Particular requirements for blankets, pads, clothing and similar flexible heating appliances
IEC 60335-2-17-2019 pdf download.Household and similar electrical appliances — Safety — Part 2-17: Particular requirements for blankets, pads, clothing and similar flexible heating appliances
Appareils electrodomestiques et analogues — Sécurité — Partie 2-17: Exlgences partlculières pour les couvertures, coussins, vêtements et appareils chauffants souples analogues.
21.108 Appliances having heating elements that are retained in position by bonded layers shall have adequate mechanical strength.
Compliance is checked by the following test.
Six samples of the bonded material, each having dimensions of 100 mm x 130 mm, are cut from the flexible part. Three of the samples are cut in the direction of the runs of the heating element and the other three samples are cut perpendicular to this direction.
From the ends measuring 100 mm, a strip of the material retaining the heating element in
position and having a width of 25 mm is cut away from one face at one end of each sample.
Another similar strip is removed from the opposite face and at the opposite end of the sample.
Any heating element situated under the removed strips is also cut away.
NOTE It may be necessary to Cut away more than one layer In otder to test the bonding ol the layers retaining the heating element
Clamps are attached to the full length of the remaining layers of material at both ends of the sample.
The sample is then suspended by one of the clamps and subjected to a total load of 1,25 kg by means of the other clamp. The test is carried out for I h at a temperature of 20 °C, and then for I h at a temperature of 80 °C.
The test is repeated on six samples taken from the flexible part of a new appliance. The layers retaining the heating element in position shall not separate.
21.109 The enclosure of moisture-proof appliances consisting of plastic sheeting shall have adequate flexibility under cold conditions.
Compliance is checked by the following test unless the appliance complies with the test of 15.102 or has an enclosure made from reinforced plastic sheeting.
The sheeting is cut into 10 rectangular samples, each being 145 mm long and 50 mm wide with the longer dimension perpendicular to any striations resulting from the manufacturing process.
Each sample is folded about its minor axis and allowed to form a loop without creases. It is stapled to a card twice, the staples being placed close together and approximately 30 mm from the edges, as shown in Figure 108.
21.110 The enclosure of moisture-proof appliances shall have adequate resistance to tearing under normal conditions of use.
For enclosures of plastic sheeting, compliance is checked by the test of 21. 110.1.
NOTE The test is not carried out it the appliance has been subjected to the test of 15.102 or if the enclosure is made from reinforced plastic sheehng.
For enclosures of rubberised or similarly treated fabrics, compliance is checked by the tests of 21.1 10.2 to 21.110.4. For enclosures of seamed fabric, compliance is also checked by the test of 21.110.5.
21.110. 1 Five samples of the plastic sheeting. as shown in Figure 109, are conditioned at an ambient temperature of 23 °C ±2 °C. The longer dimension is perpendicular to any stria lions resulting from the manufacturing process.
The shorter edges of each sample are attached over their full length to the clamps of a tensile machine, the sample and the clamps being in the same plane. The clamps are separated at a rate of 50 mm/mm until the sample tears. The maximum breaking load is measured.
The average breaking load of the five samples shall be not less than 12,5 N.
21.11 0.2 A sample of the treated fabric having a diameter of 76 mm is clamped between two disks, each having a diameter not less than 76 mm and a concentric aperture having a diameter of 26 mm ±0,7 mm. This assembly is mounted in an apparatus so that water pressure can be applied to the untreated side of the fabric. The water pressure is gradually increased and is measured when leakage occurs through the fabric. It shall not be less than 410 kPa.
This test is carried out on three samples.
The average value of the pressure shall be at least 490 kPa.
21,110.3 Three sets of three samples, as specified in 21.110.2, are conditioned as follows.
The first set is immersed in boiling waler for 1 h and then aged in a heating cabinet at a temperature of 100 °C ± 1 °C for 1 000 h. The samples are then immersed again for 1 h in boiling water.
The second set is aged in an oxygen bomb for 168 h, the oxygen having a pressure of approximately 2,0 MPa and a temperature of 80 C ± I 0C.IEC 60335-2-17-2019 pdf download.