university of sheffield engineering graduate …...technology strategy board university of sheffield...

Technology Strategy Board

University of Sheffield Engineering Graduate School Climate Change Adaptation Study

Final Report

214592/AMS/FinRep

Rev B | 16 July 2012

This report takes into account the particular

instructions and requirements of our client.

It is not intended for and should not be relied

upon by any third party and no responsibility is

undertaken to any third party.

Job number 214592

Ove Arup & Partners Ltd

New Oxford House

30 Barkers Pool

Sheffield

S1 2HB

United Kingdom

arup.com

Technology Strategy Board University of Sheffield Engineering Graduate School Climate Change

Adaptation Study Final Report

214592/AMS/FinRep | Rev B | 16 July 2012

J:\214000\214592-00\0 ARUP\0-13 ARUP SPECIALISTS\0-13-08 REPORTS\2012-07-16 FINAL REPORT REV B\2012-07-16 UOS GRAD SCHOOL ADAPTATION FINAL REPORT

REV B.DOCX

Contents

Page

Executive Summary i

Introduction 1

1 Building profile 2

1.1 The Engineering Graduate School 2

2 Climate Change Risks 4

2.1 Assessment of climate change risk 4

2.2 Climate scenarios and data 6

2.3 Other significant features 6

3 Adaptation Strategy 7

3.1 Methodology 7

3.2 Adaptation Strategy – Results 11

4 Learning 28

4.1 Summary of approach, the initial project plan and subsequent changes 28

4.2 Team 28

4.3 Tools and resources 29

4.4 Appraisal of the success of the approach 30

4.5 Influencing the client 31

4.6 Recommended resources 31

5 Extending adaptations to other buildings 33

5.1 Applying the strategy to other buildings 33

5.2 Limitations of applicability of the strategy 34

5.3 Applicability to other UK buildings 35

5.4 Skills, resources and tools developed during the project 36

5.5 Further needs for adaptation services 36

Appendix List 37





REV B.DOCX

Page i

Executive Summary

This report details the findings of a climate change adaptation study carried out on the proposed design of the Engineering Graduate School at the University of Sheffield. The building is a proposed new 5400m², 6 storey Faculty of Engineering building situated in Sheffield City Centre

Arup’s Climate Change Appraisal Framework (CCAF) was used to make an assessment of the climate change risk. CCAF is framework developed by Arup to guide a building owner or design team through a structured appraisal process for the often disparate issues surrounding adaptation. It was determined that the highest priorities surrounded internal comfort and the robustness of the exterior of the building.

Thermal modelling was carried out using IES and PROMETHEUS future weather files to evaluate the propensity of the building to overheat. An adaptive comfort threshold was used to evaluate temperatures at which internal conditions become uncomfortable.

In addition to more traditional ‘bolt-on’ adaptations, an investigation was made into the benefits of fundamentally redesigning the building to optimise the form and layout for natural ventilation, creating an ‘Engineering Led Design’ (ELD), shown left.

The Engineering Led Design resulted in lower internal temperatures but the magnitude of the changes can be matched by more realistic measures that can be applied for lower costs. These lower cost adaptations can be applied at intervals to suit maintenance and refurbishment cycles but they cannot cope with a 2080 climate.

Without incorporating the principles of the Engineering Led Design, the climate in 2080 results in internal conditions exceeding target levels as shown on the graph to the right.

However, the Engineering Led Design was not without compromise. A number of aspects of the client brief had to be put to one side in order to truly maximise the

0

20

40

60

80

100

120

140

160

20

10

20

20

20

30

20

40

20

50

20

60

20

70

20

80

Hou

rs a

bove

com

fort

lev

els Original Building

with 'stadard adaptations'

including principles of ELD

Target





REV B.DOCX

Page ii

opportunity for natural ventilation. However, it would be possible to take a pragmatic approach to the implementation of individual aspects without significantly compromising the overall effect.

Possibly the most significant drawback to the Engineering Led Design is the increased cost. The increased areas of external façade caused by the additional floors and the lower overall efficiency of the design (in terms of the gross:net ratio) result in a cost uplift of ~£1.7m or 14%. In contrast, many of the more traditional adaptations resulted in a cost increase of less than 1%. However, as shown right, there was no correlation between the cost of a measure and the resultant benefit.

As a direct result of this study, an increased focus was placed on climate change adaptation throughout the main design project. Although project timing constraints meant that the information transfer between the two projects was more informal than initially envisaged, many adaptation aspects investigated have been incorporated into the main design which has been shown to have a high proportion of spaces being comfortable in 2050.

The most relevant adaptation actions included in the design or recommended for future implementation are as shown in the table below.

Design Opportunity Implementation / recommendation

Shading - manufactured Recommended to be included during the first glazing / façade replacement cycle (~2040’s – 2050’s).

Glass technologies Reduced G-value glass incorporated into design of building

Conflict between maximising daylight and overheating (mitigation vs adaptation)

Increased ventilation rates were included into the design of the building without increasing glazed areas.

Secure and bug free night ventilation Incorporated into building design to complement exposed thermal mass

Role of thermal mass in significantly warmer climate

Exposed thermal mass was incorporated into building design

Façade robustness actions

Qualitatively considered as part of façade study. Opportunity for improvement exists at first façade replacement cycle (~2040’s – 2050’s).

Table 1: Summary of adaptation actions implemented or recommended

An adaptation strategy can be developed that relies on taking action during replacement and refurbishment cycles to implement further adaptations that will

Top floor

Chimney

Open

Plan

offices

Solar

Shading

Reduced

G-value

Reduced

internal

gains

Night

vent

0%

5%

10%

15%

20%

25%

30%

35%

40%

-£100k -£50k £0k £50k £100k £150k

Ben

efit

Cost of measure





REV B.DOCX

Page iii

further increase the ability of the building to cope with climates far into the future. However, it is likely that implementing all of the adaptations will not be sufficient to reduce overheating in all of the spaces below the target level (although the target will not be exceeded by a large amount) although it must be remembered that there is no way of predicting what technological progress will be made in building adaptation products and technologies over the coming decades.

This project has lead to an increased understanding of climate change adaptation both within the Arup building engineering teams and within the client. This increased understanding has been on many levels, from the importance of including adaptation in projects to the practicalities of running a detailed overheating study looking at performance in future conditions. Many resources and much experienced was pooled to carry out the work and TSB projects have lead to a much closer knit community of adaptation specialists that are communicating the issues to wider engineering teams.

There is the potential to use the methodologies of this study and to take guidance from the findings to apply to a large stock of potential buildings. General information on the UK’s building stock but evidence suggests that the study would be of use to ~14,000,000m² of higher education buildings. In addition, the findings would be of interest to comparable buildings in the commercial sector, estimated at ~84,000,000m².





REV B.DOCX

Page 1

Introduction

This report details the findings of a climate change adaptation study carried out on the proposed design of the Engineering Graduate School at the University of Sheffield. The building will incorporate two large lecture theatres, general teaching spaces, laboratories, post graduate and doctorate work facilities along with offices for staff and the students.

The adaptation study, funded by the Technology Strategy Board (TSB) as part of their Design for Future Climate competition, ran alongside the main design project with the intention of feeding as much information as possible into the main design project.

Arup’s Climate Change Adaptation Framework was used to evaluate the risk to various aspects of a future climate scenario.

Future overheating issues were investigated, with the overall aim being to develop a building design that could provide comfortable internal conditions in the predicted climate of 2080 without resorting to significant mechanical cooling in most spaces. Also investigated was the impact on future climate on the robustness of various façade options.

This report follows the structure specified by the TSB and consists of the following sections.

1. Building profile A description of the building, its uses, setting and context.

2. Climate change risks An assessment of the risk exposure of the building to climate change and an explanation of the future weather scenarios used for evaluation.

3. Adaptation strategy Including the methodology for evaluating the adaptation strategy and the effects of various aspects of adaptation on occupant comfort and façade robustness. The barriers to adaptation, including cost, are discussed and an adaptation strategy is recommended with immediate actions and future considerations.

4. Learning The approach of the study, the team involved and the tools used are shown along with an appraisal of the success of each element of the project.

5. Extension to other buildings An appraisal is made of the applicability of this strategy to other buildings in the UK, both within the Higher Education sector and beyond.





