Flanges? BS EN1092

[ella0509]

Hello - I am after some help.....

We have a customer that has requested a replacement vessel for one we previously supplied a few years ago. At that time the vessel used BS4504 PN16 flanges for nozzle connections. However the new BSEN1092:2002 has superceded BS4504, and these PN16 rated flanges have a reduced PT rating meaning I am unable to supply a design that would suit the required connection dimensions and the pressure/temp rating - am I correct in thinking this, or have I overlooked something??

Flange material is ASTM A182 F316L. Pressure 10 Bar.G. Temperature 200degC. Design is CAT III to the PED meaning third party appraisal by Lloyds.

Regards,
Lee

 

[ella0509]

Hi Fawkes,

Thanks for your response - the dual rating aspect is something that would be useful, and I'd never considered.

The flanges are DN100 - so the PN40 rating does not apply unfortuately.

I asked our flange suppliers and they told me that the flanges are still marked with BS4504 anyway and that if we wanted flanges to EN1092-1 then it would cost us more and take longer to get!! Also, PD5500:2006 section 3.8.1 b) states that flanges must comply with an appropriate Bristish Standard, BS1560 / BS4504 / BS EN 1092 - I thought 1092 replaced BS4504 from 2002??

The other thing that puzzles me is that the material group 13E0 seems to be a 316L equivalent (1.4404), but flanges made from this group have much higher PT ratings than the ASTM equivalent - am I missing something here?? If not, then I'd just ensure that we purchase and use flanges of this group when we design the vessel - but the design code would need to be PD5500 and not our usual ASME.

Lee