1) Operating temperature = design temperature minus temperature surcharge acc. to DIN regulations.
2) Application at more than 400°C operating temperature only admissible if no intercrystalline corrosion has to be expected.
3) At opening temperature 400°C the material of the screws is 1.4986.
4) In case of screws A4-70 with > 8 x d screw-length the mechanical strength properties acc. to table 6 of DIN 267 Part 11 have been considered.
5) Butt welding ends. 
6) At temperature > 50°C only applicable for short-time service.