REV B.DOCX

Page 2

1 Building profile

1.1 The Engineering Graduate School

The University of Sheffield Engineering Graduate School Building is a proposed new 5400m², 6 storey Faculty of Engineering building situated on the junction of Newcastle street and Broad Lane in Sheffield City Centre (Figure 1 and Figure 2 below). The project is currently at design stage and on track to achieve a BREEAM rating of ‘Very Good’.

Figure 1: Engineering Graduate School Architect’s Visualisation (© Bond Bryan)

Figure 2: Engineering Graduate School location (© Google)

The construction method is likely to be steel or concrete frame and the building will be required to complement the surrounding listed buildings. The procurement route will be traditional with tenders being based on the RIBA Stage E information from the Design & Architecture team.

The massing of the building is shown in Figure 3. The design incorporates a central atrium to facilitate natural ventilation across the floor plates and provide





REV B.DOCX

Page 3

natural light into areas of the building that would have adjoined the surrounding buildings.

Figure 3: Visualisation showing massing of building including atrium (© Bond Bryan)

The building will incorporate two large lecture theatres, general teaching spaces, laboratories, post graduate and doctorate work facilities along with offices for staff and the students. Floor layouts of the original design are provided in Appendix 1.1.

There are a number of features that will affect the resistance and resilience of the building to climate change. The glazed atrium will require careful management to being susceptible to increasing temperatures and most of the rooms are quite heavily used with higher internal and occupancy loads than might be expected in other building types. The requirements for connectivity to adjacent buildings have also placed restrictions on floor to ceiling heights on some storeys which may affect the effectiveness of the natural ventilation solution.

1.1.1 The context of the university estate

The new Graduate School forms part of the Faculty’s plans for future growth of approximately an additional 60% space over the next 15 years. The work to fulfil the future space needs of the department is currently estimated at approximately 35,000m

2 of new buildings and extensions and the refurbishment of a further

40,000m2. The Graduate School is part of the first phase of this development.

These faculty plans sit within the overall university’s estate strategy which shows a small overall expansion in space. There is the opportunity for this research to increase the understanding of climate change adaptation, and the measures required to incorporate it into the design process, at the start of this large expansion programme.





REV B.DOCX

Page 4

2 Climate Change Risks

2.1 Assessment of climate change risk

In order to make an assessment of the climate change risk, a Climate Change Appraisal Framework (CCAF) assessment was carried out. CCAF is framework developed by Arup to guide a building owner or design team through a structured appraisal process for the often disparate issues surrounding adaptation.

The framework divides the issues into two groups, mitigation and adaptation, for this particular appraisal we will consider adaptation only. Adaptation concerns the provision of increased physical resilience to anticipated climate changes and is divided into eight primary indicators, divided into Site wide and Building Asset sections. Each primary indicator is a summary of four sub-indicators.

The summary of the assessment of the project can be seen in the circular chart below (Figure 4) with colours towards the centre of the circle indicating that adaptation has been accounted for within the project. Colours towards the edge indicate that there may be opportunities for improvement.

The output of the tool is deliberately visual, encouraging investigation and analysis. The alternative of a final overall score in the style of BREEAM or other schemes generally leads to a focus on the final score to the detriment of the more subtle messages the assessment can provide.

Figure 4: CCAF 'Performance' output diagram





REV B.DOCX

Page 5

In addition to the framework being used to assess the ‘performance’ of the project, there exists the opportunity to rate each sub-indicator with regard to the risk of a problem arising (i.e. how likely is a particular incidence) and the severity (i.e. how severe are the consequences of not adapting).

By combining the risk and severity metrics to determine the potential impact, priorities for action can be determined by assessing the impact against the project performance. The output of the priority assessment can be seen in Figure 5.

The highest priorities are those based around internal comfort and the robustness of the exterior of the building. It must be said that this result does not indicate there is a deficiency in the design of the building in these areas.

However, these issues should form the basis of investigations into how the building will perform in an environment with altered climate conditions and it is these that are carried forward to the adaptation strategy that is discussed in section 3.

As a result of this investigation, this report addressed internal overheating and the vulnerability of the current façade option to climate change. As part of the overheating challenge, the acoustics of the base case and alternative internal layouts are investigated.

Further detail on the CCAF appraisal can be found in Appendix 2.1 which shows the ratings for the performance, impact and priority of each of the primary and sub-indicators.

The only aspect of adaptation that was discussed within the TSB’s essential reading adaptation report

1 that is not addressed within CCAF is the effects of a

changing climate and the construction process and conditions on site. This building is considered to be very representative of the effects of these aspects on buildings in general, having no features that would make it more susceptible or robust. It is therefore not considered in this report.

1 Bill Gething, Design for Future Climate, and adaptation agenda for the built environment, 2010,

TSB

Figure 5: 'Priority' output diagram





REV B.DOCX

Page 6

2.2 Climate scenarios and data

This study uses the probabilistic future weather data produced by the University of Exeter as part of their EPSRC (Engineering and Physical Sciences Research Council) funded project, PROMETHEUS.

The PROMETHEUS project identified a standardised methodology of producing probabilistic weather data using the UKCP09 weather generator

2. UKCP09 are

based upon estimates by the Intergovernmental Panel on Climate Change (IPCC) and are therefore a robust source of weather data. Using their methodology, the University of Exeter have produced a series of weather files for various locations across the UK including Sheffield.

They are derived from the probabilistic data of three different scenarios that were based upon three mixes of energy sources used to drive the expanding economy.

A1FI: Fossil-fuel Intensive, coal, oil, and gas continue to dominate the energy supply for the foreseeable future.

A1B: Balance between fossil fuels and other energy sources

A1T: emphasis on new Technology using renewable energy rather than fossil fuel.

For each location and scenario, weather files based a range of percentiles that quantify the likelihood of temperatures being higher or lower were produced. As an example, a weather scenario at the 90

th percentile means that within the model

there is a 90% chance that the increase in temperature will be less than this, but also a 10% chance that that it will be greater.

This study took a balanced view on future climate change. Whilst there is recent evidence that the effects of climate change are occurring at an increasing rate, the extent of this increase has not been quantified. Therefore, at the current time, the mid-way scenario of the three detailed above is the most relevant choice in our opinion. The 50

th percentile files were therefore used.

This 50th

percentile approach was also taken in response to the fact that the risk of exposure of the building was not particularly extreme. If part of the building was rendered temporarily unusable as a result of climate change impacts it would undoubtedly be inconvenient but the building contains no safety-critical or operationally critical equipment or processes.

As recommended by CIBSE for overheating analyses, the design summer year (DSY) weather files were used were utilised for this study.

Further detail of the UKCP09 data set can be found in Appendix 2.2

2.3 Other significant features

There are no further features of the risk assessment or the climate data used that are of significance to the adaptation strategy developed as part of this study.

2 M. Eames, T. Kershaw and D. Coley, 2010, On the creation of future probabilistic design

weather years from UKCP09, University of Exeter





REV B.DOCX

Page 7

3 Adaptation Strategy

3.1 Methodology

3.1.1 Overview

As has been previously discussing in section 2.1, the risks of climate change to this building are largely concentrate in two areas – overheating and the performance of the façade.

With regard to overheating, the over-riding strategy of this project was to make the building perform as well as possible in 2080 in terms of overheating without resorting to energy consuming mechanical cooling systems. This approach was taken as a result of the need to balance the adaptation potential of a building with climate change mitigation drivers.

The modelling approach is shown in the diagram below which is explained on the following page.

Figure 6: Overview of overheating modelling strategy

Original

Building

Feasible

Adaptations

Floor

Heights

Top floor

chimneys

Open plan

offices

All Shading

Engineering Led

Design

Top Floor

Shading

Floor

Heights

Top floor

chimneys

Open plan

offices

All Shading

All feasible layout options

G-values Daytime

ventilation

Night-time

ventilation Internal gains All Shading

All feasible specification adaptations





REV B.DOCX

Page 8

The overheating adaptation strategy is shown in Figure 6 and was based on the creation of an ‘Engineering Led Design’ (ELD) that looked to maximise the opportunities for natural ventilation. This design had a different massing to the original design with a narrower floor plate in some areas that necessitated the addition of a further three storeys in order to accommodate the original brief for internal floor area.

This altered design was then further changed by increasing the floor heights on certain storeys, the adoption of open plan office areas (as opposed to the more traditional cellular layout) and ventilation chimneys to upper floors. The original design also had these changes implemented.

