A special event was held at Bedford Academy to complete air tightness testing following Ashe’s first use of Passive Purple liquid vapour control membrane.
Vapour control layers or VCLs are sheets made of materials such as polythene, used to prevent moist air from accumulating in the structure of a building. They also create a seal to make a building airtight, preventing heat loss and providing thermal efficiency. However, Ashe has trialled the use of Passive Purple at the school, which is designed as a spray on application and can create a seal in hard-to-reach areas.
The airtightness test checks that a building’s envelope is sealed. The test identifies the need for any remedial work to be done if leaks are found. A blower door test was undertaken at Bedford Academy where a large fan was placed in an open door to achieve an air pressure of 50 Pascals (Pa) in the building, and a sensor measures how much air volume is changed per square meter, over a period of time. The designed air permeability for this project must be less than or equal to 2 m3.h-1.m-2@50Pa to pass the test.
Laura Memory, Ashe’s design manager explained: “To have scored 0.46 on the test is a fantastic result at this interim stage in the project.
“The school expansion will be powered solely by electricity with a large proportion of it being generated by the 212 photo voltaic panels installed on the roof. The panels specified are large enough to power the entire building but are connected to the main electricity grid as a backup on cloudy days. There is a lot of mechanical and ventilation equipment in the building so powering it through solar energy alone is a big achievement. Air source heat pumps will use the electricity to generate the heating supplied to the mechanical ventilation units in the building.”
Ben Walker Ashe’s contracts manager said: “It’s quite a sight to see all the walls such a bright colour, it’s very purple indeed, but has been interesting to see how using this product has affected the test results. The test went very well and assures us that the building will run efficiently when completed.
“We used an external company to carry out the testing independently, and certify that we are compliant.”
Of course, once the project is complete, the Passive Purple layer will be covered with the usual internal wall coverings such as plasterboard and plaster and decorated as normal.
The extension is being project managed by Pick Everard for Bedford Borough Council and has been designed to be net zero in operation by GSS Architecture. It will operate to high efficiency levels, and U Values must be stringent with very low heat loss through the façade of the building.
To round off the day, Ashe handed over a cheque for £2K to the school to help fund much needed sports kit. Students at the Academy will proudly sport the Ashe logo on their football and basketball kits.
Headteacher, Chris Deller, thanked Ashe by saying: “Thanks so much for the kind donation, so generous! This will make a huge difference to our school community.”