Design & Maintenance Guide 22

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Building energymanagement systems

SPECIALIST SERVICES, FUELS AND MECHANICAL

DEFENCE ESTATESMINISTRY OF DEFENCELONDON: The Stationery Office

January 2001

Design & Maintenance Guide 22


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DMG 22Building Energy Management

Crown Copyright 2001

Published with the permission of the Ministry of Defenceon behalf of the Controller of Her Majesty's Stationery Office

Applications for reproduction should be made to

The Copyright Unit,Her Majesty's Stationery Office,St. Clements House,2-16 Colegate,Norwich NR3 1BQ

ISBN 0 11 772934 5

First Published 2001

Printed in the United Kingdom for the Stationary Office

TJ 3543 C1 O 05/01

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DMG 22Building Energy ManagementSystems

Foreword

This Guide has been produced by Defence Estates (DE), Central Business Unit,

Specialist Services, under the patronage of the Defence Utilities Working Group.

The purpose of this Guide is to provide assistance to Project Sponsors, Property

Managers, specifiers, designers, energy managers and operators in the

procurement, use and maintenance of Building Energy Management Systems(BEMS). Due to the wide potential readership, a chart has been prepared

overleaf showing topics likely to be of specific interest to particular readership

groups.

Whilst this Guide was commissioned by the DE for use on Ministry of Defence

(MOD) contracts, it is acknowledged that it could be usefully applied to other

contracts. DE commends the use of this document by other Government

Departments. It may also be used by non-government organisations. However, no

warranty is given as to the accuracy of the content of this Guide, or its fitness for

any purpose.

When this Guide is used in connection with a Defence contract then it shall be

read in conjunction with further documents setting out particular contractualrequirements.

This Guide has been compiled for the use of the Crown, its technical advisors

and contractors in execution of contracts for the Crown. The Crown hereby

excludes all liability (other than liability for death or personal injury)

whatsoever and howsoever arising (including, but without limitation, negligence

on the part of the Crown, its servants or agents) for any loss or damage however

caused where the Guide is used for any other purpose.

January 2001 iii


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Building Energy Management ForewordSystems

The following table provides guidance to the reader on which sections of the

Guide are most likely to be of particular relevance to each type of reader:

Executive Summary

1 Introduction

2 Feasibility, design,procurement

3 Installation, commissioningperformance testing

4 BEMS operation

5 BEMS maintenance

6 Energy monitoring

and targeting

Analysis of requirements

Tender summary

Energy consumption

benchmarks

Glossary of Terms

Bibliography

Very significant

General interest

Background information

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Acknowledgements

This Guide has been compiled by consulting engineers Ove Arup & Partners.

The authors would like to record their gratitude to the staff at the following

seven sites within the MOD Estate for their time and co-operation in

researching the study:

R N Ensleigh, Bath

RNAS Yeovilton

RAF Brampton

RAC Centre Bovington, Wareham

RSS Blandford

RAF Coningsby

Defence Procurement Executive, Abbey Wood, Bristol

Gratitude is also extended to the Building Services Research and Information

Association (BSRIA) whose published guidance has been used in the production

of this document.

CONTACT FOR QUERIES

Specialist Services

Defence Estates

Blakemore Drive

Sutton Coldfield

West Midlands B75 7RLTel No: 0121 311 2294

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Abbreviations

Building Energy Management System

Building Management System

Building Services Research and Information Association

Chartered Institution of Building Services Engineers

Central Processing Unit

Direct Digital Control

Defence Estates (Formerly Defence Estates Organisation)

Defence Estates Organisation

Establishment Works Consultant

Heating, Ventilation and Air Conditioning

Heating and Ventilating Contractors Association

Information Technology

Monitoring and Targeting

Original Equipment Manufacturer

Personal Computer

Private Finance Initiative

Planned Preventive Maintenance

Public Private Partnership

Structured Cabling System

Variable Air Volume

January 2001 vii

BEMS

BMS

BSRIA

CIBSE

CPU

DDC

DE

DEO

EWC

HVAC

HVCA

IT

M&T

OEM

PC

PFI

PPM

PPP

scs

VAV


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Building Energy ManagementSystems

Contents

Section 1

1.1

1.2

1.3

1.4

1.5

1.6

Section 2

2.1

2.2

2.3

2.4

2.5

2.6

2.6.1

2.6.2

2.6.3

2.7

2.8

2.9

2.10

2.11

Section 3

3.1

3.2

3.3

FOREWORD

ACKNOWLEDGEMENTS

ABBREVIATIONS

CONTENTS

EXECUTIVE SUMMARY

INTRODUCTION

AIMS AND OBJECTIVES

TERMINOLOGY

WHAT IS A BEMS?

HISTORY

ADVANTAGES AND DISADVANTAGES

OPTIONS AND FUTURE DEVELOPMENTS

FEASIBILITY, DESIGN AND PROCUREMENT

GENERALFINANCIAL APPRAISAL

INDICATIVE COSTS

JUSTIFICATION

FEASIBILITY

DESIGN AND SPECIFICATION

Design

Specification

Types of Specification

PROCUREMENT

COMMUNICATIONS

SOFTWARE

STANDARDS AND REGULATIONS

COPYRIGHT

INSTALLATION, COMMISSIONING, PERFORMANCE TESTING

INSTALLATION

COMMISSIONING

DRAWINGS AND DOCUMENTATION

iii

V

vii

ix

xi

1

1

1

2

4

6

7

9

99

10

10

13

13

13

14

14

15

16

17

17

18

19

19

20

22

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Contents

Section 4

4.1

4.1.1

4.1.2

4.2

4.3

4.4

4.5

Section 5

5.1

5.2

5.3

5.3.1

5.45.5

Section 6

6.1

6.2

6.3

BEMS OPERATION

OPTIONS FOR MANAGING BEMS

Examples of the functions of staff who operate and manage BEMS

Other Options

OUTLINE SPECIFICATION FOR LEVELS OF BEMS OPERATOR

TRAINING

COSTS OF OPERATING BEMS

UPGRADING AND REFUBISHMENT OF BEMS

BEMS MAINTENANCE

PREAMBLE

MAINTENANCE COSTS

CONTRACT ARRANGEMENTS

Operating and Maintenance Documentation

SPARES AND CONSUMABLESRECOMMISSIONING

ENERGY MONITORING AND TARGETING

REVIEW AND RELATIONSHIP WITH BEMS

ADVANTAGES AND POTENTIAL COST SAVINGS

COST IMPLICATIONS

ANNEX A - TYPICAL COSTS AND SAVINGS ASSOCIATED WITH BEMS

ANNEX B - ANALYSIS OF REQUIREMENTS

ANNEX C - TENDER SUMMARY

ANNEX D - ENERGY CONSUMPTION BENCHMARKINGFOR MOD BUILDINGS

GLOSSARY OF TERMS ASSOCIATED WITH BEMS

BIBLIOGRAPHY

23

23

24

25

25

27

27

27

29

29

29

29

30

3031

33

33

34

35

37

39

43

45

47

49

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Executive Summary

A Building Energy Management System (BEMS) is a computer based centralised

system that helps to manage, control and monitor particular engineering

services within a building or group of buildings. Use of a BEMS can limit energy

costs and labour requirements by improving plant efficiency and effectiveness. It

can also provide a more comfortable environment for the building occupants and

act as a focal point for alarms.

BEMS have evolved from being a simple supervisory control tool to a totally

integrated computerised control and monitoring system.

