Refurbishment for Improved Energy Efficiency: An Overview PDF
Preview Refurbishment for Improved Energy Efficiency: An Overview
Refurbishment for improved energy efficiency: an overview CIBSE Knowledge Series: KS12 Principal author Kevin Pennycook, BSRIA Knowledge Series editor Helen Carwardine Editors Helen Carwardine Ken Butcher Publishing Manager Jacqueline Balian CIBSEKnowledge Series — Refurbishment cover mock-up 1 22/10/07 11:18 Page 3 The rights of publication or translation are reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means without the prior permission of the Institution. © October 2007 The Chartered Institution of Building Services Engineers London Registered charity number 278104 ISBN: 978-1-903287-88-0 This document is based on the best knowledge available at the time of publication. However no responsibility of any kind for any injury, death, loss, damage or delay however caused resulting from the use of these recommendations can be accepted by the Chartered Institution of Building Services Engineers, the authors or others involved in its publication. In adopting these recommendations for use each adopter by doing so agrees to accept full responsibility for any personal injury, death, loss, damage or delay arising out of or in connection with their use by or on behalf of such adopter irrespective of the cause or reason therefore and agrees to defend, indemnify and hold harmless the Chartered Institution of Building Services Engineers, the authors and others involved in their publication from any and all liability arising out of or in connection with such use as aforesaid and irrespective of any negligence on the part of those indemnified. Typeset by CIBSEPublications Printed in Great Britain by Latimer Trend & Co. Ltd., Plymouth PL6 7PY Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 2 Why refurbish? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 3 Refurbishment challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 4 Refurbishment assessment procedure . . . . . . . . . . . . . . . . . . . . . .8 5 Pre-refurbishment energy checks . . . . . . . . . . . . . . . . . . . . . . . . .13 6 Lower cost refurbishment options . . . . . . . . . . . . . . . . . . . . . . . .14 7 Higher cost refurbishment options . . . . . . . . . . . . . . . . . . . . . . . .22 8 Low or zero carbon technologies . . . . . . . . . . . . . . . . . . . . . . . . .33 9 Commissioning/recommissioning . . . . . . . . . . . . . . . . . . . . . . . . . .37 10 Handover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 Appendix A: Refurbishment procedures and options flow chart . . .41 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42 CIBSEKnowledge Series — Refurbishment 1 Introduction With increased awareness of the importance of energy efficiency in buildings, not only to reduce carbon emissions but also to meet regulatory and planning requirements, refurbishment of building services is currently an important subject. Whilst we build 1% of the stock new each year, 99% of the stock is already with us – whenever a building is refurbished it is an opportunity for building services engineers to add value and reduce energy costs and carbon emissions through energy efficient measures. The introduction of energy performance certificates (EPCs) may result in tenants demanding better energy performance from their buildings and this publication will show ways of achieving this. This is a joint CIBSE and BSRIA publication that will provide guidance to building services engineers who are tasked with upgrading existing services. It will help building occupiers and managers to understand the minor refurbishment steps that can be taken to improve the energy efficiency of their building services. Members from both organisations are involved in operating buildings and refurbishment presents them with a large challenge, as well as a significant opportunity. This publication brings together the wide range of sources of information available from both CIBSEand BSRIAto demonstrate to building services engineers the refurbishment options that are available to them. Retrofit for energy efficiency should not be undertaken in isolation from the other drivers and considerations relating to building refurbishment. Examples include occupancy comfort, health and productivity, future flexibility and adaptability of services and maintenance and upkeep issues. This Knowledge Series publication is intended to provide a concise overview of building services refurbishment with a focus on improving energy efficiency. It is not intended to give an in-depth review of the various refurbishment issues and options, rather it is an introduction to the various topics along with sources of in-depth guidance. Note that refurbishment options outlined in this publication include ‘lower cost’ and ‘higher cost’ options. In practice, what constitutes lower and higher cost will be highly dependant on the specific building, its existing building services and desired levels of improvement. Further information on all of the aspects covered in this publication can be found in other existing CIBSE and BSRIA publications, and these are indicated throughout. CIBSEKnowledge Series — Refurbishment 1 2 Why refurbish? Building services systems are refurbished for a variety of reasons. For example, the replacement of old and inefficient plant, changes