Viper-Skin™ is the first bi-axial, hybrid carbon and glass fiber polyurethane pre-impregnated system that blends the unsurpassed strength and stiffness of carbon with the ease and use of a moisture-cured, factory-saturated fiber


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Typical Applications

  • Transmission and distribution pipelines
  • Oil and gas risers
  • Mechanical dents and defects
  • Girth welds on vessels and pipelines
  • Straights, elbows, tees, and flanges
  • Process piping: chemicals, oil, gases, water, and steam


  • Moisture-cured polyurethane resin reduces composite preparation time by over 50%
  • Factory-saturation optimizes fiber to resin ration and provides a material with a constant strength property
  • Non-shielding
  • Can be applied to damp, sweating, or immersed surfaces
  • No heating or post-curing required
  • Can be applied to any geometry including, but not limited to elbows, Tees, and flanges
  • Design conforms to ASME PCC-2, ASME B31, ISO TS24817, DOT, API, and CSA Z662 standards for nonmetallic reinforcing solutions


As determined by NRI engineering calculations


As determined by NRI engineering calculations

Mixing & Mix Ratio

No mixing required

Pot Life

20 minutes @ 75˚F (24˚C), less at higher temperatures


Application temperature: minimum of 32˚F (0˚C) and maximum of 150˚ (66˚C)

Related Products
The following products are system components of the Viper-Skin system:

  • Load Transfer Epoxy: Syntho-Poxy™ HC Reinforcing
  • Anti-Corrosion Primer: Syntho-Subsea™ LV Epoxy
  • Insulating Glass Layer: Syntho-Glass® XT
  • UV protection: Syntho-Coat or Syntho-Glass® UV
  • Compression Film


Viper-Skin was designed to conform to ASME PCC-2, ASME B31, ISO TS24817, DOT, API, and CSA Z662 standards for nonmetallic reinforcing solutions. Consult NRI Engineering for specified use.

Surface Preparation

Surface preparation and profiling shall promote continuous intimate contact between the CFRP system and pipe by providing a clean, smooth, and circumferential surface. Surface preparation shall be in accordance with SSPC-SP1 “Solvent Cleaning” and SSPC-SP10 / NACE 2 “Near White Blast Cleaning” 1-3 mil surface roughness (25-75 microns). If an existing coating is present, roughen to degloss. The Viper-Skin composite repair system is a bond -critical composite repair system requiring a strong adhesive bond between the clean pipe and the Viper-Skin system.


Installation of the Viper-Skin System shall be performed by NRI qualified applicators only. Surface preparation, mixing of epoxy, and installation of the system are to be in accordance with NRI’s Viper-Skin Installation Guide, latest revision. Quality control inspection during and after installation of the Viper-Skin system shall be performed per NRI’s Installation Validation Procedure: Quality Control Records, latest revision.

Cleanup and Safety

For proper information regarding the safe handling, storage, and disposal of chemical products, users shall refer to the most recent SDS, latest revision, containing physical, ecological, toxicological, and other safety-related data

Shelf Life

12 months

Storage Conditions

Store in a cool, shaded area at an ambient temperature of 95ºF ( 35ºC)


Refer to individual data sheet for product packaging

Composite Laminate Properties

PropertyCircumferential DirectionAxial Direction
Tensile Modulus 8 Msi 2 Msi
Thermal Expansion Coefficient1.79 ppm/˚F 13 ppm/˚F
PropertyTypical Test Value
Laminate Thickness0.018 ”
Poisson Ratio0.132
Shore D Hardness83


Cure Schedule

TemperatureWorking Time Set Time
50°F (10°C)60 minutes 120 minutes
60°F (16°C)40 minutes 75 minutes
75°F (24°C) 20 minutes40 minutes
90°F (32°C) 12 minutes20 minutes
150°F (66°C)2 minutes10 minutes