Transforming Existing Buildings - The Green Challenge · Transforming Existing Buildings: The Green Challenge Final ... for approximately 44% of total carbon dioxide ... hotels vary

Transforming Existing Buildings: The Green Challenge Final Report March 2007 Isabel McAllister, Cyril Sweett

Contents

Subject page 1.0 Introduction 1

2.0 Benchmarks 2

3.0 Technically feasible opportunities 12

4.0 Challenges 21

5.0 Recommendations 25

Appendix A: List of references 28

Appendix B: List of improvement measures (Separate document)

1

1.0 Introduction The built environment generates significant environmental impacts, making sustainability a critical objective for the construction and property industry. The environmental impacts of the UK construction sector include: • Buildings account for approximately 44% of total carbon dioxide emissions (18% from the

non-domestic sector, 26% from the domestic sector).1 • Approximately 13 million tonnes of the construction and demolition waste produced every

year is made up of materials delivered to sites but never used.2 • Around ¼ of UK industry energy consumption is attributed to the production and

transportation of construction products and materials.3 • Built up areas (including gardens and transport infrastructure) cover 10% of the land

surface of Great Britain. In rural areas, the cover of developed land increased by about 4% between 1990 and 2000.4

• Approximately half the water abstracted in the UK is used in buildings5. Encouragingly, industry performance is improving. For example, recycling of construction waste has increased significantly, and new buildings are required to conform to increasingly stringent standards, particularly with regard to energy and water consumption. Buildings constructed in 2006 are typically 40% more energy efficient than those built in 2002.1 However, there are still opportunities to improve the sustainability performance of existing stock. Typically, these opportunities have been missed and previous efforts to improve environmental performance have primarily targeted new buildings. Existing building stock represents 98-99% of buildings in the UK at any one time. New buildings add between 1% and 1.5% to building stock each year. Improving the sustainability performance of existing stock is a key opportunity that should be pursued. This research focuses on existing commercial building stock (offices, hotels, retail and industrial buildings), rather than new buildings, which are already heavily regulated. Particular aspects of sustainability (environmental) performance in existing building stock are reviewed in this report, including energy, water, material efficiency (recycled content) and support for biodiversity and habitats. Each of these areas is of interest to a range of industry stakeholders including government agencies, WRAP, Carbon Trust, building procurers and occupiers. Each of the areas also contributes to four of the main pillars of the BRE Environmental Assessment Method (BREEAM), the UK environmental performance label for buildings. The research is presented as follows: • Typical existing building performance compared with new build (benchmarks) • Technically feasible opportunities to improve performance in existing stock • Commercial and other barriers that may prevent opportunities from being realised • Recommendations for progressing the agenda to improve the performance of existing

commercial building stock

1 The 99% campaign: greening the stock we’re stuck with. Building, 23 June 2006, pp 30-33 2 Environment Agency Sustainable Construction Position Statement 2006 3 DETR Building a Better Quality of Life: A Strategy for more Sustainable Construction 2000 4 DEFRA Countryside Survey 2000 5 Environment Agency Water resources for the future: A Strategy for England and Wales 2001

2

2.0 Benchmarks Benchmarking is essential to determine the baseline performance of existing stock in each of the four types of commercial building under review (offices, hotels, retail and industrial). The following tables compare the typical performance of existing buildings with that of new buildings, which owing to new regulations and other market forces, have much improved sustainability performance. This exercise provides a good indication of the actual justification for improvements, and of the potential effect of proposed measures. Benchmark figures are presented for: Topic area Description of measurement Unit Energy Annual units of energy (kWh) consumed per m2 kWh/m2/yr

Water Annual units of water (m3) consumed per m2 m3/m2/yr

Waste/material efficiency Percentage of total material value that is recycled % recycled content by £value*

Biodiversity and habitat Benchmark measurement technique/figures not available

N/A

* In line with the WRAP (Waste and Recycling Action Programme) Toolkit. WRAP recommends a minimum requirement for recycled content by value for a new building/refurbishment of 10%. The benchmarks presented in this report are generic, and therefore do not take into account the characteristics of buildings that might affect performance; such as age, the use patterns within the building, type of structure and superstructure, glazed areas, and staff numbers. Nevertheless, where possible, pie charts denoting typical energy and water consumption within the different building types are presented. These indicate where resources are used within each building type, and therefore provide further guidance as to significant potentials for improvement. Biodiversity and habitat benchmarks are not available, however technically feasible improvements, barriers and recommendations for this topic area are provided in other sections of this report. The data presented in these tables have been collated from a range of sources including: • Carbon Trust Energy Consumption Guides 19 and 81 • CIRIA water key performance for offices and hotels report • Chartered Institute of Building Services Engineers (CIBSE) data • Waste and Resources Action Programme (WRAP) The full list of references can be found in Appendix A.

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2.1 Offices The following table presents the typical performance of existing office buildings compared to that of new build. Benchmarks have been allocated to four types of office. Naturally Ventilated Cellular

Usually a relatively small simple building, sometimes converted from former residential use. Typical size ranges from 100 - 3,000m2

Naturally Ventilated Open Plan

Purpose built building, sometimes in converted industrial space. Typical sizes range from 500 - 4,000m2

Air Conditioned Standard

Largely purpose-built and developed for speculative purposes. They typically range from 2,000 - 8,000m2

Air Conditioned Prestige

A national or regional head office or technical or administrative centre. Typical sizes range from 4,000 - 20,000m2

The ‘improvement’ columns denote the typical improved performance in new buildings, compared with average existing stock. Table 1: Benchmarks for office buildings

Sources: Carbon Trust (2000) Energy Use in Offices CIRIA (2006) Water Key Performance Indicators and Benchmarks for Offices and Hotels WRAP data

New buildings have significantly better performance for energy and water, with the exception of energy use in new prestige air conditioned offices. The extent of building services has a significant impact on both the energy consumed (electricity consumption is more than doubled in air conditioned offices) and on the recycled content (by value) of the materials used in the building. The range in recycled content for each of the building types reflects inherent variations in cladding, structure and fit out.

Nat Vent Cellular Nat Vent Open Plan Air Con Standard Air Con Prestige

Existing New build

Improve- ment Existing

New build


New build


New build

Improve- ment

Energy (annual kWh/ m2 floor area)

E (electricity) G (gas)

E 55 G 145

E <35 G <75

E >36% G >48%

E 90 G 145

E 55 G 75

E 39% G 48%

E 225 G 175

E 125 G 95

E 44% G 45%

E 360 G 200

E 350 G 100

E 2.7% G 50%

Water (m3 per annum/m2 net area)

0.8-0.6 0.5-0.4 16 – 50% 0.8-0.6 0.5-0.4 16-50% 0.8-0.6 0.5-0.4 16-50% 0.8-0.6 0.5-0.4 16-50%

Material Efficiency (% recycled content by value)

Not available 10-20 Not

available Not

available 10-20 Not available

Not available 10-25 Not

available Not

available 10-25 Not available

Biodiversity Benchmark figures not available

4

2.1.1 Energy consumption in offices The following 4 pie charts denote where energy is used within each type of office building.

