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Uses of Fiberglass Pipe and Large Diameter Fiberglass Pipe

Applications and Key Benefits

uses of fiberglass pipeSince the mid to late 1980’s underground large-diameter composite piping has continued to grow in applications and usage. Technological advancements in the filament winding process, corrosion resistance, education and outreach, and strong market forces have contributed to the popularity of fiberglass pipe. Definitions of what constitutes large-diameter pipes can vary, but generally speaking they range from 12” to 14’ in diameter. 

Composite, or fiberglass pipe, has been utilized in a wide range of industries such as power generation, petrochemical and desalination.  Fiberglass pipe is corrosion resistant, has a life cycle that often exceeds 30 years, and has become increasingly more desirable as an alternative to steel, other metal alloys, ductile iron, and concrete.  According to an article published in 2008, titled “Large Diameter Pipe: Lasting Function in a World of Growth” more than 60,000 km (37,280 miles) of composite large diameter pipe are in operation around the world. 

Although fiberglass was once viewed as specialty product, for its ability to withstand an attack from sulphuric acid, it has now become a standard material, if not the standard in major market segments for a variety of reasons.  For example, fiberglass has been employed in drinking water projects, irrigation systems for agriculture, feed lines and penstock for hydroelectric power plants, power plant cooling water systems, gravity and pressure sanitary sewers systems, and pipeline rehabilitation “slip liners”.  Over the past two decades fiberglass has begun to transcend it’s early stereotypes as a one-trick pony (e.g. corrosion resistance) and has demonstrated its value as a cost-effective material, offering a plethora of end-user benefits.

Chief among the reasons for fiberglass increased usage and popularity are key benefits such as high strength-to-weight ratio, dimensional stability, good mechanical properties, ease of installation, reduced installation costs, reduced maintenance cost, and overall durability in extreme conditions. Similarly, another advantage of fiberglass pipe is it has a smoother inner surface when compared to traditional construction materials.  This attribute, smooth internal bore, resists scale-deposits and can create greater flow of service liquid over the life of the project.

When designing an underground large diameter pipe system many considerations need to be taken into account; local soil conditions, depth of water table, burial loads, live loads, deflection due to burial stress and operating temperatures—just to name a few.   Similarly, an American Water Works Association manual, Fiberglass Pipe Manual, also known as M45, provides equations that take into account factors such as fluid velocity and fluid pressure, head loss due to turbulent flow, water hammer, buckling pressure, and surge pressure.  Designing a proper underground piping system is a complex process that involves extensive calculations—product design should always be by qualified engineers. 

Large Diameter Pipe for Water Circulating Project

The photo shows one of many large diameter pipe spools for a circulating water project. We worked closely with the customer’s installation contractor to meet their delivery needs. The jobsite had limited laydown area and to transport each pipe multiple times onsite was not economical or efficient. We staged pipe at our facility and held a strict production schedule to ship just in time.

fiberglass pipe large resized 600

Fiberglass reinforced composite resin “fiberglass pipe” has several benefits over traditional
ductile iron, concrete, thermoplastics and vitrified clay systems:

  • lightweight and easy to handle compared to other materials.
  • excellent chemical resistant in corrosive environments.
  • high strength.
  • very low Fluid flow resistance
  • long life and durability

Fiberglass pipe is lightweight compared to ductile iron, concrete and vitrified clay. It can be easily moved into place during installation. Fiberglass pipe can be made with many different types of resin to meet the particular corrosive environments needed. Fiberglass welded joints have long wear compared to vitrified clay and concrete which may crack and be susceptible to chemical attack. Another benefit is that fiberglass pipe has a high strength ratio compared to thermoplastics. Lastly it has a very low Hazen-Williams Coefficient compared to steel and concrete. In some applications pump size can be reduced which reduces power consumption with money savings in yearly operating costs.

When you need fiberglass piping for your water circulating and waste water needs, call us here at Beetle Plastics to see how we can deliver a custom solution.

The Large Diameter Composite Pipe Market Continues to Grow

Fiber reinforced polymer (FRP) is our passion here at Beetle, which is why we were very pleased to see a recent article published by Reinforced Plastics.com. “Large diameter composite pipe is gaining market share at the expense of pipe made with commodity materials, in general-purpose as well as specialty applications, ” Ben E Bogner in the article “Large Diameter Composite Pipe: Lasting Function in a World of Growth.” It’s no secret that FRP pipe isn’t the most glamorous of FRP applications, but functionality and durability have allowed the large diameter composite pipe industry to gain in strength as pipe made with iron and concrete lose market shares.

