Building Regulations Part L1A (2006)

Transcription

1 PART L1A GUIDE ENGLAND & WALES MAY 2006 High performance insulation for new mixed development housing Building Regulations Part L1A (2006) COST EFFECTIVE THERMAL SOLUTIONS House Type A House Type B House Type D Semi detached 93m 2 TER Apartment (top) 59m 2 TER Detached 160m 2 TER House Type C Semi detached 96m 2 TER Efficient fabric insulation - Lower energy demands

2 Approved Document L1A Where do we start? Reduce the Energy Demand by providing cost effective energy efficient Thin-R Choosing the right insulation for your project is a vital step when building dwellings to the new Part L1A regulations which will result in energy efficient, comfortable dwellings. This guide provides the solutions to meet the more stringent requirements of the Building Regulations using Xtratherm Thin-R high performance insulation, providing lower U-values in walls, floors and roofs without changing traditional build methods. Rigid Thermal Insulation Further comprehensive information on regulation changes is available in a series of technical briefing notes available from Xtratherm, contact Technical Support for copies. 02

3 Save Energy Save Money Save Space Thin-R The amended Building Regulations Part L1A for New Dwellings came into force on the 6th April Submissions to Building Control from that date need to comply - the requirements are proving more complex than any previous amendments. fabric insulation The revision aims to cut CO 2 emissions in dwellings by around 20% on the previous Part L 2002, and allow for the introduction of the EPBD (Energy Performance of Buildings Directive - Energy Labelling). The directive only allows for a wholebuilding approach based on carbon dioxide emissions, setting an overall Energy Performance target for new houses. This approach allows greater flexibility in the design but with that flexibility, the complexity of available solutions leaves the design vulnerable to failure. The Elemental approach to compliance is no longer available, a greater understanding of the principals of insulation in energy conservation is required in the context of the whole building approach. The starting point for reducing emissions is to provide a well insulated building fabric - this reduces the energy requirements and therefore CO 2 emissions. Whilst other energy saving measures, such as efficient glazing, boilers and renewables will have to be replaced eventually (with perhaps less efficient alternatives) the insulation will deliver energy savings throughout the life of the building. Mixed development sites in England and Wales typically involve a number of house types, each with individual characteristics. We have taken this into consideration when formulating our specifications for the house types illustrated. Standardising thickness requirements for the insulation on a site is important. In the following examples we have achieved compliance using indicative values for all elements, allowing consistency in material specification for all house types thus reducing wastage and potential errors. Improving the air tightness of a design will improve the energy performance, and as experience and good practice develops in relation to air permeability, it might be relied upon to play a more significant part of the energy efficient design. However, because of the uncertainties at present, using the default value of 10 air changes per hour at design stage builds in a Margin of error should a better performance be measured on site. Relying on a more ambitious figure could lead to expensive remedial work having to be completed if the site test differs from an ambitious design calculation figure. Using the Xtratherm default values shown, and allowing for realistic air permeability with cost effective improvements to boiler efficiency and heating controls, the Xtratherm house types illustrated achieve compliance in an efficient, practical and cost effective manner. XTRATHERM DEFAULT VALUES U-VALUE W/m 2 K Floors 0.22 Walls 0.27 Roof - Slope 0.20 Roof -Ceiling