Some advantages that a BEMS can provide are:

simple operation with routine and repetitive functions programmed for

automatic response

flexible time scheduling of plant and heating to meet site changes such as

holidays, training exercises and operational requirements

remote switching of plant and adjustment of set points

faster and better response to occupant needs

reduced energy costs through centralised control, monitoring and energy

management programmes

ability to cycle/control site electrical demands

better management through automatic alarm reporting, historical records

and maintenance programmes

graphical representation of plant operating conditions

improved operation through integration of sub-systems (eg. lighting and

access)

improved plant performance and life expectancyreal time collection and recording of data for improved analysis of

equipment or energy uses.

To obtain a successful BEMS installation:

provision needs to be made for ongoing operation and maintenance

operators must be skilled and fully trained on the use and operation of

BEMS

existing plant (when being overlaid with a new BEMS) must be capable of

performing its required functions

the system needs to be correctly specified, installed, commissioned andoperated.

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Building Energy Management Executive SummarySystems

the functions of a BEMS

how to justify a BEMS

information required for a feasibility assessment

design and specification aspects

guidance on procurement

pointers for satisfactory installation and commissioning

the importance of record documentation

the need for ongoing operation and maintenance

the key role played by trained personnel.

xii January 2001

This Guide sets out:


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1 Introduction

1.2 TERMINOLOGY

BEMS is a generic term used to describe computer-based control systems for

engineering and building services such as air conditioning, lighting, access,

security, monitoring etc. Other titles used for such equipment are Building

Management System (BMS) and Energy Management System (EMS). The term

BEMS has been identified as the normal acronym for such systems and adoptedthroughout this Guide. Other terms are synonymous with this.

January 2001

provide a history of BEMS

list their advantages and disadvantages

address how to justify the application of BEMS

assess feasibility at a specific location

identify requirements for installation, testing and commissioning

explain the importance of operation and maintenance

demonstrate their potential for energy monitoring and targeting.

It provides background information, particularly for those who have little

detailed knowledge of such systems.

Further guidance is given in Specification 47 - Building Energy Management

Systems, due to be published in 2001.

This Guide is intended to:

selection

design

installation

testing

commissioning

use

maintenance.

1.1 AIMS AND OBJECTIVES

The principal purpose of this Guide is to provide a single source of information

regarding BEMS for those involved with:


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Section 1Introduction

1.3 WHAT IS A BEMS?

A BEMS is a computer-based system that helps to manage, control and monitor

building engineering services within a single building or a group of buildings.

Such a system, when properly designed, installed, commissioned and operated

will significantly improve the operational efficiency of the engineering

installation and its cost effectiveness in terms of labour and energy costs. It can

also help to provide a more comfortable environment for the building occupants.

A BEMS typically has at least one principal operator position (or central

station), connected via a communication network to remote outstations (or

controllers), which can function independently and provide local control to the

plant to which they are connected. They can also collect and respond to data

from the central station or other outstations. The central station is a user

interface at which various functions can be available depending on the client's

requirements. It may be located remotely eg. at a headquarters building or works

department.

Figure 1 demonstrates the components of a BEMS.

Figure 1Components of a BEMS

BEMS Central Station(Personal Computer)

Other OperatorInterface

Remote OperatorInterface

SITE DATA NETWORK

Controllers Hanger Group HQAccommodationBlock

Unitary controllersserving dedicated plant

Roomchillerunit

VAVterminal- box

AHU Standbygenerator

Heating pipework

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Section 1Introduction

Figure 2 illustrates how the BEMS controller functions.

Figure 2Example of BEMS inoperation

Temperaturesensor

Humiditysensor

Velocitysensor

Sensorinputs

Time schedules(contained withinthe controller)

Elements of building engineering services with potential for control or

monitoring by a BEMS are:

heating

ventilation

air conditioning

domestic hot and cold water

lighting

electrical supply/distribution

electrical standby services

energy consumption (ie. reading electricity, gas, water meters)

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There is no reason, however, why any system needing to be monitored remotely

could not be integrated into a BEMS to provide a central focus point.

Most current generation BEMS provide the management interface at the central

station through a personal computer (PC). The operating system for the centralstation is likely to be Microsoft Windows, since this has become an industry

leader. The component structure below the central station comprises a

communication network, local controllers and field devices (eg. sensors, actuators

and meters). Different suppliers use different communication protocols to

transfer data, and within different generations of equipment from a single

supplier there may be variations in communication standards. Where different

suppliers equipment exist, or different generations of the same supplier, it may

be possible to integrate the control components, but due to different

communication standards and operating criteria this may not be a

straightforward process. As this integration can be expensive, costs should be

compared to replacement with directly compatible equipment.

CIBSE note in their Energy Efficiency in Buildings Guide (published in 1998),

that energy savings of between 10% and 20% can be achieved through the use of

a BEMS, compared with independent controllers for each system, though

opportunities for savings of this size will not always be available.

1.4 HISTORY

The development and processing power of computers, and in particular

microprocessors, has enabled a steady growth since the late 1960s from separate,

independent and dedicated control equipment to increasing degrees of

automation, control and communication. One driving force was to reduce theamount of cabling by the use of data networks.

Early systems were structured around a central computer called the 'head end'

or 'front end' which contained the processing capability, linked by fixed wiring to

each sensor or actuator device (eg. a room thermostat or a motorised valve).

Although the processing capability was limited, only providing start/stop control

and system monitoring, a central facility became available where all control and

performance information could be accessed such as alarms, room temperatures

and on-off switching times. This reduced the need for frequent site visits and

hence offered more efficient use of maintenance operatives.

Because the central processor carried out all the functions, the system capabilitywas limited by the available capacity. Such systems were generally very

inflexible and not user friendly.

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electrical maximum demand

security/access equipment

fire detection/alarm systems

vertical transportation

specialist equipment (eg. standby facilities, smoke control and fume

cupboards etc.)

catering services (eg. ventilation, electricity and water usage)


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Section 1 Introduction

The next development was the introduction of direct digital control (DDC) and

the reduction of the dependence on the central computer by distributing the

computing power round the building or estate within local microprocessors, each

with a limited input/output capacity. This style of system became known as

'distributed intelligence'. System design and operational requirements

determined the need for a central computer. This was not essential because thesystem 'intelligence' was provided by the outstations. Provision of a

communication network to link the outstations and allow data to be passed

between them promoted the stand-alone outstations to a BEMS.

Use of BEMS for control and monitoring of building services significantly

increased over the decade from 1980. Interest increased also in the potential to

link Heating, Ventilation and Air Conditioning (HVAC) equipment controls using

BEMS for at least alarm monitoring from other stand alone systems such as

lighting, lifts, fire and security and providing a single point for alarms to be

registered.

As computer processing power increased and costs reduced, the capabilities and

applications of BEMS grew, though on occasions the installations became

difficult to manage. Installation standards were not always followed,

commissioning became difficult and not always effective, which resulted in

systems that failed to achieve their original expectations.

Building owners and operators became disenchanted with "automated systems"

which failed to deliver the promised solution. However, they accepted that if the

systems could be simplified, designed properly, installed correctly and fully

commissioned, they would be a useful tool for running properties.

As microprocessor technology developed, stand-alone controllers becameoperated alone or linked through a communication network to other controllers

and a central point of information access. Such units, where they serve terminal

units such as fan coil units or Variable Air Volume (VAV) boxes have become

known as unitary controllers. Plant manufacturers or Original Equipment

Manufacturers (OEMs), purchase unitary controllers and fit them to their own

products. These can provide an opportunity for later integration into a BEMS

through a communication network. Computer power has now become fully

distributed, with the central computer becoming the 'host' for loading

programmes, interrogating performance and recovering data. Systems have also

become more user friendly and easier to programme.