When we talk about large diameter pipe, we’re generally referring to, “pipe that is at least 12 inch in diameter. At the higher end, the sector includes composite pipe in diameters as large as 14 feet.” This sort of pipe is generally used for a number of applications, but the most common, according to the article, are:

  • drinking water projects such as raw water supply lines for potable water systems;
  • irrigation systems for agriculture;
  • feed lines and penstock for hydroelectric power plants;
  • circulation for cooling water systems, primarily for power plants;
  • sanitary sewer projects for pressure as well as gravity sewer systems, and
  • pipeline rehabilitation as ‘slip liners.’

There are a number of features that have contributed to the increased market share controlled by composite large pipes. One of the most attractive features of FRP pipe is that is it resistant to corrosion, even the corrosion you see with sulphuric acid. Composites are also a cost effective  alternative to other kinds of raw materials like pig iron and steel. Even though all kinds of raw materials costs have been steadily creeping upward, the cost of composites hasn’t increased nearly as much.

“Another reason for the increased market share is the fact that FRP pipes for the last 30 years have proven to be a reliable alternative. More than 60 000 km (37 280 miles) of composite large diameter pipe are in operation worldwide to prove that the material will perform long-term as predicted.”

To read the full article, click here.

How to Properly Bury Fiberglass Piping

Beetle Plastics has developed a series of specifications that pertain to buried flexible fiberglass piping where the fiberglass pipe, trench walls, and bedding material work together to form a complete pipe support system. This post outlines the sections covered in our engineering document available for download.

The elements of this system can best be defined by considering a section of buried flexible pipe and the loads acting on it. These loads, the dead load (backfill) and the live loads (vehicle traffic), act downward on the pipe, tending to deflect it into an oval shape. If the bedding material at the sides of the pipe is compacted sufficiently, it will resist the pipe movement and minimize the deflection and ovalization to an acceptable amount. For this reason, the construction of the trench and selection of bedding materials must be closely controlled.

These specifications cover the burial techniques required for the installation of fiberglass pipe under most conditions.

SECTION I: Fiberglass Pipe Storage and Handling

When storing fiberglass pipe directly on the ground, select a flat area free of rocks and other debris that could damage the pipe. Also, when preparing the ends for joining (butt wrap or tapered bell and spigot joints), do not roll the pipe over rocks, debris, or uneven ground that does not fully support the pipe.

SECTION II: Trench Excavation and Preparation

The actual depth of the trench is determined by the final grade, plus the depth required for the initial (bottom) layer of bedding material. The soil conditions and bedding materials being used will determine this additional depth.

Nominal trench widths are listed in the engineering guide available for download.

SECTION III: Bedding and Backfilling

The trench bottom is the first element of the pipe support system. There are many things to consider when building the bedding including pipe diameter, pipe type, soil type and density, and water table.

Schematics and details are contained in the fiberglass pipe engineering document.

SECTION IV: Concrete Structure

Where the fiberglass piping goes through or passes under a concrete structure, precautions must be taken to prevent excessive strain on the pipe due to the differential settling between the structure and the pipe. There are several methods discussed in the engineering document for compensating for settling without straining the fiberglass pipe.

Contact us today about your fiberglass pipe and tank requirements.

Fiberglass Pipe Thermal Expansion and Contraction

frp material properties, frp pipe

FRP Pipe Properties: Thermal Expansion and Contraction

Beetle Plastics 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.

The relatively low modulus of elasticity of the fiberglass pipe is an advantage which should be considered in the design of a piping system. Since thermal forces are smaller, restraining equipment (guides, anchors, etc.) need not be as strong or heavy as for steel piping. There is some growth due to end load from pressure in the piping system; but experience has shown that this length change does not need to be considered in designing a fiberglass piping system. FRP composite piping systems can handle thermal shocks between maximum rated operating temperatures and -40°F, unless the pipe joints are mechanical joint style.

