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Fiberglass Pipe ~ Past, Present and Future
By Sullivan D. Curran P.E., Executive Director
Fiberglass Tank & Pipe Institute
Purpose and Scope
Today Fiberglass Reinforced Thermosetting Plastic ("FRP") is being
used in many industrial product applications, including the storage
and transfer of corrosive materials or the handling of other
materials in corrosive environments. While FRP piping has a 30-year
history, it is considered a modern day product material with many
new emerging applications that take advantage of its corrosion
resistance, strength-to-weight ratio, low maintenance and life cycle
cost. This paper discusses the history of FRP piping, current
applications of FRP pipe and emerging future technological advances for new
applications in petroleum storage and handling facilities.
Introduction
Don’t confuse FRP piping with ordinary thermoplastic piping like PVC and
polyethylene. Those thermoplastic systems typically employ non-reinforced
extruded pipe and injection-molded fittings and flanges. What strength they have
comes from the sheer bulk of material. By contrast, FRP piping materials are
manufactured by winding processes that employ epoxy resins reinforced with
continuous glass filaments. The resins used are thermosetting i.e., they undergo
irreversible chemical reactions as they cure, resulting in superior temperature
capabilities, while the filament reinforcement makes the piping components
mechanically far more capable than ordinary non-reinforced thermoplastics. The
result is enhanced performance and lighter weight.
Also, don’t confuse hand "lay-up" with machine made FRP products. Hand lay-up
manufacturers number in the thousands and include small shops which typically
specialize in consumer products, such as bathroom vanities or pleasure boats.
However, there are relatively few machine made pipe manufacturers. These are
large manufacturers that mass produce on-the-shelf or custom piping for
petroleum, commercial, industrial and municipal applications for both domestic
and overseas markets. Machine made FRP can have a higher glass loading i. e.,
denser glass fiber filament/resin product which is more reproducible in a
quality controlled environment. Therefore, this paper is limited to advancements
made in machine made pipe and fittings that will have applications in the
petroleum industry.
Early Days
In the early days, just after Colonel Drake’s discovery near Titusville, Ohio,
in 1859, no pipe was used at all! This early oil production was pumped directly
into wooden barrels for shipment. The first pipes were made from wood and later
replaced with steel. However, steel lines were rapidly corroded by the
combination of salt water and sour sulfur crude. While FRP technology was
developed during World War II, it was later when the first pipe was made from
FRP by applying a glass fiber cloth and resin over a male mandrel by hand. This
"hand lay-up" method was suitable for some chemical industry applications, but
did not have the combination of strength and cost-effectiveness necessary to
replace steel in the petroleum industry.
Machine Made Piping
In the 1950’s centrifugal casting was the first machine made method to produce
pipe suitable for chemical and commercial applications and oil field gathering
lines. Next a filament winding process was developed to manufacture pipe with
tensioned glass fibers oriented to bear the combination of hoop and axial
forces. Filament winding with a dual angle construction called for layers of
glass fibers in a near axial orientation and resulted in developing high
pressure (up to 2,000 psi) down hole tubing for producing wells. Some of these
earlier FRP tubing strings remain in service after more than 35 years of
production.
In the 1960’s an efficient high volume continuous pipe production process was
developed for small diameter pipe rated for pressures (up to 450 psi). Large
scale use of this pipe began in 1964 and was primarily installed in two inch
crude oil gathering lines.
Codes and Standards Development
In 1959 the first nationally recognized standards and test methods for FRP pipe
were published by the American Society for Testing Materials ("ASTM"). This
first specification was ASTM D1694, Standard Specification for Threads for Glass
Fiber Reinforced Thermosetting Resin Pipe and developed by a group composed of
representatives from fiberglass pipe manufacturers, oil companies and other
industries.
In 1968 the American Petroleum Institute ("API") published their first FRP pipe
standard. This first API standard was API 15LR, Specification for Glass Fiber
Reinforced Thermosetting Resin Line Pipe. Today ASTM and API publish numerous
standards, specifications and test methods for FRP piping.
