Articles
JOIN THE REVOLUTION…THINK PLASTICS
That famous nineteenth century American physician and author,
Oliver Wendell Holmes, stated it best when he wrote, "A mind
that is stretched to a new idea never returns to its original dimension."
And what is this revolutionary new idea…the use of thermoplastic
piping systems in industrial piping applications.
Wood, clay, concrete and metal piping are just some of the piping
materials in use for decades. But with today's modern technology
there is a better piping alternative material…thermoplastics.
Listed in this article will be the many advantages and benefits
of plastic piping; but the bottom line is thermoplastic industrial
piping systems (TIPS) are more cost-effective in almost every industrial
piping application compared to alternative piping systems. And yet
in the industrial piping market where TIPS is capable of handling
an estimated 70% of all applications less than 15% is actually used.
While plastics in the last four decades have become the dominant
material in many piping markets including residential drain/waste/vent,
gas transmission, acid waste drainage, water lines, underground
irrigation, swimming pools, and water-theme parks, the bulk of industrial
and commercial markets have been slow to embrace the use of thermoplastics.
Why?
Well first, the TIPS industry must share some of the blame for
not having done a good job of educating the marketplace to the benefits
and capabilities of TIPS products. This oversight is being addressed
presently, in part, by the Plastic Pipe and Fittings Association
(PPFA), its TIPS product line committee, and the International Association
of Plastic Distributors (IAPD).
Secondly, minimal research and development of TIPS products have
been performed in the USA. As a result, few innovative products
or piping materials have been developed domestically; most new developments
are coming from off-shore manufacturers.
Thirdly, USA industries and institutions in conjunction with certain
labor unions and building code bodies have been, to a large degree,
unwilling or very slow to change their habits and recognize more
progressive and efficient piping materials. "Older" industries
such as Pulp and Paper, Electric Utilities, Oil and Gas, Petroleum,
Metal Refineries and Commercial/Institutional Building could greatly
benefit from increased use of TIPS. Also a lack of economic pressure
in past years has kept these industries from moving toward plastic
piping materials. But today's highly competitive global environment
will most likely make change easier. By American industry joining
the revolution in the use of thermoplastics, the most cost-effective
piping material, domestic products will become more competitive
in foreign markets increasing USA exports and adding more jobs.
WHY THERMOPLASTIC PIPING SYSTEMS?
The advantages and benefits of thermoplastic piping are significant
and will turn manufacturing more and more in favor of its use. Thermoplastic
features can produce considerable cost savings while increasing
piping system reliability. Advantages include:
Corrosion resistance: Plastics are nonconductive and therefore
immune to galvanic and electrolytic corrosion. Plastic piping materials
are so corrosion-resistant that they can be buried in alkaline or
acid soils or installed in above-ground environments with no paint
or special coating required.
Lightweight: Most plastics are a minimum of 1/8th the weight
of metal piping. This means less freight costs. The benefit of a
lightweight material allows easier installations in close quarters
and doesn't require expensive lifting equipment.
Optimum flow rates: The interior wall of all plastic pipes
has a Hazan and Williams C Factor of 150 or higher. This means less
energy or horsepower is required to transfer fluids or smaller diameter
piping may be used resulting in cost savings.
Low thermal conductivity: All plastic piping has low thermal
conductance, which means more uniform temperatures when transporting
fluids. Minimal heat loss through the pipe wall of plastic piping
may eliminate or greatly reduce the need for piping insulation.
Chemical resistance: The variety of common plastic piping
materials allows most chemicals at moderate temperatures to be successfully
handled. The plastics industry has a listing of hundreds of chemicals
that may be compatible with a given plastic. This helps to eliminate
the guess work for end users and specifiers.
Variety of leak tight joining methods: Plastic piping can be joined
in several leak proof ways including being solvent cemented, heat-fused,
threaded, flanged and mechanically coupled. These methods allow
easy joining and adaptability to other no-plastic piping materials.
Abrasion resistance: The molecular toughness and inner bore
smoothness of plastic pipe makes it ideal for abrasion-resistant
applications such as fly ash and bottom ash as well as many other
abrasive slurries and solutions.
Color variety: The plastic piping extrusion process allows
color to be an integral and homogenous part of the piping. No external
painting is required. Vibrant colors are especially important and
available for underground installations, so as to be highly visible
when contractors are excavating. That way, the contractors can easily
see the pipe preventing pipe damage and minimizing any safety concerns.
Piping system integrity: Most plastic piping offer complete
systems of pipe, valves, fittings, tanks and pumps. This feature
allows complete systems of one material to be in contact with all
fluid wetted parts (especially for cemented and heat-fused joined
systems).
Maintenance free: A properly installed plastic piping system
requires no maintenance. It's as simple as that. There is no rust,
pitting or scaling; no galvanic or electrolytic corrosion. External
pipe coatings are not needed and buried plastic piping is not affected
by even the most aggressive soil conditions.
