UNE EN 61482-1-2 PROTECTIVE CLOTHING AGAINST THE THERMAL HAZARDS OF AN ELECTRIC ARC
Fabrics which meet this EN ISO standard:
This part of the standard specifies test methods and materials of clothing intended to be used in clothing resistant to heat and flame, workers exposed to electric arc. This section uses a directed and constrained electric arc in a low voltage circuit, for the classification of materials and clothes in the defined protection classes. They tested two types of protection:
- Class 1 4 kA
- Class 2 7 kA.
The arc length is set in 500 ms in the two types of testing.
With the method of the test box for materials, the amount of thermal energy transferred by the flat materials is measured during and after the exposure to a specified arc. The behavior of the material under this procedure is determined from the amount of heat transferred through the test tubes and other thermal parameters.The thermal flux of the exposure and the transferred by the test tube are measured with copper calorimeters. The extent to which the temperature of the calorimeters increases is a direct measure of the thermal energy received. The heat transfer data are used to assess the onset of a second degree burn using the Stoll curve. The response of the material should be subject to a supplementary description recording the observed effects of exposure to the electric arc on the test tubes.
Four test tubes must be tested by the method of the test box. The test shall be considered satisfactory if the four test tubes obtained positive results. In the case of failure of one of the four test specimens it shall be tested a fifth test tube. The test shall be considered satisfactory if the fifth test tubes reaches a positive result. The test shall be considered unsatisfactory if the fifth test tubes yields a negative result.
At least a test tube of the garment test must be taken under the method of the test box for garments.
Curva de Stoll
Visual examination: The effect of exposure will be observed on test tube fabrics and after cooling the test tube exposed, the fabric and other panel layers will be retired with caution, noting any additional effect of exposure. The description can be effected by one or more of the following terms:
- Time of post combustion
- Formation of holes
- Behavior of garment accessories
Acceptance criteria for the materials: The test which corresponds to a certain classification of the arc conditions must be considered satisfactory if it meets all the acceptance criteria defined in the following table:
Acceptance criteria for clothing: The test shall be considered satisfactory if:
- The material of the garment has successfully passed the test of the test box, according to the criteria described in the previous table.
- The garment subjected to the test box method satisfies the criteria defined in the following table:
After exposure, the closures should continue working. Accessories should not have negative influence on the results of the burning time, of the fusion and the formation of holes.