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Comparing Base, Mid, and High-level Sanitary Finishes [Infographic]

Categorizing levels of sanitary design is helpful to professionals new to compliance regulated industries requiring custom vessels because it bridges communications regarding standards and design requirements.

In hygienic applications, stainless equipment requires a sanitary finish which generally refers to a smooth, scratch-free, non-corrosive finish. The fineness of the finish, which determines its performance, is measured in RA (roughness average). The infographic illustrates the RA of different types of mill, mechanical, and chemical finishes. The smaller theRA readingin microinches (height in millionths of an inch), the smoother the finish.

When collaborating to qualify a project, we define aBase Level Finishas a 2B/Mill, 304 or 316 stainless materials that is pickle passivated. The welds are continuous and crack and crevice-free. This type of finish is paired with a Base Level Sanitary Design and is cleaned manually. Apache’sstandard portable vessel lineare an example of the base sanitary design and finish level.

A米id-Level Finishis also composed of 304 or 316 stainless material and involves a secondary process of mechanical polishing greater than 32RA, with final finishing to include pickle or nitric passivation. The welds are continuous, crack and crevice-free, and are also ground flush and polished smooth to a specific RA. Sanitary fittings, mechanical polishing, additional passivation processes and a cleanable design with removable components are categorized as Mid-Level Sanitary Design features.

Providing the smoothest RA readings is an electropolished finish after a series of processes, including mechanical finishing to less than 32 RA, passivation, and nitric passivation, which are common forHigh-Level Finishes.The base material is 304/316 stainless. The welds are continuous, crack and crevice-free, ground flush and polished smooth to a specific RA designation less than 32RA. The sanitary fittings are also electropolished. Vessels with this level of specifications are typically cleaned automatically.

The specifications, construction and finishing of a vessel is often driven by standards and compliance requirements. All three categories, qualify for ASME UM, ASME U, FDA, 3-A, CRN, PED, BPE.

There are other factors that fall in these base, mid and high-level sanitary design categories, including construction features, processing applications and time to delivery. Download our e-book “Guide to Sanitary Design for Custom Vessels in Hygienic Industries".


Anatomy of a Sanitary Design Vessel

When evaluating a custom vesselmanufacturing partner对于一个新项目,请考虑制造卡帕bilities and experience that support the vessel’s application and sanitary requirements.

All custom design stainless vessels for the food, life sciences, pharmaceutical and health industries require sanitary construction. It is the application and automation that drives the level of sanitary componentry.

In reviewing each new custom vessel project, Apache identifies the卫生要求to categorize the vessel into a base, mid- or high-level design. Apache offers a standard line of vessels that qualify for various regulatory compliance agencies. However, these designs are considered a base level sanitary design, especially because the cleaning of the equipment is manual. Apache identifies a mid-level sanitary design vessel as having COP (Clean Out of Place) components.

In the video, a custom vessel is animated to walk through characteristics and examples in the highest and most automated level of sanitary design custom vessels.

High-Level Sanitary Design Characteristics Include:

  • CIP (Clean in Place) Process and Components
  • Continuous, crack and crevice-free welds, ground flush and polished smooth to specific RA (Roughness Average) <32 RA
  • 304 or 316 stainless material, mechanically finished to <32 RA
  • Electropolished and Nitric passivated finishing
  • Electropolished sanitary fittings, including:
    • Tri-clamp ferrules
    • Tube connections
    • NA Connects
    • Flush mount outlet valves
    • Sight glasses
    • Orbitally welded j-tubes
    • Dip-tubes
    • Polished internal coils
    • Samples Ports
    • Spray devices
    • Control panels
    • External thermal jacketing

Processes and application in high-level sanitary design vessels include heating and cooling vessels, mixing and processing tanks, WFI tanks, filtering and R & D lab equipment.

Certificationrequirements is an important part of the sanitary design criteria. Sanitary design standards include:

3A – A regulation of the design for processing equipment in the food and drug industries. A 3A certificate is proof of FDA compliance.

ASME U and ASME UM - A regulation of the design of boilers and pressure vessels, including traceability of materials, procedures, testing and documentation.

BPE – A standard within ASME that drives equipment design for the bio-processing, pharmaceutical and other hygienic required industries.

In qualifying design, safety, automation other application details, Apache will facilitate the required compliance for the vessel and provide well communicated delivery, cost and approvals required for a successful project.


Navigating Stainless Material and Finishes for Hygienic Vessels

Stainless Finishes for Hygienic Vessels are measured by anRA (Roughness Average)meter. Manufacturers of custom vessels for life science, health andpharmaceuticalindustries adhere to strict design parameters to maintain compliance in these industries. The RA is a standard for an average of peaks and valleys on the metal’s surface, measured in microinches. Here is the evolution of stainless material coming to Apache with RA designations as it is transformed into custom sanitary design vessels:

RA > 100 Mill FinishA Mill Finish has an unpolished, dull-gray, matte appearance. This material type is the basis for supply for all stainless-steel flat products as well as the basis for additional finishing operations. It is hot or cold rolled with an RA (Roughness Average) of more than 100 microinches, depending on the gauge of the material.