To determine the effects of expansion and contraction within a piping system, it is necessary to know:

  1. The design temperature conditions.
  2. The type and size of pipe.
  3. The layout of the system including dimensions and the thermal movements, if any, of the terminal
  4. points.
  5. The limitations on end reactions at terminal points as established by equipment manufacturers.
  6. The temperature changes for expansion are calculated by subtracting the installation temperature (temperature at time of final tie in) from the maximum design temperature.

Temperature changesfor contraction are calculated by subtracting the minimum design temperature from the installation temperature. Expansion and contractions of above ground fiberglass pipe may be handled by several different methods.

Four methods are:

  1. Direction Changes
  2. Anchors and Guides
  3. Mechanical Expansion Joints
  4. Expansion Loops

Guides, Expansion Loops, and Mechanical Expansion Joints are installed in straight pipelines which are anchored at both ends. The experience of users of FRP composite piping systems has shown that if directional changes cannot be used to accommodate thermal expansion and contraction, then the guide spacing design approach is usually the most economical method.

Operating experience with piping systems indicates that it is a good practice to anchor long straight pipe runs of above group piping at approximately 300-foot intervals. These anchors prevent pipe movement due to vibration, water hammer, etc.. Also, an anchor is used wherever a pipe size change occurs. When joining FRP composite piping to other piping systems, the adjoining system MUST be securely anchored to prevent the transfer of thermal end loads.

Contact us today and we can arrange a test installation in your plant comparing Beetle Plastics abrasion resistant pipe with your current piping and duct materials.

FRP and Abrasion Resistant Lining: Lined Pipe vs. Unlined Pipe

abrasion resistant lining

This is the second in a series of blog posts discussing lined FRP pipe vs. unlined FRP pipe. The first posts discusses corrosion resistance.

In this post, we discuss abrasion resistance.

Abrasion Resistance: There is an element of abrasive wear in almost all fluid service applications.  In the concern for corrosion resistance, this abrasion element of the environment is often overlooked.  Especially for pipe subjected to high flows or where there may be particulate matter contamination (i.e. cooling water applications, river water, waste handling, etc.) abrasion design needs to be considered for all FRP pipe.

As with corrosion resistance, the resin matrix provides the abrasion resistance.  With a properly designed and selected corrosion barrier/liner, the abrasion resistance (and the pipe life) can be up to ten times greater than for unlined pipe, where the glass filaments are directly exposed to the service wear.  With unlined pipe, very rapid wear can occur, with the roving filaments being “picked” away from the surface.

Through further modifications of the corrosion barrier/liner, consisting of proper resin
selection, proper type of non-glass reinforcement, and armoring modifiers, the abrasion resistance of the corrosion barrier can be further improved.

Another compelling reason for always using a corrosion barrier/liner in FRP composite pipe is to provide the capability for changes in service environment. Even if the current service environment would not benefit from the additional protection of a corrosion barrier/liner, the addition of a corrosion barrier/liner provides insurance that future changes in the service stream can take place without concern for the life of the FRP pipe.

Perhaps the nature of the waste stream may be different five or ten years from today. Perhaps even for relatively mild cooling water or river water service, the end user may want to add treatment chemicals in the future. The zebra mussel that is attaching itself to the insides of pipe has made headlines.

The addition of a corrosion barrier/liner for pipe would provide additional abrasion resistance in removing, by mechanical means or hydro blasting, such mussel buildups.  The small additional cost for a corrosion barrier/liner can be a very inexpensive insurance policy for the future. 

The final benefit to using lined FRP composite pipe is lower in-service costs.  One of the advantages of FRP composite plastic pipe is its internal smoothness over its entire service life, especially when compared to other materials such as concrete, steel, etc.  This smoothness is translated into less friction and, thus, lower pumping cost. In some cases, even a smaller diameter pipe can be used.

Even small differences in the smoothness of the FRP pipe interior can be translated into dollar savings in electricity or fuel (for the pumps). The glass smoothness of the high resin content corrosion barrier/liner is measurably better than for unlined FRP pipe. In addition, the energy savings advantage of the resin-rich corrosion barrier/liner increases with age.

Summary:

Except for conduit, in almost all instances a corrosion barrier/liner can be economically justified for FRP composite pipe. We recommend, as a minimum, a 40 mil thick C-veil and/or Nexus reinforced corrosion barrier/liner. For moderate and severe corrosive environments, an even thicker corrosion barrier/liner should be considered.

