Emergency Generator Monthly Test - 30% Threshold
When are annual emergency generator load tests required?
Any examples are for illustrative purposes only.
When conducting the monthly test of a diesel-powered emergency generator as required by EC.02.05.07/EP 5; test of each emergency generator beginning with a cold start under load for at least 30 continuous minutes.
When conducting the monthly tests for diesel-powered emergency generators the dynamic load that is applied to the generator is at least 30% of the nameplate rating of the generator or meets the manufacturer's recommended prime movers' exhaust gas temperature.
If either the dynamic load is less than 30% of nameplate rating or the recommended exhaust gas temperature is not reached during the monthly test, then the diesel-powered emergency generator must be tested every 12 months using supplemental loads either dynamic or static.
This annual test is conducted for a total of 90 continuous minutes as follows:
Cool down period is not part of the 30 and 90 continuous minutes test duration.
Tests for non-diesel-powered generators need only be conducted with available load.
Additional Resources
NFPA 99-2012: 6.4.4.1
When conducting the monthly test of a diesel-powered emergency generator as required by EC.02.05.07/EP 5; test of each emergency generator beginning with a cold start under load for at least 30 continuous minutes.
When conducting the monthly tests for diesel-powered emergency generators the dynamic load that is applied to the generator is at least 30% of the nameplate rating of the generator or meets the manufacturer's recommended prime movers' exhaust gas temperature.
If either the dynamic load is less than 30% of nameplate rating or the recommended exhaust gas temperature is not reached during the monthly test, then the diesel-powered emergency generator must be tested every 12 months using supplemental loads either dynamic or static.
This annual test is conducted for a total of 90 continuous minutes as follows:
- 30 minutes with a connected load of at least 50% of nameplate rating
- 60 minutes with a connected load of at least 75% of nameplate rating
Static load is typically a load bank brought on-site and connected to the generator to increase electrical load in order to achieve the 50% and 75% of nameplate rating loading.
Cool down period is not part of the 30 and 90 continuous minutes test duration.
Tests for non-diesel-powered generators need only be conducted with available load.
Additional Resources
NFPA 99-2012: 6.4.4.1
Manual:
Critical Access Hospital
Chapter:
Environment of Care EC
First published date: April 11, 2016
This Standards FAQ was first published on this date.
This page was last updated on November 15, 2021
Go Above and Beyond with Certification
Certifications from The Joint Commission represent the most stringent, comprehensive and evidence-based proof of the success of your program available.
Additional Resources
Train your staff with a tool to quickly and efficiently assess standards compliance with our Hospital Compliance Assessment Workbook.
Hospital Webinars
Keep learning with our Hospital Breakfast Briefings Webinar Series. Get a deep dive into our standards, chapter-by-chapter, individually or as a team.
Joint Commission Virtual Assistant