adapting to part l regulation changes · standards. this paper reviews how architects currently...

Copyright ©2013 Sefaira Ltd.

Discover how to efficiently respond to the UK government’s building regulation changes.

We use the Part L regulation in this paper as an example of how regulation can be met by

using performance based design. The principle is equally applicable for any other building

performance regulation.

ADAPTING TO PART L REGULATION CHANGES

2

CO P Y R I G H T ©2 0 1 3 S E FA I R A LT D. A DA P T I N G TO R EG U L AT I O N CH A N G E S

The UK’s Part L building regulation focuses on the conservation of fuel & power with

an aim to improve energy efficiency and cut greenhouse gas emissions from new and

existing buildings. It achieves this by specifying the minimum efficiency and performance

of the building fabric and heating and cooling systems, in order to ensure thermal

standards. This paper reviews how architects currently meet this regulation, proposes

a radical but necessary change in approach and illustrates how it can be effectively

achieved using two example projects.

The Part L regulation is directly aligned with the European Union’s Energy

Performance of Buildings Directive (EPBD). First published in 2002 to reduce

energy consumption and waste, the EPBD requires enhanced building regulations

and energy certification schemes across all EU countries. The recent changes to

the Part L building regulations will come into effect on April 6th, 2014 with the

overarching goal of reaching Zero Energy for homes by 2016 and Nearly Zero-

Energy for non-domestic buildings by 2020. The scope of Part L does not change

but the performance requirements for compliance become much tougher as

the government strives to reach its 2020 goals. The changes raise the threshold

requirements for high performance and efficient building systems within new homes

and non-domestic : they are to achieve a 6% & 9% reduction in carbon emissions

over 2010 levels respectively. The new Part L also introduces a minimum Fabric

Energy Efficiency (FEE.)

The 2013 changes mark the fifth amendment to Part L since the year 2000. With

targets set for Nearly Zero Energy buildings by 2020 and the larger goal of Zero

Energy Buildings soon after, it is safe to assume that the government will have to

implement more rigorous changes soon. Considering that the latest ammendments

will not be as stringent as initially proposed (they overlook retrofit projects which

account for a large percentage of the UK’s building stock), further revisions will be

inevitable if the government is to make a significant dent in the UK’s CO2 Emissions.

In order to meet these requirements, architects will need to integrate performance

based design much earlier in the design process than they currently do. In the next

two pages, we illustrate how architects currently work and how performance based

design can help improve the process.

Why Architects Need Performance Based Design to Achieve Regulatory Requirements

The tighter requirements in 2014 will make the path to obtaining permission more

difficult. In order for architects to adjust effectively, it will be necessary to already

carry out analysis during the design process to submit schemes for validation when

their performance levels are already known.

Part L Design Variables SAP Calculation

SAP Calculation

2014 changes mean tougher benchmarks & multiple iterations

Part L Compliance

CERTIFICATIONBUILDING EMISSION RATE

BELOWTARGET EMISSION RATE

BUILDING EMISSION RATEABOVE

TARGET EMISSION RATE

1 2a PassDesign

Fail2b

3 Comply

THERMAL ENVELOPE

LIGHTING EFFICIENCY

SYSTEM TYPES

LOW OR ZERO CARBON TECHNOLOGY (LZC)

SYSTEM EFFICIENCY

How Architects Currently Meet These GoalsThe diagram below illustrates the process through which architects currently obtain Part

L compliance. Using tools that focus on validation, not analysis, a lot of architects submit

their designs for Standard Assessment Procedure (SAP) calculations without already

having a good understanding of their performance or any certainty of whether a design

will pass or fail. If it does fail, the designer still doesn’t learn what he needs to improve to

make it pass. He will likely submit the next version, again without knowing whether it will

pass. As a result, the design process is more tactical than strategic and in many cases, last

minute fixes and design compromises are used to get approval.

Fig 1: How the compliance process currently works

4


To make compliance easier, designers need to consider performance from Day 1 of their design process. They need

tools that are designed specifically for this purpose and allow analysis with very few inputs. When using Sefaira,

designers need only three parameters- a basic envelope model, a location and an overall idea of the building program

- to design Part L strategies from the begining of their creative process. Sefaira shows Part L baselines as part of the

Sefaira for Sketchup interface, which makes it easier for designers to immediately know whether their early stage

design will meet requirements.

By designing with Sefaira, they can holistically test several iterations of their design in order to optimise and

understand their concept before submitting it for SAP calculations. Instead of only validating their design in the later

stages of the creative process, they can use real-time analysis to shape their schemes. Sefaira also allows architects

to show a documented analysis of high efficiency alternative systems -- a requirement of Part L -- and export clear

ready-to-use reports that can be submitted to show that the technical, environmental and economic feasibility of all

systems have been tested.

