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PermaWrap™
 Frequently Asked Questions

  1. What is a composite?
  2. What is the function of the fiber?
  3. What is the function of the resin?
  4. Are there any other materials used in a composite?
  5. Why is PermaWrap™ called “The Next Generation Composite”?
  6. Can we get a closer look at the materials?
  7. What materials are used to make composite repairs visible to MFL “Smart Pig” tools?
  8. What types of piping defects can be repaired using PermaWrap™?
  9. What types of defects are not to be repaired with PermaWrap™?
  10. How does PermaWrap™ work?
  11. What is the limitation of PermaWrap™ being applied to out of round pipe?
  12. Does the PermaWrap™ System meet the requirements of the D.O.T.?
  13. What types of testing have been conducted on the PermaWrap™ System?
  14. Does the PermaWrap™ System cause any shielding of the cathodic protection system?
  15. Has the PermaWrap™ been tested for cathodic disbondment?
  16. Do you have an engineering analysis tool or software for determining if PermaWrap™ is a suitable method of repair (i.e. wall loss, surface area defect, etc.)?
  17. Are there Training Requirements for Installing the PermaWrap™ System?
  18. Is the Certification for Installing other rigid composite sleeves applicable?
  19. How is the PermaWrap™ Repair System different from other rigid composite sleeving systems?
  20. How is the PermaWrap™ Repair System similar to other rigid composite sleeving systems?
  21. What is the pressure rating of the PermaWrap™ System?
  22. Will several adjoining sleeves provide the same integrity as a single sleeve?
  23. What is the edge effect and associated limits?
  24. What is the basic criteria for determining the number or width of PermaWrap™ to use?
  25. Has there been any testing of the PermaWrap™ under cyclic loading (bending) conditions?
  26. Is the PermaWrap™ susceptible to microbial attack such as Microbiologically Influenced Corrosion (MIC)?
  27. Is the PermaWrap™ resistant to corrosion or atmospheric degradation? 
  28. What external coating is recommended for protection of the repair sleeve when installed above ground?
  29. What external pipe coating is recommended to provide protection for below ground installations?
  30. How does the impact resistance of the PermaWrap™ sleeve compare to paint or elastomeric coatings?
  31. Does the ferrous metal cloth expand at a different rate than the reinforcing fiber?
  32. What protects the reinforcing fibers from corrosion, chafing, or being damage by the ferrous metal cloth?
  33. What is WeldWrap™ used for?

 

 

1. What is a composite?
A composite is a combination of a fiber-reinforcing agent (such as glass or carbon) bonded together by a polymer resin.

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2. What is the function of the fiber?
The primary function of the fiber-reinforcing agent is to provide strength and stiffness by carrying the load along the length of the fiber in the direction of the fiber.

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3. What is the function of the resin?
The primary function of the polymer resin is to transfer stress between the reinforcing fibers, act as a glue to hold the fibers in place and to protect the fibers from mechanical and environmental damage.

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4. Are there any other materials used in a composite?
Additives such as fillers, pigments and ferrous metals may be used to modify or enhance the final product.

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5. Why is PermaWrap™ called “The Next Generation Composite”?
The following is a comparison matrix showing the raw materials used in the construction of standard polymer resin composites in comparison to the materials used in the PermaWrapä Next Generation Composites.

Standard Composites PermaWrapä “ Next Generation Composites”
1.  Polymer Resin 1.  Polymer Resin
2. Fiber-reinforcing agent 2. Custom manufactured fiber-reinforcing agent

The fibers used to provide strength in standard composites.

WrapMaster’s custom manufactured bi-axial cloth used in the construction of the PermaWrapä reinforcement system.

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6. Can we get a closer look at the materials?
Yes, the following photographs will give you a close-up view of the materials used in the construction of standard polymer resin composites in comparison to the materials used in the PermaWrapä “Next Generation Composites”.