These changes were then combined on the ELD and further adaptation measures applied to it such as solar shading, altered glazing specifications, equipment specification changes. The original design also had these changes implemented.

Aligned with this work was a study into the façades of the buildings which examined the optimal shading strategy for each façade. Six alternative façade constructions were also examined for a number of attributes including their robustness to future climatic conditions.

The team working on the climate change adaptation study was lead by Arup and supported by Bond Bryan Architects and Turner & Townsend Cost Management. All of the companies and many of the individuals involved in the adaptation study were also involved in the main design project that was running concurrently.

A description of the teams and the methods of communication are discussed in more detail in section 4).

3.1.2 The ‘Engineering Led Design’

All designs are a compromise of the many influencing drivers that exist in any building project.

The original design by Bond Bryan Architects (Figure 7), an undoubtedly excellent design solution, incorporated many of the principles necessary to create a low-carbon naturally ventilated building.

However, the need to accommodate the required floor area within the number of storeys led to the

need to adjoin the building to the surrounding structures.

In turn, this led to some areas of the building having less than ideal air flow paths. The Engineering Led Design (Figure 8), on the other hand, presented an opportunity to design the building to maximise the potential for natural ventilation whilst setting aside some of the constraints facing the ‘real’ building project.

The intention was to understand what improvements could be made to the adaptability of the building if these constraints were not present. That said, however, every effort was made to adhere to the original brief laid down by the client to ensure the design was as viable as possible.

Figure 7: IES model of original design





REV B.DOCX

Page 9

A comparison of the floor layouts is shown in Figure 9. The blue lines indicate the various outlines of the original building design with the red lines indicating the extents of the ELD.

The design changes incorporated were, in summary, as follows:

Creation of a space between the existing building and the new design to create a less obstructed airflow path. Link bridges were used for connectivity.

The removal of the atrium to create more effective cross-ventilation.

The maximisation of the central narrow-plan area in order to reduce areas with deep sections

This minimisation of areas with difficult ventilation paths meant that these regions could largely be filled with ancillary areas such as staircases and toilets.

Full sets of layout drawings can be found in Appendix 3.2.

Figure 9: Layouts of the original and Engineering Led Designs

3.1.3 Metrics used to evaluate overheating

Traditionally, the metric used for overheating is the number of occupied hours a space exceeds a given temperature. There are often two threshold temperatures, a lower one where an occupant would feel warm and another where they might

Figure 8: Model of the Engineering Led Design





REV B.DOCX

Page 10

complain of being uncomfortably hot. For office type areas, these thresholds are often taken as 25 and 28°C respectively

3.

There is concern that these relatively simple metrics do not accurately represent the true perception of thermal comfort conditions. Nor do they take into account the likely increasing tolerance of higher temperatures over the timescales under investigation in this study. Put simply, if it’s hotter outside more often, people are going to be more used to being hot and what they consider to be uncomfortable will change.

The Adaptive Comfort Threshold (ACT) is a method for determining a comfortable internal temperature dependent on external temperature. The ACT calculation provides a daily varying comfort temperature. As external temperatures rise due to climate change, the comfortable internal temperature rises, as shown in Figure 10.

For example, in the current weather file, the daily ACT never exceeds 28ºC but this progressively rises until, in 2080, this temperature is considered comfortable in 76 days out of the summer overheating period of 160 days.

Figure 10: Variation of internal comfort temperature with increasing external temperature

As such, there are proposals to alter the metrics based on static temperature

thresholds and replace them with three criteria:

Criterion 1: Hours of Exceedance – the number of hours the internal temperature exceeds the Adaptive Comfort Threshold (ACT)

4 by more than 1°C

Criterion 2: Weighted Exceedance – a combination of the duration of overheating and its severity

Criterion 3: Upper temperature limit – The peak internal temperature should not exceed the adaptive comfort threshold by more than 3°C.

3 Chartered Institute of Building Services Engineers, 2005, TM36 Climate Change and the indoor

environment: impacts and adaptation, CIBSE 4 The adaptive comfort threshold is a way of relating the likely comfortable internal temperature

with the current and recent external temperatures. Further information can be found in BS15251

(Indoor environmental parameters for design and assessment of energy performance of buildings

addressing indoor air quality, thermal environment, lighting and acoustics)

0

20

40

60

80

100

120

140

160

24 25 26 27 28 29 30

No

. d

ay

s A

CT

II

exce

eds

each

tem

per

atu

re

Temperature in ºC

2010

2030

2050

2080





REV B.DOCX

Page 11

A space should meet two of these three criteria in order to be considered to not be overheating. Further detail on the calculation procedures for each criterion can be found in Appendix 3.1.

It is not appropriate in a study of this nature to use a pass/fail indicator as the amount by which a room passes or fails is very important. Using all three criteria to examine the overheating would also lead to very confusing results.

Therefore, this study will use the first criterion as its main metric using the target of 40 occupied hours over a year. The other criteria will be discussed in a separate section so that their suitability can be understood.

3.1.4 Façades

To investigate the options for the building façade, two approaches were taken. Firstly, the role of the façade in reducing overheating was analysed with the solar irradiance on each façade being calculated before the optimum shading solution was developed.

Secondly, each of six alternative façade options was investigated with respect to its potential vulnerability to each of six effects of climate change:

Hotter, drier summers

Warmer, wetter winters

Shorter periods of more intense rain

Greater temperature extremes

Increased wind speed

Prolonged wind speed

3.2 Adaptation Strategy – Results

The following sections set out the results of the overheating analysis. The results analysed are not all of the output but a sub-set selected to highlight the most significant effects.

For discussion here, each of the original building and the Engineering Led Design (ELD), sample rooms have been chosen for investigation that cover the main uses of spaces within the buildings.

Room type Identifier Floor

Original building ELD

Research Lab ResLab1 B (1st) B (1

st)

Post-graduate Research Space PGR-C C (2nd

) C (2nd

)

Flexible Teaching FlexTea2 D (4th

) D (4th

)

Academic Office (East façade) AD14-6 F (6th

) J (9th

)

Academic Office (West façade) AD3-7 F (6th

) J (9th

)

Table 2: Sample rooms used in analysis





REV B.DOCX

Page 12

In each of the following sections, the initial shaded paragraph briefly describes the changes that are being investigated. The results are presented after this description. Further details of the changes can be found in Appendix 3.3.

3.2.1 Performance of ‘Original Building’

The building specification used in this base case study was representative of a building that had been designed to current building regulations but with little specific consideration of the needs of adaptation and future overheating.

The graph below shows the overheating performance of the sample rooms in the original building.

Figure 11: Performance of sample rooms in the base-case building design

The building is performing well in the current climate and most spaces are not overheating in 2030. The exception within the sample rooms is the academic office on the East façade that receives a significant degree of solar gain at the start of the day. This, combined with the lack of solar control on the relatively large areas of glazing in these rooms is causing problems.

Looking forward, the building would be generally very uncomfortable in 2080 which is within the design life of the building. The patterns shown within the sample rooms are generally repeated in other areas, with a spread of performance due to a number of factors.

3.2.1.1 Addition of ‘specification’ adaptations and shading

The changes made here are those that could be expected to be made without significantly affecting the cost or operation of the building such as reducing the g-value of the glazing to reduce solar gains, increasing the efficiency of the lighting and computer systems to reduce internal gains and increasing daytime and night-time ventilation rates.

Shading elements were then added to reduce solar gain. The type varied according to the incident angle of sunlight, with 500mm deep vertical fins used on the East façade and 1m deep horizontal fins used on the West façade, both with 1m spacing between elements.

0

20

40

60

80

100

120

140

160

180

2010 2030 2050 2080

No. h

ou

rs a

bove

AC

T +

1°

C

ResLab1

PGR-C

FlexTea2

AD14-6

AD3-7

Target





REV B.DOCX

Page 13

The effect of the relatively simple specification changes is quite dramatic, showing what can be done to alleviate future overheating without drastically affecting the project constraints. Reductions of between 50 and 70% are seen in the number of hours annually where uncomfortable temperatures occur in the sample rooms.

The graph below is for the building performance in 2050 and it can be seen that the adaptations result in the sample rooms meeting the target of less than 40 hours above the comfort threshold. However, only AD3-7 continues this through to 2080, the remaining four all exceed the target showing that more progress needs to be made.

