ISO 9967:2016 pdf free
ISO 9967:2016 pdf free.Thermoplastics pipes一Determination of creep ratio
Compressive loading machine, capable of applying via plates (5.2) and maintaining to with a precision of±1 % both the applicable pre-load force, Fo (see 8.4), and the necessary loading force, F (see 8.5), on the pipe.The force may be applied either directly or indirectly, e.g. by use of a lever arm arrangement.
Two plates, through which the compressive force can be applied to the test piece. The plates shall be flat, smooth and clean and shall not deform during the test to an extent that would affect the results.The length of each plate shall be at least equal to the length of the test piece. The width of each plate shall be not less than the maximum width of the contact surface with the test piece while under
load plus 25 mm.
The pipe of which the creep ratio is to be determined shall be marked on its outside with a line along one generatrix for its full length. Three test pieces, A, B and C respectively, shall be taken from this marked pipe such that the ends of the test pieces are perpendicular to the pipe axis and their lengths conform to 6.2.
The length of each test piece shalll be determined by calculating the arithmetic average of three to six measurements of length equally spaced around the perimeter of the pipe as given in Table 1. The length of each test piece shall conform to 6.2.2, 6.2.3, 6.2.4 or 6.2.5, as applicable.Each of the three to six length measurements shall be determined to within 1 mm.
For each individual test piece, the smallest of the three to six measurements shall not be less than 0,9 times the largest length measurement.
If the use of even the last five points does not lead to a correlation coefficient higher than 0,990 in the regression analysis for any of the three test pieces, continue the test on all three test pieces by measuring the deflectionat 1 200 h, 1 400h, 1 680 h, 2000 h,2400h,2 818h, 3400 h or 4 000 h, in each case±48 h, or until the correlation coefficient exceeds 0,990 using the last five measurements,whichever occurs first.ISO 9967 pdf free.