Figure 3Summary of changes inBEMS technology

BEMS with outstations

1970 1980 1990 2000

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1.5 ADVANTAGES AND DISADVANTAGES

The use of a BEMS provides an integrated computer based facility for the

control and monitoring of the building engineering services.

Advantages are:

routine and repetitive functions are programmed and responded to

automatically (eg. daily on and off times, holiday scheduling, operational

programming for different buildings, periodic testing of standby plant)

relatively simple operation for trained users (eg. access to detailed

information such as room temperatures to monitor plant performance;

modifying operating times to match changes to building use)

quick response to occupant complaints about environmental conditions

(the sensitivity of BEMS can highlight potential problems and allow

adjustments to be made before occupants initiate complaints)

reduced energy consumption and hence costs by central monitoring and

control (savings may be up to 10% by constant fine tuning to match

occupational needs)

ability to cycle or control site electrical demand

improved management information such as historical records, alarm logs

and hours run can demonstrate that environmental criteria have been

achieved; alarms have been actioned and plant maintenance can be more

precisely managed

graphical representation of plant operating conditions and internal

environment, providing quick and simple understanding of the

information presented

integration of system control and operation through software links

(allowing increased opportunities for fine-tuning of controls to the

particular application)

improved plant performance and life expectancy (eg. by establishing key

operating criteria and monitoring performance efficiency).

Disadvantages that can apply include:

any BEMS installation will have costs associated with it. These will not

only be the initial design and installation, but also the subsequent

operation and maintenance (see para 2.1)

possible disruption to normal plant operation during BEMS installation

need for a skilled operator to ensure maximum use is made of the system

the effective potential of a BEMS can be very sensitive to proper

specification, full consideration of condition and ability of plant to be

controlled, commissioning by a skilled BEMS specialist and continued

maintenance

difficulty in integrating with existing equipment especially regardingcommunication protocol or the need for new controls or sensors to allow

integration

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Building Energy Management Section 1 IntroductionSystems

requires commitment at all levels throughout its operational life to

maintain maximum effectiveness

unless carefully chosen, certain aspects of BEMS can become obsolete

relatively quickly

unless correctly specified, installed, maintained and operated BEMS canincrease costs and environmental impacts.

1.6 OPTIONS AND FUTURE DEVELOPMENTS

The processing power of electronic equipment being used within a BEMS means

that any system needing to be controlled or remotely monitored could be

accommodated, providing the cost of the initial installation and ongoing

operation and maintenance can be justified.

Greater integration between different systems such as lighting, fire alarms,

security and BEMS is likely to develop as the full capabilities become

recognised. The links at present tend to be for monitoring and alarm reporting.As users investigate different options and the potential of the full equipment,

greater confidence will be developed.

Whilst communication standards do exist, different suppliers and manufacturers

still have their own for their respective systems. As clients begin to demand

system integration to allow data from different components and systems to be

viewed and managed centrally, and control functions to be enhanced by sharing

data, greater flexibility will be achieved. The components of BEMS from different

suppliers are expected to become more compatible.

Unitary controllers are likely to become standard items of plant and equipment.

This may also influence the move towards communication standards, as greater

integration between suppliers equipment will be required. Unitary controllerscan provide programmable memories for field devices such as temperature

sensors or valve actuators, allowing them to be programmed and commissioned

before delivery to site. On-site commissioning will, however, always be required.

The costs of outstations and central stations will be influenced by the continuous

developments of IT equipment, with the expectation that greater processing

capability will be obtained for less cost. The cost element of a BEMS taken up

with the installation of the communication network may be reduced where an IT

network is available. Alternatively, the use of radio communications for both

internal and external links has considerable potential to grow and develop,

particularly between field devices and their associated outstations. Overall costs

of BEMS are unlikely to reduce. Whilst some components such as electronicequipment may become cheaper, other hardware costs and the system design and

engineering will continue to be the major proportion of the price and not provide

opportunities for savings.

As the volume of data increases, the levels of management information will rise.

Exception reporting, to show potential problem areas with likely causes and

possible solutions, may be developed to enable full use to be made of the

available information.

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2 Feasibility, design and

procurement

GENERAL

This section helps to identify the factors for choosing a BEMS and provides

guidance in establishing the feasibility and requirements for a BEMS. The most

common reasons for considering the use of BEMS are:

for new builds where costs are comparable to other forms of control

to replace existing old or failing controls where the difference in costs are

outweighed by the benefits provided by the BEMS

to improve the system where the benefits outweigh the costs

where there is a need for stringent control and monitoring levels of

building services.

2.2 FINANCIAL APPRAISAL

A key factor in building a business case for a BEMS will be a financial appraisal

over the proposed life of the system. Annex A is a simple table to help provide

initial indications of the likely costs and savings associated with BEMS. MOD

Guidance and Policy for carrying out full financial appraisals is given in:

JSP 414 Part 4 Chapter 16 Investment Appraisal and Post Project

Evaluation

DEO (Works) 1996 DEO Technical Bulletin 96/04 - Through Life Costing

DEO (Works) 1996 DEO Technical Bulletin 96/03 - Value Engineering

MOD Guide to Investment Appraisal and Evaluation.

Further guidance is also given in:

Appraisal and Evaluation in Central Government (Treasury Guidance

1997)

Appropriate local guidelines should also be followed.

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2.3 INDICATIVE COSTS

As general background information, three generic types of installation are

considered with outline cost information based on Quarter One year 2000. These

are not intended to be used for budget purposes, only to provide outline guidance

of the order of costs for the different types of properties. The particularrequirements for a specific location may result in significant variations from

these figures.

Total installed

cost of BEMS

(new greenfield

site)*

Property Type One

Very large major site with numerous buildings and facilities 300,000

eg. Naval Dockyard; RAF Operational Site

Total utilities cost per annum (electricity, oil, gas, water)

1 million.

Property Type Two

Medium to large 75,000

eg. Large single building or complex of buildings

Total utilities cost per annum

200,000.

Property Type Three

Small to medium single building or small complex of 30,000

buildings

Total utilities cost per annum

(electricity, oil, gas, water)50,000

* Installation in existing buildings will require an increase of

10% to allow for additional design and installation costs.

2.4 JUSTIFICATION

All building services need controls. BEMS can be cheaper than individual

controls, particularly for new buildings where they can be justified on first costs

for almost all types of buildings. For refurbishment or replacement situations,

first costs alone may not indicate that a BEMS is appropriate. Whole life costs

should also be investigated when system flexibility, monitoring and centralcontrol capability can be taken into account. Upgrading costs will need to be

compared with potential energy savings.

CIBSE indicate energy cost savings between 10% and 20% by use of BEMS in

their 1998 Energy Efficiency in Buildings Guide. As a rule of thumb, a retrofit

BEMS can yield a 10% direct fuel cost saving against a reasonably well

maintained conventional control system when properly designed, installed and

commissioned.

The benefits of using a BEMS are the flexibility of the controls available,

communications capability (particularly for operational data between plant and

system) and overall performance monitoring.

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A BEMS can provide three key advantages over stand alone control:

provision of management information

remote operation, interrogation and alarm monitoring

greater flexibility and range of control strategies.

BEMS will not compensate for fundamentally inefficient buildings and plant.

Benefits of a BEMS can include:

improved environmental (eg. temperature) and time control from central

location

rapid communication (system monitoring, operation and control) with

remote sites, without physical visits

improved comfort for building occupants

automatic fault reporting at central location (with predetermined levels of

action)

monitoring and targeting of energy consumption

allows easy trial and monitoring of building response characteristics and

related energy saving proposals such as lunch time set back of heating.

graphical representation of plant performance and environmental

conditions.