Nat. Vent. Cellular Office

74%

3%

11%

9%

1%

2%

Heating and hot water Fans, pumps, controls

Lighting Office equipment

Catering Other electricity

Nat. Vent. Open Plan

65%

1%

3%

16%

11%

2%

2%

Heating and hot water Cooling Fans, pumps, controls

Lighting Office equipment Catering

Other electricity

5

AC standard

45%

8%15%

4%

13%

8%

1%

2%4%

Heating and hot water Cooling Fans, pumps, controls Humidification Lighting

Office equipment Catering Other electricity Computer room

AC Prestige

35%

7%12%

4%

11%

6%

4%

3%

18%

Heating and hot water Cooling Fans, pumps, controls

Humidification Lighting Office equipment

Catering Other electricity Computer room

Source: Carbon Trust (2000) Energy Use in Offices

Air conditioned and non-air conditioned office buildings use a similar proportion of their energy consumption for lighting, catering and office equipment. However, air conditioned office buildings have significant additional energy needs for cooling the building and powering fans, pumps and controls. Although they use a smaller proportion of their energy consumption for heating and hot water, the total amount of energy used for this purpose is higher due to higher overall energy consumption.

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2.1.2 Water consumption in offices The following pie chart denotes where water is typically used in an office building.

Water use in offices

43%

20%

27%

9% 1%

Toilet flushing Urinal flushing WashingCanteen/kitchen Cleaning

Source: CIRIA (2006) Water Key Performance Indicators and Benchmarks for Offices and Hotels 2.1.3 Material efficiency and biodiversity in offices The recycled content of existing buildings is unknown due to a lack of historic data on material composition. Refurbishments and new buildings present significant opportunities to use more recycled materials; however where possible, in situ reuse of materials is still preferable. There is no available data on biodiversity for existing or new buildings.

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2.2 Hotels Performance in the hotel sector varies widely depending on the quality of the building and its services. Benchmarks are available for three different categories: 5 star (luxury) Hotel: Typically in a city centre location, with large reception and circulation areas,

usually have a restaurant, conference and leisure facilities. Typical sizes range from 70-90 m2/bedroom, and they have from 100-500+ bedrooms.

4&3 star (business or holiday) Hotel:

Purpose-built, with restaurant, conference rooms and leisure facilities, business or holiday hotels vary between 40-60 m2/bedroom, and they have from 50-150 bedrooms.

2&1 star (smaller) Hotel:

Often converted from buildings with previous uses, smaller hotels usually have 20-100 bedrooms, with a floor area of 60-70 m2/bedroom.

Table 2: Benchmarks for hotel buildings

* A (air conditioned) luxury hotels can consume 40% more energy than luxury hotels that are not air conditioned. **P (pools) in luxury hotels increase water consumption by up to 400% 1 % reduction 2 Additional % recycled content Sources: Carbon Trust (1999) ECON36 Energy Efficiency in Hotels CIRIA (2006) Water Key Performance Indicators and benchmarks for Offices and Hotels New build hotels show a definite improvement for all hotel types, with electricity consumption reduced by 33-40%, and gas consumption reduced by up to 35% (depending on hotel type). Water savings are also significant, although more varied, for example water use in new business and holiday hotels is 25-86% less compared to existing hotels of the same type.

Luxury Hotel Business or Holiday Smaller

Existing New build Improve-

ment Existing New build Improve-

ment Existing New build Improve-

ment Energy (annual kWh/ m2 floor area)

E (electricity), G (gas)

*A (air conditioned)

E >150 *A

E >200

G >460

E <130*A

E <90

G <300

E >38%1 *A

E >40%1

G >34%1

E >140

G>400

E<80

G<260

E >42%1

G >35%1

E >120

G>360

E <80

G <240

E >33%1

G >33%1

Water (m3 per annum/m2 net area)

**P (hotels with pools)

200-150 *P

70-40

120-65 *P

30-15

20-67%1 *P

25-78%1

180-80 *P

50-30

60-25 *P

20-10

25-86%1 *P

33-80%1 15-10 8-4 20-73%1

Material Efficiency

% recycled content by value

Not available 10-20%2 Not available

Not available 10-20%2 Not

available Not

available 10-20%2 Not available


8

Standard Energy Consumption in Hotels

47%

20%

8%

15%

10%

Heating Hot water

Lighting Catering

Other, inc. air-con and ventilation

Source: Carbon Trust (1999) ECON 36 Energy Efficiency in Hotels Data is not available by hotel type; however this chart indicates that hotels typically use a large proportion of energy for heating and hot water.

Water use in hotels

21%

6%

12%

4%16%

2%

38%

1%

kitchens coldrooms laundry

Steam generation Locker rooms/ public toilets Pool

Guest rooms Air conditioning

Source: CIRIA (2006) Water Key Performance Indicators and benchmarks for Offices and Hotels This chart shows that the proportion of water consumed by a hotel pool amounts to only 2% of total consumption. However, the presence of a pool also increases the use of washing machines and showers. The largest proportion of water used in hotels is in guest rooms, and this proportion is likely to be larger in hotels with pools.

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2.3 Retail For benchmarking purposes, the main categories of retail building are detailed below. Sheds Such as those occupied by out of town superstores Shopping centres Located both in urban centres and on the town outskirts High Street units Located in every population centre throughout the UK Food stores Whether large or small, food store energy consumption levels are much

higher than other retail businesses, due to the need for high levels of refrigeration. This applies to supermarkets, off-licenses, and frozen food outlets.

Table 3: Benchmarks for retail buildings

Sources: 1 BRE (1999) Sustainable Retail Premises 2 Benchmarks not available, however significant water usage reductions are possible in existing buildings 3 Envirowise EN336 Reducing waste and utility use in managed shopping centres There is a marked improvement in energy use in new shed-type retail buildings (20-55% reduction). Although energy consumption benchmarks for other retail building types have also decreased in new buildings, the wide range of consumption figures for both existing and new buildings means a specific percentage decrease for new buildings is difficult to determine. Water usage figures for retail buildings are not available for either existing or new buildings, with the exception of a potentially out of date very broad benchmark for existing shopping centres.

Sheds Shopping Centres High Street Food Store


ment Existing New build


New build

Improve- ment Existing New build

Improvement

Energy1 (annual kWh/m2 floor area)

250-450 200-300 20-55% 200-400 100-300 50-75% 200-400 100-300 50-75% 200-1000 800-1000 0-33%

Water (litres/m2/yr) Not available

Not available 50%+2 17–20003 Not

available 50%+2 Not available

Not available 50%+2 Not

available Not

available 50%+2


Not available 10-20% Not

available Not

available 10-20% Not available


available Not

available 10-20% Not available


10

Annual Energy Use by Retail Type

80 100 90

230290

440

750

0100200300400500600700800

1

Retail Building Type

kWh

/m2

post offices

banks and buildingsocieties

agencies

non-food shops

department stores

food stores

supermarkets

Source: BRE (1999) Sustainable Retail Premises

The above chart provides energy usage figures for existing buildings using more specific retail categories. Supermarkets appear to be the biggest energy users, followed by food and department stores. This is partly accounted for by the longer operating hours typical of supermarkets. 2.4 Industrial The following table presents the benchmarks for the industrial sector. The table focuses on building performance, rather than the impacts of the industrial processes that take place within them.

Table 4: Benchmarks for industrial buildings

1 % reduction 2 Additional % recycled content

Table 4 indicates a definite improvement in energy efficiency for industrial buildings (17-50%). However, because information based on specific types of industrial buildings is not available, a more specific improvement cannot be determined.

Industrial


ment

Energy (annual kWh/m2 treated floor area)

350-400 200-300 17-50%1

Water (m3/m2/yr) 0.8-0.6 0.5-0.4 17-50%1



available2


11

Water use in Industrial buildings

20%

27%

9%1%

43%

Toilet flushing Urinal flushing WashingCanteen/kitchen Cleaning

Water use in industrial buildings can be compared with consumption patterns found in offices (when industrial processes are not taken into account).

