Choosing Corrosion Resistant Resin: 11 Things You Should Know

corrosion resistant resinFiber Reinforced Polymers (FRP) use has grown tremendously over the past seven decades in oil and gas, chemical processing, pulp and paper, mining and minerals, wastewater treatment, water treatment, desalination, and power generation—to name a few.  One of the primary reasons FRP has gained so much traction is that it has superior corrosion resistance when compared to other construction materials such as stainless steels, carbon steels, titanium, aluminum, and nickel alloys.  That being said, there are a wide range of corrosive environments throughout many industries and as such special requirements must be taken into consideration when designing/formulating FRP to endure optimal performance. 

When requesting corrosion resistant resin recommendations for FRP equipment applications, users or specifiers should be prepared to supply the following data:

  1. All chemicals to which the equipment will be exposed: feedstocks, intermediates, products and by-products, waste materials, and cleaning chemicals
  2. Normal operating concentrations of chemicals, maximum and minimum concentrations (including trace amounts)
  3. pH range of the system
  4. Normal operating temperatures of the equipment, maximum and minimum temperatures
  5. Duration of normal, maximum  and upset operating temperatures
  6. Abrasion resistance and/or agitation requirements
  7. Equipment size
  8. Manufacturing methods
  9. Flame retardance requirements
  10. Thermal insulation requirements
  11. Vacuum Specifications
Source: Ashland Resin Selection Guide

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Testing and Measuring Flexural Modulus of FRP

flexural modulus of frpWhat is Flexural Modulus?

There are many important properties of Fiber Reinforced Polymers (FRP) that are determined by international testing methods.  These measurements of properties are particularly useful for quality control and specifications purposes.  Flexural Modulus is an engineering measurement which determines how much a sample will bend when a given load is applied, as compared to Tensile Modulus which determined how much a sample will stretch when a given load is applied and Compressive Modulus which determines how much a sample will compress when a given load is applied.   Because composites are non-isotropic(as opposed to metals for example) these additional material properties are required in order to predict the behavior under load which complicates the design problem for the inexperienced.

ASTM D-790 is one such standard testing method that is used to determine flexural properties of FRP.  According to ASTM D-790, flexural properties may vary with specimen depth, temperature, atmospheric conditions, and the difference in rate of straining.  For example, because the physical properties of many materials (especially thermoplastics) can vary depending on ambient temperature, it is sometimes appropriate to test materials at temperatures that simulate the intended end user environment.

According to ASTM D-790:

“These test methods cover the determination of flexural properties of unreinforced and reinforced plastics, including high-modulus composites and electrical insulating materials in the form of rectangular bars molded directly or cut from sheets, plates, or molded shapes. These test methods are generally applicable to both rigid and semirigid materials. However, flexural strength cannot be determined for those materials that do not break or that do not fail in the outer surface of the test specimen within the 5.0 % strain limit of these test methods. These test methods utilize a three-point loading system applied to a simply supported beam. A four-point loading system method can be found in Test Method D6272.”

Another common standard for testing flexural behavior is ISO 178.  Similarly, this standard specifies a method for determining the flexural properties of rigid and semi-rigid plastics under defined conditions. A standard test specimen is defined, but parameters are included for alternative specimen sizes for use where appropriate. 

It is important to note the differences between ASTM D-790 and ISO 178 standards.  According to one well established leader in plastics testing, most commonly the specimen lies on a support span and the load is applied to the center by the loading nose producing three point bending at a specified rate. These parameters are based on the test specimen thickness and are defined differently by ASTM and ISO. For ASTM D790, the test is stopped when the specimen reaches 5% deflection or the specimen breaks before 5%. For ISO 178, the test is stopped when the specimen breaks. Of the specimen does not break, the test is continued as far as possible and the stress at 3.5% (conventional deflection) is reported.

This article was aimed at providing a snapshot portrait of the standard testing methods used for determining flexural properties of FRP


ASTM International, formerly known as the American Society for Testing and Materials (ASTM), is a globally recognized leader in the development and delivery of international voluntary consensus standards.

