Section 4.1 of NFPA 99, 2012 Edition, provides a good starting point for assessing risk in building systems. This Section requires that each building system in a healthcare facility be evaluated and assigned a category based on the consequences of that system failing to operate. The categories are:
|Category||Consequence of Failure|
|1||Major injury or death to patient or caregiver|
|2||Minor injury to patient or caregiver|
|3||Discomfort to patient or caregiver|
|4||No impact to patient care|
With regard to the need for emergency / UPS power, these four categories are key in determining the emergency system branch to which a load gets connected.
In general terms, the “Life Safety” branch consists of those loads which are considered essential in helping occupants exit the facility and get to safety. Life safety loads would fall under Category 1. Loads which involve patient care, Category 2, must be connected to the “Critical” branch, and loads that provide comfort to patients fall into Category 3 and must be connected to the equipment branch.
Therefore, when assessing the risk associated with a give system, two questions must be asked:
- What are the likely consequences to both patients and caregivers if power to the system is interrupted?
- How will patient care be impacted if the system experiences even a momentary interruption of power?
Answering the first question will determine whether the system should be on emergency power. If the answer is “yes”, then the answer to the second question will determine if UPS back-up is needed until the emergency power supply system assumes the load.