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What is Viscosity?

July 30, 2019

Our last blog post we looked at a case study where we were seeing a lot of slip in a Waukesha Universal 2 pump. While there are many factors that can impact a process, fluid viscosity will be one of the most important factors that decide hoViscosityw we size the proper equipment for your application. Today, we will share a brief overview of viscosity and why most applications are dominated by the effects of viscosity.

Viscosity is the measure of the internal friction of a fluid. In other words, viscosity is a fluid’s resistance to flow. Imagine a thin layer of fluid is made to move parallel in relation to another layer. The greater the friction within the fluid means the greater the amount of force required to maintain this movement. This type of force is known as shear and it is this shearing action that occurs whenever a fluid flows whether it be pouring, spraying, mixing, etc. Viscosity can help us to explain why we can more easily move through air, which has a very low viscosity, than we can move through water, which has a 50 times higher viscosity.

Newtonian vs Non-Newtonian Fluids

When Isaac Newton performed his studies on fluids, he assumed that all materials have, at a given temperature, a viscosity that is independent of the shear rate. In other words, twice the force would move the fluid twice as fast. Fluids that exhibit this type of behavior are Newtonian fluids. It turns out that Newton was only partially right—a much more complex group of fluids exists and, unfortunately, are much more common.

Thixotropic fluids –A thixotropic fluid undergoes a decrease in viscosity with time while subject to a constant shearing. Some examples include yogurt, peanut butter, soaps, vegetable oils, and some slurries.

Dilatant fluids— Viscosity increases as shear rate increases (shear thickening). Some liquids with dilatant behavior are slurries, candy compounds, and cornstarch & water mixtures.

Pseudoplastic fluids—Viscosity decreases as shear rate increases (shear thinning). Examples ketchup, molasses, syrups, blood, and some silicone oils and coatings.

As you can imagine, there are dramatic differences in fluid viscosities within the food industry. The chocolate industry presents one manufacturability challenge where the desired texture and flow of chocolate can be difficult to maintain. Not only does the production process of molten chocolate depend on a well-defined viscosity, but properties of the finished product such as the texture and taste are directly related to its viscous behavior as well. Chocolate manufacturers must carefully consider the viscosity of their product in order to achieve their desired density, texture, and taste.

In the biotech industry, investments in new drugs and devices are enormous and viscosity is a key indicator of quality in a wide range of biotech applications from pharmaceuticals to mechanical devices to medical laboratories. For example in pharmaceuticals, we would want our cough syrup to smoothly flow past the digestive tract for proper delivery. Or we would want an ointment to stay in the affected area and not flow off. Therefore it is important that the desired value of a viscosity is achieved for every pharmaceutical product.

At Holland, we offer a wide range of products and solutions for your sanitary applications regardless of viscosity. Whether you need help selecting the right peristaltic pump tubing or you need help sizing a mixer, contact a Holland Sales Engineer today  for your application needs.

Sanitary PD Pumps & Eliminating Slip: A Case Study

July 30, 2019

A few months back we looked at the various clearance options available on a Waukesha Cherry-Burrell Universal 1, 2, & 3 PD Pump. In this post we are going to look at a specific sanitary pump application that we recently ran into with a customer in the field and the impact rotor clearance played in pump performance.

Pump Slip

Is your pump slipping?

The volumetric efficiency of a pump is dependent on the fluid slip, which often occurs in a pump. Slip is affected by internal clearances of the parts, temperature, pressure, and viscosity. In a sanitary ECP pump, slip increases directly with pressure and clearance, and inversely with viscosity. The major effect of slip on ECP pump performance is the loss in flow capacity. The expanding cavity on the inlet side of the pump creates a low-pressure area that sucks fluid in to equalize the pressure. This cavity can be filled with fluid from the inlet line in normal performance. However, if the slip is high, the cavity can be partly filled with fluid flowing back through the pump from the outlet side.

Recently, we had a customer who wanted to use an existing pump at one of their sister facilities. Their target flow rate was limited to about .2 gpm due to their high downstream pressure requirement and a fluid viscosity of over 40,000 cps. We took their application data and sized them up for a U2 Model 006 pump. Now that the pump was appropriately sizes, the customer was all set to get their new pump and they ordered a Holland Universal Pump assembly  complete with a VFD. Upon installation to their line they quickly ran into a problem—the pump was simply not delivering the expected flow.

