PUW Suface Finish
PUW Suface Finish
(OP)
hey Looking for a bit of help here.
Surafce Finish for a Purified water system, I know the ASME BPE 2007 standard calls for a surface finish of between 0.38 to 0.64 micron Ra for mechanically polished parts.
But what i am wondering does this surface finish need to be the same in the pre treatment unit.( Hense the pre treatment stage) The closest surface finish i can get is 0.8 Ra microns. i want to know if this is acceptable and any supporting references would be great.
Thanks
Surafce Finish for a Purified water system, I know the ASME BPE 2007 standard calls for a surface finish of between 0.38 to 0.64 micron Ra for mechanically polished parts.
But what i am wondering does this surface finish need to be the same in the pre treatment unit.( Hense the pre treatment stage) The closest surface finish i can get is 0.8 Ra microns. i want to know if this is acceptable and any supporting references would be great.
Thanks





RE: PUW Suface Finish
The common practice is to have better surface finish from the moment purified water is generated.
RE: PUW Suface Finish
hope this makes sence !!
RE: PUW Suface Finish
Most of the rules relating to pharma/biotech or implied and we have to choose the best practically viable option.
Unlike product contact (in which case raw, inprocess and finished material all hold good) water has a definite stage after which we say PW, HPW or WFI. In your case, PW classification comes into picture after the water quality is complied with respect to conductivity, TOC and TVC. So, we can exactly say the water is purified after UV system.
So, I would take care to have good surface finish after this step. However, it is quite possible to maintain the required surface finish in UV housing and the pipe upstream side of the UV. So, they can also be finished to the specified surface finish.
0.8 microns Ra is a good finish and I don't see any problem with it. Probably, I will have a look into BPE 2007 (as I didn't have my hands on it yet) in a couple of weeks and let you know.
RE: PUW Suface Finish
Thanks for you supporting comments, got the go ahead from validation to proceed with piping,
thank again
RE: PUW Suface Finish
I would suggest reading SD-2 (Scope and Purpose) in page no.9 for pointers with respect to the issues that were not specifically mentioned. Having said that, I would prefer strict controls where ever possible. Please refer to page nos. 11 to 14.
Today, I came across with a fellow who is in the technical subcommittee of ASME BPE 2007 sufrace finishes. I put forward your question along with some other concerns I have. Let us see what we can hear from the horse's mouth.
RE: PUW Suface Finish
Would be most greatfull to hear what ASME BPE technical guy will say.
And yes i had read through the relevant sections, Hygienic design connections,dead legs etc have been taken into consideration.
Keep me posted.
Thanks
RE: PUW Suface Finish
On a personal note, (mind you they clearly mentioned that it is not official), the BPE member concurs with our idea.
Good luck,