Figure 12: Reduction in overheating due to changes to the specification of the building and the addition of solar shading

The addition of shading has less effect, possibly due to the fact that solar gain has

already been lessened by the use of more effective solar control glass.

3.2.1.2 Altered geometry adaptations

The adaptations discussed in this section are as follows:

Floor heights: Levels A, B, C and C+ have floor-to-floor heights increased from approximately 3.6m to 4.8m to facilitate natural ventilation

Top floor chimneys: a 0.5m² ventilation pathway was introduced to the inner region of the top floor offices to introduce cross-ventilation.

Open plan offices: internal walls were removed to allow more ventilation airflow

Table 3 shows the change in the hours over the comfort threshold for each of the sample rooms that are affected by the changes made (including the percentage change from the base case). The data is for the 2050 weather file.

0

20

40

60

80

100

120

ResLab1 PGR-C FlexTea2 AD14-6 AD3-7

No. H

ou

rs a

bo

ve

AC

T +

1°

C Base Case

'Specification'

adaptations

'Specification'

adaptations

and all

shading

2050

Target





REV B.DOCX

Page 14

Hrs over ACT +1°C

Base Case

Floor height Chimneys Open Plan

ResLab1 39 29 (-26%)

PGR-C 50 40 (-20%)

FlexTea2 46

AD14-6 101 47 (-53%) 52 (-49%)

AD3-7 54 31 (-43%) 25 (-54%)

Table 3: Changes seen in hours over comfort level in 2050 on original building

The increased floor heights reduced the hours of overheating by 20% and 26% in the two sample rooms that were affected by the change (those on levels B and C). This shows that increasing the height of rooms can facilitate increased ventilation airflows.

Both the introduction of chimneys and the removal of the internal walls to create an open plan office effectively halved the hours over the comfort threshold for the sample offices. This highlights the effectiveness of cross-ventilation over the single-sided solution that is employed on the base case building.

3.2.2 The ‘Engineering Led Design’

A description of the Engineering Led Design is included in section 3.1.2.

The effect of the altered design on the sample rooms can be seen in Figure 13.

Figure 13: Performance of original building and Engineering Led Design

The results are variable but this is to be expected as it is very difficult to compare like with like when such a significant massing change is involved. Discussions around the results are shown in Table 4.

0

20

40

60

80

100

120


No. h

ou

rs a

bove

AC

T +

1°

C

Original Building

ELD Target

2050





REV B.DOCX

Page 15

Sample Room Comment

ResLab1 The geometry of this particular room is similar between the two buildings. In addition, a significant proportion of the room cannot benefit from the additional ventilation flow of the ELD.

PGR-C This shows the most drastic improvement as in the original design it is only ventilated from one side whereas it is has openings on opposite walls in the ELD. This is achieved by extending the section of the building with a narrow floor plate and avoiding the deep-plan portion of the original building.

FlexTea2 A significant improvement is seen, possible as a direct result of the fact that the circulation space that the room vents onto opens to the outside in the ELD as opposed to the atrium in the original building. In addition, slightly more of the length is able to be effectively cross ventilated in the ELD.

AD14-6 In the ELD, this office has two external walls which may contribute to heat loss, avoiding higher internal temperatures. In addition, it opens out onto a ventilated corridor as opposed to an internal corridor in the original design

AD3-7 Due to the additional floors necessary in the ELD, this office receives significantly less shading from surrounding buildings, increasing solar gain.

Table 4: Commentary on Engineering Led Design results

As a more general comparison, the average of the larger set of sample rooms for both the original building and ELD can be taken. In this case, the ELD shows an improvement from 56 hours of overheating to 34 in 2050 (39%). The benefit has lessened in 2080 to a 23% improvement (from 117 to 90 hours) but this is still a significant improvement.

The reductions in overheating, whilst significant, are not as dramatic as might be expected considering the fact that the over-riding design principle of the ELD was to reduce internal temperatures. This is undoubtedly because many of the principles of good natural ventilation have been incorporated as far as possible into the original design. For example, the base ELD does not perform as well as the original building design with specification adaptations and shading, a specification which performs well until close to 2080. These relationships are discussed further in section 3.2.3.

3.2.2.1 Shading and geometry adaptations

The shading and geometry adaptations carried out on the original design were repeated on the Engineering Led Design. The geometry adaptations of floor height, top floor chimneys and open plan offices were then combined into an optimum layout.

The effect of shading was more pronounced when compared to the effect on the original building. This may be because the specification adaptations had not yet been applied so the effect of limiting solar gains was more pronounced.

Interestingly, the shading was less effective in the lower floors (8% reduction in hours over the comfort threshold) than in the upper floors (20% reduction) which is probably a result of the shading the lower floors receive from the surrounding buildings.

Table 5 shows the change in the hours over the comfort threshold for each of the sample rooms that are affected by the geometry adaptations (including the percentage change from the base case). The data is for the 2050 weather file and





REV B.DOCX

Page 16

replicates Table 3 which considers the original building. The magnitudes of the changes are broadly similar.

Hrs over ACT +1°C

Base Case

Floor height Chimneys Open Plan

ResLab1 36 24 (-33%)

PGR-C 6 4 (-33%)

FlexTea2 23

AD14-6 65 35 (-46%) 27 (-58%)

AD3-7 77 60 (-22%) 39 (-49%)

Table 5: Changes seen in hours over comfort level in 2050 on ELD

When these changes are combined, the effects are as shown in Figure 14. It shows that each of the sample rooms should now perform well in 2050, having been brought under the 40 hour target for this metric.

Figure 14: Effect of combined geometry adaptations on the ELD base building

3.2.2.2 Effect of feasible adaptations

These changes are those previously applied to the original building design and discussed in section 3.2.1.1. The difference here is that they have been applied separately in order to see their individual effectiveness.

The effectiveness of the individual adaptations is dependent on the room type. The PGR-C room is not considered as it was already performing very well but the other two large spaces, the research lab and flexible teaching area show a very similar response compared to the base case with all of the geometry adaptations applied.

0

10

20

30

40

50

60

70

80

90


No. h

ou

rs a

bove

AC

T +

1°C

ELD Base

All Geometry adaptations

2050

Target





REV B.DOCX

Page 17

Figure 15: Effect of specification adaptations on large spaces

The sample rooms on the top floor (which are now part of the open plan space occupying that storey) show a notably different pattern of responses to the adaptations (which is not unexpected given their differing characteristics). Figure 16 shows the adaptations in the same order as Figure 15. They are more affected by shading, reflecting the fact that their position on the top floor makes them more susceptible to solar gains without the effective protection of surrounding buildings. Also slightly more effective is night ventilation. This could be due to the fact that the base case has a higher degree of overheating meaning that the reduction seen is greater.

Conversely, increasing ventilation rates during the day have less effect, as does reducing internal gains. Both of these aspects could be related to the fact that these type of spaces have lower internal gains than the research labs or teaching spaces.

Figure 16: Effect of specification adaptations on small cellular spaces

0

5

10

15

20

25

30

ResLab1 FlexTea2

No

. h

ou

rs a

bo

ve

AC

T +

1°

C

All Geom. Adapts

Shading

G-value

Night vent

Incr. day vent

Red. Int. Gain

2050

0

5

10

15

20

25

30

35

40

45

AD14-6 AD3-7

No. h

ou

rs a

bove

AC

T +

1ºC

All Geom. Adapts

Shading

G-value

Night vent

Incr. day vent

Red. Int. Gain

Target





REV B.DOCX

Page 18

3.2.3 The overall effect

Examining the effects of progressing from the original building to the best performing using the route shown in Figure 17, gives an indication of the gradual improvement of the building as interventions are added.

Figure 17: Route from original building to the most adapted

It should be noted that this route is different to the way options would normally be assessed in the course of a ‘real’ building design project. Specification adaptations would probably be considered first as they are least intrusive on the client brief and cheapest. The geometry adaptations and re-design of the building would then be applied if needed. However, in this research study the effects of the building re-design and geometry alterations are of most interest so they have been applied first.

If an average is taken of the number of hours each of the five sample rooms exceeds the comfort threshold, the graph in Figure 18 is produced.

Figure 18: Progression in climate change resilience as adaptations are added

It can be seen that the original building design performs well using the current weather file and the sample rooms are broadly on target for 2030. However, in order for the target to be met, on average, in 2050, the alterations embodied in the Engineering Led Design need to be incorporated. By 2080, both the geometry and specification adaptations are required for internal conditions to be acceptable.

