By ED CUNNINGHAM
In large metropolitan areas, public utilities have numerous cables installed in cable bundles in underground ducts, conduits, and tunnels. Under normal operation and conditions, the cable jacket and insulation provide adequate thermal and electrical isolation to prevent arcing (electrical discharge) between cables.
However, low air circulation and high ambient temperatures in ducts and tunnels, especially during the summer months, combined with the heat generated by the electric cables can cause electrical breakdown of cable insulation, arcing, and cable fires that rapidly transfer fire and heat to adjacent cables, causing further arcing. This can result in a chain reaction with multiple cable failures interrupting power to most or all of the cables in a manhole, duct, conduit, or tunnel. Damage spread over a wide area results in power outages to many people, requiring days or weeks to repair and restore service.
The utility workers and first responders to these fire emergencies face severe, potentially life-threatening problems from the dense smoke generated and the toxic combustion products (carbon monoxide, hydrogen chloride, phosgene, and so on) released by the many cable wraps currently used by utility companies. When subjected to fire or high heat, the components of these cable wraps release large volumes of thick, dense smoke that reduces visibility to near zero. Entering this area and performing emergency operations are virtually impossible until proper ventilation is achieved. All of these toxic gases substantially exceed Occupational Safety and Health Administration standards for human exposure, even for a short duration.
As a result, SafTee First LLC and NoFire Technologies, Inc. developed NoFire/SafTee Arc and Fireproof Tape (patent pending) to help protect first responders and the general public while maintaining the integrity and operation of today’s increasingly complex grid of electric power distribution across the United States, particularly in severe environmental conditions. It uses currently available resins to provide the required high-voltage isolation and is protected with NoFire A18, the high performance, nontoxic, and environmentally safe intumescent fire protective coating. The tape has been tested and approved to meet Consolidated Edison of New York (Con Ed) specifications for cable protection because of high voltage, fault arcing, fire and high heat resistance, and environmental factors in underground structures. It complies with Con Ed Specification EO-5343, Arc and Fire-Resistant Materials Used for Cable Wraps, and is the only tape approved according to Con Ed Specification EO-100.
NoFire/Saftee Tape is a major improvement over currently used tapes that provide only high-voltage protection. It enables public utilities to better maintain the integrity of their high-voltage cable systems under severe underground conditions. More importantly, it helps mitigate the health and safety risks for individuals exposed to these situations. In comparison to commonly used tapes, the NoFire/SafTee Tape provides the following:
- Reduces or eliminates flame spread and fire damage to cables.
- Reduces smoke emissions.
- Eliminates the generation of toxic products of combustion.
- Prevents or reduces the spread of cable failure to adjacent cables.
- Provides increased resistance to abrasion, impact, and environmental factors including water, chemicals, and gases.
- Standard (no fiberglass) and fiberglass-reinforced versions for increased fire performance and tensile strength.
In addition to the above improvements, the tape complies with Con Ed EO-5343 requirements for the following:
- Low thermal conductivity.
- High electrical resistivity.
- High tensile strength.
- Flexibility.
- Ease of installation.
- Nonhazardous to installers.
- Thinness and light weight.
Fires in high-voltage electrical cables installed in underground ducts, conduits, or tunnels can result in widespread damage to power plants, resulting in lengthy power outages to many customers. In addition, the components of the cable insulation and currently used cable wraps emit large volumes of thick, dense smoke and toxic combustion products that make it especially dangerous to utility workers, first responders, and the general public at these emergencies.
Although many responders currently use tape to provide only high-voltage protection, the NoFire/SafTee Tape provides necessary fire and high heat protection to eliminate or substantially reduce the spread of fire, fire damage, and the production of smoke and toxic gases.
● ED CUNNINGHAMis a 31-year veteran and the retired chief of fire prevention for the Fire Department of New York. He has a bachelor of science degree in fire science and a master’s degree from John Jay College in New York City.
