A properly calibrated test apparatus the can be operated at constant rates of crosshead motion over the range indicated,and in which the error in the Load measuring system shall not exceed 1 % of the maximum load expected to be measured. This test apparatus shall be equipped whit a deflection-measuring device.
The stiffness of the test apparatus shall be such that the total elastic deformation does not exceed 1 % of the total deflection of the test piece during the test