Getting Ready : Domestic Air Permeability Test

What is an air permeability test?

An air permeability test is a process of inducing a set of environmental conditions on the buildings envelope to be able to measure the uncontrolled movement of air similar to the effect wind would naturally have on the building at equivalent wind speed of 20 meters per second. This test is required for all new build projects by Part L of the Building Regulations.

To achieve this we use large door blower fans to create a pressure differential between inside and outside of the building. Using calibrated UKAS testing equipment these pressures are used to measure the air flow through the door blower fan which enables us to calculate the overall air permeability score.

Preparing the project for an air test

Adhering to these guidelines will help ensure a successful air permeability test and compliance with building regulations. Proper planning and execution of air tightness strategies are essential for achieving energy efficiency and building performance standards.

Here is our step by step guide to getting the best results:-

Set a target for airtightness performance, which you can find in your SAP (Standard Assessment Procedure) calculation. This target will help you develop a strategy to achieve or exceed the required level.
Coordinate with your SAP assessor to determine the appropriate ventilation system, as different systems perform best with specific levels of airtightness. Consult with Part F of the building regulations to ensure your projects airtightness is compliant with your ventilation selection.
All details should be meticulously planned during the design phase to avoid last-minute decisions on site.
The airtightness barrier should be integrated into the building envelope from the initial concept design. To ensure completeness, it’s helpful to mark a continuous red line on plans and sections that covers all elements separating heated and unheated areas. Anywhere the red pen changes direction , passes through another building element or is lifted off the drawing is a weak spot and prone to leakage.
Appoint an ‘Airtightness Champion’ to oversee and manage the design implementation onsite and with other trades.
Adopt a performance specification approach.
Include the airtightness requirements and their interaction with other trades in all trade specifications.
Select components, membranes, seals, and jointing methods that ensure airtightness. Provide training to key site staff members.
For inexperienced design teams, consider hiring an independent advisor. BEAT Solutions are available to assist with this.

What should happen onsite?

The site manager must grasp the importance of the designed airtightness and the methods required to achieve it. Effective communication with the design team is essential.
Identifying crucial details that impact the airtightness barrier early in the project is beneficial.
Assign an Airtightness Champion to take responsibility and coordinate between consultants and contractors.
Consider the project in three dimensions and thoroughly inspect every detail.
Verify that trades and their work maintain the integrity of the airtightness throughout the construction process.
Use a checklist for each plot to ensure every part of the building is inspected before being closed up, keep this as a record for auditing purposes. Even better take pictures throughout the building process.

What we need to preform a successful air test?

We require a double socket (240v Mains Power) to operate the testing equipment and Laptop. To avoid using extension leads his should be located within 3 meters of the external door opening that is to be used for setting up the test equipment. Please note if you don't have mains power within the building, using generators can be problematic for running the testing equipment. We can provide a specialist generator for an additional fee. This however needs to be booked in advance as it isn't carried on the testing van as standard.
Please ensure a parking space is located within 20m of the property. This is to ensure the large and heavy testing equipment isn't being transported by hand unnecessarily and is greatly appreciated by our testing engineers. If this is not possible, please advise us accordingly so we can discuss suitable parking arrangements.
The external door opening must be no larger than 1100mm wide and 2200mm high. Ideally this would be the front door or similar sized inwards opening single door. French/Sliding doors can't be used.
All waste water traps including wash basins, toilet pans, baths, showers, washing machines outlets etc must have had water poured down them. This is to ensure the traps aren't dry.
All windows and doors must be fitted and properly sealed. Missing windows and doors are hard to temporarily seal and this must be discussed with BEAT prior to arrival as we may need to agree additional onsite time to deal with incomplete building works.
You are required to temporarily seal all extract fans that vent to atmosphere. This includes the all wetroom fans and kitchen extractor hoods. Properties with MVHR or whole house ventilation systems this includes all room terminals.
All open chimneys must be temporarily sealed for the testing procedure. This must be done in advance of our arrival. This may require correx sheeting or hardboard being fitted across the whole opening. Note this must be sealed and fixed sufficiently so that when under pressure it doesn't become removed.
All stoves and fires must be temporarily sealed for the testing procedure. This must be done in advance of our arrival.
Ensuring all the above is completed and ready prior to our arrival enables our testing engineers to spend move time actually testing and consulting with you to obtain the best possible results for the given time we are onsite.

