How to design medical buildings: Electrical, lighting, and power
Hospitals and health care buildings have become very sophisticated. Coordination among all parties, special attention to codes and standards, and a focus on patient comfort have each become highly important to engineers. Electrical and power system design are highly sophisticated.
- Randall Ehret, PE, Senior Vice President, Environmental Systems Design, Chicago
- Timothy Larson, PE, LC, LEED AP, Principal, RTM Engineering Consultants, Milwaukee
- Melisa Rodriguez, PE, SET, Director of Fire Protection Engineering, LEO A DALY, Minneapolis
- Matt Volgyi, PE, LEED AP, Principal Engineer, Southland Engineering, Garden Grove, Calif.
- Mike Zorich, PE, LEED AP, Associate Principal, IMEG, Rock Island, Ill.
CSE: Describe a recent electrical/power system challenge you encountered when working on such a project.
Ehret: The biggest challenge can be connecting to an existing electrical system and the inherent deficiencies often built into those systems. On a recent project, we encountered an electrical system to which we were simply connecting a new feeder. It had the space and the capacity. However, as we looked closely at the system, we discovered one code violation after another related to the existing gear installation. By connecting to the gear, we felt compelled to first bring the deficiencies to the owner’s attention. In the end, the cost of the repairs exceeded the cost of the original project!
CSE: Outline a recent backup, standby, or emergency power system you designed. What did it include, and what best practices did you include?
Ehret: On one recent new hospital, the EPSS was designed as N+1 and equipped with paralleling gear. Any single generator is capable of picking up all of the life safety and critical block loads in a single step. The second generator picked up all code-required equipment loads. The +1 generator was used to pick up optional loads, such as the cooling plant. This allows the facility to more effectively ride through an outage event and provide effective patient care. The optional loads would be the first to shed if a generator fails or during a system overload condition
CSE: How have lighting and lighting control systems been integrated with other systems in hospital, medical campus, and health care structures, such as the HVAC system?
Larson: Recently, we have seen an industry trend to tie the HVAC system together with the occupancy sensors used within a space for lighting. This allows for turn back of the HVAC system (where allowed by code) at times when patients/staff are not present. We have also recently tied corridor-lighting controls into the BAS, to dim lighting automatically to a lower level at predetermined times, specifically during evening hours. This enhances patient comfort and allows for staff to use one system to control the HVAC and lighting on the patient floor.
CSE: How have the changes in LED technologies and specifications impacted the design of hospitals, health care facilities, and medical campuses?
Larson: In today’s ultra-competitive health care marketplace, the advances in LED lighting have impacted three key areas: patient satisfaction, energy efficiency, and operational efficiency. Additionally, with the implementation of government health care reforms, requirements for greater energy and operational efficiencies as well as enhanced patient outcomes have also increased. By using LEDs in our lighting designs, we can help users provide care more efficiently with a continuous emphasis on raising the quality of care, providing a higher quality of light, helping prevent the spread of infections, reducing energy usage and maintenance costs, and reducing storage-space requirements for lamp and ballast replacements. The quality and controllability of LED light enhances patient satisfaction and allows caregivers to provide better care.
Security is enhanced via LED lighting in parking and entry areas, providing patients and staff with a safe and secure experience. LEDs provide more direct light out of each fixture and high-color rendering indexes (CRI), which assist caregivers in assessing patients’ health. Also, dimmable lights give patients control over light levels, and tunable lights allow the color temperature—warm amber tones to cool blue tones—to be adjusted to promote healthy circadian rhythms.
LEDs also help prevent the spread of infection in surgical suites. A combination of 405nm indigo and white LEDs emit a narrow spectrum light that kills bacteria while providing illumination for the space. Energy-efficient LEDs use half the energy, produce less heat, and can last two to three times as long as the previous standard of fluorescent lighting. The long life of LEDs and fixture components, such as drivers, reduces maintenance costs and frees up valuable square footage that used to be required to store replacement lamps and ballasts. LEDs impact the design of health care facilities in so many positive ways that they have become the new standard of care when designing lighting for these facilities.
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