With less than a 40% volumetric efficiency, the customer could not generate more flow no matter how fast the pump was run. Applying more pressure to the inlet side of the pump to ensure the pump was primed did not help. Was the downstream pressure condition much higher than expected? Without a pressure gauge anywhere downstream of the pump it was impossible to tell.

Maybe the fluid viscosity has become a factor? Could it have been higher? With a higher viscosity then maybe there is more energy loss than expected.

With some guidance from Holland, the customer ran a test of the pump with a straight horizontal hose with an equivalent total run length of their existing set up. The flow rate remained insufficient even at a full 60 Hz from the VFD. Next, the customer removed the pump and fed a bucket just downstream of the feed tank with the help of some backpressure. Their fluid was now flowing at what appeared to be almost 3 gpm! It was clear their issue could not have been a feed issue.

Videos of each of the two tests were sent in to Holland and it was clear that the pump was not delivering the required flow, but what stood out was how easily the fluid was pouring out from the tank. Perhaps their fluid behaves like a pseudoplastic; a non-Newtonian fluid where the viscosity decreases with an increasing shear rate. We also knew that the pump was outfitted with Hot Clearance rotors due to the customer’s CIP requirements. Perhaps the combination of the low viscosity and/or the Hot Clearance rotors was causing a high slip. So a pair of Standard Clearance rotors were sent for the customer to test out and just like that, the performance was instantly increased and the customer saw positive results.

While it is difficult for most end-users to predict and/or measure viscosity characteristics of their fluids under different flow conditions, today’s case study can serve as an important reminder of the various factors that can impact pump performance. The next time you are having trouble with your pump performance or need help with sizing a new pump for your application then feel free to give us a call or contact us via our website

The New EnviZion Advantage Actuator Option

June 25, 2019

On behalf of ITT, Holland Applied Technologies is pleased to announce the Envizion Advantage actuator option that is now available for the EnviZion hygienic valve product family. The Advantage actuator is a diaphragm driven, compact, lightweight actuator designed to meet the stringent space constraints of the

Envizion Advantage

The EnviZion Advantage Actuator

Bioprocessing and Pharmaceutical Industries. The unit is designed as an on/off pneumatic actuator available with three modes of closure.

The EnviZion Advantage pneumatic actuator combines the well-known and ultra-reliable Advantage actuator with the breakthrough EnviZion thermal compensation system t

o provide the ultimate in overall valve reliability. The diaphragm driven EnviZion Advantage actuator allows the EnviZion valve to be utilized in applications requiring precise control. The EnviZion Advantage actuator also allows for more flexible conversion of operating modes, change of spring sets, and maintenance of the actuator.

The Advantage actuator platform has been utilized for more than 25 years in the Biopharmaceutical industry. The EnviZion Advantage is offered as follows:

  • Valve Sizes: .75” – 2” (DN 20 – 50)
  • Operating Modes: Fail Closed (60# and 90# spring sets), Fail Open, Double Acting
  • Actuator Material: Glass Reinforced Polyethersulfone (PES)
  • Bonnet Material: Stainless Steel
  • Corrosion Resistance: Resistant to common industry wash downs.
  • Autoclavable
  • Thermal compensation system
  • Safety lock-pin
  • Visual position indication
  • Weep hole
  • 360 degree airport rotation

Let us take this opportunity to revisit the EnviZion sanitary valve and what makes it special. It begins with the top works; the bonnet for all EnviZion valves are mounted to the valve body with a simple twist and secured with a few turns of a locking cover.  The rest of the “tools” needed for assembly are all within the bonnet itself.   This simple assembly process also engages the most innovative feature of the EnviZion valve platform: a thermal compensation system that ensures a 360 degree active seal at all times – even following SIP.

Just how effective is the thermal compensation system that was engineered into this valve? The EnviZion hygienic diaphragm valve passed the testing required by ASME BPE 2014 Edition Appendix J – Standard Process Test Conditions (SPTC) For Seal Performance Evaluation.

The ASME BPE Standard was established in 1997 for the design of equipment for the production of biopharmaceuticals. The SG Sealing Components subcommittee of ASME published Appendix J as a set of standard process test conditions for seal performance including diaphragm valve diaphragms.

The ASME BPE 2014 Edition Appendix J test provided validation of the integrity and liability of the EnviZion valve’s live thermal cycle compensation system. The valve received the maximum cycle rating, classified as a Level 500 seal corresponding to the number of SIP exposure/cool-down cycles, from ASME after it completed the test at three times the required test pressure.

