PAS2035 Compliance: Ventilation and Air Tightness Strategies

by | Apr 17, 2024 | Last Articles | 0 comments

Navigating the New Ventilation and Air Tightness Requirements for PAS2035 Retrofit Projects

Building Compliance Testing – Your Building Compliance Partner

The landscape of building compliance is ever-evolving. With the introduction of new requirements under PAS2035, professionals in the field must stay abreast of the latest standards. At Building Compliance Testing Limited, we understand the importance of these changes. Here we guide you through the new ventilation and air tightness strategies that are now mandatory for PAS2035 projects.

Under PAS2035:2023, where design specifics fabric measures, the retrofit designer or coordinator shall develop ventilation and air tightness strategies. We recommend at this stage we are consulted to provide a helping hand. Most importantly, if an airtightness target is set as part of the strategy, then the design shall include a requirement to demonstrate compliance with the set standard, by means means of an approved Air Permeability Test.

Understanding the Ventilation Requirements

Ventilation is a critical component of any building’s environmental control system. The new PAS2035 standards have introduced mandatory ventilation assessments and upgrades as part of the energy efficiency retrofit measures. These requirements are designed to ensure that buildings not only become more energy-efficient but also maintain a healthy indoor air quality for occupants.

The Role of Retrofit Assessors, Coordinators and Designers

Retrofit Assessors and Retrofit Coordinators play a pivotal role in creating a ventilation strategy for a property. According to PAS2035 Annex C.2.1, for every dwelling proposed for improvement, the Retrofit Designer must use the information provided by the Retrofit Assessor to assess the adequacy of the existing ventilation system.

Criteria for Adequate Ventilation

Existing ventilation systems are assessed based on several criteria, including evidence of condensation and/or mould growth, functionality of the current system, and provision for purge ventilation of each habitable room as required by Approved Document F. Learn more about our Ventilation Testing services by clicking here.

Intermittent Extract Ventilation

If the post-retrofit air leakage rate is worse (i.e., leakier) than 5 m3/hr/m2, trickle vents with intermittent or passive ventilation are permitted.

Continuous Mechanical Extract Ventilation

For dwellings that achieve an air leakage rate better (more air tight) than 5m3/hr/m2 post-retrofit, continuous running ventilation systems like MVHR or MEV are recommended. We highly recommend these include smart controls – such as a variable humidistat fan speed controller – to promote adequate purge ventilation.

The Importance of Air Tightness

Air tightness is another crucial factor in the energy efficiency of buildings. PAS2035 has set forth guidelines for assessing and possibly upgrading the existing ventilation system if any insulation or air tightness measures are part of a retrofit project. The requirements, detailed in Clause 8 and Annex C, emphasize the need for an appropriate air-tightness standard for the dwelling after the work has been completed2. Learn more about our Air Tightness Testing services by clicking here.

Compliance and Testing

At Building Compliance Testing Limited, we offer comprehensive services to ensure your projects meet these new standards. Our team of experts is equipped to conduct thorough ventilation assessments. We provide solutions for air tightness that comply with PAS2035.

We believe that understanding and implementing these new requirements is not just about compliance. It is about contributing to a sustainable future. By enhancing the energy efficiency of buildings, we are taking a step towards reducing our environmental footprint.

For more information on how we can assist you with your PAS2035 projects, contact us today.

Let Us Be Your Building Compliance Partner

Contact Us for Retrofit Ventilation and Air Tightness Services

If you are interested in the services of Building Compliance Testing, then we highly recommend getting in contact with us by filling out an enquiry form on our website! Or if you prefer to, you can instead phone us on this number: 01621 493 594 or email us on this address:

We look forward to working with you!