4 CO 2 targets The 20% goal Compliance with Part L1A is dependent on achieving a CO 2 target emission rate lower than that of a Notional Building of the same size and shape as the designed building, using standardised energy performance, conditions of occupancy and weather conditions. Xtratherm Warm-R Eco-House Standard The goal for the designer or the developer is to improve the energy efficiency of the notional building and thus cut the CO 2 emissions by 20% - this new CO 2 emissions figure becomes the Target Emissions Rate (TER). The actual specification of the house being designed or built will provide the Dwellings Emissions Rate (DER), and should reflect the actual house as built taking into account any changes to the design that has been made during construction and the actual measured air permeability. For compehensive guidance on energy efficient design see the Xtratherm Warm-R Guide to building your own home. This final calculation should be submitted to Building Control upon completion. If the DER is below the TER the building will comply with the 1st Criteria (see opposite). Steps to Energy Efficiency and achieving the 20% Consideration should be given to the following inputs when seeking to provide energy efficient designs and thereby reducing CO 2 emissions: Increased fabric insulation with reduced thermal bridging. Improved air-tightness. Controlled ventilation. Efficient heating and hot water systems. Responsive heating and lighting controls. Efficient lighting and fittings that do not permit the use of non-efficient lighting. Input from Low and Zero Carbon Technologies. (See renewable section) An inexhaustible combination of energy efficient measures are available to the specification builder/designer to meet the new Part L Regulations. However, re-arranging these combinations on a site of different house types with different energy requirements, will lead to confusion and costly errors being made. Showing compliance with an over-ambitious design might result in failure when finished measurements taken are less robust than planned for, leading to expensive remedial costs. A builder/designer should aim to achieve an effective building fabric first - lowering the energy target required - then look at how that energy is supplied 04 FOR TECHNICAL SUPPORT CALL

5 Save Energy Save Money Save Space Thin-R 5 criteria to compliance For new dwellings, Approved Document L1A presents five criteria for demonstrating compliance with the new regulations. 1 Calculate CO 2 emissions for the proposed building (using SAP 2005). The Dwelling Carbon Dioxide Emissions Rate (DER, kg/m 2 /yr) must not exceed a Target Carbon Dioxide Emissions Rate (TER, kg/m 2 /yr). 2 Keep within Design limits. Limits for the building fabric and services must not exceed limits set within the document L1A. In reality, building fabric and services with significantly better performance than these design limits will be required to meet the carbon dioxide emissions target. Building fabric - maximum thermal transmittances (U values) for wall, floors & roofs. Approved robust details must be used (see right). Air permeability of the building fabric must not exceed 10 m 3 /m 2 hr, in a 50 Pa pressure test. Minimum efficiencies for heating appliances, minimum controls, and minimum insulation for primary pipework, warm air ducts and hot water storage cylinders. Ventilation equipment, there are design limits expressed in terms of worst acceptable specific fan-power and heat recovery efficiency. Fixed internal lighting must include at least one fitting that will accept only energy efficient lamps (efficacy > 40 lm/w) per 25 m 2 of floorspace or per four fixed lighting outlets (whichever is the greater). Fixed external lighting must either have controls that switch off the lamps (maximum 150 W/lamp) when there is sufficient daylight and when lighting is not required at night, or must use fittings that accept only energy efficient lamps. As well as achieving Target U-values, the revision has placed great emphasis on the Continuity of Insulation in the form of Robust Detailing. 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 window and doors surrounds. Details in the publication Limiting thermal bridging and air leakage: robust construction details for dwellings and similar buildings should be followed, or details should be measured to BRE IP1/06. 3 Limit Solar Gains in Summer (Over Heating) There must not be a high risk of the dwelling overheating in warm summer weather. This is demonstrated by a calculation included in the SAP 2005 energy rating calculation, which grades the risk of summer overheating. Designs with High risk do not meet the requirement. A heavy weight (Thermal Mass) building using brick/block is less likely to over heat and is easier to control. 4 Check Quality of Construction and commissioning of building services. There must be no significant thermal bridges. Accredited Robust Construction Details should be used and recorded on site. Pressure tests to establish the tested air permeability must be completed, and actual results used in a revised and final SAP submitted to Building Control. 5 Provide Information to the home owner or occupants of dwellings with operating and maintenance instructions for the building services (heating and hot water systems, and any ventilation or air conditioning systems), to allow for energy efficient operation of the building. See for installation animations 05