What does this mean for the end user? It means we’re going to eliminate a tremendous amount of downtime and further reduce the possibility of losing a batch of valuable product due to a valve leak because the Teflon diaphragm creeped. By minimizing downtime, we maximize uptime, effectively increasing the capacity of the system. These two features- decreased chance of leakage and increased productivity- make the valves extremely economic when viewed from a total cost of ownership perspective.

The EnviZion valve platform was developed with one overarching goal – to reduce the customer’s total cost of ownership. Costs associated with installation, validation, operation, and maintenance are significantly reduced with the EnviZion valve. Backed by extensive in-house testing, independent third party ASME BPE Appendix J testing, and EHEDG certification, the EnviZion valve is setting a new standard for the performance of hygienic diaphragm valves. For more information about the EnviZion valve, contact a Holland Sales Engineer today.

Product Focus – Quattroflow QF30SU: Single-Use Pump for Low Flow Rates

May 31, 2019

As an OEM for PSG Dover’s Quattroflow product line, Holland Applied Technologies is excited to announce the addition of the QF30SU Single-Use Diaphragm Pump to the Quattroflow Single Use Product line. As the leading brand of quaternary diaphragm pumps, the Quattroflow series of pumps has been one of our offerings that continues to innovate by offering our biopharmaceutical customers scalability, flexibility, and performance that traditional product offerings can’t match. Today, we will look at their latest product offering, the QF30SU, which has been developed for lower flow rates in single-use applications.


Quattroflow QF30SU 

Until very recently, the Quattroflow single-use pumps have been available in the QF150SU, QF1200SU, QF4400SU, QF5050SU, and the QF20kSU sizes. Quattroflow has now extended its Single-Use product line to the lower end. Featuring a flow range from 0.06 to 30 lph, the new QF30SU is the ideal solution for your pharmaceutical and biotech applications requiring a lower flow rate that the QF150SU couldn’t quite reach.

Retrofittable on both QF150S (Multiple Use) and QF150SU (Single Use) drives, the QF30SU pump features a disposable polypropylene (PP) wetted pump chamber with tool-free installation. Offering a small footprint with a high turndown ratio at 500:1, the QF30SU pump is ideally suited for lab and low flow applications such as chromatography, TFF and virus filtration operations.

While the maximum motor speed of a QF150 drive is 3000 rpm, the QF30 has a proportional (linear) motor speed to flow characteristic that goes up to 1000 rpm. At higher motor speeds, the flow characteristic (performance curve) starts to flatten. The brushless single phase, 230V (110V as option) 90W motor drives that are standard with the QF150 drives can be changed to limit the motor speed to 1000 rpm.

The QF30SU polypropylene pump head features 4 mm (1/8”) hose barb connectors. All soft parts are fully characterized, made of USP Class VI materials with extractable and leachable reports available. Available accessories for the QF30SU include a power box, diaphragm sensor and PID pressure controller.

With the new QF30SU, the Quattroflow series of pumps now cover a range of flow rates from 1 lph with the QF30SU to 16000 lph with the QF20kSU. For any questions about your next biopharmaceutical application or to see if any of the Quattroflow series of pumps is right for you, feel free to contact a Holland Sales Engineer. 





Product Focus: Gore Sta-Pure Pump Tubing

May 29, 2019

In today’s post we are going to take a look at the Gore Sta-Pure peristaltic pump tubing. The Gore Sta-Pure product line offers two series of products; the Series PFL and the Series PCS. Gore’s pump tubing products are engineered to deliver consistent flow even at high pressures (up to 100 psig) and chemically aggressive applications. Let us dive into what distinguishes each product.

The Gore Sta-Pure Pump Tubing Series PFL is manufactured with a patented composite of expanded polytetrafluoroethylene (ePTFE) and platinum-cured perfluoroelastomer for increased reliability with aggressive chemicals in peristaltic pumps. It is free from plasticizers, acid acceptors and other processing aids, making it one of the most pure tubing products available. The Series PFL handles nearly all aggressive chemicals, including organic solvents such as methyl ethyl ketone, toluene, and acetone. Let’s find out why…

PFL Tubing

Gore Sta-Pure Series PFL Tubing


Expanded polytetrafluoroethylene is created when PTFE—a linear polymer consisting of a carbon backbone completely surrounded and protected by fluorine atoms—is expanded, creating a microporous structure with desirable characteristics such as a high strength-to-weight ratio, biocompatibility, and high thermal resistance. This expansion process, innovated by W.L. Gore & Associates in 1969, is what makes GORE products so unique. This unique process significantly improves the mechanical properties while also maintaining the positive chemical attributes of the PTFE base material.