Alternatively, we can take a more pragmatic approach by comparing the performance of the original building with ‘realistic’ adaptations with a more ‘extreme case’ incorporating more fundamental changes (shown in Figure 19).

Original Building

Engineering Led Design

ELD with geometry

adaptations

ELD with geometry and spec

adaptations

0

20

40

60

80

100

120

140

2010 2020 2030 2040 2050 2060 2070 2080

No. h

ou

rs a

bove

AC

T +

1ºC

Original Building

ELD

ELD + Geometry Adadaptations

ELD + Geometry and Specification Adaptations

Target





REV B.DOCX

Page 19

Figure 19: More pragmatic route from the original building design

The ‘realistic’ adaptations include those that can be easily included into the original design without significant alteration of the architectural concept. They include reduced g-value glass, reduced lighting and IT gains, increased ventilation rates and solar shading.

The ‘extreme’ adaptations are those that require the move to the Engineering Led Design along with changes to floor heights, moving to an open plan office arrangement and installing solar shading.

The comparison of these options can be seen in Figure 20.

Figure 20: Performance of 'realistic' and 'extreme' design options

Taking this route for adaptation, the ‘realistic’ adaptations provide very comfortable conditions in 2050 and it is not until 2080 is approached that the target is exceeded. The However, it should be remembered that these figures represent the average of the sample rooms. There will undoubtedly be areas of the building that will be unacceptably hot in 2080 when only the ‘realistic’ options have been applied.

This suggests that more fundamental design changes need to be considered at the outset if a future rise in mechanical cooling is to be avoided in some spaces along with associated energy, carbon and running cost implications.

Of course, when considering the viability of designs and options to dates in the future, we should remember that the observations are reliant on the medium emissions scenario being followed and that any deviation towards higher emissions will shorten the timescales involved.

Original Building Design

'Realistic' adaptations

•Original design with specification adaptations and shading

'Extreme' adaptation

•ELD with geometry adaptations, specification adaptations and shading

0

20

40

60

80

100

120

140

2010 2020 2030 2040 2050 2060 2070 2080

No. h

ou

rs a

bove

AC

T +

1ºC

Original

Realistic

Extreme

Target





REV B.DOCX

Page 20

3.2.4 Other overheating metrics

As mentioned previously (in section 3.1.3), there are three criteria that are proposed to be used to evaluate overheating in the future. For clarity, most of the data in this report is presented compared to the first criterion, the number of hours the internal temperature exceeds the Adaptive Comfort Threshold (ACT) by more than 1°C.

In order to present an understanding of the relationship between the three criteria, the data for one sample room (PGR-C) in each of the Original Building and Engineering Led Design is presented here for the range of future scenarios. The performance of the room in each building against the three criteria is shown in the graphs below.

Figure 21: Graphs showing the performance of sample room PGR-C in each of the

buildings against the three proposed overheating criteria

These graphs are summarised in the table below along with the overall performance which relies on two of the three criteria being compliant.

Criterion 1 Criterion 2 Criterion 3

Overall

Act. ELD Act. ELD Act. ELD

Act. ELD

2010 Pass Pass Marg. Pass Pass Pass

Pass Pass

2030 Pass Pass Fail Marg. Fail Pass

Fail Pass

2050 Fail Pass Fail Marg. Fail Pass

Fail Pass

2080 Fail Marg. Fail Fail Fail Fail

Fail Fail

Table 6: Summary of Pass/Fail (&Marginal) for each of the conditions and criteria

The weighted exceedance criterion (no. 2) seems to closely follow the pattern of the more traditional metric of hours of exceedance (no. 1). The figures for the weighted exceedance criteria are for the entire summer season from May to September inclusive and seem to suggest that this criterion is significantly more onerous than existing or similar standards.

0

20

40

60

80

100

120

140

160

20

10

20

30

20

50

20

80

No

. H

ou

rs >

AC

T +

1K

Criterion 1, Target = 40

Actual

ELD

0

2

4

6

8

10

12

14

16

18

20 2

01

0

20

30

20

50

20

80

No

. D

ay

s W

eig

hte

d E

xce

eda

nce

> 1

0


Actual

ELD

0

5

10

15

20

25

30

35

40

20

10

20

30

20

50

20

80

No

. H

ou

rs T

emp

> A

CT

+ 3

K


Actual

ELD





REV B.DOCX

Page 21

3.2.5 Other factors studied

3.2.5.1 Acoustics

The preference amongst academics for cellular offices is well known and well understood, based upon the need for high degrees of acoustic separation between workplaces and low internal noise levels. In response to this, a qualitative acoustic appraisal of the building and proposed changes to office layouts was carried out. Full details can be found in Appendix 3.5 but a summary is provided here.

City centre noise levels are expected to slightly reduce over the long term as a result of the increasing use of electric vehicle with much quieter engines. This will lead to a corresponding lowering in the internal noise levels of naturally ventilated offices. This effect, however, may be reduced by the fact that the offices are located on the upper floors.

There are many techniques that can increase the levels of speech privacy between workspaces, with possibly the most effective being the use of acoustic ceiling baffles which work to reduce reflected sound levels as indicated in Figure 22.

Figure 22: Reduction in noise transmission as a result of acoustic ceiling baffles

In combination with ceiling baffles, the use of higher, acoustically absorptive partition screens and optimising the height of the room and the distance between workstations can reduce speech levels by up to 15dB.

However, this reduction of 15dB represents approximately a halving of how easy it is to understand the speech of someone on the other side of a partition. A standard wall with a door would provide twice the attenuation (around 30dB) and an acoustically enhanced wall even more separation (~45dB).

In conclusion, the city centre location could lead to an internal sound level of 55dB, consisting mainly of traffic noise and general speech from occupants. This background level is slightly higher than recommended for the open plan office (40-50dB) but not to the point where it should disturb concentration in those accustomed to open plan offices. This level is significantly higher than the level recommended for the more traditional cellular offices but the internal spaces could be engineered to provide a comfortable level of speech privacy.

3.2.5.2 Façades

Aside from the façades’ potential contribution to the reduction of overheating that has been incorporated into the modelling results, the current system and six alternatives were qualitatively assessed against six potential effects of climate change. The full report is included in Appendix 3.6 and a summary is included in Table 7.





REV B.DOCX

Page 22

It shows that many of the popular façade options being considered on buildings currently being designed may experience issues around the changing climate. The effects are often considered minor but façade systems can be in place for many decades before refurbishment or even remain for the entire life of the building so chances for improvement and re-engineering occur very infrequently.

Façade option

Ho

tter

, d

rier

su

mm

ers

Wa

rmer

, w

ette

r w

inte

rs

Mo

re i

nte

nse

ra

in

Gre

ate

r T

emp

. E

xtr

emes

Incr

ea

sed

win

d s

pee

d

Pro

lon

ged

UV

Ex

po

sure

Comments

Current: Stone rainscreen on Metsec backing

=

Adequate drainage required due to potential of more rain penetrating rain screen. Increased range in movement joints required.

Alt 1: Through coloured insulated render

=

Renders have high expansion capability to cope with greater extremes but coloured systems may fade due to increased UV exposure.

Alt :2 Natural copper cladding on ply

=

Thermal expansion differentials between copper and ply may cause warping or issues with the bond between the two materials.

Alt 3: Trespa panels (ventilated façade)

= = =

Trespa panels seem more resistant than some other systems to the effects of climate change with the exception of potential effects of UV exposure.

Alt 4: Load bearing brick

= =

Increased risk of water penetration due to higher wind and more intense rain. Potentially exasperating issues with freeze-thaw cycles in extreme winters.

Alt 5: Red stone cladding on solid wall

= =

Similar issues to current option with water ingress due to more wind-driven rain. Increased range in movement joints required to cope with temperature variations.

Alt 6: Lignacite concrete facing masonry block

= =

Very durable materials will cope with climate change slightly better than others and the thermal mass will act to alleviate internal temperature extremes

Table 7: Effect of climate change on alternative façade options





REV B.DOCX

Page 23

3.2.6 Barriers

As with any design change, disadvantages exist in comparison with the advantages in climate change adaptation previously. Barriers to the implementation of the adaptation interventions such as cost, client aspirations and planning restrictions are discussed here.

