General FRE® Conduit Frequently Asked Questions

1. Question: How is FRE® Reinforced Thermosetting Resin Conduit manufactured?
Answer: FRE® conduit is manufactured using a filament winding process in which fiberglass strands or rovings are pulled through either an epoxy or phenolic resin bath and then wrapped around a revolving mandrel which is controlled by a computerized winding machine. These rovings are laid over the mandrel at a predetermined angle, which establishes key product mechanical properties, while the number of passes determines the wall thickness. Once the resin is fully cured, the conduit is extracted off the mandrel and cut to length.

2. Question: What diameters and lengths are available?
Answer: FRE® conduit is available in trade sizes ranging from ¾” (21 mm) to 8” (203 mm) for Iron Pipe Size (IPS) dimensions and from 2” (53 mm) to 6” (155 mm) for Inside Diameter (ID) dimensions. All products are available in either 9.84 foot (3 meter) or 19.68 foot (6 meter) lengths. Conduit smaller than the 2” (53 mm) trade size is only available in 9.84 foot (3 meter) lengths. Larger diameters may be available upon request.

3. Question: How is FRE® joined together?
Answer: FRE® conduit employs a push-fit assembly using an integral inside tapered female bell and a male spigot. Each conduit section, other than for our Breathsaver® product line, has a proprietary watertight TriSeal™ gasket and retainer ring system that does not require an epoxy adhesive. The retainer ring provides an essential function, which is to guide the spigot end during assembly, in order not to dislodge the TriSeal™. This ensures a strong and watertight joint with a pullout strength of more than 500 lbs lb. (227 kg). Our BreathSaver®® product is not typically provided with a TriSeal™ as the gasket material would not provide the same flame and smoke characteristics as the rest of the conduit system. However, it is available with a TriSeal™ gasket by special request.

4. Question: When is an epoxy adhesive used with FRE®?
Answer: Epoxy adhesive is recommended for installations where there may be considerable vibration or significant movement due to expansion and contraction of the conduit system.

5. Question: What type of epoxy adhesive is required?
Answer: It depends on the application or installation. Our epoxy adhesive kits consist of either the mixture of two (2) distinct components (40-0161) or a dual cartridge system (20-0164) that pre-mixes the adhesive before it is applied to the conduit.

6. Question: Does the epoxy adhesive have a temperature limitation?
Answer: No. FRE® epoxy can be installed at any temperature. Note: Set up times may vary depending on temperature. It should be noted that epoxy based adhesives are well known to offer increased strength when heat cured, which allows for enhanced chemical cross linking of the adhesive system. Consult the manufacturer for additional information.

7. Question: Is FRE® conduit similar in wall thickness to PVC Schedule 40 or Schedule 80 conduit?
Answer: No. FRE® conduit is manufactured using thinner wall thicknesses than either PVC Schedule 40 or Schedule 80 conduit without compromising mechanical strength. Actually, FRE® conduit offers the highest strength to weight ratio of any conduit system. FRE® is an anisotropic material which allows for improved mechanical properties without having to increase the product wall thickness, as is required for PVC.

8. Question: Can FRE® conduit be coupled with rigid PVC, RMC or other conduit system types.
Answer: Yes. FRE Composites manufactures a variety of adapters for interconnection with all common conduit systems presently available in the marketplace, such as PVC, RMC, IMC, and EMT.

9. Question: Is FRE® conduit UL Listed?
Answer: Yes. FRE® is UL Listed for all its Below Ground, Above Ground, HazGuard™ (known as bullet resistant) and Extra Heavy Wall BreathSaver® conduit system products.

10. Question: Is FRE® conduit permitted by the National Electrical Code® (NEC)?
Answer: YES, Reinforced Thermosetting Resin Conduit (RTRC) is permitted as a Rigid Nonmetallic Conduit (RNC) for installation and use in accordance with Article 355 of the 2008 NEC.

11. Question: Is FRE® conduit CSA Certified?
Answer: Yes. FRE® is CSA Certified for all its Below Ground and Above Ground Conduit system products.

12. Question: Is FRE® conduit permitted by the Canadian Electrical Code® (CEC)?
Answer: Yes. FRE® conduit is permitted as a raceway for installation and use in accordance with rules 12-1200 – 12-1220 of the Canadian Electrical Code, Part 1, for non-hazardous locations.

