousands of volts, with frequencies up to the megaherz level.

STAR- A network topology in which terminals are connected to a central processor in a spiked configurations, like points in a star

.

STC- Sound transmission class

SYNCHRONOUS- A transmission sequence in which characters are

packaged in blocks, defined at the beginning and the end of the

transmission by codes.

SYSTEMS NETWORK ARCHITECTURE (SNA)- A communications model

developed by IBM, that integrates computer systems and other

devices

.

SYNTAX- A set of rules specifying which forms of the language are

grammatically acceptable.

TASK/AMBIENT LIGHTING- A combination of task and ambient lighting

in a given area, with the ambient lighting being lower in

intensity and complimentary to the task lighting.

164
TASK ANALYSIS- Used to determine the psychological and physical

factors essential to the adequate performance of a task.

TDM- Time division multiplex

TERRITORIALITY- The perception of a person or a group that they

possess a given place to the exclusion of others.

TIMESHARING- A function of software that enables parceling out

access to the processor among input/output devices such as VDT's

often by means of dial-up ports.

TOKEN- A software message that circulates among network nodes.

TREE- A network architecture in which stations of equal status

are aligned along a bus cable.

TRUNK- A specialized circuit used to connect circuit switches to

one another.

TWISTED PAIR- A cable comprised of two small insulated conductors

twisted together without a common covering.

TWX- A network of telegraph-grade communications lines and

terminals used to transmit messages.

UPS- Uninterruptable power systems.

USABILITY- The ease of learning a task, and ease of use.

USER FRIENDLY- Requiring only a limited amount of experience,

knowledge or training to operate.

VALUE-ADDED NETWORK- Transmission networks used to facilitate

communication among terminals and computers.

VCP- Visual Comfort Probability

VDT- Video display terminal

VDU- Visual display unit

VEILING REFLECTIONS- Regular reflections superimposed upon

diffuse reflections from an object that partially or totally

obscures the details to be seen, by reducing the contrast.

VISUAL COMFORT PROBABILITY- The rating of a lighting system

expressed as a percent of people who, when viewing from a specified location and in a specified direction, will be expected

to find it to be acceptable in terms of discomfort glare.

WHITE NOISE- An acoustical stimulus composed of all audible

frequencies at the same intensity with random phase relations

between them; it sounds like "shhhhh".

WIDEBAND- A transmission medium capable of passing more

frequencies than the standard 3Khz voice channel.

WORD PROCESSING- The keyboarding, editing, and printing of

documents on a system that includes hardware and software in many

instances

.

WORKSTATION- The general physical environment in which the user

works. It includes computer terminals, source documents, desks,

chairs, and lighting.

WP- Word processing

165

•frU.8 GOVERNMENT PRINTING OFFICE:! 9 8 6-!( 9 1- 0 7 0 140156
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U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

4. TITLE AND SUBTITLE

PUBLICATION OR

REPORT NO.

NBSIR 86-3430

2. Performing Organ. Report NoJ 3. Publication Date

AUGUST 1986

Revised Interim Design Guidelines for Automated Offices

5. AUTHOR(S)

Arthur I. Rubin

6. PERFORMING ORGANIZATION (If joint or other than N BS, see instructions) 7. Contract/Grant No. national bureau of standards

DEPARTMENT OF COMMERCE 8. Type of Report & Period Covered

WASHINGTON, D.C. 20234

NBSIR 3/85- Present

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City, State, ZIP)

General Services Administration

18th & 19th & F. Sts. N.W.

Washington, D.C. 20405

10.

SUPPLEMENTARY NOTES

J Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11.

ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bi bl iography or literature survey, mention it here)

This report is an update of an earlier design guideline (NBSIR 84-2908) . It is based

upon an additional literature search and interviews. The information should still be

considered tentative, since they are still based on judgement and practice, not formal

studies

.

The introduction of automation into offices has changed the office as a workplace.

Architects and other design professionals have responded to this technology by employing

a number of design strategies. This report identifies design issues which merit

consideration by the designer and suggests criteria and approaches that might be used

in automated office design. Technological, ergonomic and organizational factors are

all considered from the standpoint of their design implications. The present document

is a major revision of the earlier study, including more than twice the number of

reference documents than its predecessor.

12.

KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolon s) Acoustics; design criteria; electrical systems; ergonomics; lighting; noise; office

automation; office design; workstations; communication systems.

13. AVAILABILITY 14. NO. OF

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