Life Safety in Overdrive

A highly sophisticated fire alarm network achieves new heights of control at a General Motors facility in Indianapolis.

• By Barbara Horwitz-Bennett
• Dec 01, 2011

General Motors recently needed to expand its engine testing facilities in Indianapolis. To house an additional nine test cells, GM made use of an adjacent, 45,000 square-foot facility that formerly was a tool shop.

Safety is an overriding priority for General Motors. In keeping with this precedent, GM Indianapolis decided to approach its fire protection needs using the latest network technology. Instead of specifying individual systems for fire alarm, engine test cell fire suppression, hazardous gas detection, medical emergencies, digital voice command (DVC), and emergency weather monitoring, the decision was made to tie everything together into one central network.

The GM plant's managers expect efficiencies and streamlined notification with the new fire protection and emergency communications network. As Bob Downey, GM's general supervisor of Engineering Lab Support, explained, "the new networked system will enhance GM's ability to monitor the conditions and status of the facility, which is consistent with the rest of the safety culture at our facility."

System Capabilities
A fire alarm control panel housed inside a sealed, NEMA type 12 enclosure measuring 7 feet tall and 6 feet wide serves as the central control unit of the facility's fire and emergency notification network.

"You could literally spray a hose on the cabinet and nothing would happen to the equipment," said Matt Euson, president of 3S Incorporated of Harrison, Ohio. A fire protection and security systems integrator, Euson's company designed and built the entire system for GM.

Throughout the building, blue, wall-mounted LEDs indicate the location of medical emergency push buttons. When a button is depressed because of an emergency, blue strobe lights actuate throughout the building and a pre-programmed voice announcement is made over the network's speakers, indicating a medical emergency and its location. At the same time, the system automatically summons an ambulance via a telephone call to a third-party central monitoring station.

The test cells are equipped with a water mist system that is activated by flame and heat detection and can be discharged immediately. The system discharges a homogenous suspension of water in nitrogen into the room, but the water being dispensed is just three-quarters of a gallon per minute for four minutes. This is a big benefit, in terms of reducing damage to test cell equipment and to the product in test.

The water mist system is a twin-fluid system, meaning the nitrogen and water are piped separately to the emitters in the hazard area. It uses a captured water supply housed in a lined tank built for the project.

Test cells also are equipped with an automatic sprinkler system. Its flow and tamper switches are monitored by the fire alarm control panel.

Gasoline and diesel engines are operated within some of the test cells. To protect operators from abnormal emissions, hazardous gas detection systems from Honeywell Analytics are another integral part of the facility's life safety systems network. Used to sense carbon monoxide (CO), gaseous hydrocarbons, and refrigerants, these detectors are installed on the mezzanine level of the two-story facility, as well as in the test cells and control rooms. The fire protection system also monitors critical exhaust ventilation systems to ensure they remain in operation.

An additional system capability is emergency weather alerts. The weather monitoring is outsourced; when the vendor spots a major weather event within 7 miles of the facility, its personnel simply call a number that triggers the fire alarm control panel to declare a weather emergency. Amber strobe lights will be activated while a digitally recorded voice announcement goes through the system's speakers telling plant workers to take shelter.

Considering the GM plant's network includes an array of speakers set up throughout the facility, authorized users also can utilize the DVC in a public address capacity. Using fiber optic cables that are nearly impervious to damage caused by power surges, lightning strikes, and other weather-related events, Euson's 3S team was able to extend the network's DVC, weather system, and emergency medical stations to two other buildings on the GM campus. With the system being fully automated, multiple workstations can be tied into the network, allowing monitoring and control capabilities at numerous points. The GM Indianapolis plant has three graphic workstation displays located in the mezzanine, lobby, and break room that are utilized to monitor the entire network’s status and all events.

The graphic workstations also include monitored point-of-use bypass switches to be used when a system requires maintenance. Other instances that require the fire suppression to be temporarily inhibited, such as when welding needs to be done in one of the test cells, easily can be accommodated through one of these workstations.

Why Centralize?
Although GM could have shopped around and purchased different equipment from assorted manufacturers, the resulting maintenance requirements and expandability options would have added quite a layer of complexity. "I can certainly go out and put together stand-alone systems," Downey acknowledged, "but let's say I want to add voice annunciation. Then, I have to put a set of speakers in for each system, and that becomes expensive and complicated."

"Any time you can design a central system, that's the best way to go," Euson agreed. "If you have several different systems, the interconnection is a nightmare. The centralized platform is just great for delivering a uniform message, and I think that's what this site was really going for. Also, it would be incredibly simple to expand the system, as it's just a fiber optic connection to another node."

This article originally appeared in the December 2011 issue of Occupational Health & Safety.