ISO (International Organization for Standardization) is the world’s largest developer of voluntary International Standards.

FRP Well Suited for Potash Mining Equipment

It has been demonstrated many times over that modern Fiber Reinforced Polymers (FRP) are extremely durable in a myriad of applications.  Furthermore, FRP have tremendous promise in a wide range of industrial applications, such as potash mining.  Chief among the many benefits of FRP are corrosion resistance and long life cycles in extremely stringent environments—for example, chemical processing, mining and minerals, and pulp and paper.

In contemporary societies, in both industrial and non-industrial applications, we rely on complex systems of infrastructure for safety, prosperity, and economic health. The use of FRP in complex industrial has with time become more widely adopted due to their ability to withstand the harshest environments. According to an educational module released in 2006, prepared by ISIS Canada, a Canadian Network of Centers of Excellence, titled “Durability of FRP Composites for Construction,” a primary motivation for using FRP in civil engineering applications is that FRP are non-corrosive and thus they will not degrade in electrochemical environments.

Potash mining is often conducted in a low pH high chloride environment where variables such as temperature, humidity, exposure to moisture, water, and caustics are important considerations.  FRP are viewed by many as excellent construction materials that will provide protection against caustics, acids, and continuous wet or humid conditions.

In today’s world potash refers usually just refers to potassium chloride.  Potash has a key role production of fertilizer (its one of the three essential nutrients that plants need for healthy growth) and thus in food production, and is one of the crucial ingredients of the world economy. Approximately 75%-85% of the world’s potash production is used for fertilizer.  The rest is used in various chemical processes.

According to a March 19, 2013 web based article published from, titled “Inventories Up, Prices Down,” demand is up for North American potash on domestic and export markets.  In February worldwide potash exports were up 26% to 812,000 tones from one year previous.  Furthermore, potash producers remain optimistic as crop prices rise, farmers are willing to spend more on fertilizer.

With global population rising and improving diets in developing countries- potash production and other nutrients such as nitrogen and phosphorus are expected to increase.  This is welcome news for FRP producers.  FRP are viewed by many as a great material choice for both conventional shaft mining and solution mining applications of potash because of its inherent properties; corrosion and abrasion resistance, long service life, low maintenance, ease of installation, and cost-effectiveness.  From tanks to pipe, from structural shape to custom components—FRP possess a portfolio of benefits unrealized by other conventional materials.

Did You Know? Thermal FRP Expansion

thermal frp expansionAccording to the Composites Growth Initiative of the American Composites Manufacturing Association (ACMA), the Coefficient of Thermal Expansion  is the change in length (or volume) per unit length (or volume) produced by a one degree Celsius rise in temperature.

While it is commonly thought that the thermal expansion of fiberglass is several times higher than carbon steels, this is not always the case and it’s an important fact that engineers can’t ignore.   According to the American Society of Mechanical Engineers (ASME) B31.3 standard, FRP is at most 2.5 times that of carbon steel and at most 1.67 times that of stainless steels and, with some filament wound fiberglass reinforced plastics the difference is much less.

The rate of thermal expansion in FRP products is highly dependent upon the amount of glass in the product and the orientation of the glass. Again, according to ASME, this is because the thermal expansion of the resin is approximately 2.0 – 3.5 x 10-5 in./in./EF and the thermal expansion of the glass is only 0.28 x 10-5 in./in./EF.

Table 1

Typical Thermal Expansion Coefficients (valid up to 300F)


0.9- 1.5 x 10-5 in./in./EF

Carbon Steels

0.6 – 0.65 x 10-5 in./in./EF

Austenitic Stainless Steels

0.9 – 0.95 x 10-5 in./in./EF

90/10 Cu-Ni

0.9 – 0.95 x 10-5 in./in./EF

70/30 Cu-Ni

0.8 – 0.85 x 10-5 in./in./EF

Source: American Society of Mechanical Engineers, B31.3 Standard

Beetle Plastic’s fiberglass pipe is filament wound and, therefore, has different thermal expansion in the hoop and axial direction. In the hoop direction, the thermal expansion is about the same as steel. However, in the axial direction, the thermal expansion of the fiberglass pipe is about twice that of steel.

