Healthy hospital success: Electrical, power, and lighting
With hospital projects, it is imperative that engineers get everything exactly right—after all, the lives of patients treated in the health care building may depend on it. Electrical and power systems must be designed correctly.
Richard Heim, PE, LEED AP, Mechanical Project Engineer, RMF Engineering Inc., Baltimore
Tim Koch, PE, LEED AP, Electrical Engineer, HDR Inc., Omaha, Neb.
Nolan Rome, PE, LEED AP, Senior Vice President, ccrd, a WSP | Parsons Brinckerhoff Co., Phoenix
Raymond Schultz, PE, Project Engineer, CannonDesign, Grand Island, N.Y.
Kunal G. Shah, PE, LEED AP, RCDD, President, PBS Engineers, Glendora, Calif.
Tommy Spears, PE, Vice President of Design Solutions, TME, Little Rock, Ark.
CSE: Describe a recent electrical/power system challenge you encountered when working on a hospital.
Spears: During a recent hospital renovation project, the largest problem we encountered, not just electrically, was how to completely renovate an entire operating suite with 23 rooms while keeping them operational. Because many of the rooms were very specific to certain types of procedures, only one or two of them could be shut down at a time. Our team was tasked with figuring out how to build a new distribution system in a limited amount of space, while keep the existing one up and running and switching various elements over to the system as it was completed.
Shah: One recent challenge we have faced on a hospital renovation project was with respect to the segregation of power between the normal, critical, and life safety branches. The facility had done many renovations in the past, and many circuits had been cross-connected between the code-required segregation. When doing our project, our team had to be aware of these violations and ensure as we designed the project that we rectified the pre-existing inconsistencies in the circuiting. In some cases, we found the existing infrastructure to be insufficient to support the re-circuited loads. In these cases, we did evaluations of the loads and tried to find cost-effective measures to consolidate or provide new infrastructure to support the distribution.
Rome: The amount of technology that owners are requesting for operating rooms and the requirements for receptacles and circuit length are starting to require additional isolation panels.
Koch: As owners continue to repurpose buildings and spaces, a master plan to upgrade their existing infrastructure is essential. Working closely as a team with the contractor and owner's construction schedule and thinking through each outage night and weekend is key to success. Of course having a plan B or back-out plan for each outage is mandatory for realizing the goal.
CSE: What types of renewable energy systems have you recently specified in a hospital? This may include photovoltaics, ground-source heat pumps, etc.
Rome: A recent LEED Platinum-certified hospital that my team worked on included photovoltaic (PV) and solar-heating hot-water systems to meet on-site renewable energy goals set by the owner early in the project. We are also using heat recovery and heat pump chillers in health care applications on a regular basis. The simultaneous cooling/heating needs of hospitals make these ideal and at the same time result in make-up water savings.
Shah: The most common provisions we have designed are for the implementation of PV. The designs typically integrate with the utility service to sell power back to the grid to offset energy costs. On some occasions, on-site battery storage was explored. Many hospital facilities have moved toward the purchase of power purchase agreements to purchase renewable energy at a lower cost. This move allows for some of the cost benefits of renewable energy without having on-site green power-generating infrastructure.
Spears: For the majority of our clients, traditional renewable energy systems are not economically feasible because the cost associated with these systems is not offset by the tax credits that traditionally accompany these types of investments. The best way for a hospital to use renewable energy systems is by investing in those that allow the facilities to use waste heat to generate steam for the hospital, largely because these systems have additional energy-saving benefits associated with them that offset the first cost over the lifecycle of the equipment. TME has generally used heat pump chillers, but we also have explored the use of a combined heat and power gas generator to produce part of the required electricity for the hospital and use the waste heat from the generator.
CSE: How do you work with the engineer, owner, and other project team members to ensure the electrical/power system is both flexible and sustainable at the same time?
Spears: Flexibility and sustainability in an electrical system can both be achieved by incorporating redundancy and optional interruptible service (OIS) agreements. It is essential to provide enough redundancy for all critical points in the system, and hospital emergency backup requirements already ensure that this element of design will be implemented. With the capacity and redundancy levels built into the design, hospitals have a unique ability to participate in OIS agreements, saving significant cost on utility bills because they have the capability to support themselves for a period of time should the service need to be interrupted by the utility company.
Shah: The key to designing an effective electrical distribution system is to understand the end-user and facility needs. Knowing what is needed today and understanding the overall program is important in designing the size of the system and the needed capacities. Further, it is important to design a system that can accommodate functions to change and expand within the facility. In many cases, even geographic placement of the distribution equipment will help lend itself to a more flexible electrical system. Engage key stakeholders early in the design process to understand the program and the parameters the electrical engineers will need to work with.
Rome: For the PV and solar-heating hot-water system we provided recently, it was a challenge to incorporate the size of the fields and orientation into the design, which was integral to the concept and provided maintenance access.
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 hospital projects?
Spears: As previously mentioned, because hospitals have additional and unique requirements for emergency backup power and their generators need to be tested regularly, these facilities have the capacity needed to allow them to participate in an OIS and pay significantly lower rates for utilities. TME serves this need through several different utility services including utility management, utility rate design, and advocacy and utility procurement. Many owners also are requesting more advanced meter capabilities to receive real-time demand and power use for their facilities to help manage consumption.
Rome: In the health care market, facilities have been requested by utility providers to enter into peak-shaving agreements by using their existing standby diesel generator capacity. These agreements give financial incentives to the hospital facility. The challenge is that current EPA regulations do not allow Tier 2 standby systems to run for an extended period. For facilities to enter into most long-duration agreements, the standby generators would need to comply with Tier 4 standards, which increases significant exhaust treatment cost.
CSE: What unique lighting or lighting control systems have you completed?
Koch: On a recently completed women's hospital, a small networked lighting control panel was provided for each patient room to allow for intelligent lighting control as well as easy integration with the room's motorized shades and nurse-call system. Historically, the major control issue in patient rooms is the number of light switches, typically at the room entry, which leads to utter confusion for both the staff and family. By implementing an intelligent control solution, it presents the user a single keypad with labeled buttons to allow for much more intuitive control. Integration with the nurse-call system and motorized shades allows the patient to use the pillow speaker to control multiple zones of lighting within the room, as well as the motorized shades.Spears: In addition to the energy efficiency considerations that are given to every project design, the lighting and lighting-control systems that TME designs for health care institutions take patient comfort greatly into consideration. Direct/indirect lighting in patient exam rooms, flexibility in lighting levels, and placement of fixtures for various departments are all taken into consideration. Recently, the ability for patients to control HVAC and lighting at their beds has been a unique element of design. We are also in the process of exploring the ability to simulate natural daylighting to control patient circadian rhythm with artificial light.
Shah: With California Title 24 requirements, most engineers are well-versed in the implementation of energy-efficient lighting strategies. Although OSHPD facilities in California are not required to document compliance with Title 24 lighting, most of our designs use the code as a basis. Thus, using LED strategies and daylight harvesting to implement an energy-efficient system is critical for maintaining budgets and operating costs. Further, having appropriate controllability of the system is critical to appropriate function and end-user comfort. In a recent project, we had explored several methods to improve the overall lighting in an existing facility, including new lamping strategies, new fixture-specific controls, and zoning flexibility for dynamic spaces.
Rome: Most recently, we completed the design and construction administration on a patient room lighting controls system that was integrated with the BAS and also the financial patient-tracking system. Instead of the nursing staff or an occupancy sensor informing the lighting system when the room is occupied or unoccupied, the patient-tracking system sets the room occupancy without providing any patient information to the building management system (BMS).