Commonwealth Edison (ComEd) distributes electricity to over 3.7 million customers in northern Illinois and has a peak load of 23,600 MW. To supply this power, they have 90,000 miles of power lines and operate hundreds of transformer substations.

A fire in a substation can greatly impact a utility’s financial situation, reliability and customer satisfaction. Steps taken to mitigate or reduce the damage can have a big impact. “Effective fire protection is like insurance for us,” said John R. Bettler, head of the Fire Protection Engineering Group at ComEd. “It helps us to attain two of our primary goals — to keep our customers’ lights on, and to operate our business safely.”

Engaged in Major Fire Protection Upgrade

To improve reliability, ComEd recently made fire prevention and protection upgrades to a number of its substations. ComEd contracted with Luse Thermal Technologies (LTT) to design and install a fire protection upgrade package to help reduce equipment damage and the duration of outages if a fire were to still occur.

AMI-SIL® Fabric Chosen For Fire Barrier System

One component of the fire protection package is the fabrication and installation of a fire barrier system on the underside of cable support racks. Luse chose AMI-SIL® FB3600-UT, a silica fire barrier cloth from Auburn Manufacturing Inc. (AMI).

AMI-SIL® FB3600-UT is a minimum 96% pure amorphous silica cloth designed for extreme temperature protection. It has a continuous operating temperature of 1800°F (1000°C). The high temperature fabric provides protection for the cables inside the cable tray. In the event of a fire, AMI-SIL® FB3600 UT will prevent direct flame contact with the cables and cable tray. According to AMI President and CEO Kathie Leonard, “The cloth will deflect the flame and hot gasses away from the control cables. It will protect control cables from burning power cables, allowing time for the continued switching of circuits in the station. For example, when burning power cables are envisioned, the hot gasses will rise and then be deflected by AMI-SIL® FB3600-UT. This installation prevents the cable tray from acting like a large frying pan, where the control cables are cooked.”

FM Approvals Assures Product Performance

One of the major factors influencing Luse’s choice of fire barrier cloth was the fabric’s FM Approvals rating. FM Approvals is the testing and certification arm of FM Global and provides on-going certification. According to Jim Ford, LTT General Manager Specialty Construction Division, “Ongoing third-party certification is critical to safe product performance. The FM Approvals mark gives assurance that the fabrics conform to the highest internationally accepted standards for quality, safety and performance.” Currently, 17 of AMI’s high temperature fabrics are FM Approved.

Safety First

Safety on all fronts is paramount at ComEd. It is easy to see why safety is so important when descending into a typical substation basement or cable space. It is filled with cables. From every wall, power cables energized at 12,000 volts enter the station underground and rise up through core-drilled holes into the switchgear upstairs. Control cable pans hang from the ceiling, carrying hundreds of cables used for metering, power and control of the electric equipment.

Facilities Require Demanding Firestop Designs

The demands placed on the firestop designs used in the substations are much greater than those found in commercial construction. The considerable weights and mass of the bundled cables called for the development of unique firestop designs to meet the challenges of the large penetrants found in substations. LTT worked closely with the Hilti Group to develop seals for the various cable penetrations without the need to take equipment out of service. This amounted to a huge savings in time and expense.

Proactive Steps Will Help Minimize Potential Outages

The proactive step of implementing an impressive fire protection program in its substations is an excellent business decision for ComEd — one that may limit losses and downtime in the event of a fire.

About Luse Thermal Technologies

Luse Thermal Technologies, LLC, a division of the Luse Family of Companies of Aurora, IL, is a firestopping specialty contracting services company that has a written quality assurance program and has obtained Factory Mutual certification as an FM4991 Approved Firestop Contractor.