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ADF Update Service

July 2009

Changes To Standard Assessment Procedure And Building Regulations Out For Consultation

The Government has put proposed changes to the Standard Assessment Procedure (SAP), used to assess the energy performance of dwellings, out for consultation.

It has also put its timetabled revisions to both Part F (Ventilation) and Part L (Conservation of Fuel and Power) out for consultation.

Part F (Ventilation)

The main changes to the Approved Document, which have been proposed by the Government and issued for consultation, are:

  • All ventilation systems (both natural and mechanical) should be inspected and commissioned. Continuously running mechanical ventilation systems will become controlled systems .
  • For mechanical ventilation systems installed in new dwellings, air flow rates should be measured on-site as part of the commissioning process. This applies to intermittently-used extract fans and cooker hoods, as well as continuously running systems.
  • Where continuously running ventilation systems for dwellings are specified, these should have been type tested and shown to meet specified noise limits.
  • The owner/occupier should be given sufficient information about the ventilation system and its maintenance requirements so that the ventilation system can be operated to provide adequate air flow. This should apply to natural and mechanical systems in new dwellings.
  • Guidance has now been included for airtight homes. In all cases, this results in greater ventilation provisions for dwellings with design air permeability tighter than or equal to 5 m³/(h.m²) at 50 Pa.
  • The infiltration allowance for leakier homes is now the same for single-storey and multi-storey dwellings, resulting in increased ventilation provisions for single-storey dwellings up to four storeys above the ground.
  • The guidance for ventilation has been clarified when windows are replaced in an existing dwelling with the possibility that trickle vents should be installed in all replacement windows.
  • A separate guidance document has been produced covering installation and commissioning of domestic ventilation systems (and the 2006 Appendices D and E have therefore been removed).
Part L (Conservation of Fuel and Power)

The main areas targeted by the proposed changes to the Approved Document, which the Government has issued for consultation, are:

  • Improving design, particularly detailed design, so that designs are more buildable, design information easier to apply on site and the calculation of heat loss characteristics and systems performance is more robust.
  • Improving construction so that insulation is well fitted, airtightness targets are achieved and systems are installed to ensure that designed performance is realised, ensuring that both design and construction processes are subject to more rigorous performance control involving effective measurement and inspection, so as to provide feedback in time to correct design and construction as work proceeds and to improve processes from one development to another.
  • Improving modelling processes and regulatory guidance so that there is a close fit between compliance and performance.
  • Improving building control processes so that general levels of performance are identified and feedback is provided so that improvements can be made.
  • Improving understanding of the design and construction of low and zero carbon buildings at all levels within the industry from designer and energy specialist to the site operative.
  • Trickle vents should be temporarily sealed during airtightness testing.

As you would expect the proposed changes to Part L and Part F are interlinked and Titon would advise reading the documents together to gain a better understanding of the overall changes to the Regulations.

However, if you have specific questions, or would like to talk through in greater detail any of the proposals which are being consulted on, please do get in touch. You can contact us at experts@partf.co.uk.

Standard Assessment Procedure (SAP)

SAP is used by the Government to demonstrate compliance with the building regulations and to ensure standards for new homes. It is also key to the delivery of the Code for Sustainable Homes.

When the Building Regulations were last revised in 2005, a timetable was put in place to ensure they are revised on a regular basis. The consultation on SAP will be followed by the consultation on the proposed 2010 revisions to the Regulations. All the revisions are to enable the Government to meet its target for delivering zero carbon homes in 2016.

The Department for Energy and Climate Change has reviewed SAP and has suggested that a number of improvements are required to deal with extremely low energy dwellings as well as introducing general improvements now that SAP has been in place for nearly five years.

The consultation will cover eight key areas:

  • Adoption of a monthly calculation to consider energy balance for low energy buildings more regularly throughout the year
  • Use of updated weather data currently long term data from the 1960s and 70s is used
  • Carbon dioxide emission factors more comprehensive factors across all fuel types
  • Boiler systems distinctions between summer and winter, fuel types, controls etc
  • Inclusion of thermal mass and cooling calculations
  • Hot water energy use looking at the volume of hot water used
  • Auxiliary energy use lights, appliances and cooking and internal heat gains
  • Number of occupants related to floor area

All of the relevant documents can be accessed at www.bre.co.uk/sap2009 and further detailed research documents on a number of specific topics are available on request to sap2009@bre.co.uk.

According to the BRE, the reviews of SAP that are envisaged in 2012 and 2015 will primarily address improvements to the procedure to take account of developments in technology and to incorporate experience gained from the application of SAP to very low energy dwellings. Improvements may be possible also through the availability of new data (for example, there is a proposal for an Energy Follow up Survey to the English Housing Survey to take place in 2011, and this could provide useful data for refining some aspects of SAP).

We will keep this website up to date on all issues related to the SAP consultation, as well as the forthcoming consultations on the revisions to the Building Regulations.

If you have any questions, please do contact us at experts@partf.co.uk.

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