Life Safety Systems Maintenance Part III

Emergency backup power systems are an imperative component of a buildings Fire Protection and Life Safety (FPLS) systems. Both emergency power and legally required standby power are vital in ensuring essential life safety components continue to operate in the event of an emergency, and first responders are provided with all necessary tools and building functions to facilitate emergency operations. These systems typically consist of emergency generators, automatic transfer switches (ATS), backup battery power, and all associated wiring and equipment.

As outlined in our previous insights (Life Safety Systems Maintenance Parts 1 and Part 2), there has been a renewed focus in the City of Boston on the code-required testing and maintenance related to FPLS systems. This insight seeks to outline these requirements as they relate to emergency power supply systems (EPSS).

What are emergency power supply systems?

NFPA 70, National Electrical Code, outlines the three types of emergency and standby power systems: emergency, legally required standby, and optional standby power. Only the first two are code required under NFPA 110, Standard for Emergency and Standby Power Systems, with emergency power being provided for systems that are essential to life safety, and legally required provided for systems that assist in firefighting operations, or systems whose failure could result in increased hazards within a building during an emergency. Optional standby power is provided for systems that are not essential to life safety or rescue operations, but that may be imperative for day to day operation of a business or facility. This includes data-processing systems, refrigeration units, or other industrial processes. For further insight on these different systems, please visit (

What are the maintenance requirements?

The Massachusetts Comprehensive Fire Safety Code (527 CMR 1.00) requires owners, operators, or occupants to provide tests and to keep records of all maintenance, inspections, and testing of fire protection systems, fire alarm systems, smoke control systems, and emergency power equipment until their useful life has been served, as required by law, or as required by the Authority Having Jurisdiction (AHJ), Sections 10.2.5 and 10.2.6. Periodic testing of emergency power supply systems is described in NFPA 110, Standard for Emergency and Standby Power Systems.

Chapter 8 of NFPA 110 outlines the requirements for emergency power system maintenance, stating that a routine maintenance and operational testing program should be implemented based on manufacturer’s recommendations, equipment instruction manuals, requirements of the AHJ, and the minimum requirements of NFPA 110. Some key requirements outlined in NFPA 110 are as follows:

  • Transfer switches: Periodic maintenance, including visual inspection, cleaning, replacement of contacts. Monthly operation, consisting of operating the switch from the primary to the alternate position and back again.
  • Paralleling gear: Periodic maintenance, including visual inspection, cleaning, and replacement of contacts.
  • Storage Batteries: Weekly inspection to ensure manufacturer’s specifications are met.
  • Generators (EPSS): Weekly inspection of generator components. Monthly operation consisting of the following;
    • Diesel Generators: 30-minute minimum test, using one of the following criteria.
      • Load that maintains the minimum exhaust gas temperature, as recommended by the manufacturer.
      • Under operating temperature conditions, and at a load not less than 30% of the EPS standby nameplate kW rating.
    • Spark-ignited Generators: Tested at the available EPSS load for 30 minutes or until the water temperature and oil pressure have stabilized.
    • For all generators, the date and time of the operational testing is at the facility managers discretion, to not disrupt or interfere with normal building operations.
    • All EPSS operational tests shall be initiated by the ATS, either by the ATS simulating a loss of normal power or by opening the normal breaker to the ATS. Where multiple ATSs are used as part of an EPSS, the ATS used to initiate a test will be rotated monthly.
    • An annual fuel quality test shall be performed per the appropriate ASTM standard.

Also outlined in Chapter 8 of NFPA 110 is the importance of creating and maintaining records of all EPSS inspections, testing, and maintenance. This should include the date and time of all testing, identity of the service personnel, any notes on the condition of equipment, and any corrective actions needed to be taken. These records should be maintained at the discretion of the facility manager and the AHJ.



Application of any information provided, for any use, is at the reader’s risk and without liability to Code Red Consultants. Code Red Consultants does not warrant the accuracy of any information contained in this blog as applicable codes and standards change over time. The application, enforcement and interpretation of codes and standards may vary between Authorities Having Jurisdiction and for this reason, registered design professionals should be consulted to determine the appropriate application of codes and standards to a specific scope of work.