Thermal Performance: Part L1A, SAP and the new Fabric Energy
Efficiency Standard (FEES)
Thermal Performance: Part L1A
The 2016 Part L1A zero carbon requirement for new buildings is
only a few years away and to help the transition, there will be an
interim set of revisions to the Regulations in 2013. These will act
as a stepping stone to the challenging performance requirements to
come and among other changes, are likely to place more emphasis on
narrowing the gap between ‘as designed’ and ‘as built’
performance.
Whilst the 2013 Part L requirements are yet to be decided,
research undertaken by The Concrete Centre, in partnership with
producers of masonry and concrete products, has demonstrated that
existing heavyweight solutions will continue to perform well in the
run up to 2016 and beyond. In fact, some of the inherent properties
of concrete and masonry become increasingly beneficial as we move
towards ever higher standards of fabric energy efficiency. These
include the durable air barrier provided by concrete/masonry
construction, which helps ensure a low air
leakage rate can be maintained over the building life. In
addition, the thermal mass provided by
concrete and masonry has an increasingly important role to play as
we move towards ever higher standards of fabric energy
efficiency.
SAP and the new Fabric Energy Efficiency Standard (FEES)
Thermal mass is now accounted for in SAP, which is short for
‘Standard Assessment Procedure’, and is the official government
tool for calculating the CO2 emissions from housing. SAP provides
the basis for demonstrating compliance with Part L1A. The
introduction of thermal mass into SAP is in response to European
legislation and the need to improve the tool’s ability to
account for year-round fabric performance. It has also helped
facilitate the development of a new Fabric Energy Efficiency
Standard (FEES), which takes account of year round dwelling
performance, including the ability of thermal mass to reduce the
cooling load in summer and heating load
in winter. Along with Part L1A,
compliance with the FEES will be demonstrated using SAP, and is
measured in terms of a dwelling’s combined, annual heating and
cooling load in kWh/m2, for which limits have been set. FEES
compliance will be mandatory from 2016 at the latest (alongside the
2016 edition of Part L), and there is a possibility of a full or
partial launch in 2013. More detail on changes to Part L, FEES and
the relationship between the two are included in our publication
entitled
'Thermal Performance: Part L1A – the road to 2016 (zero carbon);
fabric and services'.