Examples of specific capabilities of BEMS are:

scheduling plant start / stop times

fuel consumption recording / energy metering

plant sequencing / optimisation

filter condition monitoring

electrical maximum demand limiting

lift monitoring

lighting control

hours run recording and trend logging

security management

alarm handling

'at a glance' information presentation.

Whilst these are also available using stand-alone controls, integration into a

BEMS provides the opportunity for achieving the greatest savings and operating

efficiency.

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DMG 22Building Energy Management Section 2 Feasibility, design and procurementSystems

In addition to the technical capabilities listed above, BEMS can provide the

opportunity for improved financial control, for example, by billing sub-tenants

where suitable metering is provided. Close monitoring of occupancy times and

adjusting BEMS settings can produce energy savings. Reduced maintenance

attendance by scheduling work on an hours run basis can lead to manpower

savings.

Before purchasing such a system, it is important to consider what the controls

are intended to do and how they will achieve this.

To provide a framework for this, Annex B - Analysis of Requirements provides a

series of questions to help analyse requirements at a specific location, including

a pro forma to identify which plant and services are to be covered by the BEMS.

The particular plant or system will generally determine the type of control

required. Each control requirement should be considered separately and the

details listed. It is important to avoid an over specified or unnecessarily complex

control system for the particular application. Advice on what is necessary and

appropriate, and help on completion of the check list can be obtained from the

Establishment Works Consultant (EWC) through the Property Manager or

through the Establishment Energy Focal Point.

The larger the number of systems or plant items listed for the project, and the

larger the number of control or monitoring requirements, then the greater is the

likelihood for a BEMS to be the appropriate choice for controlling the building

services.

For an existing installation, a list of questions to consider is given below:

is there an operational requirement for central monitoring or control?

do the existing controls meet current good practice? (eg. time control,weather compensation, optimum start/stop)

can the existing control be adequately operated and maintained?

does energy use compare well with published guidelines? (see Annex D -

Energy consumption benchmarks for existing MOD buildings)

is there a need to attribute responsibility for utilities to specific users?

(eg. billing of non-entitled users and resource accounting)

are consumption records needed for tariff/consumption profile analysis?

is there an opportunity to integrate control of different engineeringservices?

has the building function changed?

have good housekeeping measures to reduce energy consumption been

carried out.

are the building occupants satisfied with their environment?

These questions are included in Annex B - Analysis of Requirements

Once a decision in principle has been taken to consider a BEMS, the full

potential benefits and costs of achieving them need to be examined.

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2.5 FEASIBILITY

BEMS are becoming the norm in many larger new buildings, as their first cost is

similar to stand alone controllers.

In existing buildings, assessing the feasibility of a BEMS can be more difficult.

Where existing stand alone control equipment is available, the suitability,practicality and cost of retaining and incorporating components of it into a larger

BEMS needs to be assessed.

The following considerations are aimed at existing buildings, but could also be

applied to new buildings.

Zoning of Building Services

Are these adequate for energy efficient operation and match current

and proposed occupant requirements?

Primary Plant

Does this have stand alone control, could it be linked with a BEMS?

Existing stand alone controls

Are they still supported by manufacturers? Can they be

economically integrated into a new BEMS? Control equipment

installed in the late 80s, early 90s or earlier may have limited

functions available and be difficult to reprogramme.

Existing BEMS

Is there an existing BEMS available that could be used?

2.6 DESIGN AND SPECIFICATION

2.6.1 Design

A BEMS is a powerful tool that allows building owners, operators, and managers

to understand the function and control the operation of engineering plant and

services for which they have responsibility. It is important to note that however

a BEMS is designed or specified it can only control within the limits and

accuracy of the equipment to which it is connected.

There are a wide variety of systems available that can provide control or simply

monitor the status of plant. A purchaser needs to be clear and unambiguous

about the plant and equipment to be served by the BEMS and the degree of

control required.

The extent and method of design will depend on the size and complexity of the

installation and its controls, the technical competence of the client and any

relationship which exists with a preferred supplier.

Where the BEMS is being overlaid on existing plant and equipment, control

devices such as sensors and actuators may not be compatible or suitable for

connection to the BEMS. Allowance for this will need to be included in the costs

of the work.

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Section 2Feasibility, design and procurement

Control of different engineering systems such as HVAC, lighting, major plant

items such as chillers, and life safety (eg. fire) has traditionally been kept

independent. BEMS can provide opportunities for a degree of integration, but

this is likely to be limited to alarm monitoring or sequence initiation. The extent

of integration will be governed by the risks involved. Plant that is safety critical,

has military operational implications or operates under its own dedicated controlsystem may not be appropriate for integration.

2.6.2 Specification

The objectives of a specification are to:

14 January 2001

provide a firm basis tor a tender

identify required performance criteria

minimise misunderstanding

define responsibilities

provide like for like comparisons between different proposals.

The specification provides basic information together with exact functional

requirements, where appropriate, for the specific application. Further detailed

guidance regarding this is provided in Specification 47 - Building Energy

Management Systems to be published in 2001.

The initial step when preparing a specification is to define the building

management strategy from which a specification can be developed. To achieve

maximum benefit the strategy must take account of the function of each building

and the existing or proposed operation and maintenance manpower availability.

For large, complex applications it may be appropriate to appoint a professional

advisor for this role. Advice on this can be obtained from the EWC through the

Property Manager, or through the Establishment Energy Focal Point.

2.6.3 Types of Specif ication

Two generic types of specification can be identified:

Performance

Functional

states how the system will operate in strategic terms, with an

outline description of what is to be controlled and monitored.

gives detailed requirements for the system, including control

and monitoring strategies and the devices included, such as

controllers, sensors and actuators.

Both types of specification should describe the features to be provided, standards

to be met including materials and workmanship, testing and commissioning

requirements, training to be carried out and guarantees to be provided.

The type of specification will be dictated by the particular application and

intended procurement strategy. Where a specialist controls contractor is to be

used and competence has been demonstrated and proved on similar work, a

performance specification may suffice. The same type of specification may also be

appropriate for buildings with relatively simple engineering services and no need

for elaborate control. However, where a building has complex plant such as full

air conditioning, or where environmental conditions have to be closely controlled

within strict limits and there are considerable inter-relationships between the

control sequences, a functional specification will be required to ensure the

client's requirements are fully defined and able to be interpreted by the supplier


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and installer. Care must be taken to ensure BEMS equipment is compatible with

all systems and its operation does not allow plant to operate outside

manufactures parameters, normal duty ranges or operational limits.

In 1998 The Building Services Research and Information Association (BSRIA)

published a Library of Control Strategies (Application Guide AG7/98) as a

reference document for when the controls are being developed, specified and

configured. The strategies can be used when specifying control systems as an

independent source of control solutions. The provision of this Library does not

remove the onus from designers to ensure that an appropriate working solution

is produced.

To create a specification for a particular installation from the strategies within

AG7/98 the designer needs to:

decide which 'plant functions' are required to make up the whole system

decide for each plant function which of the available plant modulesoptions is to be used

forstrategieswhichofferalternativesoroptions, decide whichare

required in the specific application.

