[MW:28583] HDPE pipe impact strength value.

does anybody know the unnotched impact strength value for HDPE. ? how to calculate it ?

I have a question as give n below further in relation to the above :-

A DN 150 CS slip on flange impacts on a DN1000 HDPE pipe 63 mm thk PE 80 from a height of 450mm. Need to know whether the impact shall create any deformation or crack? The impact will occur from the face of the flange 

The pipe basically has a branch connection ( a saddle ) of DN150 on which the slip of flange would be fitted .

In case the sudden change in cross section at branch needs to be considered as a stress raiser, do we have to consider then the notched impact strength and if so, how to calculate it? 

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