PP-R and PP-RCT
What is Polypropylene?
Propylene (PP) is a type of plastic known as a polyolefin. It is produced by polymerizing propylene with suitable catalysts.
Polypropylene is a thermoplastic meaning that it can be heated to a molten state and when cooled returns to a solid state.
What are the uses for Polypropylene?
Polypropylene (PP) is used in both industrial and commercial products. Its characteristics, some of which are: high melt
point (320 F), hydrophobic, and durable, make it ideal for many applications including food containers, fibers (such as carpeting),
car parts, and piping systems.
What Polypropylene products are used for piping systems?
PP-R (Polypropylene Random Copolymer) and PPP-RCT (Polypropylene Random Copolymer Crystalline Temperature) are ideal for a
variety of piping systems and have been used throughout the world in plumbing and heating systems for more than 20 years.
What is the difference between PP-R and PP-RCT?
PP-RCT is the newest generation and has better mechanical characteristics than PP-R. The improved mechanical characteristics come from
the crystalline structure of the resin giving the material the ability to operate at higher stresses at elevated temperatures.
When using the higher performing PP-RCT, the designer can:
Achieve higher pressures than he would from a PP-R pipe with the same wall thickness. Or, use a thinner wall PP-RCT pipe and
realize hydraulic efficiencies and cost savings.
Where can PP-R and PP-RCT pipe be used?
Polypropylene pipe can be used anywhere where copper, steel, or stainless steel pipes are used. PP-R(CT) pipe is a better choice
in many applications where chemicals are transported via piping systems. It is not recommended for systems that exceed 180 F, or
steam systems. What high of a temperature can a PP-RCT piping system withstand? PP-RCT with the fiber composite layer is rated up
to 180 F. However as temperatures increase the permissible operating pressure decreases.
What is the life expectancy of polypropylene pipe?
Depending on the application PP-R and PP-RCT systems will give a service life of 50 or more years. High temperatures combined
with high pressures will reduce the service life of the pipe. However, a system using 1inch to 4 inch pipe will have a service
life of 50 years at 140 F and 92psi with a safety factor of 1.5.
How is PP-R(CT) pipe assembled?
PP-R(CT) is assembled through a socket or butt fusion process. Socket fusion is used on pipe 4" (125mm) and under. Butt fusion
is used on pipe over 4" (125mm). The socket fusion process melts the outside surface of the pipe and the inside surface of the
fitting to be joined (both to a specific depth). After specific heat and time requirements are met the two surfaces are pushed
together to form a permanent, seamless, leak free bond. In the butt fusion process the ends of the pipes and/or the fitting are
melted and then joined together.
What tools are needed to assemble PP-R(CT) pipe and fittings?
The smaller diameter sizes of PP-R(CT) pipe and fittings can be assembled with tools called a heating iron and fusion heads.
For sizes between 1.5" and 4" it is recommended that fusion machines be used. For butt fusion a butt fusion machine and a
heating iron are used. All of these tools are made by Ritmo and McElroy. Due to the high temperature of the heating iron it
is necessary to wear all appropriate safety equipment.
Can PP-R or PP-RCT pipe be glued?
No, you do not glue PP-R or PP-RCT pipe. Socket fusion and/or butt fusion creates a permanent, monolithic, leak free bond
that is stronger than the pipe.
Are there fittings available to transition from PP-R(CT) to other types of piping systems?
Yes, PESTAN offers a complete line of brass or steel transition fittings and flange adapters.
How safe is PP-R and PP-RCT pipe?
The material can be certified as safe for drinking water.
It is hydrophobic meaning that it does not leach into or react with water.
If burned, it releases only water vapor and CO2. In a fire situation fire fighters are recommended to wear respirators.
According the USCG, 1999 there is no apparent toxicity.
How should PP-R and PP-RCT pipes be handled?
PP-R(CT) is light weight and can be handled manually or mechanically. Care should be taken to insure that the ends are
not damaged when moving and when in storage. Care should be used when moving pipe in temperatures below 40 F. A fork
lift truck should not be used by putting the forks in the ends of the pipes or by draping the pipe across the forks.
How should PP-R and PP-RCT pipes be stored?
PP-R(CT) pipes do not contain UV stabilizer and therefore should be left in their storage bags until use. The lengths
of pipe should be stored on a flat surface. If racks are use the pipe should be supported about every 3 feet. It is
recommended that plywood or similar backing material be placed across the racks. Do not stack over 3 feet high. If
storing the pipe outside it should be placed in a shaded area and covered with a light colored tarp. Indoor storage
is best, but avoid areas where solvents, paints, glues or similar products are kept.
What type of hangers are used with PP-R and PP-RCT pipe?
Non metal hangers are recommended. When metal hangers are used the portion that contacts the pipe should be lined with
felt or rubber to protect the pipe from damage. Clevis hangers with a liner, J-hook, steel pipe clamp, roller hanger,
and split ring hanger are all types of hangers that can be used.
What is the hanger spacing for polypropylene pipe?
Hanger spacing varies based on the size of the pipe. The maximum recommended distance is 48" for .50" (20mm) to 126"
for 4" (125mm) both at 0 F.
At 126 F the distance remains the same for the .50" (20mm) and reduces to 68" for the 4" (125mm).
What are the benefits of polypropylene pipe versus steel, or copper?
Corrosion resistant Scaling resistant - lower pumping costs Chemically resistant Inert to water - no leaching of taste or
odor into water Lightweight - quick and easy installation Leak free systems via fusion No glue or solder used - no VOCs
released, no open flame Does not support biological growth - opaque nature inhibits light penetration Low expansion
coefficient - 100' of fiber composite pipe expands 2.3" at 100 F △T Low thermal conductivity - k = 0.139 for PP-R(CT), k = 227 for
copper. Absorbs noise Low coefficient of friction - lower pumping costs