5.4.1 The piston shall be made of steel. There shall be
insulation at the top as a barrier to heat transfer from the piston
5.4.2 For procedure A, the piston shall be scribed with two
reference marks 4 mm apart in such fashion that when the
lower mark coincides with the top of the cylinder, guide sleeve
or other suitable reference point, the bottom of the piston is 48
mm above the top of the die (see Fig. 1) and the timed test run
shall start within these two reference marks. The targeted
starting point shall be 46 6 2mm above the upper face of the
die. (see Fig. 1).