How far apart do the hangers have to be for Installing my PVC pipe?

Hangers & Supports for SCH40 and SCH80 PVC and CPVC pipe

 

Hanger Support Spacing

Proper support selection and spacing is critical to prevent stress concentration areas as the result of weight loading, bending stress, the effects of thermal expansion/contraction, and to limit pipe displacement (sag). As with all thermoplastic materials, proper pipe support spacing is dependant on pipe size, the locations and magnitude of any concentrated weight loads, and the operating temperatures of the system due to the effects that temperature has on the tensile and compressive strength of the material. Increases in temperature require additional supports. When operating at or near maximum recommended temperature limits, it may be more economical to provide continuous support for the system via structural angle or channel that is free from rough or sharp edges. Local building codes should also be consulted for applicable requirements prior to installation.

 

Proper support spacing can be calculated similarly to that of metallic systems by using simple and continuous beam calculations. This can be achieved using the maximum fiber stress of the material, or deflection based on the long term modulus of the material at the temperature selected as the limiting factors.

 

Hanger Selection 

Many hangers designed for metallic pipe are suitable for thermoplastics; however, hangers and supports used must provide an adequate load-bearing surface, which is smooth and free of rough or sharp edges that could damage the pipe. The use of improper supports can generate excessive sag resulting in failure. Movement caused by the effects of expansion and contraction of the system due to temperature variations, as well as movement as the result of pressure fluctuations must be considered to ensure proper hanger selection  and placement. Hangers and supports used must permit axial movement of the system; they should not compress the pipe or otherwise restrict this movement.

 

Placement 

Common practice is to install suitable hangers within two feet (2 ft) of each side of a pipe joint; changes in direction should be supported as close as possible to the fitting to reduce tensional stress. Heavy system components such as valves, flanged assemblies, tees, and other forms of concentrated stress loads must be independently supported. In addition, valves should be braced adequately to prevent movement/stress loads as the result of operational torque. Consideration should also be given for certain processes where solids accumulation within the line is a possibility.

 

Precautions 

The use of protective sleeves or pads between the pipe and the hanger may be desirable in certain applications, as their use will distribute stress loads over a greater surface area, particularly when using U-bolt and roller type hangers. Piping should not be permitted to contact abrasive surfaces that could cause damage during axial movement of the system. Protective sleeves or pads should be used when horizontal pipe is resting on concrete or other abrasive support structures. Contact with localized heat producing sources must also be avoided. Plastic piping systems shall not be installed in close proximity to steam lines or other high temperature equipment without providing appropriate protection to prevent damage from distortion and/or forces generate by the effects of expansion or contraction.

Vertical lines must be supported properly at intervals that will prevent excessive loading on the fitting at the lower end. Hangers and clamps suitable for this purpose include riser clamps or double bolt type clamps installed in such a manner that will allow for movement of the pipe due to thermal expansion and contraction. Clamps and hangers used must not compress, distort, cut, or abrade the piping. Common practice is to install clamps just below a coupling so that the shoulder of the coupling rests on the clamp. Fittings can be modified in the field to achieve this by cutting a coupling in two, just above the stop at the socket bottom, and then cutting this piece in half lengthwise to provide two halves which do not contain the stop. Then two ends are then solvent cemented to the pipe at the proper location so that the shoulder of the modified coupling rests on the clamp. Clamps used must not exert compressive stresses on the pipe; the use of riser clamps that utilize compression to the support the pipe weight are not recommended.

 

Anchor Guides 

Anchors are utilized to direct movement of the piping by providing restraint at key points in the system. Their use may be required to control the effects of movement caused by expansion and contraction, forces generated by pressure surges, vibration, and other transient conditions. Anchors and guides are typically installed on long straight runs, at changes in direction of the system, and where expansion joints and other methods of thermal compensation are utilized. Guides are necessary to help direct this movement between anchors by allowing longitudinal movement while restricting lateral movement. Since guides act as supports, they should have the same load bearing surface and other requirements of hangers designed for the system. Guides must be rigidly attached to the structure to prevent lateral movement, but should not restrict longitudinal movement of the pipe through the guide. Anchors and guides must be engineered and installed in such a manor to perform adequately without point loading the system. Reference should be made to the section concerning thermal expansion and contraction for additional information.

 

Hanger Support Recommendations 

Horizontal pipe system support spacing is greatly influenced by operating temperature. The charts show the recommended support spacing according to size, Schedule, and operating temperature. Co not clamp supports tightly – this restricts axial movement of the pipe. If short spacing is necessary, continuous supports may be more economical. Charts are based on liquids up to 1.00 specific gravity, but do not include concentrated loads, nor do they include allowance for aggressive reagents.

The following hanger supports spacing recommendations are considered conservative in nature and are based on straight runs of un-insulated lines with fluid being conveyed that have a specific gravity of 1.00 or less. These values do not consider concentrated weight loads or aggressive reagents.

