Stand-alone health care buildings: Electrical, power, lighting
Stand-alone medical buildings and specialized treatment facilities are engineering challenges, and more are being designed and built due to changes in health care requirements. Here’s a look at their electrical, power, and lighting systems.
Neal Boothe, PE, Principal, exp, Maitland, Fla.
Douglas T. Calhoun, PE, Senior Vice President, WSP | Parsons Brinckerhoff (formerly ccrd), Dallas
Caleb Haynes, PE, Principal/Director, TME LLC, Birmingham, Ala.
Brian Kolm, PE, Team Leader, Mechanical, HDR Inc., Omaha, Neb.
Craig Kos, PE, LEED AP, Vice President, Environmental Systems Design Inc., Chicago
Bryan Laginess, PE, LEED AP, Vice President, Peter Basso Associates, Troy, Mich.
CSE: Describe a recent electrical/power system challenge you encountered when working on a stand-alone medical building or specialized treatment facility.
Calhoun: Coordination of the electrical system is a constant challenge on small facilities. With buildings typically around 10,000 sq ft, the electrical service can be relatively small, but the inclusion of imaging equipment with large in-rush demands may sometimes become an issue. Finding a balance between sizing the service appropriately for the equipment to be included, and not oversizing it for the building, is key.
Kos: Oftentimes, medical office buildings are not designed to accommodate imaging equipment. The services are undersized, and no provisions have been made to accommodate supplemental services. In addition to the loads for the imaging equipment, there are oftentimes supplemental cooling and humidification requirements. Time, floor space, and budget must be allocated for coordination with the utility company, space for the new equipment, and cost for the required upgrades.
Boothe: On a recent stand-alone medical facility, the utility company could only guarantee voltage to be within +/-10% of the 480 V-use voltage (due to the location of the site). However, the CT scanning equipment planned for the building required a voltage tolerance of within +/-5% to ensure proper operation. As a result, we designed a power conditioner to be installed between the utility transformer and incoming service to the building. This power conditioner was able to regulate the incoming voltage to the building to within +/-2%.
Kolm: One challenge is understanding the acuteness of the patient and if a generator and NEC 517-designed electrical system applies to the facility. Clear direction from the owner is necessary early on, based on NFPA 99 definitions of facility type. More outpatient surgeries to be completed in medical office buildings require a "hospital design." A second challenge is confirming that the owner understands the difference between an emergency generator and an uninterruptible power supply (UPS). There are costs and inconveniences associated with redoing procedures (especially MRIs), and a UPS will ride the medical equipment through over 95% of the outages typically seen by the utility. Purchasing the UPS with the medical equipment pushes the maintenance to the equipment manufacturer, as well as guaranteeing the UPS is tested and right-sized for the radiology equipment.
CSE: How do you work with the architect, owner, and other project team members to make the electrical/power system both flexible and sustainable at the same time?
Boothe: Flexibility is always important of health care facilities, as they are known to change over time. We always design spare capacity in our electrical panels to allow for future loads to be added over time. However, you don't want to overdo it. The use of code-required diversity factors actually helps us sometimes. In general, their allowed demand factors are often quite conservative and, by using them, there is a built-in spare capacity. In regards to sustainability, the use of LED lighting is becoming commonplace, even standard, in most health care facilities. We also see owners opt for higher-efficiency HVAC systems, such as centrifugal chillers over air-cooled chillers or DX equipment.
Calhoun: We always try to build in an appropriate amount of spare capacity for future growth while keeping the project's construction budget in mind. Knowledge of any future expansion plans helps the design teams provide appropriate expansion capacities in the appropriate systems (medical gas, cooling systems, electrical systems). The increasing availability and affordability of LED light fixtures are helping reduce the energy consumption of these smaller facilities.
Kos: We have not seen the appetite on behalf of outpatient facilities for sustainable measures as they relate to alternate energy sources. We do, however, preplan for increased power needs and for space flexibility. This can be easier to accommodate for user-owned facilities where separate metering is not required. Where separate tenant meters are involved, additional planning typically will be required.
Kolm: Right-sizing telecommunication and electrical rooms early in the process is essential. Stacking the rooms will allow changes to be made to the infrastructure within the rooms, with limited impact to operations. Installing raceway paths for future cabling is inexpensive during construction and provides great flexibility for the life of the building. The architect is likely to be more of a space ally with an actual room layout versus simply asking for generic square-foot requirements. Strategically locating communication rooms can limit the number of rooms. Educating the owner and architect on telecommunication requirements early during the design phase with actual room layouts of racks and panels helps build that relationship.
CSE: What types of smart grid or microgrid capabilities are owners demanding, and how have you served these needs? Are there any issues unique to stand-alone medical buildings and specialized treatment facilities projects?
Haynes: We have seen an increase in interest for cogeneration and distributed-generation projects. The first step is to always determine the economic viability of the project. Without a reasonable economic payback, it is difficult to justify smart grid and microgrid projects. There are economic factors to consider including spark spread, available natural gas, electricity and thermal load, demand-response incentive, and several other factors. We also need to consider the added facility resiliency that a microgrid will provide. Stand-alone medical buildings are generally smaller than hospitals, and as a result, it is more difficult to justify the payback in terms that are acceptable to the executive team. In these cases, third-party ownership of the microgrid should be considered.
Kolm: In preparation for a more advanced time-of-use rate from the utility, owners are asking for service entrance meter trending. The system is typically tied to the BMS with the opportunity to load-shave mechanical equipment during peak times in the future.