GRP Pipe Types Explained: Uses in Infrastructure Projects

GRP pipes, a composite blend of glass fibers and resin matrix, are used confidentially in industrial piping systems to reach long-lasting performances over 50 years. The resin type can define which type of GRP pipes should be used based on the project’s demands. But what exactly makes these liquids flow smoothly in the water and sewer systems?

GRP pipe types include epoxy-based GRE for high-pressure or offshore systems, vinyl ester-based GRV/GRVE for chemical and industrial lines, and polyester-based GRP for water and sewage. Each type matches particular engineering, municipal, or industrial applications by using glass fibers with various resins to provide several different levels of strength, corrosion resistance, and temperature tolerance.

Whether you’re an engineer, a contractor, or a project manager striving to find the best material for your infrastructure, here we’ll provide you with a comprehensive guide to GRP, GRV/GRVE, and GRE pipes’ classifications.

Classification of GRP Pipe Types by Resin

When engineers talk about GRP pipe types, they usually classify them by the resin matrix used in their construction. The resin represents how pipe performance varies in different harsh environments. That’s why understanding of resin type will pave the way for pipe selection.

GRP: Polyester-Based Pipe for General Uses

GRP pipes with a polyester base are mostly used in water supply and sewage networks due to cost-effectiveness and high resistance to harsh water or soil conditions. This type includes such temperature tolerance up to 60 °C.

• Material Note: GRP pipes can reduce the transportation costs while keeping long-term performance due to their lightweight and good strength-to-weight ratio compared to steel pipes.

GRV/GRVE: Vinyl Ester-Based Pipe for Chemical Processing

Vinyl ester type of GRP pipe, or GRV or GRVE, is suitable for chemical and harsh environments where acids and alkalis require such a resistant pipeline for chemical handling in high temperatures. This can avoid damage under repeated pressure stress in chemical plants, power systems, and industrial wastewater piping lines.

• Mechanical Point: GRV provides such tensile strength up to 80 MPa compared to GRP pipe with 70 MPa, which boosts the durability in hard-to-resist situations.

GRE: Epoxy-Based Pipe for Superior Resistance in Harsh Environments

The most powerful of the three is GRE, or epoxy-based GRP. It can withstand temperatures near 120 °C and function under high pressure. These characteristics make it ideal for systems where a long service life is important, such as flue gas scrubbers and offshore oil and gas pipelines.

• Technical Insight: In high-pressure applications, high-pressure class pipe is required. ISO 14692-3 is for stress analysis under heavy loads.

Core Material Components

GRP pipe shows specific performances depending on how its materials are selected. The layered combination of resin and glass fiber determines how pressure, corrosion, or heat resistant the GRP pipe will be.

Resin Variants

The central factor in the performance indication of GRP pipe is the resin type, which includes polyester, vinyl ester, and epoxy resin.

• GRP, Polyester Resin: The most moderate choice in water and sewer systems for corrosion resistance and heat tolerance up to 60 °C. (Source: Amiblu)
• GRV/GRVE, Vinyl Ester Resin: Applied for higher resistance to acids, alkalis, and other solvents. Also, higher temperatures will be handled in this way.
• GRE, Epoxy Resin: The most resistant to temperature, corrosion, and pressure, which can withstand temperatures up to 120 °C in oil and gas pipelines for decades.

Glass Fiber Types

The most preferred glass fiber type in GRP pipes is E-Glass, which has such high mechanical strength. However, there is another type called E-CR glass that is used in cases of aggressive soils and harsh environments for long-term performance.

GRP Pipe Layer Composition

GRP pipes are created in three main layers.

• One, the inner smooth layer is resistant to corrosion and speeds up the flow by its smoothness.
• The second one is a structural layer made of glass fiber in a filament winding process that resists heavy loads perfectly.
• The last layer, outer protective layer, is added for UV resistance in aboveground installation that soil condition and abrasion also may threaten the pipes.

How are GRP Pipes Made? A Classification by Manufacturing Process

GRP pipes are made by passing automated and manual processes for special designs. The way they are manufactured can define how strong, resistant, and durable they perform in various industries.

Process	Typical Resins	Advantages	Applications
Filament Winding	Polyester, Vinyl Ester, Epoxy	High strength, consistent quality, precise fiber control	GRE and GRVE pipes, industrial lines
Centrifugal Casting	Polyester, Vinyl Ester	Dense walls, smooth bore, accurate sizing	GRP water and sewer systems
Hand / Spray Lay-Up	Vinyl Ester, Epoxy	Flexible for fittings, good for corrosion barriers	Custom fittings, chemical service

Filament Winding

The most common method in the GRP pipe manufacturing process includes soaking glass fibers in resin, winding them around a mandrel to shape the long section of pipes in a continuous method, and for short ones, a discontinuous process can create them to ease further transportation.

Centrifugal Casting

In this method, chopped glass fibers and resin are combined with a centrifugal force to shape those thick walls and smooth surfaces that reduce the need for pumping energy. Polyester and vinyl ester resin are primarily used in this method to make such resistant pipelines in water and sewer systems.

Hand or Spray Lay-Up

This method uses manual steps to convert glass mats to such specialized pipes. Fittings and corrosion-resistant linings are made by this method. Also, according to Scribd, epoxy and vinyl ester resins are mainly used for chemical processing pipelines.

Classification by Pressure & Stiffness Ratings

GRP pipes are classified by their central components, like pressure class or stiffness class, to show how they resist under pressure and external loads.

