thermal bridges in new dwellings..... accredited details – designing & detailing for...

• Thermal Bridges in new Dwellings.....

• Accredited details – • Designing & detailing for Compliance

Danny Kearney

Main changes to Part F for dwellings

Regulations Part F 2012 – ComplianceFabric Solutions & Thermal Bridging

2

31st Jan 2013

Lisburn and Castlereagh City Council

Xtratherm – Expect More

Presentation - Danny KearneyPresentation - Danny KearneyGroup Technical ManagerGroup Technical Manager

Contact - [email protected] - [email protected]

3Xtratherm – Expect More

1. Explain the 3 components to fabric performance – how do they compare?

U-valuesAir tightnessThermal Bridging

2. Take a semi and look at compliance specifications3. Calculating your Y value.4. Where is it likely to end up? 5. (Zero Carbon Standard & FEEs)Xtratherm – Expect More

Criteria 1 – Achieving the TER Design stageCalculate CO2 emissions for the proposed building – using SAP

Criteria 2 – Minimum Acceptable Stds Design StageKeep within Design limits set in Document

Criteria 3 – Limit Overheating Design StageLimit Solar Gains in Summer (Over Heating)

Criteria 4 – Const Quality & Commis. Post ConstructionCheck Quality of Construction and commissioning of building services

Criteria 5 – Instruction for operation Post ConstructionProvide Information to the home owner


Criteria 4 – Const Quality & Commis. Post Construction•Evidence As stated in paragraph 2.21, a recalculation of the DER is required to be given to the district council not more than 5 days after completion of the dwelling taking into account any changes in performance between design and construction and the achieved air permeability and to demonstrate that the DER for the dwelling as constructed meets its TER.•Building envelope 2.43 The building envelope should be constructed to a reasonable standard such that the insulation is reasonably continuous over the whole building envelope and the actual air permeability is within the set limits.•Party Walls Sealing must be effective – Robust (Sound Detailing) must be taken into account.•Thermal bridges 2.51 The building fabric should be constructed so that there are no reasonably avoidable thermal bridges in the insulation layers caused by gaps within the various elements, at joints between elements, and at the edges of elements such as those around window and door openings.

Criteria 4Quality & Commisioning

The TER and DER for the dwellin

g should be included with the operating

and maintenance instructions together w

ith the data used to calculate them.

This should include an electronic copy of th

e TER/DER data input file for

the

dwelling to facilita

te any future analysis that may be re

quired by the owner

when altering or improving the dwellin

g.

Pressure testing – Penalties Added• (i) where the dwelling has been pressure tested, the assessed air

permeability is the measure air permeability; or

• (ii) where the dwelling has not been pressure tested, the assessed air permeability is the average result obtained from pressure tests on other dwellings of the same type on the development increased by a margin of +2 m3/(h.m2) at 50 Pa; or

• (iii) on small developments, where the person carrying out the work has opted to avoid testing the assessed air permeability is 15 m3/(h.m2) at 50 Pa.

Accredited Detailing - Penalties Added

If not calculated – PSI values MUST be taken from SAP 2009 Table Either Default or Accredited

9

Criteria 4Quality - PENALTIES

NO EVIDENCE? - Penalties Will Be Added


So how to comply?

U-values

Airtightness

Thermal Bridging


Code for Sustainable Homes?

11

• F1 same as Code 3• FEES introduced• FEES will lead Regulations Eng & Wales


Compliance with Part F 2012 using SAP 2009.

12

So – What needs done?


How to achieve compliance – the 25%

13

RESULTS TER DER

18.24 18.24

Element Spec Result

Wall 100mm CavityTherm

0.20

Floor 100mm Hyfloor 0.16

Ceiling 300mm Fibre 0.15

Glazing Double 1.6

Doors Double 1.6

100% EE Lighting – 90% Combi Gas Boiler – Full TT Zoning -

Other

Block Dense

Mech Ventilation None

Renewables None

Permeability 5

Bridging Y value

Xtra Details

0.04

Compliance 1Good detailing


Partial FillCavity Wallusing foiled faced PIR

14

Meeting the U-values: Walls - Partial Fill


Full FillCavity WallPIR 0.021

15

Meeting the U-values: Walls - Full Fill Built in


Floors using foiled faced

PIR

16

Meeting the U-values: Floors


Roof – Slope using foiled faced PIR

17

Meeting the U-values:Roofs - Slope


Roof - Ceiling using foiled faced PIR

18

Meeting the U-values: Ceilings


Full FillPumped

19


175mm – 0.21 U-ValueY-value: Detailing?

