FAQ

Below, we have tried to answer the most common questions visitors may have. If you find that your question is not answered on this page, please email us pnasales@petroflexna.com or call us 7:30am – 5:00pm CST, M – F at 1-800-433-5711, 940-668-7283.

Questions:

1. How do I couple polyethylene?
2. How many different sizes of polyethylene conduit are available from PNA?
3. Does PNA’s polyethylene conduit come in different colors?
4. Does PNA provide sequential marking for their conduit?
5. Can PNA supply pull rope or pull tape pre-loaded in the conduit?
6. How much pull can be exerted on polyethylene?
7. What can I do to maximize my pulls?
8. What kind of cable lubricant should be used with polyethylene?
9. Can PNA provide Cable-In-Conduit?
10. Is selective back fill required when using polyethylene conduit?
11. What standards does PNA’s polyethylene conduit meet?
12. Is polyethylene REA-approved?
13. Is polyethylene UV resistant?
14. How well does polyethylene function in extreme weather conditions?
15. What is the difference between polyethylene and PVC?
16. Why should I use polyethylene when PVC has a lower cost per foot?
17. What kind of flexibility and bend radius can I expect when using polyethylene?
18. Is polyethylene available in continuous lengths?

1. How do I couple polyethylene?
PNA has a variety of coupling methods, each designed for the type of installation being performed. E-Loc® couplings are high-strength metal or Polyurethane couplings for plowing. E-Lok® couplings provide a non-metallic, non-conductive coupling for trench installations. Left/right threaded aluminum couplings install easily with a common pipe wrench. Tri-plex and multi-stage end caps are also available for sealing the wire inside conduit. Double E-Loc® couplings are reusable and are constructed similar to a compression coupling. Double E-Loc® can maintain pressures over 200 psi, even when unrestrained.  Compression couplings are also used for joining two pieces of pipe together.

2. How many different sizes of polyethylene conduit are available from PNA?
PNA can fill practically any order. We manufacture conduit from 1/2″ to 6″ diameter

3. Does PNA’s polyethylene conduit come in different colors?
Yes, PNA can supply a variety of colors. We do recommend black, due to its superior UV resistance and economy. Standard colors are black, gray, red, orange, white, blue, green, yellow and terra cotta.  A method to economically color code duct and conduit is by striping. PNA can extrude 3 stripes into the outer wall of the conduit. These stripes become an integral part of the conduit and the exterior wall remains smooth and concentric. We can stripe the conduit in any of our nine standard colors. And don’t forget that custom colors are always available for solid color and striped conduit. (Min quantities may apply)

4. Does PNA provide sequential marking for their conduit?
Yes, we do! Hot stamping and custom or sequential marking…. you have your choice.

5. Can PNA supply pull rope or pull tape pre-loaded in the conduit?
Absolutely. PNA can supply pull rope or pull tape, or even conductor in your conduit. Just let us know what you need.

6. How much pull can be exerted on polyethylene?
Just check the Ultimate Tensile Strength Chart in our PNA Product Manual. Here is just one example: Our six inch conduit with an outside diameter of 6.625 inches, and a Schedule 40 inside diameter has a tensile strength of 18,000 pounds.

7. What can I do to maximize my pulls?
For the most efficient pull, the conduit should be laid straight and level.  Even though polyethylene gives you great flexibility, using a good cable lubricant ensures longer, easier pulls.

8. What kind of cable lubricant should be used with polyethylene?
PNA’s ProPull™ cable lubricant is the best choice for making long pulls smooth. ProPull™ Lube is a nontoxic polymer gel that clings to polyethylene cable jackets and conduit, and carries the lube far into the conduit. ProPull™ Lube doesn’t contain silicone, so it won’t harm cable or other sheath material. PNA’s Product Manual and this web-site contain a Lube Quantities Chart which shows how much lubricant you’ll need, depending on the size of the conduit and the length of the pull.

9. Can PNA provide Cable-In-Conduit?
Yes, we can pre-install cable in your conduit. Call 800-433-5711 with your cable size for engineering expertise. Also click here for CableGuard™ information.

10. Is selective back fill required when using polyethylene conduit?
Selective back fill is not required with polyethylene. PVC, on the other hand, is not flexible, and can be damaged by rocks and other debris. Polyethylene is much more forgiving.

11. What standards does PNA’s polyethylene conduit meet?
PNA manufactures to ASTM D2447, ASTM D3035, ASTM D3485, ASTM D2239 and NEMA TC7 specifications. We are also listed and accepted by MSHA, most DOT’s, the Petroleum Institute, and all major telecommunications companies.

12. Is polyethylene REA-approved?
The REA (Rural Electrification Administration) is now the RUS (Rural Utilities Service). The RUS does not issue an “approved” or “unapproved” list for conduit. However, our PNA conduit and API pedestals are accepted by RUS and are RUS listed. Click here to view our RUS acceptance letters

13. Is polyethylene ultraviolet resistant?
Yes, polyethylene is UV resistant. Black conduit has the best UV resistance of any color, because the UV rays cannot penetrate the plastic. For above-ground installations, we recommend using only black conduit. PNA’s color conduit contains UV stabilizers and is guaranteed to be UV resistant in direct sunlight for one year.

Fire retardant polyethylene is not UV resistant due to the absence of UV inhibitors. Therefore, we recommend that fire retardant polyethylene not be exposed to direct sunlight.

14. How well does polyethylene function in extreme weather conditions?
We have seen polyethylene conduit installations continue, even when temperatures dropped down to 0 degrees F (17.8 degrees C). Polyethylene works well in extreme hot or cold, even when outside temperatures are -50 degrees F (-45.6 degrees C).

15. What is the difference between polyethylene and PVC?
Durability and flexibility gives polyethylene the edge over PVC (polyvinyl chloride). PVC is extremely rigid, inflexible and has cold weather restrictions. Plus, PVC has to be glued every ten to twenty feet, increasing installation labor and material costs.

HDPE is a compound whereas PVC is a mixture, thereby providing the same quality from batch to batch.  Ground shifting does not crack HDPE as it does PVC.  HDPE is much more resistant to acids, alkali and hydrocarbons than PVC.

16. Why should I use polyethylene when PVC has a lower cost per foot?
PVC may cost less per foot, but you’re only talking about the conduit. Add increased labor and material costs for all the extra connections to the PVC price, and you’ll see that polyethylene actually costs less in the ground.

17. What kind of flexibility and bend radius can I expect when using polyethylene?
Polyethylene’s flexibility means easier installations, with less bends and elbows, and that adds up to faster installations. Here is an easy way to remember flexibility and bend radius – it’s approximately ten times the outside diameter of the conduit.

18. Is polyethylene available in continuous lengths?
PNA manufactures a variety of standard sizes and lengths, from ten feet to five thousand continuous feet lengths. Since PNA is a custom extrusion manufacturer, we can manufacture special lengths whenever you need them.