When designing FRP pipe systems there are other important considerations that will be influenced by the thermal expansion.  According to a case study released by the Fluid Sealing Association in 2006, “Mechanical considerations also are important. Since FRP is a composite, there are two distinctive axial modulii of elasticity: compression and tensile. The axial compression modulus of elasticity varies from3 to 10 percent that of steel.”  Similarly, another design consideration should be the relatively low modulus of elasticity of FRP pipe. It’s an advantage of FRP which should be figured into the design of a piping system.

To view the 2009 edition of the ASME B31.3 Process Piping Guide follow the link below:

Contact us to learn more about our FRP and how we can help you meet your goals.

Building Waste Water Treatment Systems—No Problem

waste water treatment systemsEvery year there are technological advancements.  New materials are available today that once were just an idea or considered novel.  In wastewater treatment, chemical processing, desalination, or other corrosive services, Fiber Reinforced Polymers (FRP) are becoming common place, replacing conventional materials, and have the advantage of light weight (1/6 the weight of steel), cavitation resistance, low coefficient of friction, and corrosion resistance. 

Our series 5000 FRP pipe has been specially designed for severely corrosive industrial services, over a wide temperature range from sub-zero to 180⁰f and is suitable for earth burial at all depths with selection of wall thickness, ribs, and filament wind angle . 

Series 5000 is a filament wound fiberglass reinforced premium vinyl ester epoxy composite pipe with UV inhibition. It’s recommended for a wide range of applications including brine and brackish water, potable water, chlorine, oxidizing chemicals and acids, alkalies, and non-oxidizing acids—to name a few. 

This FRP pipe is ideal for salt or seawater handling and will also withstand chemicals that are commonplace in wastewater treatment and water purification, such as, chlorine dioxide, hydrogen sulfide, and sodium hypochlorite.

Our FRP pipe can be designed, formulated, and manufactured per your specifications, industry requirements and is meets ASTM D-2996 Classification Type 1, Grade 2, and Class E standards.  Similarly, the resins used in Series 5000 pipe meet the requirements of F.D.A. Regulations 21-CFR-175.105 and 21-CFR-177.2420, respectively.  Diameters, ranging from 1/2″ Ø up to 168″ Ø; wide range of lengths available.

As a custom manufacturer of pipe and fittings, we can design and build pipe to handle burial conditions ranging from live loads due to highway and rail traffic – to earth loads of 100 feet or greater. We even have experience with underwater installations. Our engineers will welcome the opportunity to work with you on a pipe design, backfill selection and installation methods to meet your specific requirements.


  • ASTM D2996
  • Classification Type 1, Grade , and Class E
  • FDA Regulations 21-CFR-175.105
  • FDA 21-CFR-177.2420


  • Nominal 40 to 50 mil Glass Veil and/or Nexus Reinforced Corrosion Liner
  • Filament Wound Structural Overlap
  • A premium grade vinyl ester resin,
  • pigmented dark grey for UV inhibition
  • Custom formulations available

FRP has proven its worth in a wide range of applications. With longer life cycles, lower installation costs, design flexibility, and superior corrosion and abrasion resistance it’s quickly becoming the go-to material throughout many markets the world over.

Using CNC Manufacturing to Create Custom FRP Products

CNC Pultruded TubingCNC stands for Computer Numeric Control. CNC Machining is a process used in the manufacturing sector that involves the use of computers to control machine tools. Tools that can be controlled in this manner include lathes, mills, routers and grinders.

CNC Dome LidThe CNC process is relatively straightforward.  First, a CAD drawing is created (either 2D or 3D), second, a code is created that the CNC machine will understand. The program is loaded and finally an operator runs a test of the program to ensure there are no problems. This trial run is referred to as “cutting air” and it is an important step because any mistake with speed and tool position could result in a scraped part or a damaged machine.

CNC Mold1The upfront cost of CNC machines can be steep, but the long-term advantages of employing CNC technology for the manufacturing of precision FRP products, far outweighs the initial cost. 