Standard Composites PermaWrapä “ Next Generation Composites”

Inside a standard composite, reinforcing fibers are far from being parallel and equidistant providing an inconsistent load transfer.

Inside a PermaWrapä composite system, the bi-axial reinforcing fibers are as close to parallel and equidistant as possible, providing a more consistent load transfer.

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7. What materials are used to make composite repairs visible to MFL “Smart Pig” tools?
Standard composites are traditionally non-metallic and unable to be detected by MFL “Smart Pig” tools. Enough ferrous metal must be added to make the repair visible to a MFL in-line inspection tool.

Standard non-metallic composites PermaWrapä “Next Generation Composites”

A ferrous metal must be added to the exterior of the repair area to make the repair visible during the next in-line inspection. Should the operator fail to install enough metal, the MFL tool will fail to recognize a repair has been made requiring the repair area to be exposed for inspection.

Inside each layer of a PermaWrapä composite system, an extremely fine custom manufactured ferrous metal cloth is placed between 2-layers of bi-axial fiber cloth. This patented process allows the MFL ”Smart Pig” tool to detect the sleeve installation as if it were a steel sleeve.

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8. What types of piping defects can be repaired using PermaWrap™ ?

  1. External defects of the pipe surface up to 80% wall loss.

  2. Defects near welded areas with a depth of up to 50% wall loss and no more than 30% of the circumference.

  3. Cracked areas in the pipe body - if the crack can be ground out.

  4. Dents with a depth up to 12.5% of the pipe's diameter.

  5. Gouges provided they have been cleaned to give them a smooth profile.

  6. Defects in the line's inners surface as a temporary repair.

(The types of defects listed above can also be repaired on curved sections of pipe.)

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9. What types of defects are not to be repaired with PermaWrap™?
Cracks, gouges or dents in longitudinal or girth welds.

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10. How does PermaWrap™ work?
PermaWrap™ prevents or controls pipe expansion by sharing the hoop stress.

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11. What is the limitation of PermaWrap™ being applied to out of round pipe?
PermaWrap™ may be applied to pipe with non-concentric profiles as established by API Specifications (12.5% for gas pipeline and 10% for liquid pipelines).

The primary concerns for installations are:

  1. Removal of stress risers.

  2. Surface preparations (NACE #3, SA 2-½ finish)

  3. The assurance of intimate contact with PermaWrap™ via the high compressive strength filler. The objective is to ensure a "load transfer" path to the composite sleeve.

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12. Does the PermaWrap™ System meet the requirements of the D.O.T.?
Yes, the PermaWrap™ System has been thoroughly tested with a particular focus on 80% defects to ensure compliance with performance standards. The approval for use of composite repair systems is in the January 2000 release of the Federal Registry.  See Regulatory information.

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13. What types of testing have been conducted on the PermaWrap™ System?
All testing of the PermaWrap™ System has been conducted by an Independent Testing Laboratory and the test program has been two-fold. 1) Testing of individual system components to establish physical properties and 2) Testing of the over-all system performance with EXTREME defects (80% wall loss). The tests included tensile, lap shear, compressive, hydrostatic burst, cyclic fatigue, etc. The test data was compared to properties of existing systems. The data reflects superior results for both the individual components and the over-all system performance.

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14. Does the PermaWrap™ System cause any shielding of the cathodic protection system?
Yes, as with all composite reinforcement systems and quality pipe coatings, PermaWrap™ is electrically non-conductive. In addition to reinforcing the defect area, the composite must perform the same function as a pipe coating.

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15. Has the PermaWrap™ been tested for cathodic disbondment?
Yes, the PermaWrap™ System has been tested by an Independent Laboratory using ASTM G 95-87 test criteria.

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16. Do you have an engineering analysis tool or software for determining if PermaWrap™ is a suitable method of repair (i.e. wall loss, surface area defect, etc.)?
Yes, the versatile window-based WrapMax® software is user friendly with features to conduct defect analyses in addition to providing a complete repair report for documentation. Standard inputs are required (i.e. pipe diameter, wall thickness, pipe grade, defect axial length, defect depth, etc.)

