Getting to the ‘core’ of LEED
In recent years, LEED has become one of the buzz terms in the architecture and design industries, to the point that it's become a benchmark standard for progressive and socially conscious owners and architects. And though there are obvious tangible benefits from the program, what drives designers and owners to the certification is not always so directed. Such was the case with the new medical office building (MOB) and data center at BJC HealthCare's Progress West Hospital in O'Fallon, Missouri-a joint venture project between Clayco and Legacy Building Group.
“I would tell you that BJC in general is very supportive of trying to be sustainable in their design and construction,” says Kirk Warden, Senior Vice-President and Partner at Clayco. “I think, from their standpoint and our standpoint, we're more interested in building a smart building that's sustainable and energy efficient and really makes sense from a long-term ownership standpoint. The fact that a lot of those things that we and BJC are interested in correlate to the USGBC LEED program, we think that it's good policy and good PR for them and us to some extent, that they go after the LEED and get a certification. It's not so much that they want to have certification; they want to have a sustainable, smart, and long-lasting building that performs well. The certification is sort of a byproduct.”
Both the data center and MOB have been designed and constructed to achieve LEED Gold certification. Though not necessarily hospital-driven-built six years ago, Project West is not LEED certified and the desire to achieve the certification on the new buildings was not necessarily a priority-LEED soon became something the project team strove toward, so much so that the MOB, in its construction stages, garnered a less prominent LEED certification, LEED Core and Shell.
“LEED Core and Shell certification is targeted at buildings like the MOB where you have future tenants moving into the space and you have a core and shell of a building-the building envelope, the core, and then the elevator cases-and the floors aren't finished out,” says Nick Bristow, Project Engineer at Clayco and the head of the firm's LEED registration. “The tenants will come in in the future and finish them out. It focuses more on the core and shell instead of some of the interior finishes.”
To achieve this certification, the project team took many of the traditional steps to achieving LEED-utilizing local materials and recycling construction waste (for this project 97% of materials that left the site were recycled and 57% of materials used were regional), taking advantage of energy efficiencies, and handling waste water in an efficient and eco-friendly way. But one of the major improvements made to the MOB in order to achieve the Core and Shell certification was an upgrade of the HVAC system and its delivery of conditioned air.
To achieve this certification, the project team took many of the traditional steps to achieving LEED-utilizing local materials and recycling construction waste…, taking advantage of energy efficiencies, and handling waste water in an efficient and eco-friendly way.
“On the MOB, they used rooftop units with variable air volume [VAV] units,” says Bristow. “What they do is they deliver the air to the tenant spaces, and in the future, the tenants-each will probably get fitted with a VAV box-each will have their own thermostat and will control their own VAV box. So what the core and shell does, using an efficient rooftop unit, is deliver conditioned air to the spaces. And when the tenant moves in, there will be a VAV box installed for that specific tenant-or they might get multiple ones-and they can control their own airflow. It can handle future tenants so it's not heating and cooling the building to one temperature, it's just on a per-tenant basis. So if one of the offices is cooling to 72 degrees and another one is cooling to 68 degrees, they can have that. It's just the overall rooftop unit that produces the air and the VAV modulates what they get.”
Though seemingly counter-intuitive-How can the ability to heat on a per-tenant basis actually save energy?-Bristow notes that there are limits placed on the system to avoid massive fluctuations from one office to the next: “Somebody can't be heating one space to 80 degrees and another space be heating to 60 degrees so they'll fight each other. Within limits, all the spaces can be controlled on an individual basis.” The system also allows the specific offices, and the building as a whole, to manage its output during hours where the facility is not in operation.
The data center presented its own set of problems when trying to achieve LEED certification. Bristow states quite bluntly, “Data centers are notorious energy users.” Managing the process load of the building as well as providing the proper safeties and efficiencies to meet the needs of the hospital was especially difficult. BJC is becoming increasingly paperless placing extreme importance and burden on this facility, and the new data center is replacing the original one as the sole data facility for the entire campus.
Managing the process load of the building as well as providing the proper safeties and efficiencies to meet the needs of the hospital was especially difficult.
“The data center is next to the MOB, not attached-it's a freestanding building on the same campus-and this is their mission critical facility and, really, their data center for their entire system. So it serves the entire BJC HealthCare organization,” says Warden. “It's a hardened design, which a lot of these data centers today have so that they can withstand more wind, elements, and events that might take place because of what they are: they're the backbone of the electronic network that supports the facility-and in a facility like BJC, that's important.”
And because of the data center's status as the facility's primary electronic data location, it had to be outfitted with extensive redundancies, making LEED certification (and the balance of energy use and process load) more difficult. To do so, the project team was able to significantly improve the insulation on the walls and ceilings, achieving continuous R-20 insulation. Also, to offset the mass of redundancies required, the data center also utilizes the VAV units used on the MOB.
“They're using three chillers as part of redundancy because of how critical this facility is to maintain operation during emergencies and what-have-you,” Bristow says. “They have variable frequency drives like on the rooftop of the Core and Shell building. Those frequency drives turn down the chillers-not just on and off, it modulates how much it puts out if it's not required to put out as much. There are a lot of computers close together creating a lot of heat, so any improvement you can make in the HVAC system goes a long way.” HD
For more information, visit www.bjc.org.
Healthcare Design 2010 June;10(6):12-14