Cost Report availableXtratherm – Expect More

PARTIAL FILL

SQUAREor

T&G


Did you know – There a U-value penalty of 0.01 if your

boards are not engineered jointed?Xtratherm – Expect More

21

Taking the same house –

Calculating the actual Y-value

using the:

•Length of each junction

•The PSI value of each junction

•The total area of heat loss

(Envelope area)

Thermal BridgingTaking advantage


• Non–Repeating Thermal Bridges.• Account for 30% of heat loss from a well insulated house• Cold spots cause condensation and mould growth• MUST be measured under part F• Account as a Y-factor in SAP


Each Junction has a PSI value – found in Table K of SAP 2009

Either

DEFAULT or ACCREDITED

Or

Use measured performance from accredited source


Criteria 4 – Thermal Bridging – Accredited Details• Bridging Calculation to BRE Report BR 497 Conventions for calculating linear thermal transmittance and temperature factors. ….no worse than (Default) in BRE IP 1/06 or Table K in SAP

•…….that an appropriate system of site inspection is in place

Dwellings constructed to quality assured accredited construction details?

•Where quality assured accredited construction details the calculated linear thermal transmittance can be used …….. Schemes that provide such construction details also accredit and quality assure the calculation of the linear thermal transmittance, accredit the details in terms of buildability and have an associated quality assurance regime that inspects a sample of sites to confirm that the details are being used correctly. CURRENTLY NOT AVAILABLE ANYWHERE

26

Criteria 4Quality & Commisioning


Which details to use? Default# Accredited# XtrathermJunction L ψ ψ ψ

Lintels 13.97 x 1.00 0.30 0.01Sill 12.17 x 0.08 0.04 0.04Jamb 29.55 x 0.10 0.05 0.00Ground Floor 19.60 x 0.32 0.16 0.16Intermediate Floor 19.60 x 0.14 0.07 0.06Corner 10.20 x 0.18 0.09 0.05Corner inverted 20.40 x -0.18 -0.09 -0.05Ceiling (Insulation at eaves) 11.00 x 0.12 0.06 0.05Ceiling (Insulation at gables) 8.90 x 0.48 0.24 0.20Party Ground floor 8.90 x 0.08 0.08 0.08Party wall Intermediate floor 8.90 x 0.00 0.00 0.00Party Ceiling (Insulation at ceiling level) 8.90 x 0.12 0.12 0.12Total (L x ψ) 32.45 14.32 8.54Y Value (L x ψ / Total Area) 0.17 0.08 0.04

Semi Detached House TER 18.24Total Envelope Area = 190.580



28

RESULTS TER DER

18.24 18.24

Element Spec Result


0.20



Glazing Double 1.6

Doors Double 1.6


Other

Block Dense

Mech Ventilation None

Renewables YES 2m2 Solar HW

Permeability 5

Bridging Y value

Accredited 0.08

Compliance 2Accredited detailing



29

RESULTS TER DER

18.24 18.24

Element Spec Result


0.20



Glazing Double 1.6

Doors Double 1.6


Other

Block Dense

Mech Ventilation

Required

Renewables YES 5m2 Solar HW?????

Permeability <4

Bridging Y value Default 0.15

Compliance 3Default detailing


30

THERMAL BRIDGING – What are Accredited/Acceptable Details

Thermal BridgingTaking advantage

31

Xtratherm Accredited Detailing

Based on UK & NI Accredited and

Acceptable Details – same inspection and

reporting regime.

Keep it simple.


Where’s the end game?


Fabric Energy Efficiency Standard (FEES or ‘full FEES’). …..the Government has committed to introducing a fabric standard for zero carbon homes, but up until now has not stated when or how such a standard will start to be introduced ….

33

CSH Updated

Oct 2

010‘’The adoption of the Code for Sustainable Homes states the intended direction of future changes to Part L of the Building Regulations, which will make dramatic improvementsin reducing CO2.


New for 2010 CSH

34

35

The metric is kWh/m²/yr covering space heating and space cooling energy demand (modelled utilising a notional dwelling assuming natural ventilation and

excluding any internal gains from the domestic hot water system)

LOOK FOR FEEs SCORE ON YOUR SAPXtratherm – Expect More

37

Crest Nicholson - Epsom

Barrett Const - Corby


39

• Thermal Bridges – such as at stepped cavity trays have until now been ignored – they MUST now be accounted for.

Insulate behind the line of trays – How does pumped insulation reach these areas?


41

Why Xtratherm?

BBA U-value and Condensation risk analysis competency scheme x 4

ISO 9001 | Quality Management SystemsISO 14001| Environmental ManagementOHSAS 18000 | Occupational Health & Safety

Technical Services


[email protected]@xtratherm.com


thermal bridges in new dwellings..... accredited details – designing & detailing for...

Documents

floors xtratherm

ceilings xtratherm

good detailing xtratherm

uvalue yvalue

roofs slope xtratherm

uvalue penalty

sap criteria

carbon standard fees