ALL PC's on a business network should have a UPS (uninterruptible** power supply) as well as the servers and network hardware (such as network switches).
A workstation or PC UPS will help to protect against hardware failure, database & file corruption and lost time due to unexpected workstation power off events. Additionally (although not really measurable) a UPS can also significantly extend the life of the PC by reducing the voltage fluctuations that come in from the energy company, and the negative effect that low voltages or "sags and brownouts" have on the PC electronics.
This is the least expensive item I can find from a reputable supplier:
CyberPower 650VA Backup Utility Powerboard UPS $88 Link
However my experience with those cheap ones is that they last for the duration of the warranty but not much more, I have had to spend hundreds and hundreds of dollars in the past on support costs for "cheap" UPS units that were purchased to save money.
A better quality unit would be something like this:
Socomec NeTYS PE Tower Line Interactive UPS, 650VA $139.88 (plus freight - and they are heavy so it can be expensive) Link
A premium product option that should last years and years (with replacement batteries every now and then).
APC SC620I Smart-UPS SC 620VA $289.99 (plus freight - and they are heavy so it can be expensive) Link
UPS power supply units contain a battery similar to a car battery. Like car batteries, they only last for a period of time. Testing the UPS batteries is an important part of system maintenance.
** The word uninterruptible, is a little misleading. Yes, a correctly functioning UPS will prevent interruptions in the event of a short power outage, if the correct size of UPS is purchased you can expect about 20 minutes of battery backup. Before that time the PC needs to be shut down automatic or manually.
The higher the overall "load" the less time you have, or, to put it another way the bigger the UPS (measured in "VA") the longer you will have on battery backup.