Today
Today the use of FRP machine made piping has grown from its original major use
in oil field gathering lines to applications ranging from handling flammable and
combustible liquids at retail consumer facilities to sewer and water mains in
the municipal and industrial markets. Following are examples of current FRP
piping applications:
In the oil and gas production industry, high pressure applications include 4,000
psi
4 inch pipe in oil field service, 2 to 16 inch pipes for water filtration
projects in climatic conditions as cold as Alaska and as hot as the Persian
Gulf, and a salt water/crude oil 12 inch pipeline operating at 290 psi at
temperatures up to 120° F.
Flammable and combustible liquid handling includes the underground piping of
gasolines, gasoline-alcohol mixtures and alcohols at most of the nation’s retail
and commercial vehicle refueling facilities. Since FRP piping was Underwriters
Laboratory Listed in the late 1960’s, over 60 million feet have been
successfully installed and serve the nation’s motoring public.
While sewer and drainage piping continues to be dominated by concrete, there are
many areas where FRP is the preferred choice. For example, concrete pipe
deteriorates rapidly in sewage due to hydrogen sulfide attack. Hydrogen sulfide
erodes the upper surface of the pipe and will eventually cause a cave-in. FRP is
unaffected by hydrogen sulfide or purging with caustic or hypochlorite to
suppress sulfide odor. As a result, FRP pipe has been used as a liner in large
diameter (48 to 60 inches) concrete pipe.
The Future
Architectural and engineering firms are now able to use computer software
programs developed to enhance the design of FRP piping systems. The program
includes liquid flow analysis, gas flow analysis, free span analysis, thrust
block design, chemical composition and installation information. The program
makes it easy to step through complicated calculations and analysis when
designing a new FRP piping system or for troubleshooting an existing FRP piping
system.
The oil and gas production industry will be requiring higher pressure rated and
larger diameter piping to control corrosion problems in produced fluid lines (It
is not uncommon to "produce" and treat seven barrels of water for each barrel of
crude oil brought out of the ground). In addition to solving corrosion problems,
FRP piping can be designed with a flame retardant additive to reduce flame
spread for non-critical areas or in critical areas, be coated with an
intumescent paint or insulated with an intumescent material i. e., the paint and
coating expands to form an incombustible foam insulation. This latter system
will maintain the serviceability of the piping for a minimum of three hours
under flow conditions. FRP firewater protection piping is solving weight
problems when designing offshore oil production platforms. Weight savings in the
design of a platform can save the owner from $2.00 to $4.00 per pound in
construction costs by reducing the weight of the support structure (e.g.,
savings up to 750 tons).
Trench-less Piping is a rapidly growing technology where micro-tunneling for new
piping and slip-lining for rehabilitating existing piping do not disturb
roadbeds or other aboveground structures.
Micro-tunneling: While tunnel boring has been used on large tunnel
projects, micro-tunneling is a new application for trench-less piping. In
micro-tunneling the FRP pipe is hydraulically jacked and pushes the cutter head
through the substrata. It takes hundreds of tons of jacking pressure to push
large diameter piping distances of hundreds of feet. For example, 18 inch
diameter FRP pipe can be jacked at pressures up to 90 tons and nine foot
diameter FRP pipe at pressures up to 1,750 tons.
In the past, stainless steel sleeves have been used as a reinforcement around
concrete pipe joints to withstand hydraulic jacking pressures. However, FRP
sleeve joints are proving to be a cost-effective replacement for stainless steel
used in concrete pipe jacking.
FRP pipe and joint systems are proving to be more cost effective than their
concrete counterpart because of the smoother outside surface and lighter weight.
These features significantly reduce the jacking pressure required and permit
jacking longer runs than concrete, reducing installation costs and time.
