In 2012, Underwriter’s Laboratories (Northbrook) conducted research on fire-testing of fire-resistant cables, and found excessive failure rates in polymer-insulated electrical cables. Concluding from their research that the sample requirements in the current UL 2196 and S139 fire-test standards are completely inadequate, in September 2012 UL withdraw certification for Electrical Circuit Protective Systems that employ fire resistive cables (FHIT and FHITC).
From the UL website:
UL has recently conducted research on a wide array of current products and systems originally certified under UL 2196, Tests for Fire Resistive Cables and ULC-S139, Standard Method of Fire Test for Evaluation of Integrity of Electrical Cables and determined that they no longer consistently achieve a two-hour fire-resistive rating when subjected to the standard Fire Endurance Test of UL 2196
After withdrawing certification, UL began to offer manufacturers recertification using a revised and more stringent sampling plan within UL 2196.
Pentair’s Pyrotenax brand MI product line underwent UL testing to the new requirements and was re-certified. Other manufacturers are going to great lengths to circumvent the UL findings by testing to the old UL 2196 / S139 test requirements at another NRTL.
UL re-classification with new sampling requirements is available to all fire-resistive cable manufacturers. In order to offer a reliable and safe product for Life Safety applications, manufacturers must prove that their products conform to these new UL sampling requirements for UL 2196. It is clear that repeating the fire test while following the old UL 2196 sampling requirements is meaningless, given the failure rates uncovered by UL.
This reinstatement is the first in the industry!
Mineral Insulated (MI) cable was first produced commercially as “Pyrotenax” in 1936. Being made entirely from copper and magnesium oxide, the cable is inherently heat resistant, and can operate continuously at 250C.
It was a ‘natural’ for fire resistant applications, and was the first fire-rated cable listed by UL. It is used world-wide for its durability and fire-resistance.
- All inorganic constructions
- Zero Smoke
- Zero Flam Spread
- Zero Fuel Contributed
- Space-saving - smaller diameter cable; no conduit required
- Ampacity advantage (NEC Table 310.14(B)(17); (CEC 4-004(11))
Protecting Critical Circuits From Fire
Date: April 3rd, 2013
Time: 8:00 am (PST)