Part L 2013 Compliance

The latest changes to Part L of the Building Regulations, have wide ranging implications for the entire build environment industry.

With over a decade of experience in providing Part L related assessment and consultancy services, Stroma Tech can help you to understand the Part L 2013 changes and how they will affect your Part L compliance strategy.


Key Changes to Part L1A 2013 and Part L2A 2013

Part L 1A 2013 – New Dwellings

Approved Document L1A 2013 introduces new compliance requirements for new dwellings, with the most significant changes occurring within Criterion 1.  A consolidation of Part L 2010’s move towards a focus on fabric performance, and alignment with the requirements for Zero Carbon Homes.

The main changes are:

  • 6% reduction in CO2 emissions compared to the 2010 standards.
  • Criterion 1 requires compliance with both a Target Emission Rate (TER) and a new Target Fabric Energy Efficiency (TFEE), with the TFEE to be compared with a new Dwelling Fabric Energy Efficiency (DFEE).   The requirement establishes a minimum standard for thermal performance within the dwelling fabric and will act as a foundation for the move towards Zero Carbon Homes in 2016.
  • SAP 2012 is used to calculate the CO2 emission rates: TER (Target Emissions Rate) & DER (Dwelling Emission Rate) as well as the TFEE (Target Fabric Energy Efficiency & DFEE (Dwelling Fabric Energy Efficiency).
  • The new Standard Assessment Procedure methodology (SAP 2012) sees comparison against a notional dwelling designed to an ‘Elemental Recipe’.
  • Within Criterion 2, the fabric performance backstops remain unchanged from Approved Document L1A 2010; however, the ‘Elemental Recipe’ now guides design standards and is based on significantly better performance than the minimum standards.
  • Criterion 3 now considers both Solar and Heat gains, affecting design considerations for dwelling overheating.

The Elemental Recipe

The new ‘elemental recipe’ introduced within Approved Document L1A 2013 is based on a set fabric standard and service specification, which:

  • Sets the TER and TFEE
  • Is a compliant solution in itself (meets Criteria 1 & 2).
  • Is a substantial improvement over Criterion 2 minimum performance standards
  • Provides a reasonable starting point to establish your own chosen design solution(s).

It approximately meets the Zero Carbon Hub’s Fabric Energy Efficiency Specification (FEES) – expected to become a mandatory standard by 2016

Part L 2A 2013 – New Non-Dwellings

The key changes that designers and assessors should be aware of within Part L2A 2013 are:

  • 9% reduction in CO2 emissions compared to the 2010 standards.
  • Criterion 2 introduces a LENI (Lighting Energy Numeric Indicator) methodology to measure lighting design compliance.
  • The Notional Specification remains key to compliance; within Part L2A 2013
  • Limiting U-values and air permeability are unchanged but there are some minor changes to limiting values for services.

In contrast with Part L1A for dwellings, there has not been an introduction of a Target Fabric Energy Efficiency (TFEE), as compliance with standards for non-domestic buildings already requires a holistic approach to fabric and services to see success.

Zero Carbon is on the horizon, but with a more distant target of 2019 and with no clear route established by Government as yet, there has been no attempt to realign the requirements of Building Regulations Part L2A with these future standards.

Part L 2013 Compliance Services

Compliance experts Stroma Tech deliver a wide range of Part L compliance services:

  • Part L 2013 compliance consultancy workshops and seminar programme
  • SAP Assessments
  • SBEM Assessments
  • Dynamic Simulation Modelling
  • Thermal Bridging Calculations
  • Air Tightness Testing & Consultancy


Here you will find some of our case studies.
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Titanic Belfast, The Signature Building
Phil Carr