Building Sciences

Air Leakage Consultancy

Part L Compliance

Part L of the Building Regulations (England and Wales, 2006) sets minimum performance standards with regard to building fabric in all new and substantially refurbished buildings (or a sample thereof). Our primary remit will include fabric airtightness and, where appropriate, insulation continuity.

The Approved Documents ADL1A and ADL2A currently state that a maximum air permeability rate of 10m³/(h.m²), at a test pressure of 50 pascals, is allowable in new dwellings and non-dwellings, respectively. However, this is likely to become more onerous over time and increasingly tight leakage rates are already being specified to achieve reductions building CO₂ emission rates in accordance with Carbon Calculations.

Where Air Pressure Testing is required, our team of experienced consultants will be on hand to help get you through, first time. The full consultancy package features a design review process – including meeting attendances and, where relevant, the development of a project specific compliance strategy – Construction Supervision in the form of site inspections, and a pre-test inspection to ensure effective building preparation.

Competent Person Scheme

On large and complex projects, where whole building testing may be deemed impractical, compliance may be achieved through a combination of design verification, sample testing, and an intensive site inspection regime (see ATTMA TS1). Building Control bodies are authorised to accept self-certification by a Competent Person, such as a Building Sciences consultant, once the compliance strategy has been approved.