Many end users of FRP products look for someone who can guide them to the most efficient production approach, one that saves time, money, and resources—CNC manufacturing is one piece to that puzzle. Here are some of the advantages of using CNC manufacturing to create custom FRP products.

  1. Precision—Once the design is programmed into the CNC machine it can be repeated hundreds or even thousands of times with a high degree of accuracy.  A CNC machine will produce replications that are an exact match and there will be no variation from component to component—thus eliminating human error and fatigue.
  2. Adaptability—Not only are CNC machines capable of handling a wide range of designs and materials from wood, metal, plastic, pultruded composites, and FRP—just to name a few.  In addition, CNC machines are capable of creating complex 3D shapes that would be extremely difficult if not impossible to achieve by a skilled machinist. 
  3. Programmability—CNC machines can be programmed by advanced design software, enabling the manufacture of products that cannot be made by manual machines, even those used by skilled designers / engineers.
  4. CNC Man Way LidSaves Time and Money—Modern design software allows the designer to simulate the manufacture of his/her idea. There is no need to make a prototype or a model. This saves time and money.  One person can supervise many CNC machines as once they are programmed they can usually be left to work by themselves.
  5. Low Maintenance—CNC machines can be used continuously 24 hours a day, 365 days a year and only need to be switched off for occasional maintenance. Their reliability, precision, ease of operation and adaptability ensure that the end user gets a cost-effective approach to their design.

At Beetle, our comprehensive capabilities include CNC manufacturing, open molding (hand lay-up and spray-up), precision molding and tooling, filament winding, vacuum infusion, equipment rebuilding, on-site modifications and custom manufacturing/fabrication.  We have over 50 years experience in fiberglass—in that time we’ve developed unmatched dedicated design and field services that enable us to guide you to the most efficient production approach.

What Makes a Superior FRP Fracking Tank?

fracking tankThere are many FRP tank options available out there on the market, so how can you be sure you’re getting a high quality product that performs?  When designing your fracking tank there are many criteria to consider, for example, corrosion barrier thickness, chemicals to be handled, and aesthetics—to name a few. You’ll want to make sure that the product you are ordering has been specially designed to withstand the challenges of corrosive and stringent environments, such as chemical media, high temperature, vacuum, and high pressure.

In addition you’ll also want to be sure the fabricator has the experience and commitment to industry standards to execute the finished product you have in mind.  Here is a short list of some basic characteristics of what we believe makes a superior fracking tank.

1. Corrosion resistance

Work with a dedicated and experienced design/manufacturing team that has the capabilities to deliver superior corrosion resistant tanks that will withstand hydrochloric acid, corrosive solutions, and other fracking fluids.

2. Aesthetics

Find a company that has the right technology, capabilities, and know-how to meet your industry requirements.  Find a manufacturer that has high standards, good quality control, will pay attention to details, aesthetics, and has a proven history in FRP.

3. Design Flexibility and Custom Components

Work with a company that has the engineering experience to offer design flexibility; build new, repair, or upgrade.  Be sure to select a manufacture that possesses the know-how to offer add-on FRP components, such as manways, hose troughs, roll over protection, tank saddles, well lines (dip tubes), drains, fitting, ports, and fixtures and interface with your fleet.

4. Custom Laminate Scheduling and Custom Paint

Find a manufacturer that understands your industry needs and can deliver custom laminate scheduling and paint—ensure you tank performs and looks good.   Be sure the manufacture knows how to select the proper resin for your specifications (i.e. corrosion barrier/liner) and offers custom formulations that can enhance your tanks service life and look.

5. Execute and Deliver

If you’re in the gas exploration industry be sure the manufacturer of your FRP tank and products understands that maintaining supply, hauling hydrochloric acid, corrosive solutions, and meeting deadlines are critical to a successful operation. Be sure they can work efficiently and schedule effectively to meet your demands.

Lastly,  cheap ain’t good and good ani’t cheap, that’s an expression that’s been correct 100% of the time, at least in my experience—in this world you pay for what you get, so be sure to keep that in mind when selecting your FRP products.