6 House Type A (TER 21.17) Detached house 160m 2 TER DER Results shown are specific to the house designs illustrated. There is an inexhaustible combination of energy efficient measures available to the specification builder/designer to meet the new Part L Regulations. Individual designs must be analysed and appraised on practicality of build and cost considerations. All U-values calculations must be calculated in accordance with BR443 Conventions for U-value Calculation SPECIFICATION U-VALUE W/m 2 K Floors 0.22 Walls 0.27 Roof - Slope 0.20 Roof -Ceiling 0.14 Glazing Performance 2.0 Other Inputs Air Changes/Hr 10 Boiler Efficiency 93% VALUE DER kg/m 2 /yr SAP Rating 81 CO 2 IMPROVEMENT 21% Secondary Heating Heating Controls Robust Detailing None Specified Separate time & temp zones 0.08 (Default) AN ALTERNATIVE OPTION FOR REACHING TER WITH INSULATION AS SPECIFIED VALUE VALUE Reduce Boiler efficiency 87% Improve Air Permeability ac/hr 8 Improve Glazing Performance 1.8 New DER New SAP Rating 81 CO 2 Improvement 21% DETACHED DWELLING - House Type A, 160m 2 06 FOR TECHNICAL SUPPORT CALL

7 Thin-R Detached House 160m 2 Specification SLOPE ROOF INSULATION (Xtratherm Pitched Roof) Hybrid roof using a vapour permeable underlay with 25mm void under. Rafters at 600mm c/s. Xtratherm PR 100mm XT/PR100 Between Rafters Xtratherm PR 25mm XT/PR25 Below Rafters 0.20 W/m 2 K WALL INSULATION (Xtratherm Cavity Wall) Partial Fill Cavity Wall - light weight block with dot & dab plasterboard internal finish. Xtratherm CW 50mm XT/CWTG W/m 2 K FLOOR INSULATION (Xtratherm Under Floor) Suspended ground floor P/A 0.58 Xtratherm UF 75mm XT/UF W/m 2 K NOTE 75mm of insulation thickness is optimum for this floor type. No requirement for brickwork coursing to be adjusted. See for installation animations 07

8 House Type B (TER 22.59) Semi-detached house 93m 2 TER DER Results shown are specific to the house designs illustrated. There is an inexhaustible combination of energy efficient measures available to the specification builder/designer to meet the new Part L Regulations. Individual designs must be analysed and appraised on practicality of build and cost considerations. All U-values calculations must be calculated in accordance with BR443 Conventions for U-value Calculation. SPECIFICATION U-VALUE W/m2K Floors 0.22 Walls 0.27 Roof -Ceiling 0.14 Glazing Performance 2.0 VALUE DER kg/m 2 /yr SAP Rating 82 CO 2 IMPROVEMENT 20% Other Inputs Air Changes/Hr 10 Boiler Efficiency 93% Secondary Heating Heating Controls Robust Detailing None Specified Separate time & temp zones 0.08 (Default) AN ALTERNATIVE OPTION FOR REACHING TER WITH INSULATION AS SPECIFIED VALUE VALUE Reduce Boiler efficiency 90% Improve Glazing Performance 1.8 New DER New SAP Rating 82 CO 2 Improvement 20% SEMI-DETACHED DWELLING - House Type B, 93m 2 08 FOR TECHNICAL SUPPORT CALL

9 Save Energy Save Money Save Space Thin-R Semi-detached house 93m 2 Specification ROOF INSULATION (Ceiling Fibre) 2 Layers Fibre insulation 100mm between joists and 200mm over. Fibre 100mm Between Joists Fibre 200mm Over Joists 0.14 W/m 2 K Placing fibre glass between AND over the joists hides the top of the joist and may lead to health and safety concerns when the roof space is being accessed. Placing a layer of Xtratherm to the underside of the joist before the plasterboard is fixed. allows for the roof space to be accessed in a safe manner - leaving the top of the joists exposed, allowing the roof space to be used for storage. WALL INSULATION (Xtratherm Cavity Wall) Partial Fill Cavity Wall - Dense Block with dot & dab plasterboard finish internal finish. Xtratherm CWTG 60mm XT/CWTG W/m 2 K FLOOR INSULATION (Xtratherm Under Floor) Suspended ground floor P/A 0.58 Xtratherm UF 75mm XT/UF W/m 2 K NOTE 75mm of insulation thickness is optimum for this floor type. No requirement for brickwork coursing having to be adjusted. See for installation animations 09