Common Leakage Areas

Hers is a list of common air leakage areas. Please bear in mind it is often dependent on the form of construction whether that be masonry or timberframe and where your air tightness layer is located as to the effectiveness of the areas listed below, therefore this is not a exhaustive and is only to be used as a guide to help you prepare a airtightness strategy.

Around the ends of floor joists or joist hangers.
Beneath inner window sills and around window frames.
Through windows and/or hollow window frames.
Through and around doors - particularly double doors.
Beneath doors and doorframes.
Along the top and bottom edges of skirting boards.
Between and around sections of suspended floors, usually timber floorboards.
Around loft hatches, negative pressure testing pulls the hatches away from the seals.
Through the eaves, ensure that vertical and horizontal insulation are joined tightly.
Around roof lights.
Through gaps behind plasterboard on hollow studwork walls.
Cracks or holes through a masonry inner leaf, perp joints not fully filled.
Around supplies from external meter boxes and distribution boards, around wall mounted fan or radiant heaters; around and through fused spurs and pull switches.
Around boiler flues.
Around water and heating pipes that penetrate hollow floor voids and partition walls, i.e., radiator tails from within the floor.
Around waste pipes passing into floor voids or boxed in soil stacks.
Around waste pipes passing through walls.
Gaps around heating pipes.
Around and through recessed spotlights.
Around waste pipes, gas and water supplies and cables which penetrate the lower floor slab.
Holes around the top of a soil stack into the roof space.
Through MVHR or warm air heating systems; around terminals.
Around and through wall-mounted extract fans, cooker hood vents, tumble dryer vents.
Through room thermostats and heating controllers.
Behind coving along wall to ceiling joints or junction of wall to ceiling.
Where locks and bolts prevent effective draught proofing.
Around internal timber joists that penetrate plaster walls.
Through sub floor air supplies to solid fuel heaters.
Through gaps in the casings of MVHR units.
Up chimneys, particularly where flue dampers are not fitted.
Through airbricks and partially closable hit-and-miss vents.
Around and through closed trickle vents.
Visible warning device (Tundish) to unvented/pressurised systems.
Behind consumer units where meter tails pass through wall, silicone seal boards to wall prior to mechanically fixing.

Cancellation & Rescheduling Policy

If unfortunately there is a need to cancel, abort or reschedule the test/s, you can do this free of charge by giving at least 48 hours (2 working days) written notice to info@beatsolutions.co.uk before the test day. Otherwise the following charges will apply.

• Plot/s cancelled or rescheduled without 48 hours written notice will incur the following charges = £45.00+VAT per plot with a minimum charge of £150.00+VAT per day.

• Plot/s cancelled, re-scheduled or aborted on the day of the agreed test will charged = £Payment in full

Should you need to cancel or reschedule a booking, we can only accept your instruction by way of one of the following:-

• Call our operations team Monday to Friday on 01489 565920 during office hours (8:30am to 5:00pm). A confirmation email of the cancellation call will be sent immediately and all calls are recorded.
• Email our operations team Monday to Friday on info@beatsolutions.co.uk during office hours (8:30am to 5:00pm) stating your request, name, site address and original test date.

If we have been booked into carry out any testing and sufficient notice has been provided, we reserve the right to charge for any works carried out in preparation to conducting the test. This shall include but not be limited to; providing consultation, calculating building envelope areas and volumes, preparing job sheets and general project and booking administration.