Borstar® HE3490-LS, the high density PE100 material, had completed 2 years of hydrostatic pressure testing at Bodycote Polymer AB. This prolonged testing beyond the 1 year requirement for MRS evaluation according to ISO 9080 supports evidence of good strength at elevated temperatures.

The creep rupture diagram from long term hydrostatic pressure testing.

The creep rupture diagram (fig 1) shows the observations and lines of ninety over water-filled pipes pressure tested at various hoop stresses, in external water media maintained at 20ºC, 60ºC and 80ºC. No failure of brittle mode is observed even at >18888 hrs (2.15 yrs) at 80ºC. No ductile-brittle knee point is observed after 2 years of testing. The absence of ductile-brittle knee point shows excellent thermal stability of HE3490-LS at elevated temperature.

Fig. 1 Creep rupture diagram of HE3490-LS.

MRS at 40ºC and 50ºC

Based on the equation obtained from SEM evaluation, Borstar© HE3490-LS has MRS (40ºC, 50yr) of 8.0MPa and MRS (50ºC, 27yr) of 6.3MPa. Simply said, Borstar® HE3490-LS is a PE80 at 40ºC and 50yr, and a PE63 at 50ºC and 27yr.

This provides solution to various industrial piping applications at elevated temperatures, say for example mining industry, industry effluent, desalination plants water piping and etc.

Calculated strength at maximum extrapolated time

The maximum test time at 80ºC, obtained by averaging the logarithmic of the five longest failure times is 1.5yrs. The allowable maximum extrapolated time at elevated temperature is of substantial duration, enhanced with high strength.