Temperature Limitations

PVC

Georg Fischer Harvel LLC PVC piping products are manufactured from a Type I, Grade I PVC compound with a Cell Classification of 12454 per ASTM D1784. GF Harvel PVC Schedule 40 and Schedule 80 pipe is manufactured in strict compliance to ASTM D1785 using this material, and consistently meets or exceeds the requirements of this standard with regard to materials, workmanship, dimensions, sustained pressure, burst pressure, flattening resistance and extrusion quality.

The maximum operating temperature for PVC pipe produced to these standards is 140°F. As with all thermoplastic materials, an increase in temperature results in an increase in impact strength and a decrease in tensile strength and pipe stiffness, which reduces the pressure rating. The mechanical properties of PVC pipe manufactured to the above referenced standards are routinely tested and recorded at 73°F based on testing per applicable ASTM material test standards. Appropriate temperature de-rating factors must be applied when working at elevated temperatures to determine maximum allowable pressure. The following temperature de-rating factors are to be applied to the working pressure ratings stated for the products at 73°F when operating at elevated temperatures:

Multiply the working pressure rating of the selected pipe at 73°F, by the appropriate de-rating factor to determine the maximum working pressure rating of the pipe at the elevated temperature chosen.

Operating Temp (°F) De-Rating Factor
73 1.00
80 0.88
90 0.75
100 0.62
110 0.51
120 0.40
130 0.31
140 0.22

EX: 10" PVC SCHEDULE 80 @ 120°F = ?
230 psi x 0.40 = 92 psi max. @ 120°F

THE MAXIMUM SERVICE TEMPERATURE FOR PVC IS 140°F.

Solvent cemented joints should be utilized when working at or near maximum temperatures. GF Harvel does not recommend the use of PVC for threaded connections at temperatures above 110°F; use flanged joints, unions, or roll grooved couplings where disassembly is necessary at elevated temperatures.

It is a documented fact that as temperatures fall below 73°F, tensile strength and pipe stiffness values increase thereby increasing the pipes pressure bearing capability and resistance to bending deflection. However, as with most materials impact resistance and ductility decrease at colder temperatures. In addition, a drop in temperature will cause the piping to contract, which must be addressed with proper system design. Due to PVC's coefficient of thermal expansion, a 20-foot length of pipe will contract approximately 3/4" when cooled from 95°F to -5°F.

Since pressure bearing capacity is not reduced with a decrease in temperature, PVC pipe is suitable for use at colder temperatures provided the fluid medium is protected from freezing, consideration is given to the effects of expansion and contraction, and additional care and attention are given during handling, installation and operation of the system to prevent physical damage caused by impact or other mechanical forces.

It should be noted that Georg Fischer Harvel LLC routinely conducts drop impact testing on our PVC piping products at 73°F as well as 32°F. The impact resistance of PVC pipe at 32°F vs. 73°F is dependent on the pipe diameter as well as the wall thickness of the product. To our knowledge, definitive testing has not been conducted to establish an accurate ratio of the actual reduction in impact strength on the entire range of sizes/dimensions of PVC piping at lower temperatures.

CPVC

Georg Fischer Harvel LLC CPVC piping products are manufactured from a Type IV, Grade I CPVC compound with a Cell Classification of 23447 per ASTM D1784. GF Harvel CPVC Schedule 40 and Schedule 80 pipe is manufactured in strict compliance to ASTM F441 using this material, and consistently meets or exceeds the requirements of this standard with regard to materials, workmanship, dimensions, sustained pressure, burst pressure, flattening resistance and extrusion quality.

The maximum operating temperature for CPVC pipe produced to these standards is 200°F. As with all thermoplastic materials, an increase in temperature results in an increase in impact strength and a decrease in tensile strength and pipe stiffness, which reduces the pressure rating. The mechanical properties of CPVC pipe manufactured to the above-referenced standards are routinely tested and recorded at 73°F based on testing per applicable ASTM material test standards. Appropriate temperature de-rating factors must be applied when working at elevated temperatures to determine maximum allowable pressure. The following temperature de-rating factors are to be applied to the working pressure ratings stated for the products at 73°F when operating at elevated temperatures:

Multiply the working pressure rating of the selected pipe at 73°F, by the appropriate de-rating factor to determine the maximum working pressure rating of the pipe at the elevated temperature chosen.

Operating Temp (°F) De-Rating Factor
73-80 1.00
90 0.91
100 0.82
110 0.72
120 0.65
130 0.57
140 0.50
150 0.42
160 0.40
170 0.29
180 0.25
200 0.20

EX: 10" CPVC SCHEDULE 80
@ 120˚F = 230 psi x 0.65 = 149.5 psi max. @ 120˚F

THE MAXIMUM SERVICE TEMPERATURE FOR CPVC IS 200°F.

Solvent-cemented joints should be utilized when working at or near maximum temperatures. GF Harvel does not recommend the use of CPVC for threaded connections at temperatures above 150°F; use flanged joints, unions, or roll grooved couplings where disassembly is necessary at elevated temperatures.

It is a documented fact that as temperatures fall below 73°F, tensile strength and pipe stiffness values increase thereby increasing the pipes pressure bearing capability and resistance to bending deflection. However, as with most materials impact resistance and ductility decrease at colder temperatures. In addition, a drop in temperature will cause the piping to contract, which must be addressed with proper system design. Due to CPVC's coefficient of thermal expansion, a 20-foot length of pipe will contract approximately 7/8" when cooled from 95°F to -5°F.

Since pressure bearing capacity is not reduced with a decrease in temperature, CPVC pipe is suitable for use at colder temperatures provided the fluid medium is protected from freezing, consideration is given to the effects of expansion and contraction, and additional care and attention are given during handling, installation and operation of the system to prevent physical damage caused by impact or other mechanical forces.

An accurate ratio of the actual reduction in impact strength on specific sizes/dimensions of CPVC piping at lower temperatures has not yet been determined with physical testing due to the numerous variables involved. However, preliminary drop impact testing that has been conducted on limited sizes reveals a reduction in drop impact strength of approximately 60% on pipe that was tested at 32°F compared to the same size of pipe tested at 73°F. The impact resistance of CPVC pipe at 32°F vs. 73°F is dependent on the pipe diameter as well as the wall thickness of the product.