10 House Type C (TER 21.62) Mid-terrace house 96m 2 TER DER Results shown are specific to the house designs illustrated. There is an inexhaustible combination of energy efficient measures available to the specification builder/designer to meet the new Part L Regulations. Individual designs must be analysed and appraised on practicality of build and cost considerations. All U-values calculations must be calculated in accordance with BR443 Conventions for U-value Calculation SPECIFICATION U-VALUE W/m2K Floors 0.20 Walls 0.27 Roof - Slope 0.20 Glazing Performance 2.0 VALUE DER kg/m 2 /yr SAP Rating 83 CO 2 IMPROVEMENT 20% Other Inputs Air Changes/Hr 10 Boiler Efficiency 93% Secondary Heating Heating Controls Robust Detailing None Specified Separate time & temp zones 0.08 (Default) AN ALTERNATIVE OPTION FOR REACHING TER WITH INSULATION AS SPECIFIED VALUE VALUE Reduce Boiler efficiency 87% Improve Glazing Performance 1.5 New DER New SAP Rating 83 CO 2 Improvement 20% MID-TERRACE DWELLING - House Type C, 96m 2 10 FOR TECHNICAL SUPPORT CALL

11 Thin-R Mid-terrace House 96m 2 Specification ROOF INSULATION (Sloped Pitched Roof) Hybrid roof using a vapour permeable underlay with 25mm void under. Rafters at 600mm c/s Xtratherm PR 100mm XT/PR100 Between Rafters Xtratherm PR 25mm XT/PR25 Below Rafters 0.20 W/m 2 K WALL INSULATION (Xtratherm Cavity Wall) Partial Fill Cavity Wall - Dense Block with dot & dab plasterboard finish internal finish. Xtratherm CWTG 60mm XT/CWTG W/m 2 K FLOOR INSULATION (Xtratherm Under Floor) Solid ground floor P/A 0.25 Xtratherm UF 75mm XT/UF W/m 2 K NOTE 75mm of insulation thickness is optimum for this floor type. Increase of thickness will result in brickwork coursing to be adjusted. See for installation animations 11

12 House Type D (TER 25.44) Apartment top floor 59m 2 TER DER Results shown are specific to the house designs illustrated. There is an inexhaustible combination of energy efficient measures available to the specification builder/designer to meet the new Part L Regulations. Individual designs must be analysed and appraised on practicality of build and cost considerations. All U-values calculations must be calculated in accordance with BR443 Conventions for U-value Calculation. SPECIFICATION U-VALUE W/m2K Floors 0.22 Walls 0.27 Roof - Ceiling 0.14 Glazing Performance 2.0 VALUE DER kg/m 2 /yr SAP Rating 83 CO 2 IMPROVEMENT 20% Other Inputs Air Changes/Hr 10 Boiler Efficiency 93% Secondary Heating Heating Controls Robust Detailing None Specified Separate time & temp zones 0.08 (Default) AN ALTERNATIVE OPTION FOR REACHING TER WITH INSULATION AS SPECIFIED VALUE VALUE Reduce Boiler efficiency 87% Improve Air Tightness 6 ac/hr New DER New SAP Rating 83 CO 2 Improvement 20% TOP FLOOR APARTMENT - House Type D, 59m 2 12 FOR TECHNICAL SUPPORT CALL

13 Thin-R Apartment Top Floor 59m 2 Specification ROOF INSULATION (Ceiling Fibre) 2 Layers Fibre insulation 100mm between joists and 200mm over Fibre 100mm Between Joists Fibre 200mm Over Joists 0.14 W/m 2 K Placing fibre glass between AND over the joists hides the top of the joist and may lead to health and safety concerns when the roof space is being accessed. Placing a layer of Xtratherm to the underside of the joist before the plasterboard is fixed. allows for the roof space to be accessed in a safe manner - leaving the top of the joists exposed, allowing the roof space to be used for storage. WALL INSULATION (Xtratherm Cavity Wall) Partial Fill Cavity Wall - Dense Block with dot & dab plasterboard finish internal finish. Xtratherm CWTG 60mm XT/CWTG W/m 2 K FLOOR INSULATION Floor is not included in this calculation as it divides two heated areas, and does not require insulation unless underfloor heating is being used. See for installation animations 13