2.7 PROCUREMENT

A number of options are available. These include:

January 2001 15

direct purchase from a specialist supplier of controls equipment

direct purchase from a systems integrator (who obtains components such

as controls equipment from a specialist supplier and designs, installs and

commissions the system to meet the user's requirements)

use of a controls specialist to design the system, tender the work and

oversee installation and commissioning

produce in-house, an outline brief of requirements and tender the work

for purchase

produce in-house, an outline brief of requirements and tender for leasing

an installed BEMS (where such a leasing agreement is deemed

appropriate). The lease agreement may include upgrades to the BEMSover the stated period of the lease agreement.

incorporate the BEMS installation within a Private Finance Initiative

(PFI)/Public Private Partnership (PPP) arrangement.

lease the BEMS through the Facilities Management Contractor.


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2.8 COMMUNICATIONS

Two aspects of communications need to be considered:

1. The information being communicated.

Computers need precise, rigidly defined rules and protocols for successful

communication.

Typically, translation problems occur when trying to connect products

made by different manufacturers, or in some cases, different versions of

products made by the same manufacturer.

Traditionally, different systems such as lighting, HVAC and life safety (eg.

fire) have had separate, dedicated controls. Relevant specialists should

be fully consulted where safety critical systems are to be connected to a

BEMS.

Communication standards allow transfer and interpretation of data

between different parts of the BEMS and integration of equipment from

different suppliers. There is no single agreed communications standard,

at present, followed by all BEMS suppliers. Several exist and are being

used by different suppliers.

2. Physical communication system between all parts of the BEMS (eg. data

cabling).

The elements of a BEMS need to be linked together to transfer data

through a communication network. The most common method is data

cabling using shielded or unshielded twisted pair. Other options include

fibre optics, which can provide increased security, radio links, which may

be more appropriate when long distances (eg. across an operational RAFsite) are involved, mains borne signalling, where the electrical

distribution system is suitable and modem links to public or private

telephone networks.

Existing communication network cabling may be available, eg. redundant

voice systems, but will need to be checked and proved suitable before

inclusion into the project scheme. Dedicated voice networks using

modems, can provide a basic communication infrastructure, particularly

on extensive sites where buildings are spread over a large area. This

application can result in prolonged times for data transfer and problems

with data accuracy which may have implications if used for generating

energy bills.

Alternatively, an existing IT cabling system may be available. Office

accommodation in particular is increasingly likely to have a structured

cabling system providing an infrastructure on each floor, with a grid of

outlet connections allowing connection of IT equipment such as PC's and

printers. BEMS may be able to use this to link major components directly

together (eg. controllers and the central station). The cost of integrating a

BEMS with an IT structured cabling systems (SCS) will depend on how

much of the SCS is required.

Where it is proposed to use an existing or proposed general use cabling

system for a BEMS, application for this must be made in sufficient time

to ensure its availability when required. The continuing availability ofshared access to the system also needs to be confirmed.

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If the SCS is installed at the same time as the BEMS (eg. on a green field

development) it can be designed to accommodate the BEMS requirements

and installed by the SCS installer.

Other benefits of using the IT network are shared network maintenance

costs, access to a robust and industry recognised communication network

and an enhanced network security (faults detected and rectified more

quickly than normal BEMS network).

Use of an IT network is likely to be for the major data interconnections such as

between controllers and the central station. Use of a local BEMS network is

more likely to be cost effective for individual plant controllers.

Radio communications applied to BEMS are very limited but offer potential for

future growth. It has been successfully adopted on large MOD sites such as

operational RAF stations with considerable distances between buildings, to

reduce the need for cable links. The technology can be applied both internally

between field devices and associated outstations and externally over a campus

type environment for communications between remote buildings. Security of

radio communication systems may not be satisfactory for particular locations.

2.9 SOFTWARE

The software elements of a BEMS determine how the controls and monitoring

functions built into it will operate and communicate. This level of software may

be termed the 'firmware' since they can be fixed components of the system whose

operating parameters and characteristics are set up to match the specific

requirements. The BSRIA Library of Control Strategies provides a set of

standards. Individual suppliers may opt for particular ways to achieve each

strategy.

BEMS software imposed above the control strategies provides the monitoring

and reporting structure of the system, including how and what reports, alarms

and historical logs are generated.

Documentation for both the firmware and software is critical because it will

define how each controller and control parameter has been configured, how

information is stored and reports are generated.

Software protection in terms of licence agreements needs to be resolved at an

early stage of the project. Copies of the software should be held in secure

locations, ideally both on and off site.

2.10 STANDARDS AND REGULATIONS

BEMS installations must comply with all relevant statutory regulations. Other

guidance in terms of standards and codes of practice should also be noted.

Examples of these are British Standards Codes of Practice and MOD guidance.

The following is a general list of some areas that should be addressed when

installing a BEMS:

January 2001 17

a safe means of access for maintenance

all BEMS panels are secured to prevent unauthorised access

the central station and controllers are password protected to prevent

unauthorised access


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DMG 22

Building Energy Management Section 2 Feasibility, design and procurementSystems

sufficient illumination is provided as required for user operation of BEMS

where they are situated in plant rooms. This may require additional task

lighting.

electrical installations comply with BS7671 1992 - Requirements for

Electrical Installations (IEE Wiring Regulations 16th Edition). Commonly

known as the Wiring Reg's

all equipment complies with the standards relating to electromagnetic

interference and is suitable for the particular application

workstations comply with the Health and Safety (Display Screen

Equipment) Regulations 1992

specific security needs for the particular application relating to hardware,

software, sensors and other electronic and IT equipment are followed.

2.11 COPYRIGHT

For a particular application, the detailed BEMS specification, software

configuration, operating parameters and reporting structures established for thespecific application will all be covered by MOD copyright and not, therefore,

available to others without authorised agreement.

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DMG 22


3 Installation, Commissioning,

Performance Testing

3.1 INSTALLATION

This is the process of translating the requirements set out in the specification

into a physically completed system (static completion). It requires labour,

materials, supervision, inspection, testing and documentation.

In a new installation the plant and equipment needing interconnection with the

BEMS should have suitable facilities already available. For existing plant and

equipment, where a new BEMS is being installed, there may be a need to replace

or refurbish existing control devices such as sensors, actuators and analogue

controls.

Installation standards should be defined in the specification, including those for

data cabling, programming, testing, documentation and cable identification.

The installation of a BEMS can be critical to its effective and efficient

performance. It is advised that installation should only be carried out, or closely

managed, by specialist BEMS installers, or organisations who can demonstrate

their particular expertise in this field.

Safety and operational interlocks are likely to be included within the specific

control strategies. These need to be identified in schedule format and proved to

be working in a safe and correct manner. The BEMS would normally only

monitor the action of such interlocks, particularly for critical operations.

Tests to confirm an installation has been completed and approved to the

satisfaction of the Project Manager should include:

an audit of the cabling and hardware

demonstration of the physical and logical integrity of the system

demonstration of all the control actions

demonstration of all the sensor calibrations

demonstration of the system software

demonstration of the system graphics

all documentation including drawings and operating and maintenance

manuals have been provided.

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DMG 22 Section 3 Installation, Commissio ning, Performa nce TestingBuilding Energy ManagementSystems

3.2 COMMISSIONING

Commissioning is the process of turning a physically completed system into a

fully operational working system that meets the designed requirements. Poor

commissioning is the most common cause of BEMS failing to meet the initial

performance expectations. This in turn can lead to unstable and underperforming plant. Suppliers can benefit from good commissioning since

subsequent warranty costs are likely to be less than for a poorly commissioned

installation.

A comprehensive specification supplemented with flow diagrams can form the

basis of the commissioning checklist and serve as a yardstick to test the BEMS

control strategies. It is beneficial to specify as much off-site testing as possible

(eg. control panels, application software and graphics) when conditions are more

suitable for testing and remedial work.

