In 2012, the 369-bed hospital began an extensive upgrade program. As a part of the upgrade, Centinela planned to replace its standby power system. The project’s specifications were so daunting many suppliers refused to bid on the project. They said it couldn’t be done. The most unnerving aspect of the job was the hospital’s extreme proximity to an apartment complex. To meet the city’s residential noise code, the generators had to operate while producing sound at levels quieter than a normal conversation, while also meeting California’s notoriously stringent environmental and seismic regulations.
With a mix of strategic problem solving and expert product application mtu and its local California-based distributor rose to the occasion. They recommended a solution that would not only meet, but also exceed requirements and expectations. Centinela Hospital was outfitted with two 1,000 kW diesel generators engineered and manufactured by mtu, each powered by an mtu 16V 2000 engine. With a 24-hour average load factor of 85 percent—15 percent over the ISO standard—mtu was able to reduce the number of generator sets needed to support Centinela’s power needs while increasing capacity and giving the health system a leap in fuel efficiency and durability over the outgoing equipment.
“Because of the generous 85 percent average load factor of these generator sets, healthcare facilities have more flexibility. This is very attractive to hospitals like Centinela that plan for future growth after a new standby power system is installed,” said Al Prosser, director of sales, North and Latin America, Gas & Diesel Systems, mtu.
Stealth whispers of power
One of the project’s biggest hurdles was the hospital’s extreme proximity to an apartment complex. Inglewood city’s sound ordinance requires that generator sets meet 45 decibels of sound (dBA) within 50 feet of the nearest property line. A typical generator set emits up to 105 dBA—equivalent to the loudness of a gaspowered lawnmower at three feet. Taming that noise down to a dBA level of 45 is no simple task.
With Centinela just 100 feet from a residential area, mtu’s local distributor played it safe and aimed for 40 decibels, which is comparable to the white noise in a large conference room.
mtu’s generator sets are contained in a rigid structure that allows the units to run smoothly with minimal vibration. This, along with a special enclosure from ACS Manufacturing, helped Centinela achieve noise reduction levels to the sound of a whisper, exceeding the requirements for a facility situated in a cluster of crowded buildings with three sides of the hospital enclosed and the opening side facing an apartment complex.
“The generators are quieter than the surrounding ambient noise. They’re even quieter than the service team’s diesel pickup truck when it’s idling in the parking lot,” said Prosser. “They often can’t tell whether the generators are running or shut down. You just can’t believe it.”
Another layer of Inglewood’s noise ordinance is its sound curfew, which lifts every morning at 6 a.m. The noise of the hospital’s original generator sets required Centinela to balance a 6 a.m. generator set startup time with the hospital’s surgery schedule to avoid interrupting the flow of electricity to the hospital’s critical equipment. Since they couldn’t start the generator sets until the sound curfew lifted due to the loudness, the start time was occasionally delayed. Today, with the new mtu generator sets, Centinela can switch the units on before the hospital begins its daily activities and procedures, contributing to increased flexibility in the power system.