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Compliance News: Emergency Generator Starting Batteries

| David Stymiest

There continue to be questions regarding the use of maintenance-free generator starting batteries since they seem to be the preferred starting battery type of most generator set manufacturers.  This article discusses the original prohibition and when it was removed from NFPA 110.

Within the NFPA 110-1999 edition presently enforced by CMS and its accrediting organizations, there was a prohibition against maintenance-free starting batteries for Level 1 emergency generators in the last sentence of section 3-5.4.5:

“3-5.4.5* Type of Battery. The battery shall be of the nickel-cadmium or lead-acid type. Lead-acid batteries shall be furnished as charged when wet. Drain-dry batteries or dry charged lead-acid batteries shall be permitted. Vented nickel-cadmium batteries shall be filled and charged when furnished and shall have listed flip-top, flame arrestor vent caps. The manufacturer shall provide installation, operation, and maintenance instructions, and, when shipped dry, electrolyte mixing instructions. Batteries shall not be installed until the battery charger is in service.

All batteries used in this service shall have been designed for this duty and shall have demonstrable characteristics of performance and reliability acceptable to the authority having jurisdiction. Batteries shall be prepared for use according to the battery manufacturer’s instructions.

Starting batteries for Level 1 installations shall not be of the maintenance-free variety.”

The NFPA 110-2002 edition, which reorganized the standard in accordance with the 2000 NFPA Manual of Style, split up the 1999 edition requirements into separately-numbered paragraphs, as follows:

“ Type of Battery. The battery shall be of the nickel-cadmium or lead-acid type.”

 And, after several more single-topic paragraphs:

 “ Starting batteries for Level 1 installations shall not be of the maintenance-free (valve regulated type) variety.”

However the 2005 NFPA 110 Report on Proposals (ROP) contained the following proposed change to NFPA 110-2002, which eventually was approved by the NFPA Standards Council and made its way into NFPA 110-2005.  This change deleted the statement in its entirety.

“110-26 Log #7 Final Action: Accept

( )

Recommendation: Delete the following text: Starting batteries for Level 1 installations shall not be of the maintenance free (valve regulated type) variety.

 Substantiation: The requirement is too restrictive, and maintenance free batteries are not necessarily VRLA batteries.”

As a result of that change, there has not been any such prohibition against maintenance-free starting batteries starting with the NFPA 110-2005 edition.

The NFPA 110-2010 edition, which is a mandatory reference from NFPA 101-2012 and NFPA 99-2012, states: Type of Battery. The battery shall be of the nickel cadmium or lead-acid type.”

And within NFPA 110-2010 Chapter 8, which discusses inspection, testing and maintenance requirements:

8.3.7*  Storage batteries, including electrolyte levels or battery voltage, used in connection with systems shall be inspected weekly and maintained in full compliance with manufacturer’s specifications.  Maintenance of lead-acid batteries shall include the monthly testing and recording of electrolyte specific gravity.  Battery conductance testing shall be permitted in lieu of the testing of specific gravity when applicable or warranted.

 The * after 8.3.7 above refers to this Annex paragraph:

A.8.3.7  A battery load test should be performed quarterly.

That same 2010 edition language is unchanged in the NFPA 110-2013 and NFPA 110-2016 editions.

And the new NFPA 110-2016 Handbook (the first NFPA 110 edition to have a handbook available that provides commentary related to that version of NFPA 110) also states: Batteries for starting the prime mover are required to be either lead-acid or nickel-cadmium type, but the standard does not provide any other specific requirements on the battery construction. It does not prohibit the use of valve-regulated lead-acid or other type of “low maintenance” or “maintenance free” batteries for prime mover starting, provided all requirements in 5.6.4 are met.”

As with all replacement components, the generator set manufacturer’s recommendations should be followed.

This is a case where an existing problem should go away when and if CMS finally adopts the 2012 codes.

For further information about NFPA 110, visit

NFPA Disclaimer: Although the author (David Stymiest, P.E., CHFM, CHSP, FASHE) is Chairman 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

Questions or comments about this article may be directed to the author at