13. Question: Are the support spacing requirements the same for RTRC conduit as they are for rigid PVC conduit?
Answer: Although RTRC has a much higher flexural strength than other Rigid Nonmetallic Conduits (RNC) such as PVC, the current NEC® spacing requirements specified in Table 355.30(B), are the same for both materials. However, the CEC® recognizes this material difference and therefore specifies longer distances for RTRC (rule 12-1216) than for rigid PVC (rule 12-1114).

14. Question: Are there any applications where support hangers can be spaced further apart for FRE® conduit than for rigid PVC conduit?
Answer: Yes. If the installation does not have to be in accordance with NEC provisions you can space hanger supports much further apart for FRE® conduit than for PVC. FRE Composites publishes a hanger span and deflection table in its AG catalog, which will guide you through your project or installation. As noted above, the CEC® specifies longer distances for RTRC (rule 12-1216) than for rigid PVC (rule 12-1114).

15. Question: How much lighter is FRE® conduit than rigid PVC or RMC?
Answer: In addition to having superior corrosion and chemical resistance, FRE® conduit is approximately 1/3 the weight of PVC SCH 40 and 1/10 the weight of RMC. For example, a 19.68 foot (6 meter) length of 4” (103 mm) SW FRE® conduit is approximately 16 lbs lb. (7 kg). A 10 foot (3 meter) length of RMC weighs approximately 112 lbs lb. (51 kg). One person can easily carry 100 feet (30 meters) of FRE® conduit to a job site.

16. Question: Does FRE® conduit expand and contract?
Answer: Yes, although FRE® conduit expands less than half as much as rigid PVC. A 120 F (67 C) increase in temperature will cause a 100 foot (30 meter) run of FRE® conduit to expand approximately 2.2” (56 mm). In comparison, rigid PVC conduit will expand approximately 4.9” (124 mm).

17. Question: Does FRE® conduit require expansion joints within a conduit run?
Answer: Yes. It is necessary to use an expansion fitting where the length change due to temperature is expected to be ¼” (6 mm) or greater between securely mounted items such as boxes, cabinets, elbows or other conduit terminations. For bridge attachments, we recommend placing an expansion joint approximately every 200 feet (60 meters) within the conduit run. For bridges under 50 feet (15 meters) in length, an expansion fitting is normally not necessary. For bridges between 50 feet to 200 feet (15 meters to 60 meters) in length, it is recommended that one expansion joint be placed at the midpoint.

18. Question: Are there different types of expansion fittings?
Answer: Yes. Two different expansion fitting designs, Single and O-Ring, are available. While similar in their intended function, the O-Ring expansion fitting adds a seal to keep out moisture, dirt and debris. The O-Ring expansion fitting also provides an internal stop ring to keep the fitting from pulling apart due to overexpansion.

19. Question: What secures the conduit in place, allowing for movement due to contraction and expansion to be between the expansion joints?
Answer: Split Stop Rings secure conduit in place at the anchoring hanger. A Split Stop Ring is easy to install as its design allows for it to open up to slide over the outside of the conduit and then be secured in place by adhesive. This fitting ensures that the expansion and contraction of the conduit run will take place at the expansion fitting located between the two fixed points.

20. Question: What other types of fittings are offered?
Answer: The following fittings are available: Double Bell Couplings, 5 Bell Couplings, Sleeves, Male and Female Adapters, Single and O-Ring Expansion Joints, 90, 60 45, 30, 22-1/2, and 11-1/4 Elbows in a variety of radii, Wobbles and Skew Wobbles, Multifit Adapters, O-Ring Expansion/Deflection Couplings, Y-Fittings, Offsets, Radius Bell Ends, Conduit Bodies, Split Stop Rings, Reducers, Pole Risers and Riserways.

21. Question: When should split conduits and fittings be used?
Answer: Split conduits and fittings are used to repair a damaged section of an existing raceway or to retrofit older installed raceways without having to remove in-service cables. Our former parent company, Canadian General Electric, patented the Split conduit design with US Patent # 4175593 and Canadian Patent # 1043277,

22. Question: Where can I find the most current information on FRE® conduit and fittings?
Answer: The information on FRE®’s website is continually updated to ensure its accuracy and to provide superior customer support.