PTFE Structure. The Carbon-Fluorine bond is among the strongest and most stable bond in organic chemistry.a caption

A perfluoroelastomer, represented by the letters FFKM or FFPM (ASTM and ISO designations, respectively), is very similar to PTFE except that PTFE is a more crystalline, or plastic, material while FFKMs can be thought of as the elastomeric form of PTFE in that it is soft and flexible at room temperature. Given the chemical structure and performance similarities between perfluoroelastomers and PTFE, it should be no surprise that perfluoroelastomers are used in sealing applications involving high temperature and/or aggressive chemicals.


Perfluoroelastomer Structure

Combining the two compounds provides better chemical compatibility than silicone and thermoplastic elastomer (TPE) tubing. In addition, the patented structure of the composite enables consistent flow rates over extended production cycles up to 60 psig. The Series PFL also withstands the rigors of clean-in-place and steam-in-place (CIP/SIP) processing, which helps simplify sterile fluid applications.


Series PCS Tubing

The Series PCS is a composite of platinum-cured silicone and reinforced with expanded polytetrafluoroelthylene (ePTFE) for added strength and resilience. With a unique composition of silicone and PTFE, the Series PCS has superior burst resistance up to 100 psi. This tubing is widely used for ultra-pure applications such as ultra-filtration, live cell transfer, fermentation, and bioreactor feed.

While platinum-cured silicone products are known for their extremely low levels of extractables and leachables and have gained a reputation for being the highest purity products, they may balloon or rupture under high pressure. The Series PCS employs a unique composite structure that overcomes this limitation and provides greater reliability and security against rupture. In a peristaltic pump, at a back pressure of 60 psi (4 atm), Series PCS tubing lasts over 1,000 hours under continuous use at 200 rpm. Under transfer conditions, it lasts more than 18 times longer than silicone rubber tubing, and almost twice as long as thermoplastic elastomer tubing at 360 rpm. The Series PCS has also been validated to operate after steam-in-place/clean-in-place (SIP/CIP) and autoclave sterilization.

Expanded polytetrafluoroethylene, or ePTFE, is the core material in many of Gore’s solutions. You likely may be familiar with the many products Gore has to offer. Today, we have seen that Gore can tailor ePTFE for chemically aggressive high purity applications in their Series PFL tubing, or high-pressure and physically demanding applications in their Series PCS.

If you have any questions on your peristaltic pump application or any of our single use products, contact a Holland Sales Engineer today.

Introducing the New

April 29, 2019

Today, we are excited to announce the launch of our newly designed website—


WebPage Screen Shot

Our new Homepage!


Our revamped website has a very new look and feel to it. It features a responsive web design and is mobile friendly so that we can provide our visitors and business partners an easy way to learn about the various products, services, and solutions that Holland Applied Technologies has to offer. Other highlights include:

The Engineering Toolbox

In addition to aesthetically re-designing our website, one of the main goals of the new site is to provide a resource for many of the CAD files and downloads we’re often asked for. Thus, the ‘Engineering Toolbox’ section was created to host these files and other product literature & technical documentation such as brochures, manuals, and parts lists. We will be adding these files overs the coming months. If there’s something you want to see here, let us know!


What else has changed? We have refined our products and offerings into a single drop-down menu—the ‘Products’ section. If you’d like to learn more about all of the products and services we offer, then the products section is where you will find this information. The Blog, Request a Quote, and other resources are still a single click away.

We hope you find the new website to have a fresh look and easy to access information. We have designed the new site with many additional functionalities in mind that will be launched at a later date. Our blog and monthly Newsletter will continue to be an important source of any new exciting information and announcements.

We value the feedback of our customers and business partners. We invite you to view and explore the new website and let us know your thoughts.

Sanitary PD Pump Rotor Clearances- Chart

April 26, 2019

Today, we give you even more information on PD pump rotor clearances. Below is an easy to use chart that provides the rotor clearance data for the Waukesha Cherry-Burrell Universal 1, 2, & 3 positive displacement pumps.

These tables will help you to determine the proper back face, rotor to body, and front face clearances. Please note that the assembly clearances stated in these tables are for reference only. Actual pump clearances may vary based on pump performance testing.

For non-standard rotors, or if the process uses special clearance rotors, please contact a Holland Sales Engineer with the serial number of the pump.