3.2.6.1 Costs

The costs for the adaptations fell into two very distinct categories. Unsurprisingly, the cost of the engineering led building was significantly higher than the original design. A cost uplift of ~£1.7m (14%) was determined. Much of this was the result of increased areas of external façade along with an increase in Gross Internal Floor Area due to the ELD being less efficient in terms of space utilisation than the more developed original building design.

The second costly element was the increase in floor height which resulted in a further 10-12% increase. Given the effectiveness of this change, it is evident that this might not be the most efficient way of increasing performance.

Apart from these high-cost items, the remaining items were relatively affordable, with most of them being less than 1% of the total build cost. Certain changes such as the open plan offices and the use of exposed soffits for thermal mass resulted in a cost reduction as shown in Figure 23.

Further information on costs including the alternative façade systems is shown in Appendix 3.4.

Figure 23: Effect of lower cost adaptation on build costs

An alternative way of looking at the cost information is comparing the cost of the adaptation with its effectiveness. Figure 24 represents this comparison with points to the bottom right of the graph indicating less effective options with high cost and points to the top left indicating highly effective adaptations with little (or negative) cost impact.

To

p f

loo

r ch

imneys

Op

en p

lan o

ffic

es

So

lar

shad

ing

Red

uce

d G

-val

ue

Red

. in

tern

al g

ains

Nig

ht

Ven

tila

tio

n

-£150,000

-£100,000

-£50,000

£0

£50,000

£100,000

£150,000

£200,000

Co

st c

ha

ng

e fr

om

Ba

se C

ost

Original building

ELD





REV B.DOCX

Page 24

Figure 24: Comparison of cost and effectiveness of adaptations

Overall, the cost/benefit ratio of the adaptations can be summarised in order of increasing cost effectiveness as shown in Figure 25. However, it must be remembered that the financial effectiveness should not the only measure of success for an adaptation. As discussed in the following section, each of the adaptations impacts on client aspirations in different ways and to different degrees.

These costs are based on the initial capital costs of the adaptation measures. Had the adaptations had direct implications on the running costs of the building, then a whole lifecycle cost approach could be taken. However, in this case, the aim of the project is for the building to operate without mechanical cooling. Therefore these adaptations have little or no effect on energy costs and the benefit need to be considered in terms of reduced overheating rather than reduced energy costs.

As a comparison, the benchmark increase in capital cost for comfort cooling strategy for a building of this size is £540,000 to £630,000

5. Whilst this is cheaper

than the £1.7m increased cost for the ELD, it is significantly more expensive than all of the specification adaptations added together.

5 SPONS M&E Services Price Book 2012. Elemental rate for alternative engineering solution

‘comfort cooling: 2 pipe fan coil for building over 3,000m² to 15,000m²’

Top floor

Chimney

Open Plan offices

Solar Shading

Reduced G-value

Reduced internal

gains

Night vent

0%

5%

10%

15%

20%

25%

30%

35%

40%

-£100,000 -£50,000 £0 £50,000 £100,000 £150,000

Av

era

ge

per

cen

tag

e sa

vin

g i

n h

ou

rs o

ver

com

fort

th

resh

old

Cost of measure

Night ventilation

Open plan offices

Reduced internal gains

Top floor chimneys

Solar shading

Reduced G-value

Engineering Led

Design

Increasing floor heights

In

crea

sin

g c

ost

eff

ecti

ven

ess

Figure 25: Cost effectiveness





REV B.DOCX

Page 25

3.2.6.2 Client brief

Some of the requirements of the client brief were not able to be met with the Engineering Led Design. It is unlikely that the link bridges to the existing Mappin building would be acceptable. However, the possibility exists that the wind path that the bridge approach allowed was not as important as the general narrowing of the floor plate. Were the Engineering Led Design be developed further, there is the possibility that a compromise could be found.

The acoustic study shows that the acoustic conditions stipulated by the brief are unlikely to be able to be met or even approached by an open plan solution. This is due to the dual requirements of a low background noise and speech separation. Whether these requirements for cellularised space are entire necessary is a discussion that is outside the scope of this study.

Finally, the alteration of the floor heights would directly contravene a requirement for connectivity without level changes with the existing connecting buildings. The effectiveness of this intervention was, however, limited.

3.2.6.3 Planning

Sheffield City Council was approached to discuss the hypothetical alternative design of the Engineering Led Design.

What might possibly be seen as the most significant change in planning terms, the increase in height compared to the original design, was not considered completely unacceptable. Concerns would be raised over the relative height of the ELD compared to residential buildings nearby but approval would have been a possibility if it was supported by a strong conceptual argument. The increased height was not a concern with regard to nearby heritage assets such as the listed portions of the Mappin building.

Other visual alterations such as the solar shading would not have caused concern and may even have enhanced the original building as the shading in the most visible areas was vertical, complementing the vertical emphasis of the overall design.

The use of the building as an engineering teaching facility would have increased the likelihood of acceptance of a design with a strong engineering reason for the form of the building following its functional requirements.

3.2.7 Recommendations

3.2.7.1 Adaptation aspects incorporated into design

Three of the aspects discussed within this report were incorporated into the main design of the building. Due to the informal nature of communication between the main design project and the climate change adaptation research study, it is difficult to exactly quantify the magnitude of the changes incorporated but the fact that this adaptation study was being conducted definitely positively impacted the main design project in terms of overheating.





REV B.DOCX

Page 26

The communication between the main design and adaptation projects was required to be informal due to the speed with which the main design project was progressing. To rely on formal communication channels would have resulted in the findings of the adaptation study being communicated too late to influence the main design. This aspect of the project is discussed further in section 4.5.

The mechanical engineers (who worked on both the adaptation and main design projects simultaneously) were instrumental in increasing the contribution of the following aspects to the design:

Reduced G-value glazing (down to a level of 0.33)

Night ventilation with thermal mass

Increased daytime ventilation rates as a result of increased open area

In addition, future weather years were also incorporated into the main design’s overheating report. UKIP02 data for 2020 and 2050 was used in addition to the current weather files in order to communicate to the ultimate client the ability of the design to cope with future climate scenarios. Of the 63 rooms measured in the main overheating report, almost 80% passed overheating criteria for the number of hours over 28ºC in 2050.

3.2.7.2 Future adaptation strategy

As demonstrated by the main engineering report mentioned above and the results of the ‘original’ building design discussed in section 3.2.1, the building has the ability to provide a relatively comfortable internal environment to around 2050.

It is clear that the transformation to the Engineering Led Design cannot now be carried out so the only options that remain for future adaptation are the specification and geometry options. In this case it is recommended that an adaptation strategy that is based on ‘triggers for investment’ be implemented. These triggers will be maintenance and refurbishment cycles of various building elements. By incorporating adaptation actions into standard refurbishment interventions, the cost uplift of considering climate change adaptation can be significantly reduced. It would be very inefficient to replace building elements purely for adaptation reasons before they had reached the end of their service life.

As the first tranche of adaptations will need to be carried out around 2050, about 35 years into the life of the building, there is the option of incorporating them into the first major refurbishment of the building that could be expected to occur around this time, given the effective lifespan of façade systems.

This would allow solar shading, increased ventilation areas and reduced G-value glazing to be incorporated very efficiently.

At this point in the building’s life (or slightly earlier), major work may need to be carried out on the roof. This action would allow the introduction of the rooftop chimneys to reduce overheating in the cellularised offices on the top floor. The possible addition of a green roof at this point in time may result in benefits from transpiration cooling although the potential results have not been quantified here.

However, it is likely that implementing all of these adaptations will not be sufficient to reduce overheating in all of the spaces below the target level (although the target will not be exceeded by a large amount).





REV B.DOCX

Page 27

Further reductions might come from technological advances between now and 2050, particularly in the area of solar control glazing. As a last resort, the amount of mechanical assistance will need to be increased but it is unlikely that large areas of comfort cooling will need to be provided in most of the general use areas.

Once again, when considering the viability of designs and options to dates in the future, we should remember that the observations are reliant on the medium emissions scenario being followed and that any deviation towards higher emissions will shorten the timescales involved.

This strategy of gradual adaptation will also benefit not only from technological advances due to the later interventions but also the cost reductions that may be realised in many of the technologies and techniques that are effective in adapting a building to climate change. These cost reductions will likely come from the increased commonness of adaptation, possibly being driven by changes to regulation emerging from national actions such as the Climate Change Risk Assessment

6.

Appendix 3.7 contains a table of adaptations that have been included in the building design or recommended for future incorporation.