Once installed, the BEMS should be fully pre-commissioned as far as

possible,(eg. data cabling interconnections, validity of sensor readings, actuator

performance). All controls are likely to be needed in 'manual' operation duringfull commissioning of the engineering services. The BEMS can then be

integrated with the building services and finally commissioned and put into

operation. Adequate time needs to be allowed for this, as a guide 30 minutes for

each BEMS sensing point should be anticipated. Attendance will also be required

by other trades and this should be reflected in the tender figures as part of the

commissioning costs.

On sites where the BEMS is commissioned and handed over in stages, the

sensors in the earliest stages may have drifted from the calibration setting by

the time that later stages are commissioned.

Where the BEMS is being installed in an operational building, careful planningis needed to maintain all services so that they continue to function during the

commissioning process.

Whilst the initial commissioning will be carried out to the original design data, it

is likely that fine tuning of the system will be required over the first full year of

building occupation to fully meet the requirements of the building operator and

the occupants. It may be appropriate to include this in the original contract cost,

particularly for more complex installations. This will lead to greater savings as

the BEMS operation and performance parameters can be optimised. Liaison

between the building user/operator and the installation contractor during the

period of fine tuning is important to ensure a full understanding of how the

building is required to function.

BSRIA Application Handbook AH 2/92, Commissioning of BEMS, provides a code

of practice including detailed check lists. Other relevant publications are:

20 January 2001

Commissioning HVAC Systems - Divisions of Responsibilities.

The Commissioning of Air Systems in Buildings

The Commissioning of Water Systems in Buildings

A Procedure for Commissioning VAV Systems

Commissioning of VAV systems in buildings

Commissioning Code C Automatic Control

TM1/88

AG3/89.1

AG2/89.1

TM2/88

AG1/91

BSRIA

CIBSE


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DMG 22


Performance testing addresses the operation of the BEMS and the associated

plant. It is aimed at ensuring both are operating in an optimum manner in

terms of energy and internal environmental performance.

The BEMS operator should be trained to monitor the BEMS performance and to

note and respond to feedback from the building occupants.

Many BEMS receive little or no maintenance. Possibly this is because a BEMS is

perceived as microprocessor based and not requiring attention. A BEMS is more

than the central station or controllers. Sensors can go out of calibration,

actuators can fail to operate. Building use will change over time, needing set

points to be revised. Performance testing will detect changes to the BEMS level

of performance and faults due to incomplete commissioning.

Reasons for performance testing include:

January 2001 21

occupant complaints about the environment

energy performance is unsatisfactory

system neglect

little information may be available about the installed control regimes

BEMS performance is inadequate/not satisfactory

unsatisfactory environmental performance

significant change to energy consumption

to evaluate BEMS performance

repeated failures or alarms need to be investigated.

fits ofperformancetestingare:

improved occupant comfort

prevents complaints arising from occupants

energy savings

reduced false alarms

improved awareness of BEMS and control strategies

confidence in BEMS records.

BSRIA Application Guide AG2/94 - BEMS, Performance Testing, provides

guidance on a general performance audit and help in resolving particular BEMS

problems.

Guidance on energy consumption benchmarks for MOD buildings can be found

in the DETR Energy Conservation Guide 75 - Energy Use in Ministry of Defence

Establishments. A copy of the summary page giving the benchmark figures from

this document is given in Annex D.

Section 3 Installation, Commissioning, Performance Testing


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Section 3 Installation, Commissioning, Performance Testing

3.3 DRAWINGS AND DOCUMENTATION

Comprehensive and accurate record drawings and documentation are essential

for the satisfactory operation and maintenance of a BEMS. These should include:

BEMS Performance Specification

written description of plant and how it is controlled

control strategy, including diagrams

operating and maintenance manual

maintenance schedules

central station software manual

points list (all analogue and digital inputs and outputs)

flow diagram

specifications for sensors and actuators

schematic wiring diagrams for outstations, field devices and control panels

controls design specification

details of set points, alarm levels, time schedules, overload settings

commissioning data

plant diagrams showing locations of field devices

software back-up copies

emergency procedures

handover/acceptance documentation

log book - to record incidents, operational information and all changes

made to the system (para 5.3.1 gives more information about this).

22 January 2001


DMG 22


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4 BEMS Operation

4.1 OPTIONS FOR MANAGING BEMS

To achieve the full benefit of a BEMS installation it will need to be monitored,

used and properly maintained rather than simply installed and ignored. The

man/machine interface of a BEMS provides ready access to plant operating data,

allows better understanding of the performance of the systems being controlled

and helps improve decision making. As such, this interface is a key element of

any BEMS.

Due to the complexities of modern BEMS systems a common problem is

identifying just who is responsible for what and in what context. To help

eliminate this it is recommended that this is agreed and documented at the

design stage, include operation, access, maintenance and communication

responsibilities.

It is essential that all personnel authorised to access or use a BEMS are

adequately trained to ensure safe and efficient operation of the system. Where

personnel have the ability to control or effect equipment or plant controlled bythe BEMS, they must be competent to do so. Risk Assessments and Safety

Method Statements should be produced and used to ensure safe and correct

operation and use of the BEMS. Individuals with the appropriate authority

should be able to demonstrate their understanding of the areas within the

BEMS to which they have access, and any implications their actions may have

relating to the Health and Safety of both themselves and others.

Authorisation for access to the BEMS or plant rooms in which they may be sited,

especially where plant/equipment settings and controls are involved, should be

approved through the Property Manager and managed throughout by the

Authorised Person. In turn the Property Manager should confirm with the

Establishment Works Consultant (EWC) and Works Services Manager (WSM), or

relevant service provider, that the individual requesting use/control of the BEMS

is deemed competent for their specific requirements. The EWC and WSM should

also be able to confirm if there are any other implications regarding existing

maintenance and operation contracts.

It would be beneficial for the main operators of BEMS to be longer term

personnel who have a good understanding of the site and any necessary

conditions or concerns. Where this is not appropriate/possible operators can help

by keeping records to pass on. Each new operator should receive full training for

the system.

Having regard to the above, Site Energy Managers would typically be included

in those with access to BEMS at the highest level. This will help ensure

January 2001 23


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DMG22


maximum benefit from the BEMS in terms of energy management, efficiency

and savings. Potential overlap between Site Energy Managers and the WSM

must be discussed and agreed at the earliest stage in the BEMS design. This

may, for example, lead to siting of BEMS controllers out of plant rooms to

facilitate safe access by the Site Energy Manager.

4.1.1 Examples of the functions of staff who operate and manage BEMS

The hours noted overleaf are illustrative only and will depend on the particular

site and application. Hours do not include for energy Monitoring and Targeting

(M&T), or interpretation of consumption information. A BEMS is a tool to aid

the staff listed overleaf. As such, the installation and use of a BEMS, within the

roles described, should represent savings in human resources, not demands on

them. This is based on the principle that the BEMS should allow existing tasks

to be done in less time. In addition, the improved quality and quantity of

information and rapid and flexible control of plant will allow much greater

effectiveness of these tasks.Site Energy Manager

The typical emphasis of this role regarding BEMS is on improved energy

efficiency and management. Typical BEMS use for this role is seven

hours per week. The role may typically include an understanding of how

the engineering plant functions and be aware of the complexities,

capabilities and design philosophy of the BEMS. The post holder 's

functions could include regular checking of plant performance and

environmental conditions, adjustment of environmental conditions to

meet changes in weather, occupancy or usage and bringing any other

areas of concern to the attention of the Property Manager. The level of

potential achieved from the BEMS in this role will strongly depend on thelevel of training, understanding, experience and delegated authority to

take necessary action.

