The standard "Renault D45 1051 Flexible or semi-rigid cellular materials air flow resistance", developed by the French automobile company Renault, describes the requirements for determining the behavior of cellular materials to air flow. This behavior is characterized by air permeability and resistance to air flow. The described method is applied to semi-rigid or flexible cellular materials, possibly coated with a primer on one of the two sides and containing a mold coating where applicable.
The test to be performed consists of providing a controlled and stable air flow through a parallelepiped test specimen cut from the cellular material to be tested and measuring the resulting pressure drop (head loss) between the two free sides of the test specimen. Permeability and specific resistance to air flow are of theoretical importance only if the material is homogeneous (skinless cellular product).
If the test specimen consists of a material with a heterogeneous surface, for example a cellular material with a molded coating or lining material on one or both sides, only the apparent permeability or resistance to air flow can be defined for a given test specimen thickness. This should be stated in the test report.
Major equipment used in testing includes:
The shape of the measuring cell is a parallelepiped with a square base, an inner side between 50 mm and 100 mm and a height greater than or equal to 150 mm. The cell contains a device that supports the test specimen during the test. This device is 50 mm from the base and consists of a 70 mm thick frame to which a grid can be added, provided that the perforation ratio (the ratio between the open surface and the total surface as a percentage) is at least 1 percent. Two flow and pressure measuring sensors are mounted on the sides of the cell.
The air circulation device makes it possible to obtain an air flow through the cell by suction up to 0,55 x 10-3 m3/s (i.e. 2.000 l/h) and to obtain stability such that the measured flow rate fluctuations over 1 minute are not greater than 1 percent of the imposed value. For example, this type of device may consist of a vane pump capable of providing a maximum flow rate of 1,10-3 m3/s (i.e. 3.600 l/h) and a set point valve to adjust the flow rate.
The measurement is recorded by a series of parallel, interchangeable flow meters with overlapping reading ranges. Only one of the flow meters is used, with the flow to be measured being between 20 percent and 80 percent of full scale. The flow meter is placed between the vacuum pump and the test sample, as close as possible to the specified sample.
The pressure measuring device must provide a differential pressure reading of approximately 1 Pa (i.e. approximately 0,1 mm of water). This device consists of a curved tube that allows readings to be taken with an accuracy of at least 0,5 Pa (i.e. approximately 0,05 mm of water).
The thickness of the test samples is measured with the test sample thickness gauge using the equipment described in the Renault D5 45 test method, with a key side of (a+ 1394) mm.
Among the numerous tests, measurements, analyses and evaluation studies that our organization has carried out for businesses in various sectors, our organization also provides testing services defined in the “Renault D45 1051 Flexible or semi-rigid cellular materials airflow resistance” standard with its trained and expert staff and advanced technological equipment.
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