in use or the extension of buildings. The principal aim when refurbishing building services systems is to provide optimum system performance for minimum capital outlay, ensuring appropriate comfort conditions are maintained at the least possible rate of energy expenditure and consequent CO2emissions. In reality these aims are not always fully realised. The benefits of refurbishment are wide and can include the following: — provide for a change in use of the building — attract higher rents — produce a higher return on capital — help sell or rent a building — retain existing tenants — create more lettable floor space — compete with other new/refurbished properties in the same market place — provide improved environmental comfort conditions — provide a lower-cost option than moving to a new building — provide better operating characteristics. The following factors influence the requirement for building services refurbishment. 2.1 Reduced energy consumption/CO2 emissions During previous decades energy has been relatively cheap and this has hindered the adoption of energy-saving building services solutions. Recent years have seen a steep rise in energy prices and it is highly likely that these prices will further increase in real terms, due to increasing world demand for energy along with strategic considerations. There is now widespread awareness of climate change and the influence of manmade CO2emissions along with the significant contribution that the buildings sector makes to CO2 emissions. These factors have raised the profile of building-related energy consumption and consequently raised the profile of building services refurbishment. 2.2 Building Regulations Approved Document L2B: Conservation of fuel and power in existing buildings other than dwellings(1)imposes a range of energy related requirements on the design of retrofitted and extended existing buildings. L2B applies to: 2 CIBSEKnowledge Series — Refurbishment — consequential improvements — extensions — buildings subject to a material change of use — material alterations — provision of a controlled fitting — provision or extension of a controlled service — provision or renovation of a thermal element. Consequential improvements, required when an extension is built or where the installed capacity per unit area of heating and cooling systems is increased, can result in a requirement to: — upgrade heating, cooling and air-handling systems more than 15 years old by the provision of new plant or improved controls — upgrade general lighting systems — install energy metering — upgrade thermal elements (walls, roofs etc), and windows and doors — increase the on-site low and zero carbon energy-generating systems. Where a building refurbishment requires the installation, extension or replacement of a controlled service, the work has to meet minimum standards of energy efficiency. These standards are provided in the Non- domestic heating, cooling and ventilation compliance guide(2). Refurbishment projects that are covered by the Building Regulations will require notification to the local authority building control or an approved inspector. Certain aspects of refurbishment may be covered by self- certification schemes. 2.3 The EU Directive on Energy Performance of Buildings This requires a range of building energy labelling measures to be implemented in the UK. This implementation is made via Statutory Instrument 2007/991 and contains requirements for energy performance certificates to be compiled for all buildings at the time of construction, sale or rent, and in some cases for certificates to be displayed. The requirements for certification, and other issues relating to the Directive such as in the inspection of air conditioning systems, are subject to a rolling timetable. A method for assessing the energy performance of an occupied building based on metered energy use that will meet the requirements of the Directive is provided in CIBSE TM22: Energy assessment and reporting method(3). CIBSEKnowledge Series — Refurbishment 3 2.4 Condition of building services Refurbishment of building services systems can be driven by the age and condition of the building services equipment. Old, outdated and inefficient plant will compromise the efficient operation of a building. Retrofitting some, or all, of the building services systems can provide the following benefits: — reduced energy consumption and CO2emissions — reducing heat output from equipment can correspondingly reduce the demand for cooling — reduced maintenance requirement — increased maintenance intervals (therefore reduced maintenance costs) — greater reliability — easier access for inspection and maintenance — improved supply of spare parts — easier to obtain suitably trained maintenance staff — ability to reduce health and safety risks. 2.5 Improved occupant comfort and productivity The primary aim of building services is to create and maintain a comfortable environment, however, many existing buildings provide a poor working environment in terms of occupant comfort. This can have implications for staff satisfaction with their working conditions, morale, absenteeism, health and safety, and staff retention. Internal environmental factors that influence occupant comfort are: — thermal comfort influenced by air temperature, relative humidity, mean radiant temperature, and air velocity — internal air quality influenced by ventilation rates, quality of the exterior air, building occupants and other sources of internal air pollution — visual comfort influenced by illuminance levels, glare, contrast and colour rendition — acoustic comfort influenced, in part, by noise from building services equipment, noise from the exterior, and noise passing from one office area to another, eg through walls or via ceiling voids. Successful retrofit actions can address the above issues. Details concerning occupant comfort are provided in CIBSE KS06: Comfort(4). 