6 UK Climate Change Risk Assessment: Government Report, DEFRA, January 2012





REV B.DOCX

Page 28

4 Learning

4.1 Summary of approach, the initial project plan and subsequent changes

The approach of the project was to investigate the potential effects that changes to the base-case building design could have on the overheating performance in future years. The approach included using the same team on the adaptation research study as on the main design project.

The steps and processes within the project plan are summarised in Figure 26 and remained largely unchanged throughout the project.

What did alter was the timings and the interaction with the main building design process. The speed with which the original building design progressed meant that it was not possible to fully complete the modelling of the adaptation study and understand the results completely before communicating them to the main design team.

This was not due to a lack of resourcing or effort on the part of the adaptation project, simply that there was a small window in time when the design had reached sufficient maturity to allow us to begin modelling and the design progressing to the point where decisions on the aspect we were investigating needed to be made.

Learning from the adaptation project was therefore less structured but no less valuable. Having the same modelling team working on both aspects meant that discussions on the results were frequent and ongoing. These aspects are expanded on in the sections below (predominantly sections 4.2.1 and 4.5).

4.2 Team

The climate change adaptation project was lead by Arup, a global firm of designer, planners, engineers, consultants and technical specialists. More specifically, the buildings engineering team in the Sheffield office were instrumental in the project. Arup specialists were brought in from the fields of acoustics and façades. External sub-consultants were Bond Bryan Architects and Turner and Townsend cost management.

A summary of the individuals involved and their roles is in Table 8 whilst CVs are in Appendix 4.1.

Name Company Role

Andy Sheppard Arup Project Manager and lead adaptation specialist

Pete Thompson* Arup Thermal modelling and analysis

Lee Kirby* Arup Acoustic implications of open plan offices

Assessment of impacts

Appraise original building design

Develop alternative building designs

Investigate effectiveness of alterations

Examine facade options

Understand cost implications

Figure 26: Project Plan





REV B.DOCX

Page 29

Name Company Role

Irene Pau Arup The impact of façades on climate change adaptation

Steve Maslin* Bond Bryan Architectural project direction

Sheila Badger Bond Bryan Design and drawing of the Engineering Led Design

Joseph Freeman* Turner & Townsend Cost analysis

Table 8: Team members and roles

* All individuals named were part of the climate change adaptation study team. Those with marked with an asterisk were also members of the main project team.

4.2.1 Communication

It was found that having a number of people working on both the main design project and the adaptation study project was invaluable to assist the flow of information between the two projects. The fast pace of the main design project would have meant that effective communication between two completely separate teams would have been very difficult.

Had this been the case, it is likely that the learning from the adaptation project would have been too late to influence the main design project. Instead, the knowledge transfer between the two projects was effectively instantaneous and interim results from the adaptation project could be used to influence the main design project without waiting for a finalised set of complete results before communication.

4.3 Tools and resources

4.3.1 Tools

A number of specialist and more mainstream tools were used during this project.

Tool Role Comment

Arup Climate Change Appraisal Framework (CCAF)

Appraisal of climate risks

CCAF was very suitable for this project, allowing the visual comparison of many different aspects of climate change adaptation along with an appraisal of the risk exposure of the project to each of the potential impacts. The framework was found to have a high degree of correlation with the categories defined in the TSB’s report

1.

IES Dynamic Simulation Modelling, predominantly of internal temperatures

IES has a wide range of modules that can carry out steady state and dynamic thermal calculations, bulk air flow analysis, Building Regulations compliance and solar shading assessments. Analysis of building services systems can also be carried out using the ApacheHVAC module however this is a less developed element of the software. The software’s ability to perform a multitude of analyses within a single model allows for efficient and relatively quick calculations. The software has a simple graphical user interface and building geometry is a straight forward affair. IES can import 3D geometry however this is limited to simple models with well defined vertices and planar faces. IES has clear post-processing functionality and is able to output summary reports however data files can be excessively large





REV B.DOCX

Page 30

Tool Role Comment

Microsoft Excel

Data analysis

Whilst there are more complicated mathematical analysis software tools available, Excel is perfectly suited to this type of data processing due to its familiarity. The only issue experienced was around the size of the data files created, with 200Mb files not being uncommon. The complex inter-relationships between various files also needed to be carefully managed to avoid confusion and the incorrect interpretation of results.

Autodesk Ecotect

Initial solar gain analysis, solar studies, sun paths, and shading studies

Ecotect is an appropriate tool for the level of information needed and for the early concept stage nature of the work carried out. It is good for importing geometry and especially good for visualising results. However, for more in-depth studies that involve using the solar radiation results in conjunction with the thermal performance of the envelope or energy performance, for example, it might be more appropriate to use a more robust tool such as EnergyPlus (if a good graphical user interface is available), IES, or eQUEST.

Table 9: Tools used in the course of this project

4.3.2 Resources

The main external resource was the Prometheus weather files. These were found to be easy to use and compatible with the software we were using. The larger number of file locations compared with the CIBSE equivalent meant a more appropriate file was able to be used for Sheffield.

A list of papers used as direct or indirect references in this study is provided in Appendix 4.2.

4.4 Appraisal of the success of the approach

One aspect of the project methodolgy that was particularly successful was to decide at a very early stage how to analyse the vast amount of data that the project was going to generate. Making these decisions before seeing the data can be difficult and does carry some risk but the benefits are a significantly more efficient analysis process.

At the outset the analysis strategy was determined including the exact modelling runs, the relationships to be examined, the metrics used and how the information was to be presented. This allowed template spreadsheets to be created and lead to a consistent and error-free process giving confidence in the analysis of a very large and complicated set of data.

This degree of preparation also lead to probably the biggest issue with the approach. That is the fact that results of the work as it progressed highlighted results that warranted increased investigation that then needed to be integrated into the methodology. Thankfully, the efficiency that had been incorporated into the process allowed these investigations to take place.

Finally, complexities arose in the relationships between the main building design project and the adaptation study that were not foreseen. Difficulties were caused by the stop-start nature of the aspects of the main project that aligned with the adaptation project. This is not an uncommon characteristic of many design projects. Having the same team working on the adaptation study and the main





REV B.DOCX

Page 31

project was beneficial for communication but lead to difficulties in resourcing as both projects had the same peaks and troughs in workload.

4.4.1 Recommended methodology

The team is confident in recommend the methodology used to others, with the caveat to be aware of the issue of trying to do too much. It is very easy to get side-tracked from the main direction of the investigation and get drawn into sideline issues that can take a significant amount of time to resolve.

Any project has a finite amount of resource that can be allocated to it. It is essential to ensure that both the depth and breadth of the study are appropriate. On the one hand, going into too much detail and not being able to address the full scope of the study will lead to questions going unanswered. On the other hand, setting an ambitiously broad scope may lead to the underlying issues not being understood due to a lack of time available to investigate them.

4.5 Influencing the client

It quickly became apparent that the main project was progressing at such a pace that, had we completed a section of the adaptation study, analysed the results and then arranged a meeting to formally communicate the results to the client, the main project would have progressed to a point where design decisions had already been made on issues we were investigating. The magnitude of the study we were undertaking was such that there simply wasn’t time to take this approach.

Therefore, as has previously been mentioned, the most effective way of providing links between the main project and the adaptation study was through informal and frequent communication within our organisation and with other members of the design team. These communications were necessarily less formal but overall, it is felt that the adaptation study has definitely had a positive impact on the main design project.

The most effective way of influencing the client to consider climate change adaptation aspects of a building design is to embed adaptation considerations into the main design process. This was done in on the main design project for this building through the incorporation of the performance of the building against future weather years in the standard overheating report.

The design of the building resulted in a good performance against the future weather years but, had the message been less positive, the issue of longevity of comfortable internal conditions would have been easily raised.

4.6 Recommended resources

Regarding recommendations on resources, the main tool, IES, proved perfectly capable. Arup have experience of many tools of this kind and all have their strengths and weaknesses. The most important aspect in choosing the tools is to use ones that are familiar to the team. The complexities of such a comprehensive study mean that it would be very easy to make mistakes if the tools are not





REV B.DOCX

Page 32

intuitive to use. Dynamic Simulation Modellers have many levels of inputs and having an in-depth understanding of the inputs, how to change them and the effects of doing so is absolutely invaluable. Otherwise the data will seem to raise more questions than it answers.