RA 15 – 40 2B Mill Finish2B Mill finish is widely used in food, chemical and pharmaceutical equipment applications. It is corrosion resistant and has a typical RA range of 40 (7 gauge) to 15 (16 gauge) microinches.

RA 29 – 58 No. 3 and No. 4 Finish米echanical polishing achieves these finishes. The No. 3 Finish uses a 120-grit abrasive and has a semi-polished finish with an RA range of 36 – 58 microinches. The No. 4 Finishes uses a 150-grit abrasive and has a polished, brushed surface. The RA range is 29 – 40 microinches.

RA 18 – 31 No. 4AAlso identified as No. 4 Dairy Finish, this finishes is required to meet the basic FDA 3-A standards. It uses a 180 grit and has a RA range of 18 – 31 microinches.

< 32 RA Pickle PassivationPickle Passivation often follows other manufacturing processes including welding and grinding. Also called Pickling, it is the immersion of the metal in a pickling bath or coating the material with pickling solution, such as nitric-hydrofluoric acid. The process removes both metallic contamination and heat-treating scales. Pickle passivated stainless steel has a matte appearance. Apache’s tests have confirmed improvements up to 25% in RA readings on material that has been pickle passivated.

Lowest RA ElectropolishingElectropolishing is an electro-chemical process that removes surface material from stainless steel. The process includes an immersion of the stainless-steel component into a temperature-controlled bath of electrolyte that is charged with a DC power supply. Electrolytes used in electropolishing are concentrated sulfuric and phosphoric acid solutions. The finish has a mirror appearance. Apache’s before/after tests have shown improvements in RA smoothness up to 50%; results vary depending on stainless material.

In the highest level ofsanitary design applicationsthe vessel is pickled after manufacturing and polishing, then electropolished.


What's Right for my Operation: Pressure v. Vacuum Closures


Vacuum or Pressure closures for small/portable ASME vessels

米any processors come to Apache for a vessel solution in the incubation stage of their business. In some cases, they are looking for help to choose the right kind of vessel that will suit their needs and fit their budget. While Apache providescustom ASME vesselsfor a range of industries, we also offer a line ofstandard vesselsthat often solve what these manufacturers need for their process.

船的使用将决定a pressurized solution, non—pressurized or vacuum vessel solution.

Vessels that require a minimum of 50 PSI, utilize a pressure closure. Numerous applications, including heating or cooling process, containment, and pressurized dispensingoften utilize pressures at or above 50 psi.

It is important to note the safety and ASME requirements for pressure vessels, anASME UM-markis required for:

  • Vessels 5 cubic feet of volume or smaller with pressures not exceeding 250 psi.
  • Vessel 3 cubic feet of volume or smaller with pressures not exceeding 350 psi.
  • Vessels 1.5 cubic feet of volume or smaller with pressures not exceeding 600 psi.

For vacuum requirements or non-vacuum applications, such as a storage vessel or collecting vessel, a vacuum closure may suit the application.

In the video, Nick Buchda, Apache’s Small Vessel Representative, demonstrates vacuum and pressure closures on our standard line of vessels.

Apache has produced stainless vessels withASME certificationfor over 45 years, with other accreditations for pharmaceutical, life science and health industries including ASME UM, ASME U, FDA, 3-A, CRN, PED and BPE.

Whether the vessel needs fit a standard vessel, modifications to a standard vessel or a custom solution, Apache has the experience to fulfill a range of critical, sanitary-design vessel solutions.


Round Up on ASME Marks

ASMEis a leading developer of codes and standards in the mechanical engineering community. These standards enhance public safety and health as well as promote innovation.

The ASME (American Society of Mechanical Engineers) mark is a single certification marketing to signify the international mark of safety and quality. Recognized worldwide, manufacturers that provide ASME have a rigorous quality program, and a third-party review to authorize the use of the mark.

The U markcertifies that the pressured tanks or vessel conforms to the latest edition of the ASME code and that the pressure vessel has been designed and manufactured in accordance with ASME. All aspects are approved by a Third party ASME Authorized Inspector (AAI). U stamps require an ASME inspector to witness the ASME hydro test.

Companies with a U mark undergo a review with the National Board every three years.

The UM markcertified that the pressure vessel or tank conforms to the latest edition of the ASME code and that the pressure vessel has been designed and manufactured in accordance with ASME. The UM vessel’s designation is related to the size of the tank/vessel.

  • Vessels 5 cubic feet of volume or smaller with pressures not exceeding 250 psi.
  • Vessel 3 cubic feet of volume or smaller with pressures not exceeding 350 psi.
  • Vessels 1.5 cubic feet of volume or smaller with pressures not exceeding 600 psi.

While the American Society of Mechanical Engineers writes the rules for the new construction of pressure vessels and tank, the National Board of Boiler and Pressure Vessel Inspectors write the inspection code for new and repaired vessels.

The National Board of Boiler and Pressure Vessel Inspectors require a Certificate of Authorization andR stampfor the repair or alteration of boilers, pressure vessels and other pressure retaining equipment.

Apache has been ASME certified for over 45 years. In addition to ASME, Apache is accredited in many other global standards. By setting parameters for quality and compliance, we offer greater value for our custom stainless ASME tanks and vessels.


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