Durcor
Expansion Data
Durcor Wall Thickness Calculations Based on ASME B31.3 Chapter VII
Ref. Section A304.1.2 "Straight Pipe Under Internal Pressure"
For RTR (Filament Wound) and RTM (Centrifugally Cast) Pipe
Based on Section A302.3.2, the design stress (S) is determined by onetenth of the minimum tensile strength of Durcor. The tensile strength of Durcor is 43,500 psi, therefore, the (S) is determined to be 4,350 psi. The conservative service (design) factor is 0.5.
Wall Thickness  

In all cases, wall thickness exceeds minimum pressure design thickness using the 0.5 service (design) factor. 

Size (in)  Gage Pressure  Calculated Wall (in)  Actual Wall (in)  Actual/ Calculated 
1  275  .080  .160  2.00X 
11/2  275  .115  .155  1.35X 
2  275  .140  .150  1.07X 
3  225  .172  .215  1.25X 
4  200  .198  .240  1.21X 
6  175  .256  .285  1.11X 
8  150  .288  .325  1.13X 
Design for Expansion and Contraction
Simple supported Durcor piping can be easily designed by considering the degree of thermal expansion along straight runs of pipe and any possible pressure thrusts created by closed end systems.
Length changes due to thermal expansion in an unrestrained condition
All piping materials will expand linearly with increasing temperature when in an unrestrained condition. Durcor piping exhibits extremely low expansion rates with increasing temperatures. However, these changes do need to be considered in piping design. The amount of linear thermal expansion of Durcor pipe is consistent over the operating range and is determined to be 6.7 X 10^{6} in/in/°F (1.2 X 10^{5} in/in/°C).
The formula for determining expansion:
Example: Determine how much thermal expansion to expect when installing 300 feet of Durcor piping at 70°F intended to operate at 200°F.
Thermal Expansion
The effect of thermal gradients on piping systems may be significant and should be considered in every piping system stress analysis. Pipeline movements due to thermal expansion or contraction may cause high stresses or even buckle a pipeline if improperly installed. Several piping system designs are used to manage thermal expansion and contraction in above ground piping systems. They are listed below, according to economic preference:
 Use of inherent flexibility in directional changes
 Restraining axial movements and guiding to prevent buckling
 Use expansion loops to absorb thermal movement
 Use mechanical expansion joints to absorb thermal movement
To perform a thermal analysis, the following information is required:
 Isometric layout of piping system
 Physical and material properties of pipe
 Design temperatures
 Installation temperature (final tiein temperature)
 Terminal equipment load limits
 Support movements
Durcor^{®} vs. Competition  

Temperature Change (°F)  Durcor  Fiberglass  PVC  CPVC  Carbon Steel  Stainless Steel 
25  0.20  0.31  0.90  1.14  0.22  0.27 
50  0.40  0.61  1.80  2.28  0.44  0.54 
75  0.60  0.92  2.70  3.42  0.65  0.82 
100  0.81  1.23  3.60  4.56  0.88  1.09 
125  1.00  1.54  4.50  5.70  1.10  1.36 
150  1.21  1.84  5.40  6.84  1.32  1.63 
175  1.41  2.15  6.30  7.98  1.54  1.90 
200  1.61  2.45  7.20  9.12  1.76  2.17 
Unrestrained Piping
Unrestrained Durcor piping will not exhibit a measureable change in length due to the thrust effects of internal pressure. This is unique for fiberglass reinforced piping. Typically, accommodations for growth must be factored for FRP piping as the axial elastic modulus of typical FRP piping is significantly less than the radial elastic modulus. Due to this anisotropic property and combined with Poisson’s ratio, growth for typical FRP piping from internal pressure thrusts from 150 psi can be from 1/4” to 1/2” per 100 feet of piping.
The axial elastic modulus of Durcor piping (2.76 X 10,^{6} psi) is over 50% greater than that of typical FRP pipe. With a radial elastic modulus of 2.10 X 10^{6} psi, the axial component accounts for the majority of the stiffness of the pipe. This relativity results in unmeasureable growth from internal pressures. Length growth from pressure thrust in unrestrained Durcor piping is only .03.06 in/100 ft.
Unrestrained Thermal Expansion Uninsulated Pipe 


Change in Temperature (°F)  Pipe Change in Length (in/100 ft) 
25  0.20 
50  0.40 
75  0.60 
100  0.81 
125  1.00 
150  1.21 
175  1.41 
200  1.61 