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3.0 Technically Feasible Opportunities The previous section demonstrated the disparities in environmental performance between existing and new buildings, and consequently, the need to focus efforts on improving performance in existing commercial stock. Much can be done to address the imbalance between old and new; and if improvements are implemented, resource consumption and local environmental impacts could be significantly reduced. Relatively simple measures such as implementing good practice plans and programmes, and more effectively engaging building users, can significantly reduce energy and water consumption. However, the measures presented below by topic area focus on how buildings can be physically retro-fitted to reduce their environmental impact. The tables identify and quantify measures that can be implemented when planning a part or total refurbishment. Each of the four environmental topic areas under review (energy, water, waste/material resource, biodiversity and habitat) is presented as a separate table. Each table assesses relevant improvements for the different building types, which are listed in the column headings. Clearly, some environmental improvements are location specific, rather than building or sector specific. Only those improvements that are not significantly constrained by location/site considerations are listed. The data presented in the ‘Improvement’ column shows the percentage improvement that can be achieved in the performance of the particular building element being enhanced. For example, if glazing is upgraded from single glazed to a double low-e glass, a 70% improvement in the thermal performance of the glazed surfaces will be achieved. Where data (rather than a tick or cross) is shown in columns, this indicates a different improvement rate for that particular building type. The tables demonstrate that while many improvements are applicable across a range of building types, some only apply to a specific type (e.g. swimming pool management is only relevant to hotels). Likewise, some improvements only apply to the most complex, highly serviced buildings; and others to the simplest. ü Generally feasible û Generally not feasible

v Site-dependent

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3.1 Energy opportunities

There are many improvements that can be made to all types of commercial buildings to reduce energy use. Some are applicable to most commercial building types, while others are limited. Information based on generic building types is useful, and more specific guides such as those available from the Carbon Trust on energy efficiency in various building types can point a project in the right direction. However, the impact of each solution depends on a range of site-specific factors, and cannot usually be predicted in a generic sense. For example, naturally ventilated offices use the largest proportion of their energy for heating; therefore solutions that reduce heat loss are particularly desirable, whereas for air conditioned offices, solutions that decrease the energy required for both heating and cooling are important. An understanding of the building’s component energy use is critical to arriving at the most efficient solutions for reducing heat loss and heat gain.

Offices Hotels Retail Industrial

Improvement Nat Vent Cellular

Nat Vent Open plan

Air Con Standard

Air Con Prestige 5 stars 3-4 stars

1-2 star B&B Sheds

Shopping Centres

High Street

Food store Shed

ENERGY Enhance glazing (double)

30%

Reduced heat loss/gain through glazing ü ü ü ü ü ü ü v v v v ü

Enhance glazing (low -e) 25% Reduced heat loss/gain

through glazing ü ü ü ü ü ü ü ü ü ü ü ü

Enhance glazing (triple) 60% Reduced heat loss/gain

through glazing ü ü ü ü ü ü ü v v v v ü

Fill cavity wall with insulation >50%

Reduced heat loss through walls ü ü ü ü ü ü ü ü ü ü ü ü

Roof insulation 60% Reduced heat loss through roof ü ü ü ü ü ü ü ü ü ü ü ü

Floor insulation 25%

Reduced heat loss through floor ü ü ü ü ü ü ü ü ü ü ü ü

Energy efficient lighting 60%

Reduced energy used for lighting (+ reduced internal heat gain)

ü ü ü ü ü ü ü ü ü ü ü ü

Shading devices 20-40% Reduced heat gain ü ü ü ü ü ü ü ü ü ü ü ü

14



Nat Vent Open plan

Air Con Standard


1-2 star B&B Sheds

Shopping Centres

High Street

Food store Shed

ENERGY Energy efficient policies and staff awareness and training

Variable General reduced energy consumption ü ü ü ü ü ü ü ü ü ü ü ü

Optimize length and size of hot water pipes, recirculate mains circuit

10-15%

Reduced heat loss from pipes


Place hot water pipes above cold ones to reduce heat transfer

5%

Reduced heat loss from pipes


Upgrade to more efficient boiler 15-60%

Reduced boiler energy use ü ü ü ü ü ü ü ü ü ü ü ü

Upgrade chillers 15-60% Reduced energy used by chillers û û ü ü ü ü û ü ü ü ü ü

Upgrade pumps 15-60% Reduced energy used by pumps û ü ü ü ü ü ü ü ü ü ü ü

Upgrade Mechanical Ventilation system

15-60% Reduced energy wastage û û ü ü ü ü û ü ü ü ü ü

Incorporate BEMS Up to 50%

Improved control and monitoring û û ü ü ü û û ü ü û ü ü

Maintenance plans and energy audits

Up to 50%

Reduced heat loss and energy consumption generally

û û ü ü ü û û ü ü û ü ü

Light sensors for daylight 10-15% Reduced energy used for

lighting û v ü ü û û û û ü û û ü

Heating control zoning

10-15% Reduced energy used for heating v v v v ü ü ü ü ü ü ü ü

Lighting control zoning 10-15%

Reduced energy used for heating û ü ü ü û û û û û û û ü

Adjust light levels to type of activity to undertake

up to 50%

Reduced energy used for lighting


Use pale colours in walls and ceilings 5 to 10% Reduced energy used for

lighting ü ü ü ü ü ü ü ü ü ü ü û

15



Nat Vent Open plan

Air Con Standard


1-2 star B&B Sheds

Shopping Centres

High Street

Food store Shed

ENERGY Fit draught stripping around windows and doors

10 - 15% Reduced heat lost through windows and doors

ü ü û û ü ü ü û û û û û

Careful choice of internal space temperature. Divide building into heating zones. Warehouse/ storage areas do not need be as heated as others

20-40% Reduced energy used for heating û û ü ü ü ü û v v v v ü

Energy efficient fridges and freezers 60% Reduced energy used for

refrigeration ü ü ü ü ü ü ü ü ü ü ü ü

Energy efficient washing machines and dishwashers

30-40% Reduced energy for washing û û û û ü ü ü û û û û û

Micro wind turbines 2 -5% Reduced energy taken from grid ü ü ü ü ü ü ü ü ü ü ü ü

Photovoltaic cells 1-10% Reduced energy taken from grid ü ü ü ü ü ü ü ü ü ü ü ü

Solar water heating Variable Reduced energy taken from grid ü ü ü ü ü ü ü ü ü ü ü ü

Combined Heat & Power unit 30%

Reduced energy taken from grid v v v v ü ü v û û û û v

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3.2 Water opportunities

There are a number of improvements that can be made, largely through management plans and new fittings, to reduce water consumption in commercial buildings. Solutions should be chosen based on the building’s component water use. Where benchmarks are not available, targets for water consumption can be adopted from the BREEAM credits. BREEAM Offices provides credits based on water consumption/m3/person/year. Other versions of BREEAM such as Retail, award credits based on water fitting specifications rather than consumption benchmarks. Water use is dependent on building type, building use, staff numbers, and fittings. The characteristics of the building itself are not likely to influence water use as they would for energy, however the activities occurring within the building will. Watermark has made available an online benchmarking tool that compares a building’s water use against the benchmark for that building type and number of staff. However, this tool does not cover hotels or industrial or retail buildings.