14 Summary U-value calculations to BS EN ISO:6946 For Technical Support call The combinations available to the designer/builder to achieve the required Target Emissions Rate (TER) are inexhaustable. The specifications for the house types shown, are practical, cost effective solutions that can be relied upon - well insulated building fabric, with efficient boilers and controls. Maintaining consistency in fabric materials simplifies purchase of materials on site for all house types. Using fabric U-values less than those indicated may necessitate the inclusion of more costly technologies and better than normal site practice from sub-contractors to improve air permeability. The goal of achieving best practice in air-tightness should be strived for, but not depended on at this stage to achieve compliance. Detailing in accordance with the Xtratherm Guide to Robust Detailing and the BSRIA Paper 11/ should be consulted. House Type A TER DER Walls Floors Roof SPECIFICATION 50mm Xtratherm 75mm Xtratherm 100/25mm Xtratherm House Type B TER DER Walls Floors Roof SPECIFICATION 60mm Xtratherm 75mm Xtratherm 300mm Fibre* House Type C TER DER Walls Floors Roof SPECIFICATION 60mm Xtratherm 75mm Xtratherm 100/25mm Xtratherm House Type D TER DER Walls Floors Roof SPECIFICATION 60mm Xtratherm N/A 300mm Fibre* 14 *Placing fibre glass between AND over the joists hides the top of the joist and may lead to health and safety concerns when the roof space is being accessed. Placing a layer of Xtratherm to the underside of the joist before the plasterboard is fixed allows for the roof space to be accessed in a safe manner - leaving the top of the joists exposed, allowing the roof space to be used for storage.

15 Save Energy Save Money Save Space Thin-R FAQs When did the revised Part L come into effect? The Part L Revision came into effect on April 6th all plans submitted to Building Control for approval from that date need to meet the new standards. What is the TER & the DER? The TER is the TARGET (CO 2 ) EMISSIONS RATE and is the maximum permitable amount of CO 2 that your design is permitted to create when built. The DER is the ACTUAL (CO 2 ) EMISSIONS RATE of the design. Both the TER & the DER are calculated by SAP 2005, and both are required for building control approval. Can I use the worst allowable U-values quoted in the Part L Document? Much better U-values than 0.35 W/m 2 K for Walls and 0.25 W/m 2 K for floors and roofs can be achieved within traditional contruction methods by simply substituting inefficient insulation materials with Xtratherm PIR. Many traditional insulations will just achieve the worst case U-values - resulting in a lesser performing fabric AND will have to be compensated for by other less cost effective measures. What is Robust Detailing? The Part L Revision places great emphasis on Continuity of Insulation and states that all thermal bridging, or breaks in the insulation layer, be accounted for in the calculations. Xtratherm Insulation Systems, that include Tongued & Grooved wall insulation (T&G jointing is recommended as best practice by the EST) and Floor Perimeter Insulation, have undergone testing by the University of Caledonia and have been found to perform favourably over the default figures given in SAP 2005 for vulnerable junctions. Using Xtratherm Robust Details will ensure an improvement in the SAP Calculation (See the Xtratherm Technical Briefing Note: Xtratherm s Guide to Robust Detailing). What Air Permeability should I design for? Improving the air tightness of a design will improve the energy performance, and as experience and good practice develops in relation to air permeability, it might be relied upon to play a more significant part of the energy efficient design. However, because continuity of site practice cannot be relied upon (variation in teams of sub-contractors and house types for example), using the default value of 10 air changes per hour at design stage builds in a Margin of error should a better performance happen to be measured on site. Relying on a more ambitious figure could lead to expensive remedial work having to be completed if the site test differs from an ambitious design calculation figure. Should I provide insulation at ceiling level - or insulate the rafter slope? Indicative values of 0.14 W/m 2 K have been suggested by many manufacturers as being the required insulation target at ceiling level. This will typically require 300mm of fibrous material to be laid between and OVER the joists, leading to health and safety difficulties when accessing the loft area and necessitate the compression of the fibre at the eaves to allow for ventilation, which leads to thermal bridging and increased condensation risk. Insulating the roof area at the rafter line has the advantage of freeing up the roof area to be used for storage or indeed valuable living space. Why Partial Fill cavity wall insulation? The main goal for the Part L Revision is to reduce the CO 2 pollution caused by new buildings in the UK. These emissions are leading directly to Global Warming, a consequence of which is heavier, more persistent wind driven rain becoming more common in our weather patterns. The most effective protection from wind driven rain is maintaining an air space between the inside of buildings and the outer skin. Xtratherm Partial Fill Cavity insulation has tongued and grooved edges to provide the Robust Jointing specifically asked for under Part L. The advantage of being able to inspect the insulation as it is being built into the building fabric offers reassurance that this continuity is achieved, and indeed enhanced when used as a system with the preformed corner and reveal panels that are provided by Xtratherm. Why 75mm Xtratherm in the floors? Xtratherm Thin-R provides the most efficient means of insulating a floor to the new 2006 standards. Typical floors in the UK have a Perimeter/Area ratio of between 0.4 and mm of Xtratherm will achieve a U-value of between 0.20 and 0.22 W/m 2 K in this range achieving the higher standards within traditional build practices and tie in with brick coursing. Should my design include renewable technologies? Using Low and Zero Carbon Technologies is beneficial in cutting the amount of CO 2 produced by the building, but should be considered only once that energy requirement has been minimised through good design; ie; a well insulated fabric that utilises solar gains and thermal mass to make use of the natural resources (Solar Gains) that are already available to all homes. A well insulated building fabric will last for the life of the building, most other technologies, including glazing, will have to be replaced in a relatively short period of time. Guidance on such systems can be found in the ODPM publication Low or Zero Carbon Energy Sources: Strategic Guide. Will all houses on a site have to be pressure tested? Building Control may ask for one dwelling of each house type to be pressure tested upon completion. If the development is less than 2 dwellings, a default figure of 15 ac/hr can be used when calculating the DER, or if the developer has tested a similar house type in the past 12 months, that test result can be used. Further comprehensive guidance on the new building regulations and best practice advice can be downloaded from the website: 15

