Is Your Generator NFPA 110 Compliant?

For many businesses, a backup power system is critical to preventing costly business disruptions and preserving human life. Companies from hospitals to commercial real estate developments all rely on generators to keep equipment running if the power goes out.

If your business owns a commercial generator, chances are you’ve heard the phrase “NFPA 110.” And if you have oversight over any part of your company’s backup power system, it’s important that you’re familiar with NFPA 110 and its implications.

This article gives a detailed overview of NFPA 110—what it is, why it matters, how to tell if you’re compliant, and how to get there if you’re not.

What is NFPA 110? 

NFPA 110 is a document published by the National Fire Protection Association that outlines the requirements for designing, installing, testing, and maintaining emergency generators. It’s available from the National Fire Protection Association website here.

Here’s how the NFPA explains the 110 standards on their website:

This standard covers performance requirements for emergency and standby power systems providing an alternate source of electrical power in buildings and facilities in the event that the normal electrical power source fails. Systems include power sources, transfer equipment, controls, supervisory equipment, and accessory equipment needed to supply electrical power to the selected circuits.

In other words, if you have an emergency power system, NFPA 110 tells you what it should be able to do and how to take care of it. Designers, manufacturers, maintenance professionals, and government authorities all refer to NFPA 110 when installing, commissioning, and inspecting emergency generators.

Why is NFPA 110 Important?

All businesses depend on electricity, but electrical power isn’t always reliable. People in the Bay Area are all too familiar with unplanned power outages disrupting life and business activities.

Depending on the business, losing power can mean losing millions of dollars or even human life.

Organizations such as hospitals and care centers depend on electricity to run critical life support equipment like oxygen compressors, mechanical ventilators, and cardiac monitors. Businesses like these where the emergency power system is necessary to protect human life are legally required to comply with NFPA 110.

Other businesses like data centers, food storage warehouses, agricultural facilities, or technology companies don’t directly support human life, but can still experience serious business disruptions and liability if they lose power. 

Even though it’s not legally required, manufacturers and maintenance providers both recommend applying the NFPA 110 standard because of how critical uninterrupted power is to business operations.

The bottom line is this: If you have an emergency power system, you should make it NFPA 110 compliant. It’s the best way to ensure that your backup power supply will function properly during an outage.

How Does Emergency Power Work?

Picture this: You’re in your office when power goes out. Your screen goes black, the lights shut off, and you hear that telltale whoosh of equipment everywhere powering down.

What happens at your business?

Well, if you don’t have a backup power system, nothing happens. You’re helpless until your utility company can fix the issue and restore power.

If you do have a backup power system, the lights will blink back on within seconds thanks to a series of automatic processes in the background. 

Here’s what happens to restore power when you have an emergency generator system:

  1. The automatic transfer switch (ATS) senses the loss of normal power.
  2. The ATS sends a signal to the standby generator to start.
  3. The generator starts and begins to ramp up to 1800 RPM.
  4. The ATS senses voltage from the generator ramping up and transfers the buildings electrical load to the generator. 7-10 seconds have elapsed since the ATS sensed the loss of normal power.
  5. The generator continues to provide emergency power until the ATS senses the return of normal power. 
  6. Once utility power returns, the ATS runs the generator in parallel with utility power for a predetermined amount of time in case it shuts off again.
  7. After a few minutes have elapsed, the ATS transfers the building’s load back to utility power.
  8. The ATS cool down timer now kicks in and the generator runs for a few minutes on the cool down timer.
  9. When the cool down timer finishes, the ATS sends a signal to the generator to shut down.
  10. The system is now back in standby mode ready for the next outage.

As you can see, emergency power systems are complicated systems with a lot of different mechanical parts that each have to function properly for you to have power restored when you need it.

NFPA 110 ensures that your system is designed to handle the loads you need it to, and that it’s maintained in such a way that it will be ready to perform in an emergency. 