The above information was taken from the Waukesha Universal 1, 2, 3 Maintenance Manuals.


Sanitary PD Pump Rotor Clearances

March 29, 2019

In today’s post, we are going to look at the different clearance options that are available on a Waukesha Cherry-Burrell Universal 1, 2, & 3 PD Pump.

As you may know, the Waukesha Alloy 88 is the standard rotor material for the Universal 1, 2, & 3 PD pumps. This alloy was developed to provide the advantage of excellent corrosion resistance and close operating clearance requirements. The clearance between rotating parts (rotor) and stationary parts (pump head) is very important in limiting slip and maximizing efficiency.



Slip is proportional to clearance to the 3rd power


Here is a summary of the different clearance options for a U1 & U2 PD pump:


“Standard” and “Wine” clearance rotors may be used with liquid temperatures up to 180°F (82°C).

However, between 160°-200°F (71°-93°C), it is best to consider other application factors such as:

  • Speed of operation
  • Differential pressure
  • Lubricating properties of liquid being pumped
  • Product viscosity

If these factors trend toward a difficult application (high speed, high pressure, non-lubricating) then “Front Face” or “Hot” clearance rotors are recommended. Wine clearance rotors (same operating parameters as listed for standard rotors) provide additional clearance between the rotor hub and the cover bore area only. They give extra protection against contact in this area.

“FF” (Front Face) clearance rotors provide additional clearance in the front face area only. They are recommended for use with liquid temperature between 180°F (82°C) to 200°F (93°C). They give better pumping efficiency (less slip) than “Hot” clearance rotors when used with low viscosity liquids. Do not use “FF”, however, rotors if they will be subjected to temperature shock (extreme, rapid temperature change.)

“Hot” clearance rotors are recommended for use with liquid temperatures between 180°F (82°C) to 300°F (149°C). They provide additional clearance in the front face area plus rotor to body areas. Because of this additional clearance there is more slip (inefficiency) with low viscosity liquids, which the pump must overcome with higher operating speed (rpm.) VHP (viscous horsepower) is slightly lower when using hot clearance rotors. Hot clearance rotors are also used when the product viscosity is above 200 CPS.

“316SS” clearance rotors are used with rotors made from 316 stainless steel material (in place of standard non-galling alloy 88) and recommended for use at temperatures up to 200°F (93°C). These rotors provide additional clearance all around (more than Hot clearance alloy 88 rotors) to insure no running contact between the 316 SS rotors and other 316 SS pump components. Because of this additional clearance there is more slip (inefficiency) with low viscosity liquids, which the pump must overcome with higher operating speed (rpm). VHP (viscous horsepower) is slightly lower when using “316SS” clearance rotors.

Some models in some series have a “316SS Hot” clearance rotor option for temperature above 200°F (93°C).

NOTE: Consult Holland Technical Services for applications near 300°F or above 200°F with 316 SS rotors.

“Extra Hot” clearance rotors are recommended for use with products such as chocolate, which tend to “plate out” and build up on rotor surfaces. These rotors require special selection procedures. Contact SPX FLOW Technical Services for assistance.


The model U3 pump uses slightly different nomenclature and clearance options:

“Low Viscosity” rotors are similar to the U1 & U2 “standard” clearance rotors in that they may be used with liquid temperatures up to 180°F (82°C). Between 160° (71°C) and 200°F (93°C), other application factors must be considered such as; speed of operation, differential pressure, lubricating properties of liquid being pumped, and product viscosity. If these factors trend toward a difficult application (high speed, high pressure, non-lubricating) then “Standard” clearance rotors are recommended.

“Standard” clearance rotors are recommended for use with liquid temperatures between -40°F (-40°C) and 300°F (149°C). They provide additional clearance in the front face area plus rotor to body areas. Because of this additional clearance there is more slip (inefficiency) with low viscosity liquids, which the pump must overcome with higher operating speed (rpm.) VHP (viscous horsepower) is slightly lower when using standard clearance rotors. Standard clearance rotors are also used when the product viscosity is above 200 CPS.

There are many factors to consider when sizing a PD pump for a specific application. The different rotor clearance options available on the Waukesha Universal series positive displacement pumps allow our Holland Sales Engineers to size a pump that will maximize pump performance. Contact a Holland Sales Engineer today with your next sanitary pump application.

Stainless Steel Finishes: What Makes A Weld Sanitary?

March 8, 2019

In today’s post, we are going to focus on welding and what makes a weld sanitary in today’s sanitary (hygienic) processing facilities.

