We all know that, sooner or later, the big one is coming. If you are a facility manager or company executive/manager, you need to be sure that your facility is equipped with the proper emergency power systems when it does.
This especially holds true for health care facilities, which for obvious reasons, have special requirements for emergency power systems.
Every health care facility is different with regards to its emergency power needs. Should a natural catastrophe , such as an earthquake , take place, a company’s management team should be familiar with their particular facility’s systems to ensure they will adequately support their power needs in the event of normal power failure.
Electrical power systems are divided into two categories: essential and non-essential. Essential usually applies to fire alarms and pumps, exit lights, emergency lighting, egress lighting, security systems and certain mechanical equipment.
With health care facilities, essential systems are expanded to include operating room equipment, life-support systems, and other equipment vital to patient health and safety.
Within the essential category, loads are ranked from most to least critical. Non-essential systems include those such as closet lighting and air conditioning in common areas, or areas not related to patient care, research or development.
– Emergency Power
Should Start In Seconds
For health care facilities, emergency power to critical and life-safety systems must, by code, be able to kick in within 10 seconds after failure of the normal power source.
The codes set in place by the state of California are strict about the type of emergency power systems health care facilities must have in place, and require regular testing of the systems and annual inspection of the facilities.
Emergency power sources are usually comprised of two types: standby generators and uninterruptible power supply.
Standby generators, the oldest type of standby power source, are most commonly used for critical applications. Generators can normally start in less than 10 seconds, so they can only be used to backup equipment that is not affected by brief power interruptions. For this reason, most facilities with critical power requirements utilize a combination of the two types of standby power source.
While generators powered by diesel fuel, natural gas, propane or gasoline are available, health care facilities have to, by code, utilize those powered by an onsite fuel source , namely diesel fuel or propane.
During an earthquake, natural gas lines can break. As the entire state of California is considered an earthquake zone, natural gas generators are not allowed in health care facilities in the state. Gasoline-driven generators cannot be utilized in health care facilities, either, as it is too dangerous to store gasoline onsite. Most hospitals rely on diesel-powered generators, as it is the most economical.
– Continuous Power
An uninterruptible power supply is generally used to provide continuous power to critical systems, so there is no downtime between when normal power is lost and when the generator kicks in. The generators take time to come online, and computerized systems cannot have a power interruption without losing valuable data. The power supply also serves to filter the voltage noise, sags and surges, in order to protect the critical systems.
An uninterruptible power supply consists of a bank of batteries; inverters that convert DC battery power to AC power; a filter; a battery charger; and control circuits.
There are only two or three manufacturers that design such systems for direct patient care systems , such as a single-patient machine , for liability purposes. Most manufacturers only provide systems that supply backup power to indirect systems, for instance, to power an entire floor.
The systems can continue to supply power from as little as 15 minutes to as long as eight hours , depending on the usage , after normal power fails. Due to economical constraints of keeping that large of a battery supply on hand, most facilities utilize models that provide power for up to 30 minutes. In the event that an uninterruptible power supply is needed for longer than the battery can provide, most models are able to be recharged by generator.
While most facility experts know the types of systems they are required to have, there are always the exceptions. Even in health care facilities with all of their state-mandated rules, there are still certain things that are left up to people’s best judgment.
– Adjustments Needed
For Individual Systems
How many generators does a facility need, for instance. If a hospital’s essential systems have a demand of 1,000 kilowatts, do they purchase one generator that outputs 1,250 kilowatts, or do they purchase two generators that output 600 kilowatts?
The UCSD Medical Center in Hillcrest uses three diesel-powered generators to back up a majority of its systems. The generators are connected in parallel; if one fails, the other two redistribute the load. For some of its special equipment, such as its CT scan machines, the hospital utilizes an uninterruptible power supply.
Although backup generators are tested often, and the chance of failure is slim, most health care facilities rely on more than one generator for emergency power. That way, if there is a failure, or even if one generator takes longer to start, the most critical systems are online with the good generator.
Lamb Sr., P.E., is president and founder of Lamb Consulting Engineers (formerly JRL Associates), an electrical engineering firm. Founded in 1995, the company employs a staff of six in headquarters located in the Middletown area of San Diego.