Implementing FRP Pollution and Odor Control for Wastewater Treatment

frp pollution controlFiberglass Reinforced Plastic (FRP) components boast design flexibility and durability.  They are used in some capacity in most odor and air pollution control applications at wastewater treatment facilities. They have demonstrated usefulness in both biological odor control systems, as well as, industrial and municipal systems that utilize chlorine dioxide.  Furthermore, their corrosion resistant properties make them an ideal material to handle noxious and corrosive gases, such as hydrogen sulfide—a common byproduct of many wastewater treatment systems.

FRP has been employed in a wide range of waste water treatment applications, for example it is used to make scrubber vessels, pipe, ductwork, fans, stacks, and chemical feed systems.  In addition to direct use as odor control devices, FRP products are often used in wastewater applications for structures, such as grating and decking, or equipment that may be exposed to odorous and potentially corrosive environments.  One of the critical differences that truly separate FRP from metals and metal alloys is that it can be formulated to be corrosion and abrasion resistant in the harshest environments—this helps FRP achieve long service life in many applications from chemical processing, pulp and paper to petrochemical, water treatment, and mining and minerals.

According to a 2006 case study, titled, “Performance Validation of Shell-Media Biological Odor Control System,” published by the Water Environment Federation, a not- for profit technical and educational originization that represents water quality professionals around the world, FRP demonstrated it can play a key role in both structure and equipment demands. 

The pilot project was conducted by Orange County Utilities, Florida.  The test pilot used a shell-media based biological odor control system at the Stillwater Crossing Pump Station. The shell media has the desirable qualities of availability, low cost, long life, and high sustainability.  According to the study, the purpose of the pilot testing was to verify that the system could provide acceptable H2S and odor removal. A skid-mounted, modular pilot unit consisted of a bolted FRP paneled housing, seashell media, control panel, two FRP irrigation sumps, two water recirculation pumps, and a fan with unit-to-fan ductwork and a vertical exhaust stack.  A sampling program at the test site for duration of 8 months yielded good results in airflow and also demonstrated good odor removal efficiencies. 

Many questions still exist about what role FRP will play in this industry, but they have demonstrated their worth beyond this example as superior construction materials. Similarly, FRP have demonstrated their usefulness in plants that use chlorine dioxide, a powerful oxidant used for controlling noxious, irritating, or pungent odors.   FRP have many benefits that have made them ideal materials in the wastewater treatment industry.  For example, FRP have a high strength-to-weight ratio, offer impact resistance, UV resistance, are smoke and flame retardant, possess good dimensional stability, will not take on moisture, and are electrically and thermally non-conductive.


Five Unique Characteristics of FRP

characteristics of frpFiber Reinforced Polymers (FRP) are unique composite materials in many respects.  For starters, they can be formulated to be corrosion, abrasion, and UV resistant, as well as, smoke and fire retardant.  FRP are often a cost-effective choice in many industrial applications; they have long life cycles and have demonstrated durability in stringent environments with reduced maintenance costs.  Here are five reasons FRP stand out when compared to metals and metal alloys.

  1. High Strength-to-Weight Ratio FRP are lightweight and strong; they posses a vast range of mechanical properties, including tensile, flexural, impact and compressive strengths.  When compared to most other metals they can deliver more strength per unit of weight then most metals.  Their light weight also lends itself well to logistics—it’s easier to ship and install.
  2. Customizable- Every industry has unique problems to solve. With FRP engineers have the ability to tailor or modify the design of their FRP to meet their specific requirements.  For example, consider the benefits of altering resin, glass content to optimize your corrosion and or abrasion resistance—you can’t do this with metal. 
  3. Anisotropic- Engineers can maximize the performance and efficiency of the structure when they take advantage of the inherent anisotropic properties of FRP.  Because the maximum strength is in the direction of the fiber reinforcements engineers can optimize the design to optimize the materials and the overall performance of the structure.
  4. High Tensile Strength with Low Modulus of Elasticity-FRP have high tensile strength due to its composite properties.  Engineers can specify unique resin, fiber-reinforcement compositions when working with FRP manufactures.  The design control inherent to FRP will enhance performance and can only be realized when working with composites, not metals.
  5. Ability to Form Complex Shapes- Engineers can harness ultimate design flexibility when using FRP—an advantage over traditional materials such as metal, concrete, and wood.  When you integrate FRP design into your project into your project also consider the added benefits of part consolidation, noise reduction and streamlined design.

