Regional Operation Centers: Electrical System Reliability| November 19, 2019
Medical supplies for hospitals are traditionally stored on site at the hospital. However, space within the hospitals is at a premium. Every square foot is scrutinized in order to optimize efficiency and provide the most effective care for patients; which makes it challenging to allocate adequate storage space on site. Due to storage requirements, logistics of shipping and receiving medical supplies to hospitals, and the potential increase in economic and operational efficiency; Regional Operations Centers (ROC’s) are becoming more prevalent especially within urban areas. Although ROC’s may appear similar in many ways to a traditional warehouse, they are critical to the operation of multiple healthcare facilities, often all facilities within a healthcare system or network. Therefore, the electrical distribution systems must be resilient and reliable. The facility is required to maintain operation throughout almost any condition to ensure that the uninterrupted operation of the healthcare facilities they serve.
Normal Power Distribution
Since the major function of a ROC is to ensure a hospital is properly supplied, the normal (utility service) electrical distribution system within the ROC must have a reliability similar to the facilities they serve. Unlike most warehouse applications, providing the facility with (2) sources of utility power is a recommended option to consider. This will significantly reduce the risk of experiencing an extended power outage and also removes a potential common mode failure point in the electrical distribution system. A common mode failure is the loss of several systems, in this case the entire building electrical supply, due to a single incident, such as damage to a single utility pole that may note even be on the building site. Providing a second utility service fed, ideally from a separate utility substation, eliminates that common mode failure risk.
Each utility service should supply the switchgear arranged in a main-tie-main configuration with automatic transfer controls. This configuration includes a main circuit breaker in the switchgear for each service and a tie circuit breaker that splits the bus within the switchgear, giving the facility the ability to operate from both services simultaneously, or entirely served from a single utility feeder if there is an issue with one of the utility services. The automatic transfer controls electronically interlock the main and tie circuit breakers and constantly monitor both services. If there is a loss of power or an abnormal condition on either utility service (voltage spike, voltage dip, phase loss, etc.), power is then automatically transferred to a single utility source.
This allows the facility to continue operation under a single utility failure and helps protect facility electrical and mechanical equipment if there is an abnormal power condition from one of the utility sources. For an ROC under normal operating conditions, the electrical system would utilize both utility sources / transformers with the switchgear tie circuit breaker open. This ensures that a single transformer is not overloaded during normal operating conditions; which helps maximize the life expectancy of the transformers, since overloading / overheating transformers is damaging to the equipment.
Emergency Power Distribution
Standby emergency power for the facility is also important to prevent the loss of both time and products within the facility. This is especially important if a second utility service is not available or employed, as discussed previously. Ideally, the generator is in addition to the (2) electrical utility services. When sizing the generator and designing the emergency power distribution system, the two primary methodologies are; a generator with the ability to fully (and indefinitely with access to re-fueling delivery) maintain operation of the facility; or a generator supplying the critical systems and areas to support the most critical healthcare network functions. Either option should support the facility in the event of storm events or other natural disasters that can result in loss of utility power.
Providing the facility with a fully rated generator to maintain operations through an extended utility outage provides the facility with the most flexibility. However, a smaller generator can be employed that still allows the facility to continue operations in a limited capacity. In the latter option, right sizing the generator to ensure critical operations are maintained is very important.
A cost benefit analysis or choosing by advantages evaluation may indicate that ‘critical support only’ generator is the best option. A decision on the standby generator options (full building vs. critical equipment only) should be discussed early and often during the design process to meet the healthcare organization’s specific goals for the facility.
For more information on Regional Operation Center design for MEP/FP, look for F&T’s Guide on “The emergence of the regional operations center in support of modern care delivery,” coming next week!