BS EN 61479-2001 pdf download.Live working Flexible conductor covers ( line hoses ) of insulating material.
NOTE The properties of vulcanized elastomeric materials change continuously with time, these changes being particularly rapid in the period immediately following vulcanization.
7.3.2 Mechanical puncture resistance Type test and sampling test.
Three circular test pieces 50 mm in diameter shall be cut from a sample pad and clamped between two flat 50 mm diameter test plates.
The top plate shall have a circular opening. 6 mm in diameter and the bottom plate, a 25 mm diameter opening. The edges of both openings shall be rounded to a radius of 0,8 mm (see figure 5).
A needle shall be produced from a 5 mm diameter metallic rod and, one end shall be machined to produce a taper with an Included angle of 12° and with the tip rounded to a radius of 0,8 mm (see figure 5). The needle shall be clean at the time of use.
The needle shall be positioned perpendicularly above the test piece (clamped between the two plates) and shall be driven Into and through the specimen. The rate of traverse shall be (500 ± 50) mm/mm. The force required to perform the puncture shall be measured.
The puncture resistance shall be greater than 30 N.
7.3.3 TensIon set
Type test and sampling test.
This test shall apply only to conductor covers made of elastomer.
Three test pieces, having the size and outline shown in figure 6, shall be cut from the sample pad. The test pieces shall be fitted, by their ends, in a straining device consisting of a metal rod or other suitable guide and fitted with a pair of holders, one fixed and one movable.
The measurement of the unstrained reference length (shown as l.,, in figure 6) shall be checked to the nearest 0,1 mm and the test piece put in the holder. The test piece shall be extended at a speed between 2 mmls and 10 mm/s to a (150 ± 10) % elongation and held for 10 mm. After this time, the strain shall be released at a speed of between 2 mm/s and
10 mm/s, and then the test piece shall be removed from the holder and laid free on a flat surface. After a 10 mm recovery time, the reference length shall be measured again.
The tension set in the sample shall not exceed 15 %. Any materials not meeting this criteria shall be discarded.
7.3.4 Tensile strength and elongation at break Type test and sampling test.
Three test pieces, having the size and outline shown In figure 6 shall be Cut from a sample pad prepared as in 7.3.1.
Reference lines, 20 mm apart, shall be marked on these test pieces. symmetrically placed on the narrow part of the dumb-bell.
The test pieces shall be tested in a tensile testing machine which shall be power driven at a sufficient speed to maintain the rate of traverse of the driven grip substantially constant up to the maximum force of the machine. The rate of traverse shall be (500 ± 50) mm/mm.
The tensile strength shall be calculated by dividing the force at break by the initial area of the cross-section under test. The average of the three test pieces shall be not less than 4,8 MPa for Category Z conductor covers and 11 MPa for other categories.
The elongation at break shall be calculated by subtracting the initial distance between the reference lines on the test piece from the distance between the lines at breaking point and expressing the result as a percentage of the initial distance.
The average of the three test pieces shall not be less than 350% for elastomers and 150 % for plastics.
NOTE 1 The machine should be equipped to give a continuous indication of the force applied to the test piece and a graduated scale to measure the elongation.
NOTE 2 After the test piece has been broken, the machine should give a permanent indication of the maximum force and, where possible, the maximum elongation.
7.3.5 Tear resistance test Type test and sampling test.
This test shall apply only to conductor covers made of plastic.
Three rectangular test pieces having the outline shown in figure 7 are cut from a sample pad prepared as in 7.3.1.BS EN 61479-2001 pdf download.