Nat Vent Open plan

Air Con Standard


1/2 star B&B Sheds

Shopping Centres

High Street Food store Shed

WATER Implement water management plan Variable Reduced water

usage generally ü ü ü ü ü ü ü ü ü ü ü ü

Dual flush toilets 55% Reduced water use by toilets ü ü ü ü ü ü ü ü ü ü ü ü

Aerated taps 50% Reduced water use by taps ü ü ü ü ü ü ü ü ü ü ü ü

Taps with flow regulators 50% Reduced water use by taps ü ü ü ü ü ü ü ü ü ü ü ü

Waterless urinals 95% Reduced water use by urinals v ü ü ü ü ü v ü ü v v ü

PIR sensors for urinal flushing and water supply 60% Reduced water use

by urinals v ü ü ü ü ü v ü ü û ü ü

Showers with =<9l/s 50% Reduced water use by showers ü ü ü ü û ü ü û û û û ü

Rainwater recycling 20% Reduced in water use for irrigation ü ü ü ü ü

30% ü

30% ü

30% ü ü ü ü ü 50-60%

Mains leak detection (connected to BMS if present)

Variable Reduced water wasted through leakage

v ü ü ü ü ü ü ü ü û û ü

Swimming pool management 10-15%

Reduced water used by swimming pool

û û û û ü ü û û û û û û

Mediterranean style garden Variable

Reduced water used for irrigation ü ü ü ü ü ü ü ü ü ü ü ü

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3.3 Material efficiency opportunities

The solutions presented in this report are those which have been identified through case studies and are known to be effective. Experience has shown however, that there are no common answers and solutions cannot be applied generically. Rather, every building is different, and so the most appropriate solutions are specific to each case. When embarking upon a refurbishment, the best way to arrive at the most appropriate solutions is to go through the process of analysis with the specific building attributes in mind. A toolkit is available on the WRAP website (www.wrap.org.uk/construction), which produces a report of best solutions based on project specifications. If this analysis is done at an early stage in the planning of a refurbishment project, solutions can be easily factored into the refurbishment plan. High recycled content solutions can be found for all buildings types. Many of these solutions are both cost and value effective, and are therefore known as “Quick Wins”.



Nat Vent Open plan

Air Con Standard


1-2 star B&B Sheds

Shopping Centres

High Street

Food store Shed

WASTE

Carpet replacement Up to 85% ü ü ü ü ü ü ü û û ü û û

Vinyl flooring replacement

40-100% ü ü ü ü ü ü ü ü ü ü ü ü

Underlay 30-100% ü ü ü ü ü ü ü ü ü ü ü ü

Ceiling tiles replacement 52-84% û ü ü ü v v v ü ü ü ü ü

Blockwork replacement for partitions

25-50% ü ü ü ü ü ü ü û ü ü û û

Plasterboard replacement (partitions, column casing...)

50%

Potential

material

recycled

content

available at

no extra cost

ü ü ü ü ü ü ü û ü ü û v

18



Nat Vent Open plan

Air Con Standard


1-2 star B&B Sheds

Shopping Centres

High Street

Food store Shed

WASTE

Demountable partitions (chipboard, timber/steel frame, metal stud)

10-60% ü ü ü ü ü ü ü ü ü ü ü ü

Raised floors 40 - 85% û ü ü ü v û û û û û û û

Chairs with recycled content

~40% ü ü ü ü ü ü ü ü ü ü ü ü

Recycled content in boards for furniture

Up to 65%


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3.4 Habitat/ Ecology/ Biodiversity opportunities There are a number of technically feasible improvements that can be made to buildings to provide habitat for native species, and consequently support local biodiversity; however there are complex considerations involved in designing such improvements. First, sufficient knowledge of local ecology is required to know which species require additional habitat. Second, a solution that replicates their natural habitat requires careful design. Green roofs are quickly gaining popularity, and these can provide habitat for a range of species and a number of other benefits including thermal insulation, rainwater attenuation and recreational space. However, the potential biodiversity benefits are not always achieved. The roof itself must be assessed for habitat suitability, including climatic conditions (e.g. wind flow, exposure, and sunlight). In addition, design and implementation guidance, and ecological expertise, is needed. There is a wide range of green roofing and green walling products, suppliers and contractors in the UK, and solutions can be found to suit almost any building type. Retrofitting is considered broadly feasible for most buildings; the challenges involved in designing and constructing a retro-fitted green roof are generally the same as for new buildings. The only difference is the need to work within the constraints of the existing roof structure.


Habitat benefits

Nat Vent

Cellular

Nat Vent Open plan

Air Con Standard


1-2 star B&B Sheds

Shopping Centres

High Street

Food store Shed

Biodiversity

Living roof – intensive Can support small trees/shrubs and variable soil depth

ü ü ü ü ü ü ü û ü ü ü û

Living roof - extensive

Shallow substrate, suitable for a range of small hardy species

ü ü ü ü ü ü ü v ü ü ü v

Living roof - aggregate

Self -sustaining habitat. Particularly suitable for species requiring variable soil depth and rocks for shelter


Green walls Vertical habitat f or birds, insects etc ü ü ü ü ü ü ü ü ü ü ü ü

Nesting/roosting boxes

Shelter for target species, usually birds and bats or insects


20


Habitat benefits

Nat Vent

Cellular

Nat Vent Open plan

Air Con Standard


1-2 star B&B Sheds

Shopping Centres

High Street

Food store Shed

Biodiversity

Voids and perches

Suitable for birds and bats. Provides shelter and/or resting space


Additional roof top or terrace planting

Provides shelter and food plants for local species


Enhanced external landscaping

Additional habitat for local species if appropriately planted and landscaped


Water features (e.g. ponds, swales, fountains)

Habitat for fish, amphibians and birds. May also provide water attenuation


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4.0 Challenges Although there is significant potential to improve the environmental performance of existing buildings, there are also often a number of challenges that can preclude the successful adoption of solutions. The following tables present a broad comparison of technically feasible solutions that achieve a range of building enhancements relating to energy, water and material efficiency, and biodiversity/habitat. Important considerations relating to each solution, including barriers, opportunities and relative capital cost, are summarised. Solutions are compared based upon a generic evaluation not specific to building size, form or use. Where applicable, a comment has been made under the column heading ‘Implications on different building forms’ to indicate the practicability of the solution relative to building size, form and use. ‘Relative capital cost’ has been evaluated on a simple rating basis, as follows: £ low cost ££ medium cost £££ high cost ££££ very high cost The ratings do not relate to a specific cost range, but rather provide an indication of the relative cost of the typical alternative solutions for achieving each improvement. For example, fitting draught stripping around windows and doors is cheaper (£) relative to replacing window units with double glazing (£££). The evaluation of each typical solution considers the implications of incorporating the enhancement into existing commercial buildings. The practicalities and financial viability of a number of the solutions will vary (typically improve) in the context of a radical refurbishment or new build development. 4.1 Energy Appendix B demonstrates that the fabric of an existing building may present barriers to the adoption of energy efficiency improvements. Other issues also determine the applicability of some improvements, for example installing roof insulation may be difficult if there are service installations on the roof. Improvements may also alter a building in an unacceptable way, e.g. by reducing natural ventilation or floor space, or changing the building’s appearance. There are technical, cost, and operational implications that can present barriers, such as: • Unacceptable levels of disturbance during installation • The need for ongoing maintenance • Planning approval processes • Installation costs (i.e. specialist contractors) • Relatively low operational cost benefits

