Standard Test Method for Obtaining Hydrostatic Design Basis for Thermoplastic Pipe Materials or Pressure Design Basis for Thermoplastic Pipe Products

Importancia y uso:

4.1 The procedure for estimating long-term hydrostatic strength or pressure-strength is essentially an extrapolation with respect to time of a stress-time or pressure-time regression line based on data obtained in accordance with Test Method D1598. Stress or pressure-failure time plots are obtained for the selected temperature and environment: the extrapolation is made in such a manner that the long-term hydrostatic strength or pressure strengthis estimated for these conditions.

Note 3: Test temperatures should preferably be selected from the following: 68 °F (20 °C), 73 °F (23 °C), 140 °F (60 °C), 176 °F (80 °C), 180 °F (82 °C), and 200 °F (93 °C). It is strongly recommended that data be generated at 73 °F (23 °C) for comparative purposes.

4.2 The hydrostatic or pressure design basis is determined by considering the following items and evaluating them in accordance with 5.4.

4.2.1 Long-term hydrostatic strength or hydrostatic pressure-strength at 100 000 h,

4.2.2 Long-term hydrostatic strength or hydrostatic pressure-strength at 50 years, and

4.2.3 Stress that will give 5 % expansion at 100 000 h.

4.2.4 The intent is to make allowance for the basic stress-strain characteristics of the material, as they relate to time.

4.3 Results obtained at one temperature cannot, with any certainty, be used to estimate values for other temperatures. Therefore, it is essential that hydrostatic or pressure design bases be determined for each specific kind and type of plastic compound and each temperature. Estimates of long-term strengths of materials can be made for a specific temperature provided that calculated values, based on experimental data, are available for temperatures both above and below the temperature of interest.

4.4 Hydrostatic design stresses are obtained by multiplying the hydrostatic design basis values by a service (design) factor.

4.5 Pressure ratings for pipe may be calculated from the hydrostatic design stress (HDS) value for the specific material used to make the pipe, and its dimensions using the equations in 3.1.11.

4.5.1 Pressure ratings for multilayer pipe may be calculated by multiplying the pressure design basis (PDB) by the appropriate design factor (DF).

Subcomité:

F17.40

Referida por:

F2905_F2905M-24A, F2969-12R20, F2880-21, F2968_F2968M-24, D2513-25, F3524_F3524M-23, F1960-24, D3139-19R25, F2896-23, F1282-23A, D2846_D2846M-24, F2817-13R23, F3181-16R23, D2737-25, F0714-25, F2619_F2619M-20, F2829_F2829M-21, F3687-24, F1674-18, F2145-23, F2818-10R23, D3350-24, F1924-25, F3373-21, F2769-24, F3123-22, F2788_F2788M-25, F1483-23, F3348-23A, D1598-24, F0412-25, F2261-06R23, F2159-23A, F2623-25, F3034-21, F2854-21, D1998-21, D2241-25A, D1785-21A, F2767-24, F3506-24, F3346-24, D3035-22, F2785-21, F2806-23, F2720_F2720M-20, F2929-25, D2239-25, F0894-24, F2855-19R24, F3508-21A, F0877-25, F0876-25, F0442_F0442M-23, F3753-25E01, D1784-25, F0441_F0441M-23, F3378_F3378M-22, F2735-23, F3253-25, F2945-18R23, F1759-97R24, F2207-06R23

Volúmen:

08.04

Número ICS:

83.140.30 (Plastic pipes and fittings for non-fluid use)