


CONQUEST^{®} Flangeless Piping
Thermal Expansion & Expansion Loops
Like other piping materials, CONQUEST flangeless piping from Crane
Resistoflex requires the designer or specifier to consider system
movement caused by thermal expansion and contraction of piping
components. This movement can typically be compensated for by using
expansion loops and direction changes, along with the proper placement
of piping supports and anchors.
You may find it necessary to conduct a computergenerated stress
analysis of your piping system because of its size and complexity.
Although most stress analysis programs simulate the movement of a single
piping materials and plasticlined piping is a composite of plastic
and steel, use the coefficient of thermal expansion for steel in your
stress analysis. That's because Crane Resistoflex PlasticLined
Piping Products uses a swaging fabrication process for
CONQUEST piping that locks the
liner inside the steel shell and restricts its movement relative to
the steel. The locking process distributes the liner's thermal
expansion and contraction stress evenly throughout the entire steel
pipe.

Coefficients of Thermal Expansion for Plastic Liners
and Steel 
Material 
α (in/in/°F) 
α (mm/mm/°C) 
Polypropylene (PP) 
4.8 x 10^{5} 
8.64 x 10^{5} 
Polyvinylidene Fluoride
(PVDF Homopolymer) 
6.68.0 x 10^{5} 
11.914.4 x 10^{5} 
PVDF/Hexafluoropropylene
(PVDF/HFP Copolymer) 
7.8 x 10^{5} 
14 x 10^{5} 
Polytetrafluoroethylene (PTFE) 
5.5 x 10^{5} 
9.9 x 10^{5} 
Perfluoroalkoxy (PFA) 
7.8 x 10^{5} 
14 x 10^{5} 
Steel 
5.9 x 10^{6} 
10.6 x 10^{6} 
How to Calculate Expansion Loop
Size and Dimensional Change  The expansion and contraction
(ΔL) of a piping system is a function of the coefficient of thermal
expansion for the piping material (α), the length of the pipe, and
the upper and lower temperature limits of the system. These limits
are the highest and lowest temperatures the system will experience at
startup, shutdown, and during operation.
Use Equation 1 to calculate the growth of shrinkage of pipe after a
thermal cycle, where: 
ΔL = 
Dimensional change due to thermal expansion or contraction
(inches). 
α = 
Expansion coefficient (in./in/°F or mm/mm/°C), refer to
Table 1 for steel. 
(T_{1}  T_{2}) = 
Change in temperature (°F or °C). 
L = 
Length (in inches or mm) of straight pipe being considered. 
Equation 1: L = α x
(T_{1}  T_{2}) x L
The minimum offset and loop size can be determined from the calculated
dimensional change using Equation 1 & 2.
The loop size is a function of the pipe diameter and the length the
pipe moves during a thermal cycle. See Equation 2. The expansion loop
depicted in Figure 1 can be fabricated by using a combination of
straight pipe, elbows, and/or MULTIAXIS^{®} precisionbent pipe.
To calculate loop size, use Equation 2 where: 
R = 
Minimum expansion loop length (in feet or mm) 
D = 
Actual outside diameter of the pipe (in inches or mm) 
ΔL = 
Change in length (in inches or mm) due to expansion or contraction 
Equation 2: R = 6.35 x (D x ΔL)^{1/2}
(Metric)
R = 76.4 x (D x ΔL)^{1/2}
Example: To determine how much expansion and contraction will occur
in a 530foot straight length of 2" PVDFlined pipe and how long the
expansion loop will have to be to compensate for this, you must first
determine the highest and lowest temperatures the system will
experience. Assume the pipe will be installed at 60°F, operated at
75°F, and experience temperatures of 0°F in winter and 120°F
in summer.
With this information, use Equation 1 to determine the dimensional
change of the straight pipe section.
ΔL = 5.9 x 10^{6} x (1200) x 530 x 12 = 4.5 inches
The change in length of the straight pipe section due to
expansion is 4.5 inches. Substituting 4.5 inches for ΔL in
Equation 2, determines the loop size to compensate for this expansion.
R = 6.35 x (2.375 x 4.50)^{1/2} = 20.8 ft.
Therefore, the minimum expansion length offset or direction change is 20.8 feet. 
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