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Despite the challenges, in most cases solutions can be found to suit the building in question. The appropriateness of solutions depends on several factors, including: • Building component energy use • Where the building’s heat gains and losses are occurring • The acceptable level of disruption during installation • The acceptability of changes to the building’s dimensions and appearance • Cost constraints (installation and maintenance costs compared with cost savings) An improvement that presents few barriers is the installation of energy-efficient lighting. It is a cost-effective solution that results in little or no disruption to the building’s normal functioning. In offices and hotels, lighting typically accounts for 8-16% of energy use, therefore installation of energy-efficient lighting reduces overall energy use by between 4 and 10%. Heating can represent the largest energy use in commercial buildings; therefore improvements that reduce heat loss can potentially provide the greatest benefits. Improvements to the heat retention capacity of glazed areas, walls, floors and roofs usually result in some disruption during construction or installation. If such solutions are found to be cost-effective, and the building is undergoing a major refurbishment, improvements such as wall insulation or double (or triple) glazing may be considered appropriate. However, if the building is to remain occupied, less disruptive improvements such as secondary double-glazing and roof insulation may be preferable. A program of improvements should include the following steps: 1. Collect data on building component energy use and specific areas of heat gain and loss 2. Identify technically feasible improvements (i.e. no physical or other unacceptable barriers

to implementation). 3. Predict energy savings from each improvement (based on component energy use) 4. Compare energy savings with the cost of implementing the improvement, and consider

other factors such as disruption and maintenance. 5. Implement a timetable for improvements 4.2 Water Some improvements are easy to retrofit, while others are more convenient and cost-effective when implemented as part of a major refurbishment. For example, Appendix B shows that installing aerated or flow regulated taps poses minimal disruption and is a reasonably cost effective means of reducing water consumption. On the other hand, placing hot water pipes above cold water pipes to reduce heat transfer is an expensive option with minimal return, and is therefore more suitable to new buildings or major refurbishments. Choosing the most appropriate improvements should involve the following steps: 1. Collect data on building component water use 2. Determine where consumption can be reduced through behaviour change, and where

physical improvements will be effective 3. Compare water savings with the cost of implementing the improvement, and consider

other factors such as disruption and maintenance 4. Implement a timetable for improvements

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4.3 Waste/material efficiency Commercial refurbishments present many opportunities to incorporate recycled content in carpets, vinyl flooring, underlay and plasterboard. Products are available (typically at no extra cost) that contain recycled and/or reclaimed materials. Furthermore, some products can be sent back to the manufacturer at the end of their usable life for recycling, e.g. carpet, and in some cases off-cuts can be sent back for reprocessing (e.g. plasterboard). The only barrier to choosing recycled products is the limitation that may be posed by the product range. The use of such products clearly only improves material efficiency if the existing products are in need of replacement. When replacing these materials, it is possible to plan ahead to minimise the waste produced by the next refurbishment. Purchasing carpet from a manufacturer who will remove, clean and reprint the carpet is one solution. The waste produced by the current refurbishment can also be minimised by finding opportunities for recycling or reprocessing. Although this requires some planning and research, it may reduce the costs of sending materials to landfill. Assuming the existing materials must be replaced, the following considerations provide a guide to choosing the most materially efficient refurbishment solutions: 1. Look for opportunities to reuse, recycle or reprocess the materials that will be removed

from the building 2. Look for products with recycled content 3. Where possible choose manufacturers who can recycle the product at the end of its life,

or reprocess off-cuts from the current refurbishment The WRAP toolkit facilitates the above process. 4.4 Habitat and biodiversity There are few physical barriers associated with most biodiversity improvements. Site attributes may limit the number of applicable solutions, however generally any building with some surrounding landscaped areas can at the very least, be improved with additional planting of local species. Many solutions also provide benefits such as increased thermal performance and aesthetic improvement. Green roofs in particular provide enormous potential for additional habitat and other benefits in built up areas. In many cases, paving slabs are used to protect waterproofing membranes on existing buildings. A green roof can weigh less than paving slabs, and also provides more effective protection for waterproofing. For the majority of existing commercial buildings, some type of green roof structure would be feasible, and in many cases an intensive roof (deep substrate and soil layer) could be installed to provide not only habitat, but also recreational space. The structure of a shed-type industrial building may limit the extra weight the roof can support. For example, if the structure is lightweight it is preferable to choose a roof with an even depth and a known weight. In this instance a sedum blanket (succulent) roof will most likely be chosen, providing very little in the way of biodiversity or habitat. It is important to set clear objectives for the building’s contribution to local habitat and biodiversity, and design a program of improvements to meet these objectives. It is advisable to seek the advice of an ecologist at the outset. If a green roof is considered, the ability of the

24

roof structure to support the required habitat must be thoroughly investigated. If there is sufficient space around the building, providing habitat on the ground may be a more effective solution. Alternatively, if there are local endangered bird or bat species that require habitat; bird or bat boxes can provide important habitat services. Developing a set of biodiversity/habitat improvements should involve the following steps: 1. Gain an understanding of local biodiversity, including endangered and threatened

species, and their habitat requirements. 2. Evaluate whether the building and its surroundings could provide the appropriate habitat

for local species (e.g. soil type, wind speed on roof). 3. Factor in other objectives, such as thermal performance and aesthetics, and identify

solutions that meet multiple objectives. 4. Assess the benefits of the identified improvements against habitat/biodiversity and other

objectives. 5. Compare potential benefits with the cost of implementing the improvements, and consider

other factors such as disruption and maintenance. 6. Implement a programme of improvements Some objectives may initially appear to be incompatible, for example a green roof may be required to fulfil the need for landscaped recreational space whilst improving biodiversity. It is entirely feasible to design a green roof that is both landscaped and also supports biodiversity. Careful design ensures that habitat/biodiversity improvements also meet other objectives and that additional costs can be justified.

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5.0 Recommendations This report has presented the available benchmarks for energy and water use, and material efficiency in existing commercial buildings. It has also identified and evaluated technically feasible solutions for improving performance. From this review, it has become apparent that more information and technical assistance is required to assist building owners and developers in improving the environmental performance of existing buildings. Benchmark data on ‘typical’ performance and best practice energy and water use are required for a comprehensive range of building types. These data will contribute to the development of modelling tools. In addition, support for sustainable refurbishment is needed through guidance and standards, requirements and regulations, fiscal incentives, awareness raising and training. 5.1 Benchmark data Further work is needed to provide energy consumption benchmarks for component energy use and technical and commercial solutions for specific building types. Through the provision of more robust data, building owners and developers will be able to compare building energy and water consumption with typical practice for new buildings and adopt appropriate improvement targets. At present, usage breakdown figures by component water use in commercial buildings are not available, as confirmed in a recent report by CIRIA (Water key performance indicators and benchmarks for offices and hotels). Such figures are urgently required, and should be made available by sub-category, e.g. type of hotel. Yearly consumption benchmarks for new and existing retail buildings are also urgently required. For materials efficiency, benchmarks for existing buildings are less relevant than for new buildings, as it is already efficient to continue to use existing buildings and fittings. However best practice examples would be useful to provide guidance for refurbishment projects. There are currently no biodiversity or habitat benchmarks for commercial buildings as ecological values are difficult to quantify. In this instance, benchmarking is not a particularly useful tool for planning a programme of improvements. Rather, a building’s ecological potential should be context specific to determine how the site’s provision for biodiversity and habitat could be improved. 5.2 Modelling tools Modelling tools should be developed to factor in site-specific information (e.g. number of employees) and compare a building’s consumption with specific and relevant benchmarks. Such models would be extremely useful to assist with energy efficiency and water use improvements if they covered all commercial buildings types and were able to: • Assess building component energy and water use and compare this to typical and best

practice benchmarks, taking into account project specifics (e.g. staff numbers and building use)

• Assess the technical and commercial feasibility of different improvements (taking account of project-specific variables such as component energy and water use, acceptable disruption, and building physical characteristics)