4 CIBSEKnowledge Series — Refurbishment 3 Refurbishment challenges 3.1 General Guidance Due to the nature of construction sites, health and safety issues present a challenge to designers and project managers. The most frequent causes of Guidance concerning the essential tasks accidental death and injury are: for achieving health and safety objectives on construction sites is given in the HSE publication – Managing health and safety — falls in construction(36). — mobile plant — falling material and collapse — electrical accidents — trips. In addition, ill health can result from: — exposure to asbestos — injuries resulting from manual handling of heavy and awkward loads — noise and vibration from tools — chemical exposure from materials. As part of many refurbishment projects it is likely that hazardous waste (referred to as special waste in Scotland) will be encountered. Examples of hazardous waste include: — asbestos — lead-acid batteries (eg used in UPS systems) — electrical equipment containing hazardous components — fluorescent light tubes — chemical wastes. Organisations that dispose of waste (including the original ‘owners’ of the waste) have a duty of care to ensure that any waste product is handled safely and within the law. In England and Wales, sites disposing of hazardous waste will need to register as producers with the Environment Agency. Guidance concerning the disposal of waste from refurbished buildings is given at the following website: www.netregs.gov.uk. Depending on the nature of the refurbishment project, disruption to the building occupants may occur. Disruption can be reduced by performing refurbishment on a floor-by-floor basis and replacing building services plant/systems out of season, eg replacing a heating system during the summer. Disruption to the occupants and residents of adjoining properties can be minimised by following the guidance produced by the Considerate Constructors Scheme (www.considerateconstructorsscheme.org.uk). CIBSEKnowledge Series — Refurbishment 5 3.2 Building services specific The building imposes practical constraints on the refurbishment project, not just the design but the removal and installation of plant. The following should be taken into account during the design stage of any retrofit project. Table 1: General Presence of asbestos (removal/encapsulation) Design considerations for Location of existing services refurbishment Isolation of existing services Safe removal of redundant equipment. Space and Items of plant access Routing of flues, pipes, ducts etc Equipment installation access Maintenance access Repair access Replacement access. Space for plant Plant rooms Riser shafts Floor voids Ceiling voids Conditioned areas. Weight Plant rooms constraints Riser shafts Ceiling voids Conditioned areas. Weight loading Floors constraints Ceilings Roofs Walls. The refurbishment assessment and subsequent design stage may be hindered by a lack of documentation concerning the existing building and its building services plant. Examples include details of the building fabric thermal properties and operational capacity of plant. Much of this information can be gathered during the carrying out of condition surveys. It is likely that much refurbishment work will be influenced by the requirements of the Building Regulations (Approved Document L2B and its associated second tier guidance documents). Examples of how Approved Document L2B can influence refurbishment are given in section 2.2. 6 CIBSEKnowledge Series — Refurbishment 3.3 Refurbishment specific Due to the nature of carrying out refurbishment work, especially where part of the building may remain occupied during the work, there are a number of additional considerations that need to be taken into account, such as: — how to identify and isolate the refurbishment work from live services that need to be protected and remain operational for the building occupants, eg gas, electricity, broadband — issues relating to the possible interfacing of existing and new building services, for example, ensuring that existing hydronic systems are clean before connection to new systems — how to reduce the impact of noise and dust on occupants — the complicated logistics of working around occupants — the continued operation of life saftey systems where appropriate, such as fire detection and security detection systems, along with the maintenance of evacuation routes — the importance of reducing inconvenience to any neighbours. Most of these issues will need to be considered and addressed during site surveys before work begins. As with any project, whether new build or refurbishment, co-ordination between those involved in the design and subsequent construction stages is crucial for success. CIBSEKnowledge Series — Refurbishment 7
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