Site Maintenance Staff/Consultants (Other Service Providers)

The typical emphasis of this role regarding BEMS is on maintenance and

operation of the site infrastructure, without necessarily having any

specific direction on energy management. Typical BEMS use for this role

is three hours per week. The principle use of the BEMS in this role is to

confirm plant is operating correctly, identify and respond to plant failure

alarms and use information for proactive maintenance management. In

many cases, it will also include operation of plant and equipment. This

role requires detailed understanding of how the engineering plantfunctions and all aspects of the BEMS.

Energy Warden (or Building Custodian)

This is often a supporting role to the Site Energy Manager or Property

Manager, normally associated with a single building or small group of

buildings. Typical BEMS use for this role is up to two hours per week.

The role requires ready access to information from the BEMS such as

time / environmental settings and actual conditions for the relevant

area(s). Any anomalies can then be manually verified or investigated as

required and recommendations made or action taken using local

knowledge. A basic understanding of the relevant functions and

capabilities of the BEMS would be beneficial. This role does not normallyhave authority for any control function but may have access for limited

adjustment to environmental set points.

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Section 4 BEMS Operation


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DMG 22


Property Manager/EWC (Management)

This role primarily requires access to information from the BEMS to aid

in the management role or provide clear and rapid understanding of

relevant systems through the schematics. Use is dependent on

requirement. Typical BEMS use would be up to one hour a week. Only a

basic understanding of the plant or BEMS function or capability is

required. This role would not normally access the control functions. Full

understanding of plant or BEMS functions or access to the control

functions would be achieved through the Site Energy Manager, WSM or

EWC, as required.

4.1.2 Other Options

A Bureau Service could be used to provide 24 hour monitoring of BEMS alarms

remote from the site. There may be scope for this function to be provided by the

site security organisation when the main tenance contractor is not in attendance.

Instructions on how to respond to each alarm type or priority level would need tobe established along with contact details for unexpected situations. Maintenance

contractors and other commercial organisations often provide such a facility, at a

cost, if required.

A more effective use of a Bureau Service would be to audit the BEMS

performance, rather than only provide a reactive alarm monitoring function.

This would require the Bureau Service to have skilled and experienced staff who

could interrogate the BEMS, interpret the results and monitor that appropriate

action had been taken. As such, this role would not be suitable for site security

staff.

Use of a Bureau Service would need to be considered in relation to the existing

contractual arrangements to determine whether scope is available for this.

Another option would be to use the enthusiasm and expertise of existing Site

Energy Managers by extending their role and responsibility across a number of

sites. Dependent on site sizes, one Site Energy Manager could potentially have

responsibility for several sites if linked through a suitable communication

network. The BEMS at each location would provide local control and reporting.

The Site Energy Manager would interpret the data and, from intimate

knowledge of the sites, be able to initiate the appropriate action. This role

would be further enhanced by access to a comprehensive energy M&T system.

4.2 OUTLINE SPECIFICATION FOR LEVELS OF BEMS OPERATOR

To provide a better understanding of the different potential operating roles of

BEMS, the following four categories show typical aspects of various levels and

typical posts in which they would be suited. Important Note: Any adjustments,

control function or accessibility to BEMS plant should be approved in writing by

the Property Manager. This should detail the specific tasks and level of

controlability to be authorised including the name(s) of the individual(s) being

given the authority. These levels are generic and actual allocation of roles and

responsibilities would benefit from input by experienced personnel.

Level One- typically fits within the role of Energy Warden and may include/

require:

basic understanding of BEMS purpose and method of beneficial operation

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Section 4BEMS Operation


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no or very limited permission to make alterations to set points

ability to call-up and view data from schematics and points list

ability and access to view and interpret trend logs for relevant areas

access to pertinent limited areas of the site only.

Level Two - typically fits within the role of the Property Manager or other

Managers and may include/require:

as Level One above but also requires access to information and data for

the whole site. Not normally permitted to make alterations to set points.

Level Three- typically fits within the role of the WSM, EWC or other similar

service provider organisations and may include/require:

a detailed understanding and knowledge of all aspects of the BEMS required

a detailed understanding and knowledge of all plant integrated with the

BEMS. Able to call up and view point data from schematics and pointslist for whole site

full access to all control functions, liaison with Site Energy Manager,

advised if environmental set points or time setting to be altered

ability and access to acknowledge system alarms

ability and access to add analogue and digital inputs and outputs to the

system

ability and access to change control strategies

ability and access to view trend logs.

Level Four- typically fits within the role of the Site Energy Manager and may

include/require:

a full understanding of the BEMS architecture, design philosophy and

capabilities

a full understanding of the functions of the engineering systems

controlled by the BEMS

access and ability to call up and view point data from schematics and

points lists for the whole site

access and ability to view all system data and set up trend logs or

exception alarms

visibility of all system alarms for relay on to relevant maintenance

personnel

access and ability to make changes to time and occupancy controls and

set points and alarms

ability and access to add or change graphics

ability to change control strategies and add analogue and digital inputs

and outputs to the system.

These four levels are only indicative and the particular site and its requirements

will dictate those appropriate. In some instances, levels may be combined, inothers, sub-levels within those shown may be created.

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Section 4 BEMS Operation


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4.3 TRAINING

To obtain the full benefit of a BEMS it is essential that people who are

authorised to use, operate and maintain it, are trained to allow them to have a

good understanding of its capabilities, purpose and potential. Such training

needs to be an ongoing process.

Operators need to understand the prime function of the BEMS, which may have

changed since the original design specification was produced. They also need to

be trained in the operating method of the system. Problems that may arise when

established procedures are not followed should be part of the training

programme. The procedure for making changes, alterations or additions to the

BEMS should already be defined, but will need to be explained, together with

how to record system malfunctions or concerns about incorrect performance to

enable them to be resolved by the maintainer.

BEMS operators will need to be trained to understand the displays, how to

monitor and change time schedules, set points and environmental control

settings, acknowledge and cancel alarms and take action following alarmmessages. They should also be able to carry out routine maintenance of the

system central station hardware (eg. replace printer cartridge).

Maintenance staff require training in any specialist procedures related to the

specific installation. They also need to understand the generic requirements set

out in the HVCA maintenance schedules for BEMS. (See Section 5.3).

4.4 COSTS OF OPERATING BEMS

These can be divided into two elements. The first is maintenance of the installed

equipment. An indicative annual cost for this is some 7% of the original installed

cost for the complete controls installation. However, the controls components(sensors, actuators, controllers etc.) will need to be maintained in any event. The

cost of maintenance of the BEMS components (ie. control operator station and

communications network) should be identified separately. In the absence of

other information, a value of 0.5% of the total installed cost could be considered.

This value is included within the 7% stated above (see 5.2 Maintenance Costs).

The second element is the operator cost for the system. This will depend on the

role of the person acting in this capacity, and whether energy M&T is included.

For BEMS operation, an indicative figure of 10% - 20% full time attendance

would need to be available for this role. Should energy M&T also be included,

the time proportion increases to 30% - 40%.

4.5 UPGRADING AND REFURBISHMENT OF BEMS

The cost of upgrading or refurbishment of BEMS will need to be demonstrated to

be cost effective. Anticipated energy savings are likely to be the principle

jus tification, though other potential advantages, listed in para 1.5, may also be

appropriate. A life cycle cost analysis showing anticipated operating,

maintenance and repair costs of the existing equipment, compared with the cost

of upgrade or refurbishment, over say 15 years, can help to make the case.