26

• Provide data on potential energy and water savings and the long-term cost benefits provided by each recommended improvement

It is expected that such models will become available, to enable existing building energy certification in line with the European Building Performance Directive requirements. An online benchmarking tool is currently available for comparing a building’s water use against the benchmark for the building type and number of staff. However, this model is aimed at public sector buildings and therefore does not cover hotels, industrial or retail buildings. The WRAP Recycled Content Toolkit is an effective modelling tool for assessing recycled content in refurbishment projects and is freely available on-line. 5.3 Guidance and standards Additional technical and commercial guidance is needed to inform developers and building owners about appropriate methods for installing improvements, particularly green roofs, which require careful design to provide the appropriate habitat. There is currently limited policy or standards in the UK to guide planners or developers, and no fiscal incentives for building green roofs or providing other habitat services on and around buildings. The German standards for green roof construction are the most widely accepted in the UK, in lieu of standards specific to British conditions. CIRIA is currently undertaking a project to provide guidance on greening buildings, including a review of technical information on the design and construction of alternative roofing systems, and technical guidance for incorporating alternative roofing and other biodiversity features into building design. In particular, the following are required: • British Standards for green roofs and other improvements (e.g. landscaping, green

walls, perches, voices and nesting boxes) • Accessible technical guidance (particularly whilst standards are not available) 5.4 Requirements and regulations Sustainable refurbishment requirements should be included in Building Regulations and planning policy. The majority of emphasis to date in terms of policy and Building Regulations has been on new buildings. Consequently, there is relatively little obligation for the construction and property industry to deliver sustainable refurbishments, unless client requirements are to do so. The Sustainable and Secure Buildings Act (2004) permits the inclusion of sustainability measures in Buildings Regulations, however little change has been seen to date (other than Part L 2006). 5.5 Fiscal incentives Current fiscal incentives for sustainable refurbishment are relatively limited. For example the Enhanced Capital Allowances scheme is only available to a small percentage of the property industry, and many of the grants and loans systems are challenging to access. Increased fiscal incentives such as stamp duty allowances for purchasers or business rates reductions for occupiers of green buildings (as practised overseas) would generate rapid change in the market.

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5.5 Awareness raising Another primary issue affecting sustainable refurbishment is a lack of awareness of the available opportunities. For example, a recent survey of professionals carried out in London showed that 92% of developers believed the structure of many buildings would prevent the installation of green roofs, compared to only 27% of engineers. To encourage green roof retrofitting, increased availability (and coordination) of information relating to technical options and their feasibility to types of structure, is needed. Good case studies can be found both in the UK and overseas, however more examples will be required to change mainstream perceptions. In addition to technical data, case studies should include clear indications of the cost effectiveness of various options (i.e. capital and lifecycle costs). Once modelling tools have been developed to assist with energy and water improvements in refurbishment projects, published case studies would help demonstrate that the models can be used to set and achieve targets in a cost-effective manner. 5.6 Training for professionals As with any ‘new’ topic area; there is a need for additional training amongst the various professional disciplines. It is also critical that the various disciplines are encouraged to share information in what is still an emerging sector. Both technical and commercial training is required, as it is commonly (often incorrectly) perceived that sustainable options are prohibitively costly, even if technically deliverable. A better understanding of economic ‘quick wins’ could be readily achieved following the production and dissemination of an industry-accepted checklist of economic quick wins for each of the 4 topic areas, specific to various building types, similar in format to that generated by the WRAP toolkit for recycled content

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Appendix A: List of References BRE (1999) Sustainable Retail Premises: an environmental guide to design, refurbishment and management for retail premises Building (23/06/2006 pp 30-33) The 99% campaign: greening the stock we’re stuck with Carbon Trust (2000) Energy use in offices. Energy consumption guide 19 Carbon Trust (1993) Energy efficiency in hotels – a guide for owners and managers. Energy consumption guide 36 Carbon Trust (2002) Benchmarking tool for industrial buildings – heating and internal lighting. Energy consumption guide 81 CIBSE (2004) Guide F: Energy Efficiency in Buildings CIRIA (2006) Water key performance indicators and benchmarks for offices and hotels DEFRA (2000) Countryside survey - Accounting for nature: assessing habitats in the UK countryside www.defra.gov.uk/wildlife-countryside/cs2000/08/03.htm Livingroofs.org The University of Sheffield (2005) Feasibility Study for the Retrofitting of Green Roofs Watermark online benchmarking tool www.ogcbuyingsolutions.gov.uk/energy/services/services_conservation_water_benchmarking.asp# WRAP Recycled Content Toolkit http://rctoolkit.wrap.org.uk/ and Procurement Guidance

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ISBN: 978-1-84219-325-9

Building Enhancement Typical Solution Technical ImplicationsOperational Implications

Implications on different building

forms

Relative Capital Cost

Opportunities Barriers to Implementation Overall Considerations

ENERGY

Secondary double glazing

May be installed within existing window opening/depth of existing building envelope

Least disruptive option to occupants and building fabric

Unaffected by shape and size of building as product fitted internally; most suitable for window units rather than full height glazing

£

May have implications on natural ventilation/clash with internal blinds or shading; not practicable for all glazing within a building

Reglazing existing window units; replacement of single glazed panes with double

Only possible if window frames can be adapted to accommodate additional thickness of glazing; sliding sash windows would require re-weighting

Subject to how works are carried out, may cause significant disruption to occupants; may require decanting while work carried out

No significant effect if works can be carried out internally; if external access is necessary scaffolding required for upper floors

££ - £££Not a practicable option for all window types

Replacement of complete units with double glazed units

May require remedial works to disturbed adjacent finishes to reveals and window boards

Significant disruption to occupants; may require decanting while work carried out

Requires external scaffolding to upper floors

£££Would be most cost effective as part of a major building refurbishment

Replacement of complete units with triple glazed units

see above see above see above £££Could incorporate a ventilated outer cavity to reduce solar gain

see above

Fit draught stripping around windows and doors

As building enhancement

Simple to retrofit to existing windows and doors; would be an integral part of new installations

£Potentially simple, and relatively cheap to install

Internal blinds - manually operated

Can either be retro fitted or provided as an integral part of new window units

Unaffected by shape and size of building as product fitted internally

£ Simple and quick to installCost may prove a barrier if the building has large areas of external glazing

Internal blinds - automatically operated

Can either be retro fitted or provided as an integral part of new window units; would require dedicated power supplies and control equipment

May add to building maintenance regime

Unaffected by shape and size of building as product fitted internally

££Cost may prove a barrier if the building has large areas of external glazing

Integral blinds should be considered if window replacement is being considered

External blinds

Operated by manual activation or solar cells; would require a power supply to operate but could be incorporated into the building's energy management system

Would affect the external cleaning/maintenance of the building envelope

May not be required to all elevations depending on orientation of building

££ - £££Would affect the external appearance of the building and may also be subject to a planning application

Brise soleilWould require structural support through external fabric

Would affect the external cleaning/maintenance of the building envelope

May not be required to all elevations depending on orientation of building

£££Would affect the external appearance of the building and may also be subject to a planning application

Filling existing cavity wall with injected cavity wall insulation

Can be difficult to ensure complete filling of cavity

Potentially noisy and disruptive to occupants. Would require scaffolding of building.

Only applicable to masonry construction.

££

Internal lining of external walls with insulation and dry lining

Would require relocation of services mounted on the external walls

Highly disruptive to occupancy of building

££ Would reduce overall floor space

Over cladding building externally with insulated panels

Systems available specifically for high-rise buildings

Overcomes the problem of cold bridging. Would require scaffolding of building.