Flexibility: Thermoplastic piping materials are relatively
flexible compared to other piping materials. This feature, coupled
with optimum flow rates, allows some plastic pipe to be used as
insertion liners in existing non-plastic piping. Also, the flexibility
of plastic piping in underground piping reduces the use of fittings
with the allowable bending radius in plastic pipe to as little as
20 times the outside diameter of the pipe.
Codes: There are dozens of plastic piping standards used
or referenced in Building, Plumbing, Mechanical, and Electrical
Codes and AWWA, FM, NFPA, AGA, EPA, DOT, DOD, and API publications.
These standards contribute substantially to the uniformity of thermoplastic
product characteristics, which in many cases, allows each manufacturer's
products to be used interchangeably with others.
When all of the above features are considered, substantially (50%
or more is the rule) less cost is required for TIPS than other piping
materials.
APPLICATIONS
While there is no limit to the possible new applications for plastic
piping, the following examples serve to demonstrate the varied use
of TIPS in many industries and markets:
Food Processing: Most plastic piping materials are approved
by the National Sanitary Foundation and receive Food and Drug Administration
approval when required. The purity of the end product in any food-processing
application is critical and plastics fit the bill beautifully.
Surface Finishing: The automotive, aircraft, electrotyping,
and canning industries use TIPS where possible in their plating
processes. Plastics are a natural in this market, since almost every
metal-salt plating solution can be handled easily including brass,
cadmium, chrome, copper, gold, lead nickel, rhodium, silver, tin,
and zinc.
Steel Mills: Ironically, steel mills are replacing steel
piping with plastics. The mills realized that their manufacturing
costs improved with use of plastics because of reduced maintenance,
lower material costs and longer life provided by TIPS.
Pulp and Paper: These plants handle four types of media:
liquids, steam, water, and stock. Except for steam, plastic piping
can handle most of the other fluids under 275 F and 150 psi.
Electronics: The manufacturers of solid-state electronics
products such as semiconductors, rectifiers, and printed circuitry
demand ultra-pure water to clean their products and prevent contamination.
Thermoplastics are the preferred materials for handling ultra-pure
water in which an ion exchange or demineralization system is employed.
PVC, CPVC, polypropylene, PVDF and other fluorocarbons are used
for water distribution systems. TIPS also are used for handling
etching media such as sulfuric, nitric, hydrochloric and hydrofluoric
acids. Wastewater and air-handling systems required in the electronic
industry also use TIPS throughout.
Photographic Laboratories: All manufacturers of photographic
process equipment and photographic chemicals specify and use thermoplastics.
Mining/Oil/Gas: Plastic pipe, itself a derivative of oil
and natural gas, has successfully been applied in handling most
crudes, salt water, and natural gases. Most natural gas distribution
today uses millions of feet of plastic pipe. Polyethylene piping,
colored beige or orange, is the preferred material for this application.
In the mining industry, the most popular use of thermoplastics is
in ore leaching, in which the ore is treated with dilute sulfuric
acid or sulfides and then with ferric sulfate solutions. PVC, CPVC,
ABS, and polyethylene piping are used in many of the leaching process
stages. Plastics also are used for the movement of ore slurries
and other piping applications in under and above ground mining.
Marine Applications: Shipbuilding, marinas, fish hatcheries,
marine research, aquariums and theme-water parks are using significant
amounts of plastic piping especially in salt water environments
where internal and external corrosion resistance is important.
Water/Waste Treatment Plants: Whether in primary or secondary
treatment phases, plastics are used throughout water and sewage
treatment facilities. Influent and effluent lines, sludge lines,
chlorine and sodium hypochlorite lines, fluoride and alum lines,
and many other piping lines use TIPS.
Heating/Air conditioning/Refrigeration: Thousands of feet
of PVC and CPVC piping have been used in central air conditioning
systems of institutions and commercial buildings, condensate return
lines, handling brine solutions in refrigeration processes, and
the use of polyethylene piping for the refrigeration process in
ice skating rinks.
Institutional Facilities: Hospitals and school complexes
are large users of TIPS particularly in acid-waste drainage lines
for chemistry, physics and hospital laboratories. The preferred
plastic material for this application is polypropylene.
Additional applications for TIPS include power plants, plumbing,
and heavy construction. In fact, uses for plastic piping systems
seem to be limited only by one's imagination.
"Plastics" the famous one-word line from the 1967 film
"The Graduate" was said to be the key to the future. Never
was this prediction truer than it is today for the upcoming revolution
of USA industry converting wherever possible to TIPS.
Portions of this article were adapted from the book "Plastic
Piping Systems, Second Edition, "by David A. Chasis, published
by Industrial Press Inc. The author is President of Chasis Consulting
and Chairman of the PPFA/TIPS product line committee.