Using two scenarios, we illustrate how Sefaira can drive sustainability in response to regulatory demands.

Part L Design Variables SAP Calculation

Multiple iterationsoptimise variables

Part L Compliance

CERTIFICATIONBUILDING EMISSION RATE

BELOWTARGET EMISSION RATE

2 Pass1 Designusing Sefaira

3 Comply

THERMAL ENVELOPE

LIGHTING EFFICIENCY

SYSTEM TYPES

LOW OR ZERO CARBON TECHNOLOGY (LZC)

SYSTEM EFFICIENCY

How Performance Requirements Can Be Met More Easily

Fig 2: How the compliance process could work with Sefaira

In this example, we carry out performance analysis on a government funded new

build project which already meets 2010 Part L requirements. Our ensemble is made

up of a city hall, concert hall and theatre, in East London.

In order to comply with 2014 regulations, our design needs to be adjusted to achieve

a 9% reduction compared to 2010 acceptable carbon emissions. We will test

scenarios with different envelope options, HVAC systems & efficiencies, as well

as low carbon technologies, such as solar PVs, to see which single and combined

variables help us reach our goal.

Fig 3: Our proposed scheme

Scenario 1: New Build

To reach a 9% reduction, our annual CO2 production needs to fall from 1,398, 901

kgCO2 to a value below 1, 272, 999 kgCO2.

Baseline Concept

6


With this knowledge, we are now able to make relevant adjustments to the design

to improve its performance at an early stage. In this instance, we’ll focus on the

fabric, glazing, solar shading and HVAC system efficiency.

A first round of analysis reveals that our building is susceptible to high solar gain and

that it loses heat through ventilation and conduction.

Fig 4: Baseline calculation showing CO2, Energy Consumption, Space Cooling & Heating rates. These outputs were selected as they directly relate to the conservation of energy.

Fig 5 & 6: A great proportion of our heat loss is through the ventilation system and conduction through the building fabric.

Heat gains in summer months Heat loss culprits

Our next step is to test single improvement strategies to see what impact they have

on the design.

Improving Design Performance

It is safe to assume that adjusting the glazing ratio and applying solar shading are the two strategies that have the least

impact on our design. Adding an Mechanical Ventilation Heat Recovery System appears to be a crucial strategy; it offers

a 9% reduction in carbon emissions- significant enough to make it a stand-alone measure.

Fig 7: Some of the changes we made to the builidng fabric.

Strategy 1. Figure 7 shows that specifying more efficient fabric

properties such as the facade and roof glazing U Factors, the

solar heat gain coefficient, the wall U Factor, air leakage, and

surface reflectance gets us a 5% reduction.

Strategy 2. Glazing Ratio & Solar Shading adjustments offers

approximately 1% savings in carbon emissions.

Strategy 3. Adding a Mechanical Ventilation Heat Recovery

System that operates at 70% efficiency contributes a 9% saving

to the baseline.

It is essential to check the combined effect of different strategies as you cannot always expect an additive outcome. In

this example, we tested several combinations. The most rewarding bundle is a fabric, glazing and shading upgrade as

well as the addition of a MVHR system. A combined 13% reduction in Annual CO2 Production goes well and beyond the

2014 requirements for meeting Part L.

Combining Strategies

Fig 8: The selected strategies showing improvement in places and worsening performance in others.

1

2

3

Stra

tegi

es

8


Fig 9: Results for single and combined interventions do not always impact the design’s performance in an additive way.

Bund

les

Stra

tegi

es

A majority of 2050’s building stock has already been built according to

a United Nations Environment Programme estimate. From a Lifecycle

Approach, 80% of greenhouse gas emissions occur during the period of

building use. In order to significantly lower carbon emissions, it is clear that

retrofits will have to play a crucial role.

Considering the long lifespan of buildings, it is important for designers

to bear 2050 targets in mind already, so that investments and upgrades

made now remain beneficial and relevant in the long run. The 2014 UK

Part L regulations require a 9% reduction in CO2 emissions from new non-

domestic projects. If this is expected within 4 years for new builds, we can

assume that within the next 10 years, retrofits would realistically have to

achieve around 20% reductions, and above.

Our next example is of a potential retrofit project to be carried out in 2014.

Our goal is to ensure our retrofit strategies remain relevant to any potential

future carbon targets within the next 10 years.

Scenario 2: Retrofit

“ If we are to hit our national carbon reduction target of 80% by 2050, almost every building in the country will need a low energy makeover. That means we have to improve nearly one build-ing every minute, and we have to get the interventions right, first time. That is a challenge.”

