PVC Pressure Pipe Class Selection The Sustainable Solution

1. PVC Pressure PipeClass SelectionThe Sustainable Solution

2. Pressure Rated Design Hydrostatic Design Stress (S) S = HDB x Service Factor HDB for PVC is 4000 psi for water pipe compounds for HDPE HDB = 1600 psi Service Factor = 0.5 (Defined in Appendix of ASTM D2241) Service Factor = 1/Factor of Safety (2.0) For PVC S = 4000 x 0.5 = 2000 psi For HDPE S = 1600 x 0.5 = 800 psi

3. Pressure Pipe Design D Free Body Diagram ________________________ Internal Forces Balanced By External Forces t P L S S (ISO Equation)

4. t OD Dimension Ratio = DR = SDR DR = ODavg /tmin

5. PVC Pressure Rated Design “In Terms of DR” (DR=SDR) ISO Equation: Rearranged: Given D/t = DR:

6. PVC Pressure Ratings S = 2000 psi =HDB X SF (4000 X 0.5) P = 2S/ DR – 1 For DR 18; P = 2(2000)/18-1 = 235 psi For DR 25; P = 2(2000)/25-1 = 165 psi As a Comparison with HDPE S = 800 psi = HDB X SF (1600 X 0.5) For DR 18; P = 2(800)/18-1 = 94 psi For DR 25; P = 2(800)/25-1 = 65 psi

7. AWWA C905Pressure Test Requirements

8. PVC Pressure Class & Short Term Rating (STR) STR = 1.6 x PC (approx. ½ Burst Pressure)

9. Pressure Class Selection AWWA Design Checks: 1) WP ≤ PC X FT 2) WP + PCrs ≤ PC X FT 3) WP + Pos ≤ 1.6 X PC X FT 1.6 X PC = STR WP = working pressure (psi); maximum operating pressure in a pipeline exclusive of surge pressure PC = pressure class (psi) FT = temperature coefficient (dimensionless) Prs = recurring surge pressure (psi) Pos = occasional surge pressure (psi)

10. Example DR Selection Given: 36 Inch Transmission Main with a maximum operating pressure of 145 psi and maximum velocity of 4.0 fps. Only occasional surges are experienced. System is operating at normal temperature of 65 degrees F. What is the appropriate DR (PC)?

11. AWWA C905Pressure Test Requirements

12. Pressure Class Selection AWWA Design Checks: 1) WP ≤ PC x FT 2) WP + PCrs ≤ PC x FT 3) WP + Pos ≤ 1.6 x PC x FT = STR x FT 1.6 x PC = STR 1) 145 ≤ 165 x 1 2) 145 ≤ 165 x 1 3) What is Pos ? For V = 4.0 & DR 25 it = 4.0 x 14.7 = 59 psi 145 + 52 = 197psi STR x 1 = 264 x 1 = 264 psi 197psi ≤ 264psi Therefore DR 25 is the appropriate choice.

13. PVC Thermal De-rating Factors

14. PVC Surge PressuresPer 1.0 fps Velocity Change

15. PVC vs. HDPE CIOD PVC DR 25, PR 165 psi.; PE DR 11, PR 160psi.

16. PVC & PE Basics PVC • AWWA C900 & C905;4”- 48” • 54” & 60” Coming • Tensile Strength = 7000 psi • HDB = 4000 psi • Safety Factor = 2.0 • Modulus of Elasticity =400,000 psi PE • AWWA C906; 4” – 63” • Tensile Strength = 3500psi • HDB = 1600 psi • Safety Factor = 2.0 • Want to move to 1.59 • Modulus of Elasticity = 110,000 psi

17. PVC & PE Basics Press Class (P) = 2S/(DR-1) Press Class (P) = 2S/(DR-1) S = HDB/Safety Factor S = 1600/2 = 800psi For DR 11 P = 2(800)/ (11 – 1) = 160psi Trying to reduce Safety factor to 1.59 (Service factor = 0.63) P = 1600 x 0.63 = 1005 For DR 11 P = 2 x 1005/ 11-1 = 200 psi • S = HDB/Safety Factor • S = 4000/2 = 2000psi • For DR 25 P = 2(2000)/(25-1) = 165psi

18. Questions

20. All Ductile Iron pipe in Table 3 represents the minimum Pressure Class available. PVC Pipe Stiffness Ductile Iron Pipe From DIPRA Table 3

21. 54” & 60 InchFittings and restraints

22. Star Fittings Protecto 401tmLined Fittings

23. Star Restrainers Series 1100 PVC Restrainers

24. Star Restrainers

25. 45 degree bend 90 degree bend Star Fitting Configurations

26. Star Fitting Configurations

27. Star Draft Fitting Spec