At the design stage, adequate spare capacity should be provided in the system

for known or anticipated system expansion. This extra capacity needs to be

available at the central station, outstations and the communications network.

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Specific site requirements and known proposals should be used as the basis for

expansion planning. However, in the absence of detailed information an

allowance of 20% should be made in each of the component elements with

potential for expansion such as the central station, outstations and

communication network.

If the BEMS is a modular system, it may be reasonable to provide minimal

expansion capability during the initial installation and provide additional

modules when required.

When upgrading an existing system, the initial consideration is likely to be to

use the same equipment supplier. This should avoid problems with the

communication standards protocols and interfaces between different suppliers'

equipment. The age, reliability and performance of an existing system may

influence the decision to continue with the same supplier.

When an existing BEMS has insufficient capacity to upgrade to meet current

requirements, it may be practical to retain field devices and the communication

network to limit the project cost. It is possible that the existing equipment from

a particular supplier may not be compatible with their current product range.

BEMS equipment suppliers claim to be able to interface with the majority of

competitors equipment. Careful programming of the project will be required to

ensure all systems are operational during the upgrading.

CIBSE have published the following economic life factors for BEMS components,

which may be useful when considering upgrading or refurbishment. The specific

applications and quality of maintenance will dictate the remaining life of

existing components.

Equipment Item Typical Life

Factors (Years)

BEMS operating system 5-10

AutoDial modem 5-10

Communication network (hardwiring) 25-30

Network communications services 10-15

Damper actuators 10-15

Outstations 5-15

Sensors 3-10

Control valves 15-20

Control dampers 15-20

Utility sub-metering 10-20

Electronic controls 12-18

Hydraulic valve actuators 10-15

Pneumatic valve actuators 15-20

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5 BEMS Maintenance

5.1 PREAMBLE

With the increasing complexity of BEMS it is essential that their integrity

(including software and applications) is checked and the requirements reviewed

at regular intervals. Ignorance of a system's capabilities, coupled with poor

commissioning and lack of client commitment can result in a BEMS becoming an

expensive time clock.

If the equipment is not correctly and fully commissioned and maintained by

specialist, trained personnel and supported by the manufacturers, the benefits of

the investment will be lost, energy wasted and operational costs will rise.

Where a BEMS is installed, the client should be aware of the need for

continuous monitoring of performance. Switching off because of a malfunction or

lack of data update can negate the considerable investment and give rise to

unacceptable environmental conditions and energy wastage.

Building operators with a BEMS should ensure that the operators have had

appropriate training to understand the equipment and carry out routine daily

and weekly maintenance tasks, such as monitoring and changing time

schedules, set points, environmental control settings and simple computer

hardware maintenance (eg. changing printer cartridges). Such training needs to

be an ongoing process.

5.2 MAINTENANCE COSTS

It is essential to make provision for the ongoing maintenance of a BEMS once it

is installed. As a budget indicator, an annual cost of 7% of the installed cost (ie.

the hardware, software, outstations, sensors and actuators, and communication

interfaces) should be allowed for the complete controls installation. This figurehas been obtained from suppliers, BEMS specialist maintenance contractors and

MOD users. This would cover, depending on the size of the installation,

maintenance of the central operator station, data communications, controllers

and software functions, calibration of sensors, and operational checks of

actuators. Spare parts and replacements would be additional costs. As noted in

para 4.4, Costs of Operating BEMS, the maintenance of the BEMS components

is a small proportion of the 7% figure.

5.3 CONTRACT ARRANGEMENTS

The HVCA have produced a series of standard maintenance specifications for

mechanical services in buildings. Volume III covers Control, Energy and

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DMG 22Building Energy Management Section 5 BEMS MaintenanceSystems

Building Energy Management Systems. The HVCA Standard can be used as a

means of checking that work has been carried out and conforms to the

requirements. It is essential that the specialist engineer appointed for BEMS

maintenance is familiar with the equipment and the manufacturer's

maintenance manual.

Maintenance schedule or contract needs to be in place from the date the BEMS

is handed over to the client. One option for the initial twelve month period is to

include the cost in the supply contract. If this is done, the cost details need to be

separately identified in the tender document.

Contract options are:

direct contract to specialist or equipment supplier

arrange call-out facility only with specialist or supplier

place BEMS maintenance through main M&E maintenance contractor.

Details of the arrangement also need to be addressed, such as minimum call-out

response time, whether a fully comprehensive contract is required (ie. costs

include all spares, consumables, and replacement following breakdown).

Maintenance contractors undertaking BEMS maintenance should have

specialists with:

necessary training

knowledge of the installed system

up-to-date awareness of manufacturers equipment

access to up-to-date diagnostic equipment

good technical support

access to good stocks of spares.

5.3.1 Operat ing and Maintenance Documentat ion

It is essential that a detailed manual be kept on site. This site manual records

the responsibilities of all parties involved with the BEMS, together with the

installed equipment, normal settings, control diagrams and location of theOperating and Maintenance manual relating to the specific plant and control

equipment. This site manual can also serve as a service log to record faults and

observed by the BEMS operator, changes to control parameters, set

points, program algorithms plus reasons why the change was necessary. It can

also be used to check when each entry is resolved.

5.4 SPARES AND CONSUMABLES

Investigation of typical BEMS installations at various MOD locations indicated

that spares and consumables may not need to be stored on site, as they are often

readily available from manufacturers and could be charged for on an 'as

required' basis.

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Therefore, it is not recommended that BEMS spares be held on site unless

particular requirements such as equipment serving a strategically essential

system justify this.

Items which are known to be regularly replaced such as sensors, valves and

actuators, which are common throughout the site, would justify being held at

minimum levels to allow replacement to be carried out.

5.5 RECOMMISSIONING

Over time, BEMS settings, performance and operating parameters will change

as items become worn, electrical items drift and other circumstances change.

Regular recommissioning of the BEMS can help ensure it is operating at its full

potential, maximum energy savings are being achieved and plant performance

and expected life is maximised. The frequency and areas of the BEMS for

recommissioning should be based on regular monitoring of the BEMS

performance and any major changes in the use or layout of the areas being

managed by it.

An indicative cost for recommissioning should be based on around 30 minutes

per point to be covered.

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Figure 4

Energy monitoring andtargeting

6 Energy monitoring and targeting

6.1 REVIEW AND RELATIONSHIP WITH BEMS

A target can be defined as a measurable objective to be achieved in a given time.

In terms of energy management, it may be a forecast over a twelve month period

of the expected utility consumption eg. electricity, gas, oil, water. For heating,cooling and lighting loads, there will be fluctuations over the twelve month

period due to variations in external weather conditions and the available hours

of daylight. This is in addition to the specific building requirements such as

changes in the hours of occupancy.

Figure 4 shows an exampletargetconsumption for an officetype building, with a

tolerance margin around the target line of 10% to show acceptable performance

criteria.

7000

6000

5000

4000

3000

2000

1000

0

By plotting the actual consumption on the target graph on say, a monthly basis,

a good indication of performance against target can be obtained, as shown by the

white line. As weather conditions are never the same year to year, or even month

to month, the results may need to be normalised by the use of degree-day

information. This provides detailed meteorological information of the days when

heating (or cooling) would have been required, which allows target information

to be modified to actual local weather conditions.

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Target ConsumptionTarget 10%

Actual Consumption

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Design & Maintenance Guide 22

Documents

Transcript of Design & Maintenance Guide 22