Background Ventilation Testing
To assess adequate background ventilation, assessment of existing dwellings is required. This can be summarised using the below process:
- Understanding current ventilation, infiltration rates and occupant use, and proposed improvements, to determine a proposed ventilation strategy.
- Pre-works visual inspection and checklist.
- Whole-house background ventilation testing, and room-based testing as appropriate
- Homeowner engagement.
- Installation of energy efficiency measures and required ventilation upgrades.
- Post-works background ventilation testing, air permeability test (if required) and sign off.
What is Background Ventilation?
Background ventilation refers to the provision of a continuous supply of fresh air to maintain indoor air quality. This is typically achieved through small, adjustable openings such as trickle vents in windows or air bricks in walls.
According to the Insulation and Assurance Authority (IAA) and Approved Document F (Part F) of the Building Regulations, background ventilation is crucial for ensuring adequate air exchange in buildings, especially when energy efficiency measures like insulation and airtightness are implemented.
Part F Building Regulation Requirements
Key points from Part F:
- Background ventilators should provide a minimum equivalent area of 5000mm² for each habitable room and 2500mm2 in kitchens and utility rooms.
- The total number of background ventilators must equal the number of bedrooms plus two additional ventilators.
These measures help prevent issues like condensation, mould growth, and poor indoor air quality by ensuring a steady flow of fresh air into the building.
PAS2035 Requirements
PAS2035 seeks to build upon the building regulations, ensuring that background ventilation is quantified pre- and post- any building works. This is to ensure properties achieve a balance of air tightness and adequate ventilation to allow for energy efficiency, healthy and comfortable homes.
This follows the building regulations ‘make no worse’ principle.
Whole House Test Procedure
Background Ventilation Assessment includes a Background Ventilation Test. For this test no artificial sealing of ventilators or mechanical ventilation is carried out – just closed and isolated.
All internal doors should remain open and waste water traps filed. All external doors and windows should be closed for the duration of test.
Unconditioned spaces such as garages and unheated conservatories are excluded, by closing doors, but again with no artificial sealing.
A normal a air testing procedure is then followed however the output is recorded as air changes per hour (ACH). For this the building volume needs calculating instead of an envelope area which is used for air leakage.
Defining Adequate Ventilation
When the background ventilation test result for the whole house test is greater than >1.0 ACH @ 4 Pa the property is deemed to have adequate ventilation. If the result is lower, room based testing can be carried out and/or ventilation improvements assessed.
For specific room testing, to define adequate ventilation, the result needs be greater than 1.5 ACH @ 4 Pa.
Air Tightness Testing Q&A
Do you have more questions about Air Tightness Testing? Visit our Q&A page by clicking here.
The Building Compliance Package
Don’t forget, we are a multi-disciplinary environmental consultancy. We can help with environmental planning conditions and a range of building regulation testing. Visit our services page here.
Have a project in mind? Let’s get to work
We’re friendly and knowledgeable bunch so why not get in touch for a chat. You can always contact Building Compliance Testing with any questions through phone, email or our online chat service.
Don’t worry, we don’t charge for advice given over the phone, so why not ask for a free quote?