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Is non-polished stainless steel considered a sanitary surface?

sanitary design non-polished stainless equipment design grades of stainless food grade ss food grade surface cleanable surface

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#1 sqf girl

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Posted 16 May 2017 - 05:29 PM

Our company just had a piece of equipment manufactured.  It has arrived and to my complete and utter dismay, the exterior and interior are composed of non-polished stainless steel.  It looks as though it is almost an anodized stainless.  Does anyone have any experience with this type of finish?  I can't even seem to scrub the maintenance mans dirty hand prints off of the exterior, let alone running product in this large vessel which will only be a CIP cleaned surface, as it is an incredibly tall tank, with most of it that is inaccessible from the opening.  This vessel is impossible to have someone have enter via a confined space permit.



#2 Charles.C

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Posted 17 May 2017 - 11:16 AM

Our company just had a piece of equipment manufactured.  It has arrived and to my complete and utter dismay, the exterior and interior are composed of non-polished stainless steel.  It looks as though it is almost an anodized stainless.  Does anyone have any experience with this type of finish?  I can't even seem to scrub the maintenance mans dirty hand prints off of the exterior, let alone running product in this large vessel which will only be a CIP cleaned surface, as it is an incredibly tall tank, with most of it that is inaccessible from the opening.  This vessel is impossible to have someone have enter via a confined space permit.

 

Hi sqf girl,

 

It likely comes down to Product Specifications.

 

The 3-A Sanitary Standards (1), as well as USDA guidelines specify that all surfaces, including fabricated, welded and  soldered  joints,  shall  be  at  least  as smooth as a No. 4 (150 grit) finish and shall be free of pits, folds, crevices, cracks, and misalignments in the final fabricated form.

Attached File  characteristics of food contact surfaces - Stainless Steel.pdf   972.02KB   18 downloads

 

In the majority of applications, a finish at the high end of No. 4 is considered food grade (see Stainless Steel Finishes sidebar). This finish is achieved using a high-grit abrasive in the range of 150-220 and is identified by short, parallel lines that run the length of the material. The success of the finish can ultimately be determined by a surface roughness average (Ra), measured by height in millionths of an inch (µin.), or microinches. A profilometer determines Ra values by moving a diamond stylus across the workpiece’s surface for a specified distance and using a specified contact force. It measures small surface variations and calculates their average to determine the roughness. In most food-grade applications, 60-36 Ra is achieved with 150-220 grit. Because milk products spoil more quickly and carry more bacteria than other food and beverage items, dairy applications should have a finer finish, No. 4A, which is 40-24 Ra and achieved with a 220-grit abrasive or finer.

 

http://www.thefabric...de-applications


Kind Regards,

 

Charles.C


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#3 Ryan M.

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Posted 18 May 2017 - 08:20 PM

What Charles said.  Request information on meeting the 3A standard guidelines.

 

Additionally, any new stainless surface should be passivated before using to help ensure it does not pit or corrode...in case you didn't know.







Also tagged with one or more of these keywords: sanitary design, non-polished stainless, equipment design, grades of stainless, food grade ss, food grade surface, cleanable surface

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