To start, let’s look at a very general definition and overview of welding. Welding is the joining process in which two (or more) parts are coalesced at their contacting surfaces by application of heat and/or pressure. Welding is achieved by two basic categories; fusion welding and solid state welding. Fusion welding is accomplished by melting the two parts to be joined, and in some cases, adding a filler metal to the joint. Examples of fusion welding processes include arc welding, resistance welding, and laser beam welding. Solid state welding involves the application of heat and/or pressure but no melting of base metals occurs and no filler metal is added. Some examples include forge welding, diffusion welding, and friction welding.

The American Welding Society AWS D18 Committee was formed by the request of the 3A Sanitary Standards Committee for help in outlining welding standards for use in the manufacture and construction of dairy and food product processing plants. Within the AWS D18.1/D18 Specification is where it is defined that all welds for austenitic stainless steel tube and pipe are to be done by the gas tungsten arc welding (GTAW) process (also known as the tungsten inert gas, or TIG, process). This process uses a non-consumable tungsten electrode along with an inert gas (argon or helium) for arc shielding. The purpose of arc shielding is because at high temperatures, metals are chemically reactive to the oxygen, nitrogen, and hydrogen that is present in air, and thus without a shielding gas the mechanical properties of the joint are subject to oxidation. So the advantage of the GTAW welding process is that it produces high quality welds with little or no post-weld cleaning.


Weld Nozzle

GTAW Welding


According to the AWS D18.1/D18 Specification, welds are to be fully penetrated to the ID to prevent the formation of crevices which could entrap product and lead to contamination. In order to determine acceptable oxidation levels, the AWS D18.2/D18 Specification provides a visual examination guide to aid in the inspection of color in the heat affected zone (HAZ) for welds in piping systems. The heat affected zone is the area of base metal that has experience temperatures below melting point, but high enough to cause changes in the properties and microstructure of the metal.



AWS Weld Discoloration & Acceptance Criteria Scale


As the demands of the bioprocess industry for clean, smooth product contact surfaces increased, advances in process piping technology and equipment fabrication technology have followed. Orbital welding was developed as an automated process to address the risk of operator error in GTAW processes. Orbital welding offers the advantage of a computer controlled system that combines arc current, feed and speed to allow the ‘orbital weld head’ to travel around the tube in a steady manner in order to produce consistent and repeatable weld profiles. Hooray for automation.

The 3A Standard was extensively used by the pharmaceutical food and dairy industries but with the emerging bioprocess industry, higher standards were needed for equipment design that would be both cleanable and sterilizable. The ASME published the first edition of the ASME Bioprocessing Equipment Standard in 1997 (BPE-97) to help address this need. Part MJ (Materials Joining) of the ASME BPE Standard requires that the weld criteria of ASME B31.3 – Process Piping be met for acceptable metallic materials. While ASME B31.3 prohibits weld discontinuities such as cracks, voids, porosity, lack-of fusion, and incomplete penetration, the ASME BPE Standard also provides visual examination acceptance criteria to determine the hygienic condition of the piping system. It should be noted that the BPE standard specifies orbital welding as the preferred joining technology for bioprocess tubing, and that manual welding may be performed with owner/user and contactor agreement.



Acceptable and Unacceptable Weld Profiles


Hopefully this blog has provided a good overview of the welding practices used in our industry and what criteria and standards define practices to be sanitary. For over 50 years, Holland Applied Technologies has built a reputation as being one of the highest quality sanitary stainless steel fabricators in the US. All sanitary welding is done using cryogenic Argon and our orbital welders have automated Oxygen sensing systems. If you have a custom sanitary process piping application, call us at (800) 800-8464. We can help you with your design and work with you to come up with the most cost effective, high quality solution for your application.

Sanitary Surface Finish Chart

February 6, 2019

Below is a comprehensive graphic for surface finishes that we hope you find useful. The Surface Roughness Conversion Chart will help to convert surface finish between selected industry standard units. The Common Names table lists some common surface finish names and how they are defined by their Ra number. Lastly, the Sanitary & BPE Surface Finishes table defines the surface finish requirements as established by the ASME BPE 2016 Standard. This table is also useful in that it relates surface finish codes from various manufacturers to the ASME BPE Standard.


Surface Finish Chart


N = New ISO (Grade) Scale numbers

Ra = Roughness (average), measured in microinches (µin) or micrometers (µm)

RMS = Root Mean square, microinches (µin)