We will be glad to work with you in selecting the best corrosion barrier/liner for their service
environment.  We are confident that “lined” FRP pipe will provide the end user their lowest cost per year of service life and, thus, their “Best Buy”.

Contact us today and we can arrange a test installation in your plant comparing Beetle Plastics abrasion resistant composite FRP pipe with your current piping and duct materials.


Improvements to Abrasion Resistant Pipe made from FRP Composites

abrasion resistant pipeJack Mallinson of FMC Corporation’s plant in Front Royal, Virginia, working in conjunction with Beetle Plastics, then located in Fall River, Massachusetts, conducted some of the earliest work in improving abrasion resistance of FRP pipe. These original developments took place
in the late 1960’s and early 1970’s.

This work found that significant increases in abrasion resistance could be achieved by adding armoring modifiers to the resin used for the internal corrosion barrier of the pipe. In those early days, the best modifiers were various forms and grades of aluminum oxides. There were problems in getting the aluminum oxide to disperse and “wet out”. However, once the aluminum oxide dispersed, improvements of abrasion life in the magnitude of two to three times over a non-modifi ed resin were achieved. The resin matrix used in those days was typically the Hetron 197 polyester resin.

While some companies that make so-called abrasion resistant pipe still use that same filler approach and formulation from the late 1960’s, Beetle continued to find a better way. In the early 1970’s, working with the late Walt Szymanski of Hooker Chemical, Beetle Plastics made major advances in the technology of abrasion resistance in FRP composites. In an extensive series of tests conducted in conjunction with Hooker, Beetle discovered that three fabrication techniques significantly influence the resulting abrasion resistance of the composite laminate.

Type of Resin: The type of resin used in making the inner abrasion/corrosion liner of the pipe influences the resulting abrasion resistance of the pipe. Special developmental elastomeric and epoxy vinyl ester resins signifi cantly increase the abrasion service life. Beetle Plastics
worked closely with Dow Chemical and Interplastics in developing these experimental resins. The selection of the proper resin, along with specifi c resin modifi cations, increases abrasion resistance by a factor of two to three times over a standard polyester or epoxy resin.

Type of Reinforcement: Beetle also discovered, in these series of Hooker tests, that the type of reinforcements used in the matrix signifi cantly infl uenced the abrasion resistance of the inner abrasion/corrosion liner. The tests demonstrated that specific types of
reinforcements greatly improved abrasion resistance of the laminate.

Also, a specific combination of selected reinforcements was critical to obtaining the optimum abrasion resistance. As the result of that knowledge, Beetle Plastics now uses a unique combination of laminate reinforcements that help significantly improve the total abrasion resistance of the composite laminate.

Armoring Modifier: Building on the early work done with FMC, Beetle conducted extensive tests to improve armoring modifiers. Beetle succeeded in developing a new type of modifier that provides superior armoring of the FRP composite. This material compares in toughness to
basalt, which in its natural form is often used as abrasion liners for steel pipe.

Over the years, Beetle Plastics has fine-tuned the specific grades of this armoring modifier material, selecting those that demonstrate the best performance in abrasion resistant FRP composite pipe. Beetle also developed techniques to gain the optimum dispersion and wetting out of this armoring modifier within the resin. Getting this ideal resin “hook” to the armoring modifier is also an important consideration when developing the best possible abrasion resistance of FRP laminates.

In order to gain maximum abrasion resistance from FRP composite pipe and laminates, it takes careful selection of all three of the important factors (resin, reinforcements, and armoring modifiers), in the proper ratios and interactions.  Test results from this research indicate reductions in abrasion loss in FRP composite laminates to just one-tenth that of non-modified laminates. In other words, you might expect increased service life of ten times, or more, from Beetle Plastics abrasion resistant composite pipe and ducts.

But, to paraphrase an old saying – “the proof is in the pudding”. For FRP composite abrasion resistant pipe, the proof is in the service life obtained in actual fi eld installations.

In tests, control installations showed substantial abrasion wear and failure in just several months of service life. Regular six-month and annual inspections at these plants of Beetle Plastics abrasion resistant pipe and elbows (an elbow is an area of high abrasive wear) showed little discernable wear.