How NFPA 110 Works

Important terms

To understand NFPA 110, there are a few important terms used throughout the document you need to be familiar with:

  1. Emergency power supply (EPS)

    The emergency power supply (EPS) is the source of electrical power used in your backup power system (in other words, your generator). It is independent of your primary source of power and will kick on if that primary source fails.
  2. Emergency power supply system (EPSS)

    The emergency power supply system (EPSS) refers to the backup power system in its entirety. It includes the generator (or EPS), but also the transfer switches, load terminals, and all the other equipment required to provide a safe and reliable alternative source of power for your facility.
  3. Authority having jurisdiction (AHJ)

    The authority having jurisdiction (AHJ) is a broad term referring to the agency or agencies responsible for enforcing code compliance in your particular city or region. In the Bay Area, that’s usually the fire marshall.
  4. Approved

    NFPA 110 defines something as approved when it’s “acceptable to the AHJ.” This is important: The NFPA doesn’t approve any equipment or installations as being “compliant” with NFPA 110—your local authority does.
    The only way to guarantee your installation, procedures or equipment are compliant is to work with your AHJ to ensure it aligns with all applicable standards, policies and codes, while referencing this standard and your manufacturer’s recommendations. To accomplish this, it’s helpful to have an experienced service provider like Electro-Motion that understands local regulations, has extensive experience with your equipment, and can guide you with specific recommendations based on your situation and needs.

Level, Class, and Type

NFPA 110 defines both what type of generator system (EPSS) you need and how to take care of it to keep it ready for use.

When it comes to what EPSS you need for your business, NFPA 110 classifies them in three ways: Level, Class, and Type.

These categories are key to understanding the requirements for NFPA 110 emergency generators, from what type of equipment to use to how much fuel you need to store on site.

NFPA 110 Level

There are two EPSS levels defined by NFPA 110: Level 1 and Level 2. 

NFPA 110 Level 1 systems provide power where failure would result in “loss of human life or serious injuries” (4.4.1). NFPA 110 Level 2 systems carry loads “less critical to human life and safety” (4.4.2). Level 1 and Level 2 systems have different equipment and installation standards.

It’s important to note that NFPA 110 does not state which applications qualify as Level 1 or Level 2—that is up to your local authority’s interpretation (1.1.5). They do, however, provide some examples of situations where a Level 1 or Level 2 EPSS might be required.

  • Possible NFPA 110 Level 1 applications
    Life safety illumination, public safety communication systems, fire pumps, ventilation equipment (A.4.4.1).
  • Possible NFPA 110 Level 2 applications
    Heating and refrigeration systems, sewage disposal, some industrial processes (A.4.4.2).

Since both Level 1 and Level 2 systems have a direct impact on life safety, they must be permanently installed on site.

As mentioned before, it’s recommended that even businesses with backup power systems that don’t qualify as Level 1 or Level 2 still follow these guidelines since power failure could still result in costly business disruptions.

NFPA 110 Class

Your EPSS Class is the duration (in hours) your system must be able to run at its full rated output without refueling.

From example, Class 2 requires your generator to run for two hours without adding fuel, Class 48 requires 48 hours, and so on. “Class X” generally translates to 96 hours of rated output.

NFPA 110 Type

Your EPSS Type refers to the time (in seconds) it takes your system to be up, running, and carrying your Levels 1 and 2 loads. For example, Type 10 takes 10 seconds, Type 60 takes 60 seconds, and so on.

For emergency power—defined as Level 1 in NFPA 110—10 seconds is the standard. That means all Level 1 loads need to be transferred to your EPSS in 10 seconds, no matter how large or small your system is.

You need your EPSS to kick on within a reasonable timeframe after power failure—and you need it to fulfill your load requirements in full until your primary power source comes back on. The NFPA 110 classification method is designed to ensure your EPSS system can do that.

NFPA 110 Generator Requirements

How can you tell if your generator is compliant?

We’ve looked at what NFPA 110 is and why it’s important. So how can you tell if your generator is compliant?

The are three main areas you need to consider to make sure your backup power system is NFPA 110 compliant: equipment specifications, fuel requirements, and maintenance and testing requirements.

Let’s look at these one at a time.

Equipment specifications

The equipment specifications refer to whether or not your EPSS meets the NFPA 110 requirements for your system’s level. 

The authorities in your jurisdiction will have certain class and type requirements for your system depending on your level. If your system is designated Level 1 or Level 2, then you will have to meet these equipment specifications upon installation.

If your system is not designated Level 1 or Level 2, then these requirements are optional but still recommended as industry standard guidelines. For example, let’s say your business has a data center where a loss of power could result in costly business disruptions and legal liability. You might decide that you want Level 1 emergency power system protection against outages. 

In that case, NFPA 110 would still provide you and your service provider with the appropriate guidance on what kind of equipment you need. It would specify, for example, that your EPSS needs to be at least Type 10—capable of transferring all loads to your EPS within 10 seconds of a power loss.

