PSA D41 5601 Absorbent and Insulating Felts - Free Particle Ratios

The standard “PSA D41 5601 Absorbent and insulating felts - Free particle rates”, developed by the French automobile company Renault, describes a procedure that allows measuring the probability of losing particles during the use of a fibrous absorbent or insulating product in finished products, by determining the mass loss of the fibers and the number of free particles during mechanical stress.

According to this test method, a sample with defined dimensions and weight is tested under mechanical force such as vibration for a certain period of time. The first step consists in determining the mass percentage of lost fibers corresponding to the tensile heavy fibers of the sample. The second step consists in determining the number of free particles lost by the sample. The counting is carried out by means of a particle counter (0,5, 1, 2, 3, 5 and 10 µm).

Major test equipment used in these tests includes:

• The vibration test bench is equipped with equipment for speeds between 200 and 0 rpm plus/minus 2200 rpm, with a power of approximately 50 W.
• The powder cabin is a polymethyl methacrylate cabin with dimensions of 400 mm in length, 400 mm in width and 600 mm in height. The distance between the probe and the cabin bottom is 550 mm.
• A conditioned room is a room maintained at a temperature of 23 degrees plus/minus 2 degrees and a relative humidity of 50 percent plus/minus 10 percent.
• Antistatic film is a film with antistatic adhesive properties.
• The particle counter is an equipment with an air flow of 14644L/min, complying with the “ISO 28,3 Clean rooms and related controlled environments package” standard. It counts particles of 0,5, 1, 2, 3, 5 and 10 µm.
• Plastic bags are 500 mm wide plastic film rolls used to make plastic bags 450 mm long and 250 mm wide.
• Heat sealer is used to seal the width and length of plastic bags.

The following test equipment is also used in the tests:

• scissors
• Plastic beaker (diameters from 120 to 150 ml with 500 mm)
• Precision scales (accuracy 0,1 mg)
• Timer
• Ruler (1 cm with 50 mm precision)
• USB key
• Dust cloth and ethanol
• adhesive tape
• Personal protective equipment (jacket, mask and safety shoes)

Test samples should be representative of the scale to be characterized. In order to ensure this representation, the basic characteristics of the studied population must be revealed. Selection criteria for test samples must be stated in the test report in accordance with the A10 0156 standard. In case of doubt about sampling, the PSA Group should be contacted to learn the directives to be followed.

When preparing samples, first of all, the samples should be flat and samples should be taken from plates or pieces. The samples should be 210 mm x 290 mm plus/minus 2 mm in size and their thickness should be between 5 and 30 mm. Two of the 12 samples taken from the flat material or the part to be tested allow the control of the material (thickness according to PSA D45 1195 standard and surface mass according to PSA D45 1012 standard). The samples should be conditioned in the room for at least 24 hours plus/minus 1 hour and protected from any contamination.

The first stage of the tests: Study of heavy particles “mass loss of fibers.

450 bags of 500 mm x 4 mm plus/minus 5 mm are made with thermal insulation material. The following procedure is followed on the five samples:

• The sample is weighed with a beaker and its weight is recorded.
• The first bag is weighed in the same way.
• The felt is fixed to the holder of the vibrating test bench inside the cabin.
• The metal bar is pulled to open the holder.
• The felt (A4 format) is placed vertically in the holder attached to the vibration test bench. If the felt has an adhesive side, a heavy mass or a non-woven side, this side is placed immediately in front of the particle counter probe.
• The plastic bag is placed around the felt and with adhesive tapes. The bag is attached to the vibrating test bench, taking into account the sample and its holder.
• The height of the free part of the felt is measured. This value is reported in the same way for the following felts plus/minus 5 mm.
• The rotation speed of the vibrating test bench is fixed at 1000 tr/min. Rotation is started for 15 minutes.
• When finished, the bag is taken out, the tapes are removed and the bag is weighed again in the beaker.
• The value of the bag containing the dust is recorded.
• The cabin is cleaned with a dust cloth and ethanol.
• The steps are repeated sequentially for the other four samples.

First stage of tests: Particle counter.

The following procedure is followed in succession for five samples. The purpose of this test is to perform the vacuum measurement for the first time. The felt is fixed to the holder of the vibrating test bench without any demand and the particle counter starts counting for 1 hour. The device continuously performs counting cycles of 5 minutes with a 15-second break between each cycle. The vibrating test bench is then operated for 15 minutes, measuring free particles during mechanical force. The counter records the data at each step according to the process diagrammed in the standard. To continue, it corresponds to 1 hour of measurement without felt demand and 15 minutes of measurement with mechanical demand.

Among the numerous tests, measurements, analyses and evaluation studies that our organization has carried out for businesses in various sectors, it also provides testing services defined in the “PSA D41 5601 Absorbent and insulating felts - Free particle ratios” standard with its trained and expert staff and advanced technological equipment.