Beetle continues to refine our FRP pipe abrasion resistant technology. As a result, you can confidently turn to Beetle Plastics for the best FRP composite abrasion resistant piping system available.

Customers at numerous projects have achieved outstanding FRP piping service life in highly abrasive applications such as lime slurry, fly ash slurries, and the extremely abrasive bottom ash service.

Contact us today and we can arrange a test installation in your plant comparing Beetle Plastics abrasion resistant pipe with your current piping and duct materials.

Lined Pipe vs. Unlined Pipe – Pipe Strength and Structural Integrity

lined pipe vs. unlined pipeIn earlier posts, we discussed the first reason to choose lined FRP pipe: abrasion resistance and corrosion resistance. The third major reason to choose Lined FRP pipe is Structural Integrity.  While typically the corrosion barrier/liner is not counted on for adding strength to the FRP pipe, it does enhance the structural integrity.  Depending upon the service environment, sometimes the structural properties of the SPI type corrosion barrier/liner are included in determining the pressure rating of the FRP pipe.

One of the advantages of properly designed and manufactured fiberglass filament wound composite pipe is that it will typically show signs of “weeping” through the pipe wall when over-pressurized, long before a catastrophic failure occurs.  Such weeping occurs by fluid wicking following the continuous glass roving used in filament winding.  The weakest portion of the structural wall is the glass/resin interface. The corrosion barrier/liner, thus, serves to prevent the fluid media from getting to that continuous fiberglass filament.

From a purely structural viewpoint, the ideal corrosion barrier/liner would be a rubber bag. This rubber liner would continue to stretch, allowing the structural wall to fully take advantage of the superstrong, continuous glass filaments until they actually broke.  A properly designed resin corrosion barrier/liner serves the same function allowing the structural wall to take the full load without concern for pipe wall weeping.

Contact us today and we can arrange a test installation in your plant comparing Beetle Plastics abrasion resistant composite FRP pipe with your current piping and duct materials.

Lined Pipe vs. Unlined Pipe – Corrosion Resistant Pipe

corrosion resistant pipeIt has always been our contention that all FRP composite pipe for fluid service should have an internal corrosion barrier/liner.  Therefore, it has been our policy to supply all pipe, with such a corrosion barrier/liner.  The type and thickness of this corrosion barrier/liner will depend upon the specific service environment.  The thickness of a corrosion barrier/liner can range from a 40 mil (0.040″) for cooling water applications, to over 200 mil (0.200″) SPI type for wet chlorine gas service.

The purpose of this blog post series is to detail why we believe it is important to provide FRP composite pipe with an internal corrosion barrier/liner.

We will take each major reason and discuss in each blog post.

The first major reason to use lined FRP pipe is Corrosion Resistance.

We realize that some pipe manufacturers market a pipe without a corrosion barrier/liner (typically called unlined pipe). Interestingly, in most cases, the resins used for the unlined pipe series also have lower corrosion resistance capabilities, and lower service temperature limitations.  All pipe manufacturers provide a corrosion barrier/liner in their pipe intended for moderate to severe corrosive applications.

Since fiberglass reinforced composite pipe is typically used for applications where corrosion is a consideration, it seems only logical to use a corrosion resistant product.  In FRP composite pipe, the resin matrix provides the corrosion resistance. The higher the resin content of the laminate exposed to the service environment, the “better” the corrosion resistance. Also, within the limits of the resin system, the thicker the corrosion barrier/liner, the greater the corrosion resistance.

Unlined pipe typically has a resin content of just 30 to 40 percent in the surface exposed to the service environment.  In pipe built with a corrosion barrier/liner, the resin content is typically 80 to 90 percent.

What does all this mean to the end user?  In a filament wound composite pipe, the cost of adding a  corrosion barrier/liner is not all that great in comparison to the true cost of the pipe. The selection of the proper type and thickness of the corrosion barrier/liner can more than double the service life of the pipe.  Since fiberglass pipe is typically being bought to provide longer service life than other alternate materials, the addition of a corrosion barrier/liner can become an important cost savings to the end user, providing the lowest cost per year of service life.

Contact us today and we can arrange a test installation in your plant comparing Beetle Plastics abrasion resistant composite pipe with your current piping and duct materials.