Transamerica Pyramid
The iconic Transamerica Pyramid needed a more reliable solution to its 1970s era air handler fans. NSW and Nortek stepped in to provide a state-of-the-art FANWALL® system that is quieter, redundant, and energy saving.
The 1970s era air handler fans serving floors one to 18 of the Transamerica Pyramid required continual maintenance. Any replacement system needed to minimize tenant disruptions, reduce energy costs, and lower sound levels.
The Challenge - A Four decade Old Fan
The Transamerica Pyramid is a Class A 48-story high rise office building with approximately 90% full occupancy located in the heart of downtown San Francisco, CA. The HVAC system is comprised of water cooled chillers with cooling towers. There are built up air handlers that sit on the 5th, 19th, and 49th floor penthouses. Housed fans deliver the air for the HVAC system in the interior of the building. There are induction boxes in the space to provide zone control. It had a large supply fan that delivered 101,000 CFM at 7.0” total static pressure. Inlet and discharge silencers were required to attempt to keep the noise levels from the housed fan out of the building. The housed fan sat on a concrete inertia base in the mechanical room that had vibration isolation to try and minimize vibration transmission into the building. Rigging and space requirements made it very difficult and costly to remove an old housed fan and install a new one. Demolition of several walls and high rigging costs would be required just to install a new housed fan in its place.
Existing Supply Fans
Catastrophic Fan Failure Was Highly Likely
Vibration or bearing failures in large housed fans can cause catastrophic failures. Typical lifespans for housed fans is 20-25 years in an office application with 8 hour day/ 5 day a week operation. The current fan was built around 1971 according to the motor serial number. This means that the supply fan was 12-17 years beyond its recommended lifespan. And the building had no redundancy. Meaning that if it failed, it would require a lot of time and money to get the supply air back up and running.
Time for an Upgrade
NSW suggested a Huntair FANWALL® system. A FANWALL® uses multiple direct driven fans in place of a single fan. This technology would replace the existing single vane axial fan with smaller fan sections that could fit easily through standard doorways and hallways of the building. And weighing approximately 250 lbs, including the fan and motor, it could be easily moved through the building.
The Benefits Keep Coming
The FANWALL® was installed downstream of the cooling coil in the inlet plenum room. The inlet silencer, fan, associated transition ductwork, and discharge silencer would be removed resulting in a significant total static pressure savings. This savings corresponded directly to horsepower and associated lower operating costs.
With multiple fans delivering the total volume of air, a motor failure no longer means the entire air conditioning system is down. Direct driven motors also eliminate belt maintenance and replacement, and the fan wall array typically has smaller, 1 to 10 horsepower, motors. These motors are readily available off of the shelf and weigh 75 to 125 lbs. This amounts to a quicker easier motor replacement that won’t involve a motor removal rail or gantry. The NSW FANWALL® solution turned a motor removal replacement from a catastrophic failure into a simple routine maintenance item.
Transamerica Pyramid FANWALL® during installation