Overall, there are no tools that we cannot recommend to others assuming they have the level of expertise necessary to operate them.

Finally, in terms of personnel resource, the importance of a high level of competency in using any data analysis software should not be underestimated.





REV B.DOCX

Page 33

5 Extending adaptations to other buildings

5.1 Applying the strategy to other buildings

The details of adaptation strategies are individual to the buildings they have been developed for. They depend on many building characteristics such as location, form, orientation, mechanical systems and ventilation levels along with aspects of usage such as occupation patterns and levels of internal load.

Therefore it is unlikely that this exact adaptation strategy can ever be completely applicable to another building.

However, and more importantly, the individual effects of the adaptation study and its findings could be applied to other buildings. For example, the large potential improvements shown on testing cross-ventilation chimneys on the top-floor cellularised offices can easily be transferred to other similar floor plans and can act as a catalyst to more specific detailed studies.

Fundamentally, thought, in order for the overheating aspect of this study to be applicable to another building, that building must have certain characteristics. It must be predominantly naturally ventilated as the study is based on increasing the effectiveness of natural ventilation in order to allow the building to cope with increased temperatures using this low-carbon ventilation mode.

Certain adaptation interventions would also only be applicable to new buildings due to the fact that they would need to be designed-in from the start. Data and information on other adaptations would be relevant to some degree to refurbishment projects (depending on the building characteristics and degree of refurbishment).

Adaptation intervention New build Refurbishment

Reduced g-value glazing Yes Either through the replacement of the glazing units or through the application of films to existing glazing

Reduced internal gains Yes Yes

Increased daytime ventilation Yes Increased ventilation openings are often possible within exist glazing apertures

Night ventilation Yes Often more a building management and security issue as opposed to the provision of ventilation

Solar shading Yes Possible in some circumstances

Floor heights Yes Floor-to-floor heights are fixed but the removal of suspended ceilings or raised floors may have the same effect

Top floor chimneys Yes Yes

Open plan offices Yes Dependant on structural considerations

Table 10: Applicability of adaptation interventions to refurbishments

The studies carried out into the robustness of façade systems is also highly transferrable as the systems investigated are common to many types of non-domestic buildings.





REV B.DOCX

Page 34

In this way, the individual components of this study might be applied to many other buildings as part of an initial scoping study to assess whether there is merit in performing more detailed analysis. It is hoped that this study shows the potential for improvement that exists in even very well designed buildings such as the main design project for the Grad School.

Ultimately the questions around the adaptability of a new building design rely on the right questions being asked in the first place.

Even if the final strategy is not directly applicable to other projects, the methodology is highly transferrable and could easily be transferred to other buildings on the assumption that they do not have a high degree of mechanical cooling.

In particular, the method of using a climate change adaptation appraisal can be used on any building project and would provide the invaluable starting point of identifying the climate risks that require further attention.

Further analysis on which buildings may learn from this adaptation strategy can be found in section 5.3 and Appendix 5.1

5.2 Limitations of applicability of the strategy

There are a number of reasons why this strategy would not be ideally suited to other buildings, some of which are summarised in the table below. However, in all of these circumstances, there are always some elements of the work that could provide some learning, there will just need to be an extra degree of care taken in the interpretation of the results.

Building Characteristic Potential reason for limited applicability

Ventilation mode

If the building is air conditioned then there will be no issue with overheating as long as the system can cope with increased temperatures. Future issues will be based around energy costs which would require a different type of analysis based on annual consumption figures as opposed to peak temperatures.

Location

If the building has a significantly different climate to that tested then the results may need more interpretation. This may apply to buildings at the extreme North and South of the UK when compared to the relatively central test building.

Setting Buildings that are in very exposed settings or with other aggressive atmospheric condition such as a coastal environment may need a different emphasis on a façade robustness study.

Building type Buildings with a significantly different plan-form will probably have a natural ventilation strategy different to the study building.

Usage

The effects of overheating are affected by the internal gains within spaces from equipment, lighting and occupants. Buildings with significantly different internal gains or occupancy patterns will have a different balance between internal and solar gains.

Table 11: Potential limitations of applicability of the strategy





REV B.DOCX

Page 35

5.3 Applicability to other UK buildings

Building types and usages within the Higher Education (HE) sector vary significantly. However, the study building is relatively generic and so can be considered to be representative to some degree of the rest of the HE estate that is not residential in nature. In 2008-09, the 160 HE institutions in the UK had a net internal area (NIA) of non-residential uses of 14,200,000m² a consistent level that has been seen for the last 5 years. The property within the sector was worth £60bn in 2008-09

7.

Due to the transferrable nature of the work that was undertaken, learning from it could be applicable to most of this estate. More specifically, there is 3,000,000m² of research space that would directly compare to the building studied.

In addition to the Higher Education sector, these results could equally well be applied to commercial offices as many of the building characteristics that can vary between sectors such as internal gains, room sizes and occupancies and hours of occupation are either addressed within the study or are similar between the sectors. The commercial office sector has been estimated as being of the order of 84,000,000m².

8

Figure 27: Applicability of study multiplies due to transferability to other building types

The rate of replacement and refurbishment of the buildings in these sectors will obviously affect the potential size of the estate this study is applicable to. In addition, the aspects such as those considered in Table 11 will affect applicability. Further discussion on this aspect can be seen in Appendix 5.1.

7 Higher Education Funding Council for England, Performance in Higher Education Estates, 2011,

HEFCE (data taken from Table 7) 8 Communities and Local Government, 2009, Floorspace and rateable value of commercial and

industrial properties 1 April 2008, (England & Wales) – table P401

3 14 84 0

10

20

30

40

50

60

70

80

90

HE research HE non-resi Commercial

Est

ate

siz

e (m

illi

on

m²)

Building Type





REV B.DOCX

Page 36

5.4 Skills, resources and tools developed during the project

The main skills developed during the overheating aspect of this project lay in the data analysis processes. The implications of the volume of data generated during a project such as this cannot be underestimated. One of the most powerful tools developed was template spreadsheets that allowed raw Dynamic Simulation Modelling (DSM) outputs to be easily converted into useful overheating metrics.

Whilst this is undoubtedly a stop-gap measure until the DSM packages catch up with changing methodologies, it has given us a head-start in understanding the new metrics along with a deeper understanding of why rooms pass or fail that would not have been developed if we had relied on the output of ‘black-box’ calculations. In addition, the methodologies developed will be easily adaptable and transferrable to other overheating adaptation studies.

In terms of the façades study, this is the first time that the adaptation properties of alternative façade systems has been examined in such detail. The frameworks and techniques developed will allow subsequent studies to be approached more efficiently, making them more attractive to building owners.

Overall, there has been a significant amount of increased understanding of the requirements of climate change adaptation as a result of this project. The project and its results and findings have been included in numerous internal presentations and have been used to discuss the issue of adaptation on our well attended discussion forums. The TSB work has also been instrumental in inspiring a follow-up piece of internally funded research into adaptation in rail sector buildings examining the potential impact of the effects of climate change on the transport network as a whole.

This learning has been throughout the building engineering team within Arup and has not been restricted to a separate stand-alone team dealing with building sustainability.

Other resources that have been developed are around the dissemination activities surrounding the project. The adaptation study is planned to be used as part of university courses in architecture and engineering. In addition, dissemination to the wider sector is planned, potentially through the Environmental Association of Universities and Colleges (EAUC) and the Association of University Directors of Estates (AUDE) along with communication to various individual institutions

5.5 Further needs for adaptation services

There are no aspects of this methodology that we need to develop further in order

to provide adaptation services. The only need is for an enlightened client or a

regulatory structure to be present to require the study to be undertaken.





REV B.DOCX

Page 37

Appendix List

The following appendices are included providing further information on issues covered in this report.

1. Building Profile

1.1. Floor layouts of original building

2. Climate Change Risks

2.1. CCAF output report

2.2. Relevant subsets of UKCP09 data

3. Adaptation Strategy

3.1. Calculation procedures for overheating metrics

3.2. Floor layouts of altered building

3.3. Details on the changes made (Pete’s costing note)

3.4. Costs

3.5. Acoustic report

3.6. Façades report

3.7. Table of adaptations

4. Learning from work on this contract

4.1. CVs – Just needed Irene’s

4.2. Recommended information sources

5. Extending adaptation to other buildings

5.1. Sources of data

university of sheffield engineering graduate …...technology strategy board university of sheffield...

Documents