When testing a specimen with a structural core other than
steel, thermocouples should be fixed to the core material in positions
corresponding to the surface thermocouples mentioned in 7.5.1.1.
The thermocouples should be fixed so that their hot junctions
are attached to the appropriate positions by suitable means, including
peening into the structural core. The wires should be prevented from
becoming hotter than the junction. The first 50 mm should be in an
isothermal plane.