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Fire-Rated Wiring vs. Concrete Construction

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Are You Meeting NFPA Life Safety Code?

Traditionally, the encasement of non fire-rated cables in 2” of concrete was accepted as a form of fire building protection. However, changing codes and listings mean that new technology may be needed to ensure a building is fully protected for two hours. 

Don’t Skimp on Safety 

Over time, as building design and construction has evolved, so have safety standards. By 2017, 42 U.S. states and Canada mandated a minimum two-hour fire rating for critical circuits in buildings. 

This means, circuits must operate for a minimum of two hours during a fire test, as specified by National Fire protection association, per the American Society for Testing and Materials (ASTM) test-temperature curve.

Is Concrete Fire Resistant Enough?

The fire resistant concrete method is the practice of: 

  • Encasing non fire-rated wiring in 2” of concrete
  • Surrounding cables with drywall, or  gypsum board 
  • Running cables through concrete blocks 

These methods were developed when codes only required one hour of fire protection. To achieve the listed requirements, concrete construction now needs to be four or five inches thick. 

With availability of fire proof cable, building professionals are better equipped to specify safety systems that can be tested, and guarantee protection.




Concrete Encasement


YES (30 Years)


Inorganic Construction



UL/ULC Fire Rated



Free Air Rated



Broad Distribution



Trade Sensitivity



Space Required



Ideal for Retrofits 



Mechanical Strength (Ability to withstand a blow, falling concrete, etc.) 



cable amapacity

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nVent PYROTENAX Fire-Rated Wiring Specifications on MasterSpec® Powered by Deltek SpecPoint®

nVent PYROTENAX MasterSpec

nVent PYROTENAX MI two-hour fire-rated wiring cables meet the most stringent fire testing standards for safety in buildings and infrastructure. They ensure safe operation of critical emergency circuits under fire conditions – which is essential for safe evacuation and to allow firefighters to continue their efforts during an emergency.

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Don’t take our word for it. Download the latest research report published by the National Fire Protection Agency on the concrete fire resistance rating. You’ll also receive our whitepaper laying out the evolution of NFPA codes and standards.

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