The Retrofit Challenge: Deliver-ing Low Carbon Buildings. The Centre for Low Carbon Futures

“

Our example building is an existing retail space and residential project in Leyton,

East London. The table below shows a baseline concept that meets 2010 Part L

regulations.

Initial analysis tells us that our building is heating dominated. Looking in more

detail at the chart below, we see that heat is lost mainly through conduction and

infiltration. Our retrofit could therefore focus on improving our building fabric and air

tightness in order to reduce our heating load.

Fig 10: Perspective view showing residences with balconies over retail.

Fig 11: Our Annual Space Heating value is just over three times more than Annual Cooling load.

Fig 12: Monthly Heat Loss chart showing the two major causes of heat loss.

10


Fabric Improvements

One strategy for improving the building’s fabric would be to increase the U-Values

for the roof and walls. Insulation could be applied to the facade of the building to

maintain the existing building floor area. The roof could be insulated internally

or replaced with a green roof, improving insulation and also adding to the local

ecosystem.

The pie chart shows that most of our fabric conduction loss in descending order is

through the roof, the glazing and finally the walls. We could also adjust our HVAC

system where possible to improve our heating efficiency.

In addition, the heat gain chart on the right tells us most gains come from the sun

suggesting we could introduce shading where possible in order to reduce our cooling

load. However, we will need to size our shading devices properly to make sure that

we don’t block out beneficial heat gain in the winter.

Fig 13: Chart showing what building elements are contributing to conduction losses.

Fig 14: Our heat gains are predominantly from the sun, particularly in the summer months.

Fig 15: Details of our fabric improvements.

Another strategy would be to switch from a light to a medium core structure with the

aim of increasing the building’s thermal mass. Exposing thermal mass through the

floors can be done by taking away carpets and replacing it with a polished concrete

finish. By doing this our floors will store thermal heat, releasing it during cooler times

of the day and helping us maintain a more even temperature throughout the day and

over seasons.

Reducing the building leakage levels give a considerable 12% reduction in CO2

production. In combination, this strategy offers a 19% reduction in CO2 levels, a 35%

reduction in Energy Consumption as well as a 61% drop in Annual Space Heating.

Cooling has increased by 2% considering the building is now much warmer overall.

By changing the Heating Efficiency of our boiler from 0.7 to 0.9, we gain a CO2

reduction of 7%, Energy consumption drops by 13% whilst Annual Space Heating

reduces by 22%.

Boiler Upgrade

Fig 16: Details of our shading & glazing improvements.

Fig 17: Details of our boiler improvements.

Shading & Glazing

Upgrading the facade glazing in addition to horizontal shading contributes 3% to our

CO2 reduction but also reduces Annual Space Heating by 11%.

12


Fig 18: Details of all strategy details

By combining all three strategies, our design benefits from a 23% saving in CO2

production and a 43% reduction in Annual Energy Consumption. The 4% increase

in Annual Space Cooling can be attributed to the tighter envelope and as a result,

a warmer interior. A staggering 77% saving in Annual Space Heating makes this

combination worth investigating further.

Armed with Sefaira’s building physics analysis tool, it is now possible for designers

to rapidly and accurately test and adjust their designs in response to unforeseen

regulation, brief or budget changes.

A Bundle of All Three Strategies

Sefaira allows you holistically test several iterations of your design in order to

optimise it before submitting it for SAP calculations. Whilst other analysis tools

focus only on validation in the later stages of the design process, Sefaira offers

architects the only real-time analysis tool for early stage design within the architect’s

design environment. The flexible interface allows you set relevant benchmarks for

investigating the optimum thermal envelope, system types and efficiency, lighting

efficiency as well as renewable technology for your design.

It also enables designers show a documented analysis of high efficiency alternative

systems, a requirement of Part L - Export clear, ready-to-use reports that show

you’ve explored the technical, environmental and economic feasibility of all systems.

How Sefaira Can Help

+1 855 SEFAIRA (US)

+44 (0)203 427 6565 (UK)

[email protected]

linkedin.com/company/sefaira

twitter.com/sefaira

FOLLOW SEFAIRACONTACT SEFAIRA

About Sefaira

Sefaira was founded in 2009 with a mission to promote more sustainable buildings

by helping the building industry design, build, operate, maintain and transform all

facets of the built environment.

Our applications are based on deep expertise in combining building physics and

computer science, and this unique expertise has enabled us to be the first and only

company able to provide true real-time physics based analysis to the global building

design community.

Visit us online at www.sefaira.com

adapting to part l regulation changes · standards. this paper reviews how architects currently...

Documents