££££Would affect the external appearance of the building and may also be subject to a planning application

Installation of additional insulation within existing pitched roof construction

May be applied to either plan or pitch of roof subject to access

Access to roof space required; may cause disruption to occupants

£ - ££

Insulation of existing flat roof construction; additional insulation overlaid on existing roof covering

May increase the dead loads imposed on the existing roof structures

Minimal disruption subject to obtaining satisfactory access

If roof has plant areas this will complicate installation or reduce completeness

££Installation may be carried out in isolation of other works; simple to apply on un-obstructed roofs

Installation difficult if roof area contains intensive services installations

Insulation of existing flat roof construction; roof coverings replaced

Some disruption subject to obtaining satisfactory access

If roof has plant areas this will complicate installation or reduce completeness

£££Installation difficult if roof area contains intensive services installations

Most cost effective as part of a major building refurbishment

Enhancement of insulation to external wall construction

Enhance glazing insulation (double, low-e, triple…)

Shading devices to reduce heat gain

Roof insulation

Transforming Existing Buildings The Green Challenge - Appendix B.xls\Common Improvements 29/03/07



forms



Floor insulationApplication of additional insulation within floor finish

Works applicable to ground floor slab only; may require removal of existing floor finishes and possibly internal partitions in the areas affected; may reduce clear floor to ceiling heights

Highly disruptive in the areas where works will be carried out

£ - ££Reduction in clear floor to ceiling heights may limit future use of space


Use pale colours in walls and ceilings As building enhancementNone; product selection issue

Effectiveness may reduce over time; would require regular re-application

£

Very easy to implement; provides a simple opportunity to change/improve the ambiance of existing space

May require increased re-decoration cycle to be most effective

Upgrading of existing lamping

None; provided compatible lamps are selected

General maintenance required

£ Easy to implementLuminaires must be receptive to new lamps

Simple and cheap solution to lower energy costs

Up-grading of luminaresMay require specialist advice (i.e. lighting designer)

Would cause disruption to occupants; may necessitate ceiling replacement

Lighting strategy would differ for buildings of different form and use

£££

Permits the installation of simple, more modular wiring and intelligent controls; would reduce operational costs through lower energy use and less onerous maintenance regime


Daylight Sensors Installation of sensorsDaylight sensors can control switching, and light dusk and dark periods

May cause disruption to occupants

£ - ££Can be linked to an existing lighting system

Use generally limited to perimeter/external lighting

Most cost effective as part of a major building refurbishment including an upgrade of existing luminaires

Enhance daylight by placing lights where they are most cost-effective. Adjust light levels to type of activity undertaken

May be provided by discrete task lighting in existing situations or incorporated within a fundamental lighting redesign

Lighting designed to achieve lower general lux levels with enhancement provided in specific areas

May have implications on fit-out design

£ - £££

Potential overall reduction in lighting load; CIBSE guidance suggests that working plane lux levels can be assisted by local lighting

May restrict use of space; a low cost solution using task lighting etc. would require the existing permanent system to have a minimum amount of zonal control to be effective

Anything other than the low cost (task lighting solution) should only be considered as part of a major building refurbishment

Reflective baffles for luminaires As building enhancementCould be installed to an existing lighting system

Most suited to deep open plan offices

£May enable the use of lower lux fittings; permits use of exposed thermal slab cooling

Only really applicable to lighting schemes applied to exposed soffits

Upgrade to more efficient boiler As building enhancementMay require redesign/renewal of existing system

Would require down time of existing system

Boiler size affected by spread of building due to heat loss in travel

££Cost may be a barrier where an upgrade would mean the replacement of a perfectly good existing boiler

If building is of sufficient size, this enhancement might be considered as part of a Combined Heat and Power (CHP) system

Optimise heat recoveryBy use of thermal wheel, plate heat exchanger or run around coil

Typically considered where there is a large fresh air requirement

TW £££PHX £££Coil ££

Thermal Wheel (TW) most efficient, Coil next and Plate Heat Exchanger (PHX) least efficient

Cost may be a barrier; cannot be retro fitted

All need to be designed into the system at inception

Optimise pipe sizes and layouts to reduce resistance to fluid flow

As building enhancementsee Overall

Consideration

This option is unlikely to show a significant scope for improvement, and would represent a risk to building performance

Could only be considered as part of a major refurbishment or system replacement contract

Upgrade pumps As building enhancementTo be done as part of routine maintenance at life-end

Equally applicable to all building types

££Inverter pumps are most energy efficient and qualify for Enhanced Capital Allowances (ECAs)

Optimize length and size of hot water pipes, recirculate mains circuit


Consideration

This option is unlikely to show a significant scope for improvement as this should be considered in good design

Could only be considered as part of a major refurbishment/system replacement contract

Solar water heating Roof mounted tiles

Requires prominent south facing rooftop position; may require back-up hot water heat generation from boiler

£££Grants are available to promote the investment in solar thermal; good potential payback period

May have planning implicationsMost suited to large south-facing roof areas

Place hot water pipes above cold ones to reduce heat transfer


Consideration


Energy efficient lighting

Movement sensors can control switching and light in occupied areas only

Would cause disruption to occupants and may necessitate ceiling replacement if the building needs to be re-wired to accommodate the new controls

Requires the installation of simple, more modular wiring

Lighting Control ZonesInstallation of movement sensors

££

Most cost effective as part of a major building refurbishment including an upgrade of existing luminaires




forms



Heating control zoningLTHW (low temperature hot water)

If LTHW system was reconfigured as a ring main it would be possible to include motorised valves and controls

Would incur disruption to building fabric; extent of disruption dependant on existing heating layout

Effectiveness will be dictated by degree of cellularisation of building layout

£££

Would allow flexibility of future cellularisation and permit the individual heating of selected areas

Control valving can increase the costs considerably

Would only generally be considered as part of a general replacement contract

Upgrade Mechanical Ventilation systemOptions include: Tempered fresh air supply system, Full Mechanical Ventilation

Would incur significant disruption to building fabric

Most appropriate strategy will be influenced by building form

£££

Mixed-mode ventilation offers the best opportunity for optimum comfort conditions and best value on operational cost

Would only generally be considered as part of a major refurbishment/system replacement contract

Optimise duct sizes and layouts to reduce resistance to fluid flow


Consideration

This option is unlikely to show a significant scope for improvement as this should be considered in good design


Upgrade chillersOption; Ammonia chillers in lieu of air or water cooled chillers

Ammonia chillers are generally more efficient

Potentially may present an increased localised hazard due to risk of ammonia leakage

£££

Ammonia has a much lower Ozone Depletion Potential and Global Warming Potential than most refrigerants

Cost may be a barrier; ammonia chillers use less energy but are more expensive to procure; ammonia leakage also a risk

Would only generally be considered as part of a general replacement contract

Combined Heat and Power (CHP) System As building enhancementLarge plant space required. Needs constant load to operate at high efficiency

Operation may be managed by an energy services company

Most suitable for hopsital or hotel development with a constant heat demand

££££Excess power generated may be sold back to local provider

Economically feasible only for situations with a constant energy load and heat demand throughout the year

Most suitable for large schemes, although micro CHP installations are available for smaller schemes

Ground source cooling As building enhancement

Various configurations are possible, depending on availability of land and local ground conditions.

Low maintenance requirements, although there should be access to the system componenets, pumps, etc.

