Canadian Consulting Engineer
Protecting Calgary’s Bankers HallEngineering
Busy construction towers mark the fact that Calgary is booming these days. One of their progeny, the new 52-storey West Tower of Bankers Hall, was completed last March, a mere 22 months after owners T...
Busy construction towers mark the fact that Calgary is booming these days. One of their progeny, the new 52-storey West Tower of Bankers Hall, was completed last March, a mere 22 months after owners TrizecHahn decided to capitalize on the four per cent vacancy rate in downtown office space.
The timetable was greatly helped by the fact that the foundation and parking for the new tower had been previously built when the 52-storey East Tower and seven-storey retail podium were completed in 1989. That project successfully incorporated the smaller Royal Bank Tower, as well as the historic six-storey Hollinsworth Building.
Today the final complex is an elegant twin tower structure clad in semi-reflective glass, gold for the West Tower and silver for the East, set in panels of rose-coloured polished granite. The building’s footprint covers two full city blocks — everything from 2nd and 4th Street between 8th and 9th Avenues. Tenants in the 3.2 million s.f. complex include Talisman Energy Resources and Royal & Sun Alliance Insurance.
The complex houses one of the largest and most complex life safety systems in Western Canada.
Actually Bankers Hall has two independent life safety systems. Rather than doing an expensive upgrade or replacement of the existing, perfectly functional 10-year-old system in the East Tower and podium area, TrizecHahn’s electrical engineering consultants Mulvey & Banani International recommended integrating the existing system with a new one for the West Tower. That was fine, but both systems had to operate as if they were one.
“We treat Bankers Hall as one complex so life safety systems have to work in concert with each other,” says James Moore, TrizecHahn Corporation’s head of engineering. “We also wanted to install the system, terminate it, power it up and have the two towers communicating the first time [we tried]. The schedule was very tight. There wasn’t going to be time to go back and fix problems,” Moore notes.
Seamless integration of the two systems was one of the main criteria, along with ease of use, reliability and survivability — the ability of the system to function when damaged in a fire. Ultimately Edwards Systems Technology, the manufacturer of the East Tower’s 8500 life safety system, was contracted to provide a state of the art EST3 system and integrate it with the existing one.
“It’s like getting an old 486 computer to work with a new Pentium III,” says Mulvey & Banani’s project co-ordinator Alwin Friess about the challenge of integrating the systems. The consulting engineers’ approach was to keep the level of interactions between systems to a minimum, and to take outputs from the older and make them inputs in the newer, and vice versa. “We kept it very simple without losing operational functionality,” says Friess.
Part of the “keep it simple” philosophy meant having graphical control panels that use images rather than text. And to further improve ease of use for building security and firefighters, Edwards custom built a graphic panel depicting the new tower for the EST3 system, so it provides the same type of detailed building schematic image as the older existing fire alarm and smoke system control panels in the main control room. “Anyone can walk in the room and understand where the alarm is coming from,” says Freiss.
To the casual observer it all looks like one system that went in yesterday, says Moore. The graphic panels display stairwells and risers, and air handling, smoke exhaust and fire alarm systems for the entire complex. For example, damper positions are graphically displayed so building staff know if the correct dampers have closed or opened if there is a fire. The operator also has manual control over many of those systems from the control room. “It’s a pretty slick system,” says Moore.
Even though the work had to be done in an occupied complex, the installation of the EST3 in the West Tower went a lot easier than with the old 8500, says Cal Wakelam, Western Electrical Management’s site supervisor. One factor is less wiring. The EST3 has a communication trunk, transponders every three floors, and uses Edwards’ intelligent 4-D multisensor detectors. With this fully programmable, distributed control system, the West Tower has less than 25 per cent of the wire used in the East Tower. “That really cuts down on the cost of wiring and installation,” he says.
Less wire, and distributed control, also increases the ability of the system to survive, says Freiss. Should a fire destroy a part of it, the system will continue to function on the floors above and below.
Depending on the type of occupancy in each area of the building, 30 or 40 multisensor detectors, manual pull stations, speakers and other devices are connected to each EST3 transponder. Each of these devices is programmable and has unique bar codes. These are logged into the system so that when an alarm is activated, its location and zone can be identified on the main panel. Detectors are microprocessor-based and have self-monitoring programs that indicate when cleaning is needed. “That’s important because during construction they get dirty very quickly,” says Wakelam. “They alert us before they get into a false alarm or improper function situation.”
The West Tower has Edwards 4D Signature multisensors which adjust their alarm thresholds to virtually eliminate false alarms by compensating for environmental conditions such as humidity, air pressure and velocity, temperature and even dirt. Multi-sensors also offer the best fire detection because they incorporate photoelectric, heat detection, and ionization sensors. The detectors perform their own sensitivity tests, track alarm history, internal troubles and the date a detector was last serviced. They do not have to be manually set or configured since they are software driven. They also indicate where they are connected into the building wiring relative to the control panel and other devices via a unique “mapping” feature.
Multisensor detectors use microprocessors to monitor the outputs of the three types of sensors and compare these with a data set of known fire characteristics. An alarm condition results when certain benchmarks are exceeded. If this happens in the Bankers Hall West Tower, the EST3 will go into first stage alarm at the main control in less than three seconds.
“There was almost no difference in cost between a standard single sensor detector and the 4D multisensor from Edwards,” says Friess in regards to the West Tower.
Installation and testing
In order to meet the timetable, the installation, testing and verification of the fire safety systems followed on the heels of the main construction floor by floor, starting six months before the building was finished. Normally construction dust and welding would cause endless false alarms, but by simply plugging a laptop into the nearest EST3 transponder, alarms were bypassed. The system could also pinpoint the locations of ground faults as the installation went along. As a result, the final month of testing and verification was nearly flawless. “The very few errors were easily corrected through programming,” says Don Nicholson, project manager with the electrical contractor, Western Electrical. “Both TrizecHahn and Mulvey and Banani said they were very impressed with the ease of installation,” he says.
Moore is also happy to have a software-based system like the EST3. “It enables us to make changes and revisions without incurring large costs,” he says. This gives tenants maximum flexibility in the design of their own premises and to meet their own system requirements such as a pre-action system for a computer room. Even the operating parameters of the fire detectors are programmable to compensate for the local environment, such as an area with high air flow that could cause false alarms.
The virtual elimination of false alarms is necessary in a large complex like Bankers Hall, but is all the more difficult given the multitude of user areas, from parking, to cooking areas, to computer and mechanical rooms. “We have 18 different smoke managemen
t systems and 25 air-handling systems in the existing project,” says Moore. All this has to work together seamlessly with the addition of another million square feet in the new tower. “And it did [so] the very first time we powered up.”
“This has probably been the smoothest fire alarm project that downtown Calgary has seen in some time,” he says.
By Stephen Leahy
The article was supplied by Edwards Systems of Owen Sound, Ontario.