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17. Are there Training Requirements for Installing the PermaWrap™ System?
Yes, the PermaWrap™ System may only be installed by Trained Personnel.

Level 1 Installer: 1-day course trained in the field by WrapMaster Personnel or Certified Trainers. This level of training provides specific application technique and general product knowledge.
Level 2 Installer: 1-½ day course (classroom & hands-on) either at the Customer's or WrapMaster's Facility. This level of training provides application techniques for all scenarios and thorough product knowledge.
Trainer: 2-day course (classroom & hands-on) either at the Customer's or WrapMaster's Facility. This level of training provides application techniques for all scenarios, thorough product knowledge, use of engineering analysis software, etc. The individual will be fully qualified to train others to install the PermaWrap™ Repair System.


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18. Is the Certification for Installing other rigid composite sleeves applicable?
Yes, previous Installer training with rigid composite applications is applicable. The Installer may forgo the PermaWrap™ training by passing an exam to ensure fundamental knowledge of application technique (i.e. removal of sharp edges, surface preparation, defect limits, etc.).

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19. How is the PermaWrap™ Repair System different from other rigid composite sleeving systems?

  1. The PermaWrap™ Sleeve is "magnetically detectable" to enable smart pigs to identify repaired areas enabling the operator to only address the defect areas not previously rehabilitated.

  2. The PermaWrap™ Sleeve has a superior laminate construction enabling distinct advantages over the other rigid composite sleeves.

  3. The PermaWrap™ "Diamond Grip" embossment technology provides a mechanical locking system allowing the individual layers of the wrap to nest within each other even on an incline or in the vertical position.

  4. The PermaWrap™ System is more economical because the system is offered in five (5) standard widths - 6", 9", 12", 15" & 18". This enables the operator to only purchases the required materials based on the defect length.

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20. How is the PermaWrap™ Repair System similar to other rigid composite sleeving systems?

  1. The construction of the PermaWrap™ Sleeve uses equivalent raw materials thus previous testing - characterizing material behavior is still applicable. The materials are manufactured to provide a superior laminate construction enabling distinct advantages over the other rigid composite sleeves.

  2. The PermaWrap™ Adhesive and Putty system's also uses materials in the same chemical family but with superior performance. When coupled with the PermaWrap™ composite sleeve - provides an "overall" superior system.

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21. What is the pressure rating of the PermaWrap™ System?
There are no pressure limits to using PermaWrap™ because the design of PermaWrap™ is based on the Maximum Working Stress of Steel Pipe. All pipelines are designed in accordance with the basic formula, where the maximum allowable wall stress is a constant regardless of pressure.

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22. Will several adjoining sleeves provide the same integrity as a single sleeve?
Yes, the standard PermaWrap™ sleeve is sized for the respective pipe and forms eight (8) circumferential layers when applied. Several units may be butted together for long axial defects. In addition, the seam at the interface provides at least the same reinforcement as the main body of the composite because of the "edge effect". This strength of material characteristics is reflective of any type of reinforcement.

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23. What is the edge effect and associated limits?
"Edge effect" is a strength of materials phenomena not exclusive to PermaWrap™ in which residual reinforcement extends beyond the physical limits of the actual reinforcing material. In the case of PermaWrap™ Reinforcement, it is our position that the mutual diminishing reinforcement limit is ½"maximum. This limit is utilized for designing bend repairs. For straight pipe the limit is ¼"maximum to prevent inappropriate use of PermaWrap™ Systems.

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24. What is the basic criteria for determining the number or width of PermaWrap™ to use?
The repair sleeve or sleeves (when multiple units are deployed) must extend a minimum of 1½" beyond both sides of the defect.