Slip-lining: Slip-lining is a trench-less method of rehabilitating an
existing pipe with a minimum of excavation. New and rehabilitated sewer and
drainage pipes are no longer limited to relatively small diameter FRP
slip-lining methods. Centrifugal cast FRP pipe technology has advanced and
yields a machine-made pipe with close outside diameter tolerances in diameters
up to 96 inches. The light weight and smooth outer surface permits jacking the
pipe inside an existing pipe, thus rehabilitating leaking concrete sewer pipes
up to 102 inches i.e., nine feet in diameter. This system of rehabilitation
minimizes the jacking pressures required to push the FRP pipe through the
existing concrete pipe and is done even as sewage flow continues. For example, a
trench-less project is underway to rehabilitate 6,000 feet of 102 inch sewer in
Los Angeles with a minimum of excavation by using nine foot diameter FRP pipe.
Chemical processing typically involves piping exposure to such chemicals such as
acetone, methylene chloride, hydrochloric acid, ethylene dichloride, phenol,
toluene, xylene, ethyl acetate and methyl acetate. Specialty metals such as
titanium are typically used for resistance to such chemicals, but are
prohibitively expensive. However, resin selection such as furan based materials
are extremely solvent resistant and cost-effective.
Petroleum Marketing Facility Applications
Traditionally petroleum marketing facilities used steel piping which was low in
cost and met the 2 hour 2,000° F fire code requirement for the handling of
flammable and combustible materials. While retail facilities have adapted to new
material advancements e. g., FRP underground tanks and piping and flexible
connectors, distribution terminal designers and contractors have been slow to
apply non-steel technologies. Following are several areas where the terminal
facility designer should consider FRP piping applications:
Underground Piping: Underwriters Laboratory has UL 971 Listed FRP piping
for flammable and combustible service in diameters of 2, 3, 4 and 6 inches. The
1996 edition of NFPA 30 references UL 971 and permits using these FRP pipe
diameters in distribution terminals. While terminal designers prefer to locate
steel piping aboveground for ease of environmental testing i.e., visual
inspection rather than periodic pressure testing, the Uniform Fire Code revised
their rule in 1995 and now require the installation of piping underground.
Underground steel piping will require cathodic protection systems and its
inherent periodic testing requirement. Therefore, a cost effective alternative
to underground steel piping and cathodic protection is FRP pipe consistent with
UL Listed diameters.
Sewer and Drainage: Pollution prevention-related projects include
containment, recycling, discharge reduction and sewage treatment. Concrete
piping is not suitable for the handling of petroleum related effluent because of
the high leakage rate in the pipe joining methods available, and steel piping
will corrode underground. Large diameter FRP piping is available up to nine feet
in diameter and designed with leak free joints. As described above, trench-less
new or slip-lining rehabilitation piping methods are cost effective and provide
a minimum of disruption in operations.
Corrosive Chemicals: Today it is becoming more common to blend motor fuel
additives at the terminal. Many of these additives are corrosive to traditional
carbon steel. With blending systems located at the truck loading rack,
underground piping is common and lends itself to FRP piping.
Firewater Protection: Scale from internal corrosion of steel piping in a
firewater protection system is known to plug nozzles and sprinkler heads. To
combat the effects of corrosion and internal scaling, metallic systems require
continuous maintenance. Even then, it is questionable how much of a metallic
system is in an effective operating condition at a given moment. FRP fire
resistant material systems are being developed and should prove to be cost
effective in certain fire protection applications.
References
- Spring, 1996, Composites Institute article "FRP pipe finds its niche in
specialty applications," Karen F. Lindsay
- April, 1993, Ameron Fiberglass Pipe Division, Product literature
- May, 1996, Smith Fiberglass Products Inc., NACE
Materials Performance article "Thirty Years of Fiberglass Pipe in Oilfield
Applications", Kenneth J. Oswald
- April, 1996, HOBAS Pipe Inc., Case histories
- February, 1996, Composites Institute Conference, "Development of Fire Resistant
Fiberglass Pipe", paper by Joie L. Folkers, Ameron Fiberglass Pipe Division
FRPipePastTdyFtr 6/96
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