16 The Xtratherm range of high performance insulation boards provides the complete solution for newbuild and refurbishment. Thin-R/PR Pitched Roof Effective insulation of roof area Reduced insulation thickness Reduces thermal bridging Minimizes intrusion into living area Suitable for insulating: Ventilated Pitched Roof Warm Pitched Roof Hybrid Pitched Roof Thin-R/TP Flat Roof Insulation & decking in one fix For new & refurbishment roofs Easy to handle & install Rapid weather proofing Suitable for insulating: New Flat Roof Refurbished Flat Roof Thermal Decking Thin-R/CW Cavity Wall Robust tongue & groove jointing Clear cavity maintained No exposure restrictions Low emissivity foil facings Extra thermal performance Suitable for insulating: Partial Fill Cavity Walls Thin-R/TL Thermal Lining High thermal performance Drylining & insulation in one fix Shorter drying time Responsive insulation system Suitable for insulating: Masonry Walls Sloped Rafters Ceilings Thin-R/UF Under Floor Extra thermal performance Suitable for under floor heating Reduced insulation thickness High compressive strength Suitable for insulating: Solid Block Floor Under Screed Floor Suspended Timber Floor Technical Support The Xtratherm Technical Support team provide a single point of contact to offer assistance on a wide range of issues for both the Designer and Builder and can be contacted by phone, fax or . Full details of all Xtratherm products, along with full technical literature can be downloaded from the web site at: Good workmanship and appropriate site procedures are necessary to achieve expected thermal and airtightness performance. The example calculations are indicative only. Default values for components and cavities have been used, for specific U-value calculations contact Xtratherm Technical Support. Comprehensive guidance on installation should be consulted. Xtratherm technical literature and Agrèment certification is available for download on the Xtratherm website. The information contained in this publication is, to the best of our knowledge, true and accurate but any recommendations or suggestions which may be made are without guarantee since the conditions of use are beyond our control. Zero O D P Zero Ozone Depletion Potential Xtratherm UK Limited Park Road Holmewood Chesterfield Derbyshire S42 5UY Tel: Fax: info@xtratherm.com