Compliance News: Weekly Generator Run Tests

By David Stymiest, PE, CHFM, FASHE



A question that I am commonly asked is whether weekly generator run tests are required. This question occurred almost a half dozen times at the recent ASHE Annual Conference.

NFPA 110 requires weekly Emergency Power Supply System (EPSS) inspections as stated in this excerpt from NFPA 110-2010 (The EPSS consists of the generators downstream to the transfer switch load terminals, inclusive):

“8.4 Operational Inspection and Testing.
8.4.1* EPSSs, including all appurtenant components, shall be inspected weekly and exercised under load at least monthly.”

However NFPA 110 does not require weekly emergency generator run tests. In fact NFPA 110 clarified this issue in the 2010 edition Annex as stated below:

Generator O&M Manuals and Generator Logs

Question: What are the requirements for my generator O&M manuals and my generator logs?

NFPA Disclaimer: Although the author is Chair of the NFPA Technical Committee on Emergency Power Supplies, which is responsible for NFPA 110 and 111, the views and opinions expressed in this message are purely those of the author and shall not be considered the official position of NFPA or any of its Technical Committees and shall not be considered to be, nor be relied upon as, a Formal Interpretation. Readers are encouraged to refer to the entire text of all referenced documents.  NFPA members can obtain NFPA staff interpretations at http://www.nfpa.org/.

The following excerpts are from NFPA 110-1999 (the edition presently imposed by CMS and TJC):  NOTE paragraph 6-2.2 on instruction manuals and paragraph 6-3.4 on the logs:

Generator testing - dynamic vs. static loads

TJC Standard EC.02.05.07, EP5 requires annual load testing under certain conditions.  Specifically the EP states "The emergency generator [20 to 40 day] tests are conducted with a dynamic load that is at least 30% of the nameplate rating of the generator or meets the manufacturer’s recommended prime movers’ exhaust gas temperature.  If the hospital does not meet either the 30% of nameplate rating or the recommended exhaust gas temperature during any test in EC.02.05.07 EP 4 then they must test each emergency generator once every 12 months using supplemental (dynamic or static) loads of: 25% of nameplate rating for 30 minutes, followed by 50% of nameplate rating for 30 minutes, followed by 75% of nameplate rating for 60 minutes, for a total of 2 continuous hours."

Hospitals often want to know what the difference is between dynamic loads and static loads.  Simply put, dynamic loads are the hospital emergency power loads that are connected to the transfer devices - motors, lights, receptacle loads, and the like.  Static loads, on the other hand, are load banks.

NFPA 110 does not use this terminology.  The related paragraph from NFPA 110 only refers to "supplemental loads."

Readers may also want to refer to my separate blog entry discussing the "not less than" terminology found in the latest version of NFPA 110.

NFPA Disclaimer: Although the author is Chair of the NFPA Technical Committee on Emergency Power Supplies, which is responsible for NFPA 110 and 111, the views and opinions expressed in this message are purely those of the author and shall not be considered the official position of NFPA or any of its Technical Committees and shall not be considered to be, nor be relied upon as, a Formal Interpretation. Readers are encouraged to refer to the entire text of all referenced documents.  NFPA members can obtain NFPA staff interpretations at http://www.nfpa.org/.

Generator Testing

If during the monthly emergency generator test a critical procedure interrupts the testing of the automatic transfer switches and some of them do not get tested at that time, must the untested switches be tested prior to the next scheduled monthly generator test?