 

                                       Support Spacing Chart for Harvel Plastics, Inc. PVC Pipe 

                                                           PVC Pipe Support Spacing (ft)  

                                                                          Schedule 40

                                                                        Temperature (°F)

Pipe size

60°

80°

100°

120°

140°

1/4"

4’

3-1/2’

3-1/2’

2’

2’

3/8”

4’

4’

3-1/2’

2-1/2’

2’

1/2"

4-1/2’

4-1/2’

4’

2-1/2’

2-1/2’

3/4”

5’

4-1/2’

4’

2-1/2’

2-1/2’

1”

5-1/2’

5’

4-1/2’

3’

2-1/2’

1-1/4”

5-1/2’

5-1/2’

5’

3’

3’

1-1/2”

6’

5-1/2’

5’

3-1/2’

3’

2”

6’

5-1/2’

5’

3-1/2’

3’

2-1/2”

7’

6-1/2’

6’

4’

3-1/2’

3”

7’

7’

6’

4’

3-1/2’

4”

7-1/2’

7’

6-1/2’

4-1/2’

4’

6”

8-1/2’

8’

7-1/2’

5’

4-1/2’

8”

9’

8-1/2’

8’

5’

4-1/2’

10’

10’

9’

8-1/2’

5-1/2’

5’

12”

11-1/2’

10-1/2’

9-1/2’

6-1/2’

5-1/2’

18”

13’

12’

11’

8’

7’

20”

14’

12-1/2’

11-1/2’

10’

8-1/2’

24”

15’

13’

12-1/2’

11’

9-1/2’

                                                                                Schedule 80
   
                                                                         Temperature (°F)

Pipe size

60°

80°

100°

120°

140°

1/4"

4’’

4’

3-1/2’

2-1/2’

2’

3/8”

4-1/2’

4-1/2’

4’

2-1/2’

2-1/2’

1/2"

5’

4-1/2’

4-1/2’

3’

2-1/2’

3/4”

5-1/2’

5’

4-1/2’

3’

2-1/2’

1”

6’

5-1/2’

5’

3-1/2’

3’

1-1/4”

6’

6’

5-1/2’

3-1/2’

3’

1-1/2”

6-1/2’

6’

5-1/2’

3-1/2’

3-1/2’

2”

7’

6-1/2’

6’

4’

3-1/2’

2-1/2”

7-1/2’

7-1/2’

6-1/2’

4-1/2’

4’

3”

8’

7-1/2’

7’

4-1/2’

4’

4”

9’

8-1/2’

7-1/2’

5’

4-1/2’

6”

10’

9-1/2’

9’

6’

5’

8”

11’

10-1/2’

9-1/2’

6-1/2’

5-1/2’

10’

12’

11’

10’

7’

6’

12”

14’

12’

10-1/2’

7-1/2’

6-1/2’

18”

14-1/2’

14’

12’

11’

9’

20”

15-12’

14-1/2’

12-1/2’

11-1/2’’

9-12’

24”

17’

15’

14’

12-1/2’

10-1/2’

Note: Although support spacing is shown at 140 ° F, consideration should be given to the use of CPVC or continuous support above 120° F. The possibility of temperature overrides beyond regular working temperatures and cost may make either of the alternatives more desirable. This chart based on continuous span and for un-insulated line carrying fluids of specific gravity up to 1.00.                             

         

                                                            CPVC Pipe Support Spacing (ft) 

                                                                            Schedule 40

                                                                          Temperature (°F)

Pipe Size

73°

100°

120°

140°

160°

180°

1/2"

5’

4-1/2’

4-1/2’

4’

2-1/2’

2-1/2’

3/4"

5’

5’

4-1/2’

4’

2-1/2’

2-1/2’

1”

5-1/2’

5-1/2’

5’

4-1/2’

3’

2-1/2’

1-1/4”

5-1/2’

5-1/2’

5-1/2’

5’

3’

3’

1-1/2”

6’

6’

5-1/2’

5’

3-1/2’

3’

2”

6’

6’

5-1/2’

5’

3-1/2’

3’

2-1/2”

7’

7’

6-1/2’

6’

3-1/2’

3-1/2’

3”

7’

7’

7’

6’

4’

3-1/2’

4”

7-1/2’

7-1/2’

7’

6-1/2’

4-1/2’

4’

6”

8-1/2’

8’

7-1/2’

7’

5’

4-1/2’

8”

9-1/2’

9’

8-1/2’

7-1/2’

5-1/2’

5’

10”

10-1/2’

10’

9-1/2’

8’

6’

5-1/2’

12”

11-1/2’

10-1/2’

10’

8-1/2’

6-1/2’

6’

14”

12’

11’

10’

9’

8’

6’

16”

13’

12’

11’

9-1/2’

8-1/2”

7’

                                                                            Schedule 80
                                                                          Temperature (°F)

Pipe Size

73°

100°

120°

140°

160°

180°

1/4"

4’

4’

3-1/2’

3’

2-1/2’

2-1/2’

3/8"

5’

4-1/2’

 4’

3-1/2’

3’

2-1/2’

1/2"

5-1/2’

5’

4-1/2’

4-1/2’

3’

2-1/2’

3/4"

5-1/2’

5-1/2’

5’

4-1/2’

3’

2-1/2’

1”

6’

6’

5-1/2’

5’

3-1/2’

3’

1-1/4”

6-1/2’

6’

6’

5-1/2’

3-1/2’

3’

1-1/2”

7’

6-1/2’

6’

5-1/2

3-1/2’

3-1/2’

2”

7’

7’

6-1/2’

6’

4’

3-1/2’

2-1/2”

8’

7-1/2’

7-1/2’

6-1/2’

4-1/2’

4’