The Air Tightness Testing & Measurement Association (ATTMA), have recently updated the Technical Standard L1: “Measuring air permeability in the envelopes of dwellings”, including changes and clarifications in order to reduce and remove ambiguity within the testing industry.

This Technical Standard sets out to provide detailed guidance and clarification of BS EN 13829:2001: “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” and ISO 9972:2015: “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method”, in order to ensure consistency by testing companies.

To download and read the full document  please visit the ATTMA website.