Horizontal or vertical system can be installed for any building type, depending on the availability of adjacent land

£££

If heat pumps were included in the system, then it would be possible to provide both heating and cooling to the building

Incorporation of ground source cooling to an existing building would require a potentially large area of adjacent external space, or incur high costs to drill wells for a vertical system. A suitable distribution network would be required in the building.

Consistent form of low cost, low maintenance, low energy cooling

Micro wind turbines As building enhancementFeasibility study required to determine available wind resource on site

Operation for medium scale turbines may be managed by an energy services company

Possibility of additional structural requirements if turbines are to be roof mounted

££Excess power generated could be sold back to the grid

Noise/visual impacts may limit the size/location of the units. A suitable location is required to achieve an economic and efficient installation.

Would provide a supplementary supply only

Photovoltaics Roof mounted tilesLarge area required for any useful power output

Low maintenance requirements, although access for regular cleaning will be required


£££Can be incorporated as roof tiles, as glass laminates, or on free-standing framework

Long payback period. Likely to supply only a small portion of the overall energy demand.

Most suited to large south-facing roof areas

Building Energy Management System (BEMS)

As building enhancementEqually applicable to all building types

£££Modern systems feedback data to energy audits more easily

Expensive to replaceTypically whole systems are replaced as technology is difficult to integrate into existing systems

Maintenance plans and energy audits As building enhancementLearning by recording data should lead to more efficient maintenance strategies


£Staff can feel part of a company's efforts to improve their environmental profile

Simple to implement

Energy efficient policies and staff awareness and training

As building enhancement

Should lead to the effective implementation of energy saving solutions through better awareness

Education of staff should lead to reduced operational energy costs and reduced maintenance regimes



Simple to implement




forms



Meter consumption Provision of water meters

Leads to effective implementation of water saving solutions through better awareness

Education of staff should lead to reduced operational costs and reduced maintenance regimes



Is a mandatory requirement on new build

Implement a water management plan As building enhancement

Leads to effective implementation of water saving solutions through better awareness

Education of staff should lead to reduced operational costs and reduced maintenance regimes



Simple to implement

Rainwater recycling As building enhancement

Requires separate supply pipe work to suitable equipment/sanitary ware; will require separate storage facility from mains supply

Reduces exposure to risk of water shortages and imposed restrictions on use

Most suitable for buildings with a larger roof area; also increased distribution costs may prove uneconomic on taller buildings

££ - £££

Can be considered during minor alterations, most effective as part of major refurbishment and redesign

Grey water As building enhancementWill require separate waste pipework system

Reduces exposure to risk of water shortages and imposed restrictions on use

Can be incorporated in most buildings, however, increased distribution costs may prove uneconomic on taller or larger buildings

£££

Can be considered during minor alterations, most effective as part of major refurbishment and redesign

Dual flush toilets As building enhancement £ Easy to retrofitWould be most cost effective as part of a complete refurbishment of the existing building

Aerated taps/flow regulated taps As building enhancementMinimal disruption as push-tap adapters may be retrofitted

£ Easy to retrofit

Optimise length and size of water pipes to minimise volume of water required to run before reaching desired temperature; recirculating mains circuit

Recycling hot water main with short tails to individual outlets

Widely used in hotels; potential advantage in apartment blocks and houses if outlets are widely dispersed from heat source

see Overall Consideration

Requires substantial design engineering


Place hot water pipes above cold water ones to reduce heat transfer


Consideration


Reed bed water treatment As building enhancement

Large buildings typically require a lot of reed bed space a good distance from the building

£££Useful for buildings with an abundance of outside space

Time is needed post-installation to 'bed in' the system to optimum performance levels

Drainage irrigation As building enhancement ££May be considered in lieu of water butts

Large footprint requiredCould only be considered as part of a major refurbishment/system replacement contract

Insulation on heating/hot water pipes As building enhancement £Now standard in most installations

Carpet replacement

Selection of carpet with high level of recycled content (eg around 85%) and potential for reuse at end of life

None None None No impact

An easy requirement to introduce that reduces the environmental impact of flooring (flooring has high whole life environmental impacts because of the number of replacements throughout the building life).

Many of the largest commerical carpeting companies make use of significant quantities of recycled materials in their new carpets, however specific branding or colour requirements can restrict choice. Some companies will remove, clean and reprint their carpets.

Easy to incorporate the requirement into specifications for new carpeting (subject to colour/branding requirements) with no cost impact and quantifiable environmental benefit.

Vinyl flooring Selection of vinyl flooring with high level of recycled content (eg around 40-100%)

None None None No impact See comments above See comments above See comments above

UnderlaySelection of carpet underlay with upto 100% recycled content

None None None No impact See comments aboveSome carpeting options will not need a separate underlay in which case this option is not appropriate

Where used, this is an easy way of increasing the use of recycled materials in a refurbishment project.

Plasterboard replacement (For partitions, column casing…)

Use of plasterboard containing high levels of recycled material, minimising the wastage of boards (through accurate purchasing and sizing) and returning offcuts to manufacturer for reprocessing.

None None

Where only relatively little boarding is used it can be more difficult to arrange collection of offcuts for return to manufacturer

No impact

Appropriate for refurbishments incorporating refinishing of internal walls or reconfiguration of internal spaces.

WASTE

WATER




forms






forms



Green roof

Extensive (shallow substrate usually planted with sedum, grass or moss) OR Intensive (deep substrate capable of supporting larger plants; can be used as a garden or park)

Type of green roof determined by roof structure and access arrangements. Requires specialist contractors to install and specialist advice (i.e. ecologist) to meet habitat requirements. Requires timely coordination of construction

May require reticulation during dryer months if a manicured look is desired; an extensive roof will require minimal maintenance (i.e. twice yearly check), while an intensive roof requires regular maintenance

Shed-type industrial buildings unlikely to support intensive roof, but may support extensive type

£££

Increased protection for waterproofing membrane. Provides thermal insulation for the building. An intensive roof will provide additional usable space

Load bearing capacity of existing roof. Extent of equipment on roof.

Careful consideration of green roof options against project objectives is fundamental if the roof is to provide the sought after benefits and avoid undesired maintenance requirements

Green wallExternal vertical planting structure or terrace planting

Choice and style of planting will be influenced by building structure. May require specialist advice (i.e. ecologist)

Depending on the complexity of the reticulation system, some degree of maintenance will be required

Most commonly found on office buildings

££Can improve building aesthetics. Provides some insulation and air quality benefits.

Bird and bat boxes As building enhancement

Would require sealing of adjoining structure to restrict unwanted access into main building

Would require consideration in maintenance plans to prevent disturbing installations

£Would attract wildlife and improve local ecosystems

Perches and voids As building enhancement

Would require sealing of adjoining structure to restrict unwanted access into main building

Would require consideration in maintenance plans to prevent disturbing installations

£Would attract wildlife and improve local ecosystems

Additional roof top or terrace planting As building enhancementWould require regular maintenance

£

Enhanced external landscaping As building enhancementWould require regular maintenance

££

Would attract wildlife and improve local ecosystems. Would improve appearance of building surrounds

Water featuresPonds, swales and fountains

Would require specialist advice regarding site drainage and local ecology. Selection of feature will depend on available space

Some degree of maintenance would be required

Potential benefits for office buildings and hotels with underutilised surrounds

££

Would attract wildlife and improve local ecosystems. Would improve appearance of building surrounds

Site must be suitable

ECOLOGY


Documents

Transforming Existing Buildings - The Green Challenge · Transforming Existing Buildings: The Green Challenge Final ... for approximately 44% of total carbon dioxide ... hotels vary