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25. Has there been any testing of the PermaWrap™ under cyclic loading (bending) conditions?
The PermaWrap™ is not designed to resist axial bending moments. The Pipeline Operator is to secure the pipe to their satisfaction with respect to the repair area. PermaWrap™ is designed to prevent "bulging" in ductile pipe by transferring the hoop stress from the pipe to the PermaWrap™.

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26. Is the PermaWrap™ susceptible to microbial attack such as Microbiologically Influenced Corrosion (MIC)?
Although MIC is a serious problem with metal, they pose no difficulty with FRP materials because bacteria has no appetite for high molecular weight polymers. Due to this known fact, the FRP Industry has never seen any evidence of MIC corrosion. At times people have been concerned with fungus because some thermoplastics can be degraded by fungus. With FRP, there has never been any proof that this happens. In cases where fungus attack was suspected, a close examination reveals that the apparent fungus growth is really on soil particles, which are physically adhering to exhume FRP. Gasoline tanks buried in sulfate containing soils are virtually unaffected after thirty years or so, while metal tanks under the same conditions would be severely corroded by sulfate reducing bacteria.

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27. Is the PermaWrap™ resistant to corrosion or atmospheric degradation? 
The PermaWrap™ is UV sensitive and a protective coating is always required when installed above ground.

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28. What external coating is recommended for protection of the repair sleeve when installed above ground?

No specific coating is recommended and any may be used as long as the coating is opaque and will bond to composite material. 

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29. What external pipe coating is recommended to provide protection for below ground installations?
The completed PermaWrap™ assembly is to be treated as a standard pipe repair requiring an external barrier coating. The only specific recommendations in reference to pipe coatings are:

  1. It must be applied after the PermaWrap™ adhesive has cured (approximately 2 hours after installation).

  2. It must bond to composite.

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30. How does the impact resistance of the PermaWrap™ sleeve compare to paint or elastomeric coatings?
The failure mode for a coating has more to do with shear strength while the failure mode for PermaWrap™ has to do with inter-laminar fracture toughness. In relation to elongation, most paints have at least 6% while elastomeric coating can have up to 200%. The PermaWrap™ sleeve typically has approximately 1% elongation and the adhesive has approximately 40% elongation. Although the cured PermaWrap™ system will typically have a higher impact toughness than the coatings, it is advisable that the PermaWrap™ be inspected whenever the coating shows evidence of impact.

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31. Does the ferrous metal cloth expand at a different rate than the reinforcing fiber?
The Coefficient of Thermal Expansion (CTE) for the glass reinforcing fiber is 5.4x10^-6 (in/in/ºF) or .0000054. The CTE for the ferrous metal cloth used in the sleeve for MFL “Smart Pig” detection is 5.7x10^-6 (in/in/ºF) or .0000057. This difference is negligible. Examples of similar applications are glass fiber reinforced pipe, composite satellite dishes and some composite circuit board designs with wire heat sink material inside.

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32. What protects the reinforcing fibers from corrosion, chafing, or being damage by the ferrous metal cloth?
The PermaWrap™ sleeve is designed such that the reinforcing fibers never come into contact with the ferrous metal cloth.  There are additional transverse glass fibers incorporated as a protection barrier between the reinforcing fibers and the metal cloth. 

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33. What is WeldWrap™ used for?

WeldWrap™ is a 10-layer Composite Reinforcement System (same specifications as PermaWrap™). The first 2-layers are slotted at the manufacturer to fit a standard girth weld. This new innovative single unit design replaces the traditional repair method requiring 3 sleeves be installed to reinforce girth weld areas. Use of the single sleeve design, expedites repairs and is a significant cost savings to the customer.

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Disclaimer: This document has been prepared solely for the purpose of providing information about WrapMaster, Inc. products. No representation is made as to the completeness or accuracy of the information it contains. In particular, you should be aware that this information may be incomplete, may contain technical inaccuracies, typographical errors or may have become out of date. WrapMaster, Inc. reserves the right to add, modify or delete any of this information at any time.

 

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Revised 01/10/2007 WrapMaster, Inc.
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