Sorry. I forgot to say several other points-of-view in my last mail:
Even the ESCR test is only used as approval test of new grade of material. But I still think it is not bad to equip the VSM lab with this ESCR tester. Once we have it, we can also check the behavior of thermoplastics in different kinds of agents, for example the grease used in VSL project sites or any other special agents only appears on certain job-sites.
The ASTM D 1693 is actually only for PE material. Nevertheless fib75 specifies this test also for PP material.
One 600hrs ESCR test costs 1100CHF in lab spiez/CH. The unit cost is 1.5CHF/h plus lump sum of 300CHF for the test report. Before I though the ESCR tester only costs like 2000-3000CHF. The machine is a laboratory vibration water bath with improved control of temperature and time.