Amendments outline
Amendments to Part L of the building regulations were published in 2011; the amendments consolidated all Part L amendments since 1997 and created the new TGD L on the Conservation of Fuel and Energy – Dwellings 2011. This Appendix outlines the provisions of TGD L -- Dwellings 2011 insofar as they relate to the issue of air leakage (air permeability).
These changes to the building regulations have the aim of taking further steps towards achieving carbon neutral housing, which in turn will help reduce Ireland's greenhouse gas emissions. The air permeability of buildings is one of the included provisions that aims to reduce energy consumption and CO~2~ emissions.
Key requirements
Regulation L3 [c] requires that a building should be constructed in a way that minimizes the heat losses through it but makes use of the available gains. Air permeability should be of high concern when designing and constructing a building to limit the amount of heat loss.
Achieving compliance
Regulation L3 [a] states that the primary energy use and CO~2~ emissions of a newly constructed dwelling must not exceed the set-out levels when they have been calculated by the DEAP.
Building Regulations 2011 - Technical Guidance Document
The Building Regulations require that all newly constructed dwellings be subjected to an Air Permeability Pressure Test and should have a reasonable upper limit air permeability of 7 m^7^(h.m^2^) that is the quantity of air (in m^3^) that leaks into or out of the dwelling per hour divided by the envelope area (in m^2^) of the building fabric at 50 Pa (Pa or Pascals -- standard unit of pressure measurement between inside the dwelling environment and outside).
As explained, a series of factors need to be addressed in order to limit the use of fossil fuel energy and CO~2~ emissions arising from the operation of the dwelling. The upper limit air permeability performance level of 7 m^7^(h.m^2^) is a backstop minimum performance level. In order to comply with the requirements of Regulation L1 in relation to reduced energy consumption and CO~2~ emissions, it may be necessary to improve on this performance level.
