Generator Testing

Q: Does our hospital have to test the generator for 30 minutes every week, and then 1-hour once a month? We have programmed our generators to operate every Wednesday at 12 noon and run for 30 minutes. We do ATS test once a month and record information when running.

A: According to section 9.1.3.1 of the 2012 Life Safety Code, emergency power generators must be tested in accordance with NFPA 110. Section 8.1.1 of NFPA 110-2010 says the routine testing of the emergency power generators must be based on all of the following:

  • Manufacturer’s recommendations
  • Instruction manuals
  • The requirements of NFPA 110
  • The AHJ’s requirements

While NFPA 110 does not have any requirements to operate the generator on a weekly basis, there may be manufacturer requirements or AHJ requirements that do. Section 8.4.1 of NFPA 110-2010 specifically says generators must be inspected weekly but operated under load on a monthly basis. Section 8.4.2 requires the monthly load test to operate for 30 minutes. I suggest you check with your generator manufacturer and your state and local AHJs to see if they have specific weekly run-tests of the generator.

Generator Testing

Q: We have a generator that doesn’t meet the 30% load for the monthly run so we have to do an annual run with the load at 50% for 30 min and 75% for 60 min for a 90-minute continuous run. Our contractor did the annual run but he ran it with 52 % for 30 min , 75% for 30 min and 81% for 30 min, then he continued to run it for 2½ more hours dropping the percentages as he went for 4 continuous hours at not less than 30%. My question is does these meet the intent of the standards for both an annual and a 3-year load test?

A: Yes… I would say the test as you described meets both the annual requirements and the 3-year test requirements. The generator load testing requirements are minimum load settings, and it is permitted to exceed these minimums.

Generator Testing

Q: In a business occupancy and an ambulatory occupancy do we need to test our generator on load each month or can we do a load bank test once per year?

A: Yes… Monthly load tests are required for emergency power generators at ambulatory healthcare occupancies and business occupancies. According to the 2012 Life Safety Code, sections 20/21.5.1.1 for ambulatory healthcare occupancies and 38/39.5.1 for business occupancies, compliance with section 9.1 on utilities is required (just like healthcare occupancies).

Section 9.1.3 requires compliance with NFPA 110-2010 regarding emergency power generators, and section 8.4.1 of NFPA 110 requires monthly load tests.

Now… there is an exception to all of these testing requirements…. Section 9.1.3 says emergency generators, where required for compliance by the LSC, must be tested and maintained in accordance with NFPA 110-2010. So, if you are not required to have emergency power generators at the ambulatory healthcare occupancy or the business occupancy, then you do not have to maintain them according to NFPA 110.

Generator Testing at Business Occupancies

Q: Does a diesel generator that is located in a business occupancy require the same testing frequencies as the one at our hospital requires?

A: It depends if the generator is required by the Life Safety Code. Sections 38/39.5.1 of the 2012 Life Safety Code says utilities in business occupancies must comply with section 9.1. Section 9.1.3 says emergency generators, where required for compliance with the Life Safety code, must be tested and maintained in accordance with NFPA 110, which is the same standard requirement for healthcare occupancies.

So, the question now becomes, is the generator in your business occupancy required by the LSC? Business occupancies do not automatically require emergency power like healthcare occupancies do. For business occupancies, it depends on a variety of issues.

For new business occupancies, emergency lighting is required where any one of the following is met:

  • The building is two or more stories in height above the level of exit discharge;
  • The occupancy is subject to 50 or more occupants above or below the level of exit discharge;
  • The occupancy is subject to 300 or more total occupants.

For existing business occupancies, emergency lighting is required where any one of the following is met:

  • The building is two or more stories in height above the level of exit discharge;
  • The occupancy is subject to 100 or more occupants above or below the level of exit discharge;
  • The occupancy is subject to 1000 or more total occupants.

When emergency lighting is required it must meet the requirements of section 7.9 of the 2012 Life Safety Code. Section 7.9 does not mandate that emergency lighting be powered by a generator, but section 7.9.2.4 does say if the emergency lighting is powered by generators, then the generators must be tested and maintained in accordance with NFPA 110.

So, if your business occupancies are required to provide emergency lighting, and the emergency lighting is powered by generators, then the generator must be tested and maintained in accordance with NFPA 110, which is the same requirement as hospitals.

Generator Load Tests

Q: Is it allowed to combine the 3-year 4-hour generator load test along with the annual 2-hour load test? Our generator test company plans on running the generator at 50% load for the first two hours and then elevate to 75% load for the last two hours. In your opinion would this satisfy both the 2 hour and the 4 hour load test?

A: You are allowed to combine the 2-hour load test and the 4-hour load test. The 2-hour load test is required to be conducted once per year when the generator cannot meet the load test of 30% of nameplate rating every month. When this occurs, you still conduct the monthly load tests but once per year you need to conduct a 2-hour load test (usually by connecting the generator to a resistive load bank) that consists of the following sequences:

  • 25% load for 30 minutes, then
  • 50% load for 30 minutes, then
  • 75% load for 60 minutes for 2 continuous hours.

The scenario that you described allowed 50% load for the first two hours and then a 75% load for the last two hours. This would be acceptable in meeting both test requirements since the percentages listed in the standards are minimum settings, and you are permitted to exceed them. But you need to be careful, because if you combine these two tests and start out at 25% load (as required for the 2-hour load test) for the first 30 minutes, then you are out of compliance with the 4-hour test, unless you run an extra 30 minutes after you reach or exceed 30%.