There are many other reasons one should consider using FRP.  For example, they offer high dialectical strength, thermal cycling, dimensional stability, impact resistance, low coefficient of friction, and do not require cathodic protection—just to name a few.

The real gem of FRP is that they are customizable and can be designed and modified to meet almost any chemical/physical requirement.  This is primarily why FRP have been chosen by so many industries as the material for corrosion resistance applications—where other materials fail, FRP thrives.  With so many benefits, it’s no wonder that FRP are viewed by so many as a cost-effective alternative to conventional materials.

A Tale of Two Materials – Chemical Resistance of FRP vs Alloys in Wet Processes

chemical resistance of frpThere are many important predictors of service life in industrial chemical processes; for example, humidity, temperature, pressure, and stress.   Similarly, chemical resistance is a key predictor of FRP service life in phosphate fertilizer processes where high chloride and fluoride levels exist.  FRP have a considerable chemical resistance advantage in corrosive environments and they are cheaper to fabricate—all good news considering there is an increased demand for new corrosion solutions in these plants.

According to a case study titled, “The Use of FRP in Phosphate Fertilizer and Sulphuric Acid Processes,” (2007) released by Ashland Performance Materials, Dublin, OH,  FRP made from epoxy vinyl ester resin has the chemical resistance necessary for long-term service life- in many cases 50 years and counting. When compared to Alloy C-276 (clad carbon steel), 2205 stainless steel, and nickel alloy, FRP demonstrated superior chemical resistance and cost-effectiveness in “wet process” phosphoric acid and sulfuric acid environments found in phosphate fertilizer plants.

Epoxy Vinyl Ester Resin Chemical Resistance Compared to Metal


Sulfuric Acid

Hydrochloric Acid

Acid Chloride Salts

FRP made with epoxy vinyl ester resin

100˚C to 30%

80˚C to 15%

100˚C all conc.

2205 stainless steel

30˚C to 30%

60˚C to 1%

65˚C to 2000ppm @lower pH

Alloy C-276

100˚C to 30%

80˚C to 15%

65˚C to 50ppm @ lower pH

* Taken from the 2007 Ashland Performance Materials Case Study-
 “The Use of FRP in Phosphate Fertilizer and Sulphuric Acid Processes”

The demand for corrosion resistant products began to increase in 2007 when nickel hit an all time high of $24/lb. According to the International Monetary Fund, as the global economy strengthens and developing nations increase their infrastructure build, base metal pricing – most notably copper, nickel and stainless steel are expected to continue their upward march.  While the price of nickel has come down considerably the market is generally considered volatile and the demand for corrosion resistant products continues to increase.

According to a different study released in 2011, by Ashland Performance materials, considerable savings can be realized when choosing FRP construction materials.  In 2011, shop and field fabricated FRP approximately cost $50-$75/Sq Ft. compared to 2205 stainless steel at $225/Sq Ft. and C-276 clad carbon steel at $330/Sq Ft. respectively.

So where does this leave FRP and is there any anticipated growth? According to a 2009 study by the Food and Agriculture Organization of the United Nations (FAO), titled “World Fertilizer Trends and Outlook to 2013,” based on longer-term population and income projections, global food production needs to increase more than 40% by 2030 and 70% by 2050 –all things considered the phosphate and FRP industry could stand to benefit from the projected increased demand for calories, combined with upward trending metal prices.

As global food production increases along side population growth, so will the need for phosphate bases fertilizers —FRP will be ready.  FRP are a superior chemical and corrosion resistant materials option, at a price much lower and much more stable than that of traditionally used alloys such as nickel- in “wet process” phosphate fertilizer plants.  Furthermore, FRP provide engineers, architects, and designers with a reliable, cost-effective construction material that can be employed in a myriad of corrosive applications.