• The pressure class (PN) represents the maximum ability of pipes to handle pressure that ranges from PN 6 to PN 32 in special use cases and designs. The higher the PN gets, the better the pipeline can tolerate pressure in water, oil, or chemical piping systems.
• The stiffness class (SN) defines the way that a GRP pipe will resist under heavy loads with no deflection or deformation included. As highlighted in FuturePipe, these rates, from SN 2500 to SN 10000, show the pipe’s ring stiffness in deep burials and heavy traffic cases like highways.

How can the performance of GRP pipe change in different types of resin matrix?

Polyester GRP pipes are manufactured with low to medium PN and SN classes, while vinyl ester GRV has higher ranges, and epoxy GRE includes the highest pressure class and stiffness class for perfect tolerance of pressure and temperature in offshore or industrial piping systems.

GRP Pipe Type Applications

Let’s see where GRP pipes really excel! Based on the type and strength of the resin, each kind of GRP, GRV/GRVE, and GRE has a distinct function that makes them ideal for particular projects.

GRP (Based on Polyester)

Because they are resistant to corrosion, GRP pipes made of polyester resin are excellent at distributing clean water. They are popular in budget-conscious cities because they can easily manage sewage systems and municipal waste with little maintenance.

GRV/GRVE (Based on Vinyl Ester)

Vinyl ester resin-powered GRV/GRVE pipes flourish in chemical lines and can withstand harsh acids and alkalis in chemical plants. Long-lasting performance in demanding, harsh conditions is ensured by their construction for industrial sewage and corrosive fluids in applications like desalination or mining.

 GRE (Epoxy-Based)

Epoxy resin-based GRE pipes are intended for high-pressure, high-stress applications, such as gas and oil pipelines.

• Pro Tip: Because of their mechanical strength, they are perfect for scrubber systems and offshore applications where they can dependably withstand high temperatures and corrosive gases.

Industry Standards & Compliance

GRP pipes follow international standards and guidelines that design the way of achieving safe and reliable installation and long-term performance.

ISO

On the one hand, ISO 14692 is one of those famous standards that are used globally to adapt infrastructures to international requirements. In this case, components such as design policies, fabrication, testing, and material composition are inspected in resin types like vinyl ester in GRVE pipes.

ASTM, AWWA, and European Cases

On the other hand, ASTM (American Society for Testing and Materials) for material testing, AWWA (American Water Works Association), and European ones like EN and BS are some other well-known standards that are used to guide manufacturers to align their products with global demand.

Regional Cases

Furthermore, there are many countries like India that support manufacturers by their own regional standards and guidelines. Indian IS standards mainly work for reliability in such infrastructure of GRP, GRV, and GRE piping systems.

Selection Guidelines For GRP, GRV/GRVE, and GRE: When to Use Each?

In order to choose the best GRP pipe, the resin type must be in line with the particular requirements of the project. Before moving on to real-world use cases, we describe how to match GRP, GRV/GRVE, or GRE pipes to the medium, environmental exposure, pressure/stiffness ratings, and budget.

Medium

In water distribution systems, GRP pipes made of polyester resin handle non-aggressive fluids like water or municipal sewage.

Vinyl ester resin-based GRV/GRVE pipes perform exceptionally well in chemical lines that contain corrosive fluids like acids or alkalis. Epoxy resin-built GRE pipes are perfect for high-pressure fluids like gas or oil.

Environmental Exposure

GRP pipes function dependably in mild soils or climates. GRV/GRVE or GRE pipes with protective coatings or E-CR glass guarantee durability in harsh environments, such as acidic soils or UV-exposed areas.

Pressure and Stiffness Ratings

GRP pipes are suitable for stiffness classes (SN2500–SN5000) and low to medium pressure classes (PN6–PN16).

GRE pipes support high PN ratings (up to PN120) and SN ratings for demanding applications, whereas GRV/GRVE pipes handle moderate loads.

Budget

GRP pipes are an affordable option for municipal projects. While GRE pipes are more costly, they offer long-term durability for vital systems, while GRV/GRVE pipes strike a balance between cost and performance.

Use Cases Scenarios

GRP pipes are inexpensive and resistant to corrosion for a city’s water supply system. GRV/GRVE pipes reliably handle corrosive fluids in a chemical processing facility. GRE pipes guarantee mechanical strength for an offshore oil pipeline even in the face of severe marine conditions and high pressure.

Final Wrap-Up

GRP pipes include a variety of different types by their resin type. Each pipe includes specific properties that work for various applications. For instance, GRE manages high-pressure offshore pipelines, GRV/GRVE is superior in chemical lines, and GRP is appropriate for low-cost water systems. Standards and guidelines also match these pipes with global demands to ease the selection for engineers and contractors around the world.

FAQs

1- What are the different types of GRP pipes based on resin?

GRP pipe types include epoxy-based GRE for high-pressure or offshore systems, vinyl ester-based GRV/GRVE for chemical and industrial lines, and polyester-based GRP for water and sewage.

2- What are the typical applications for GRP pipes?

GRP pipes are primarily used in water supply and sewage networks due to cost-effectiveness and high resistance to harsh water or soil conditions.

3- Where are GRV/GRVE pipes used?

Vinyl ester type of GRP pipe or GRV or GRVE is suitable for chemical and harsh environments where acids and alkalis require such a resistant pipeline for chemical handling in high temperatures.