Question: It is my understanding that there is NOT a requirement under NFPA 110 to run the generator weekly. I believe the reason is to avoid/reduce wet stacking. Aside from a specific generator manufacturer’s recommendation to run a generator on a particular interval, are there any facilities running the generators weekly?  If so, what are the benefits of doing so?

Answer: Although not a requirement in NFPA 110 that generators be started and exercised every week, we advocate the weekly run as a “best practice” with or without load. If without load, then for no more time than it takes for the coolant temperature to rise and stabilize. Usually, this shouldn’t be for <5 minutes. *

The starter’s wear is minimal, but any time you engage a starter, that’s just one more time closer to a failure.

I previously owned a generator maintenance, alternator, and starter rebuild facility for almost 40 years and stated that most starter failures were because of overheating/overcrank issues.  Fortunately, generators have over-crank shutdowns that prevent overheating and excessive battery drain.  The generator has three (3) chances to start, and if it doesn’t, the circuit will open.  (See: and Table, and

With all this said, most designers today call for two (2) starters per engine…for a reason—paranoia rules.

Emissions issues will always be with us, and if the rumor is accurate, they will become more stringent.  Therefore, you will have to comply with whatever regulations are adopted.  No way around that unless you know people who know people.

The definition of “best practice” is determined by the AHJs, and possibly a jury if someone is compromised because of an EPSS failure.  I would use whatever protocol you are comfortable in defending after discussing the matter with legal counsel.

42 CFR 482.15 (SOC guidance) gives latitude to the Alternate Equipment Management (AEM) plans permissible for equipment management.  While this latitude is welcomed because of the reasons mentioned, it also places a burden on Directors if they choose to go in a different direction than stated in published standards and manufacturer’s recommendations.

As to why an OEM service technician would suggest weekly testing, I would get it in writing, no matter which side of the debate you prefer.  It will likely be fuel pressure issues and make the 10-second mark on newer Tier-rated engines.  Keeping a film on bearings is another…and the list goes on.

OEM dealer technicians are in fact factory representatives.  An attorney will be quick to point that out.  If you do not have an OEM dealer servicing your equipment, then that’s another issue for discussion.

OEM technicians in the field are the people whom both the plaintiff and defense attorneys will depose in case of a legal action as they are responsible for the IMT on your equipment.  I would tend to have my protocols reflect their statements.

Personally, if I were a director, I would not venture too far off the reservation by following any AEM program that didn’t agree with manufacturers’ “best practices” that have been accepted/approved by their representatives.

To make sure I haven’t misled anyone, I am not in favor of an AEM on any EPSS component where an AHJ includes the CMS, state, legal staff or local pundit, etc. would contract heartburn.  Manufacturers are included in the etc. group.

As to the monthly test recommendations, here is the first from a manufacturer’s representative:

“We need to run a newer electronic (emissions compliant) standby unit weekly due to the complex check valves in place to ensure fuel is at pressure during start-up.  Some of our sites that removed weekly unloaded test runs experienced a starting delay that pushed them outside of the ten-second window.” That said, we only need to run the engine long enough for the alternator to recharge the batteries when there is not an electronic battery charger.”

*There are no specific standards in NFPA 110 mandating weekly testing.  But, a few points, and then a summary:

  1. NFPA 110 standards are “minimum standards,” and 8.1.1 states: The routine maintenance and operational testing program shall be based on all the following:

(1) Manufacturer’s recommendations

(2) Instruction manuals

(3) Minimum requirements of this chapter

(4) The authority having jurisdiction

  1. If you ask any EPSS technician with over ten years experience, if weekly running of the generator set is a “best practice,” you will get a positive reply. (As previously stated, if unloaded, or under 30%, the length of the run should be limited.)
  2. If a generator fails and a patient is compromised, the hospital will be sued.
  3. If the plaintiff’s attorney discovers existing protocols call only for monthly testing, they will employ an SME (more than likely a seasoned EPSS technician) to explain why a weekly run is “best practice”.

Summary:  The people in the jury box are there because they did not know how to get out of jury duty; and they will know nothing about emergency power supply systems…. the plaintiff’s attorney will make sure of that during the jury selection process.  They have probably never heard of NFPA 110, but they understand what “best practice” implies.  The hospital will lose the case because of #4 above and the fact that most jury members are anti-hospital even before opening remarks.

The risks associated with weekly testing are minimal, especially if under load.  Emissions are an issue, and some locales have specific regs on when generators can be tested, but I’ve never met an AHJ yet that said he wouldn’t mind getting his chest cracked, knowing it had been 30 days since the generator had started.  (I’ve had several meetings with AHJs on this issue and have never walked away without permission to perform at least minimum weekly testing at some time during the week.  Remember that an AHJ can be taken to task if they are opposed to a best practice compromise.)

P.S.  As a side issue, I’ve had meetings with orthopedists and neurosurgeons on the benefits of having both normal and emergency sides of ATSs hot during critical procedures.  They all got it.  A micro-second blip is more acceptable than a 10 second period of anxiety.