Fuel requirements

Depending on your EPS class, NFPA 110 specifies how much fuel you need to store on site to power your generator. In general, NFPA 110 goes by a 133% rule, whereby you’re required to keep 133% of the fuel specified by your class on hand.

For example, let’s say you require 9,000 gallons of fuel to run your EPS for 48 hours because you have a Class 48 EPSS installation. According to the 133% rule, you’d need to store at least 12,000 gallons of fuel on site.

The NFPA 110 fuel storage and testing requirements require you to carefully size your fuel tanks and perform regular fuel maintenance to ensure compliance. You should also consider fuel supplier delivery logistics—where can you get additional fuel if necessary, and how long will it take to have it delivered? 

This is one of many areas where working with an experienced service provider is critical—they can help you think through your fuel needs and come up with a fuel storage and maintenance plan that complies with NFPA 110 and all applicable codes, without being cost prohibitive.

Maintenance and testing

In addition to the type of equipment you need and fuel requirements, NFPA 110 also requires regular maintenance and testing of your generator system to ensure that it’s ready to perform in an emergency.

Chapter 8 of NFPA 110 covers maintenance of your backup power system. In general, it suggests you follow your manufacturer’s maintenance recommendations, but outlines an alternate maintenance program if no manufacturer guidelines are available.

Your maintenance needs will be determined largely by your particular situation, your manufacturer’s recommendations, and what your local authorities require. That’s why it’s important to partner with a trusted service provider that can create a maintenance plan that fits your needs and meets the requirements of your unique equipment and situation.

NFPA 110 Generator Maintenance

What a good maintenance plan looks like

What an NFPA 110-compliant maintenance plan looks like will depend on your unique situation, your specific equipment, and your location in addition to the guidelines provided by the standard. 

At Electro-Motion, here’s what a fully NFPA 110-compliant maintenance plan looks like for most of the emergency power systems we service:

  • Maintenance inspection (3x per year)
  • Two to four hour load bank test (1x per year)
  • Automatic transfer switch maintenance (1x per year)
  • Fuel testing and tank inspection (1x per year)
  • Insulation resistance testing (1x per year)
  • Annual maintenance (1x per year)

Other services, such as a battery replacement, cooling system services, and valve adjustments only need to happen once every two to three years—but still have to be done on a regular schedule to ensure compliance.

NFPA 110 testing requirements

In addition to regular maintenance, there are several tests that should be performed on a regular basis to make sure your backup power system is already ready for operation and to help you identify problems early.

So how often should the emergency generator be tested at a minimum? Here are some of the NFPA 110 generator testing requirements:

  • Diesel EPS energy converters must be tested annually under building load with supplemental load banks as required at not less than 50% of rated (nameplate) kilowatt load for at least 30 minutes.
  • Spark-ignition EPS must be exercised once a month with the available building load for 30 minutes.
  • Where multiple ATS are installed, they must be rotated to verify each start signal is functional. You can learn more about NPFA 110 ATS testing here.
  • Level 1 EPSS circuit breakers must be exercised annually.
  • Once a year, a Level 1 EPSS must be tested continuously for two to four hours (known as load bank testing). You can learn more about NFPA load bank testing here.

Again, you’ll need to work with your maintenance provider to determine which tests are relevant to your system and establish a schedule to conduct them.

For more detail, you can look at our full list of services and tests you need to stay NFPA 110 compliant. For each one, we have a clear description of the test or service, what the impact is to business activities, and how often they need to be done.


NFPA 110 is a standard published by the National Fire Protection Association that governs the installation, maintenance, and testing of emergency backup power systems. They are legally required for systems that support life safety, but are also used as industry-standard guidelines for all backup and emergency power systems.

Where applicable, NFPA 110 compliance is enforced by local authorities such as a fire marshall. These authorities are ultimately the ones who determine which systems are compliant and which are not using NFPA 110 as a guide.

Backup power systems are complex. There are many tests that need to be conducted and components that need to be maintained. Different types of equipment and different jurisdiction can all have unique maintenance and installation requirements. 

With that in mind, it’s important to partner with an experienced maintenance provider who can help you design a plan that meets NFPA 110 and local requirements while still fitting your budget.

If you’re in the Bay Area, Electro-Motion has been providing NFPA 110 maintenance to our customers for over 50 years. Hospitals, assisted living centers, data centers, grocery chains, hotels, and commercial real estate developments all depend on us to ensure that they will have uninterrupted power no matter what happens on the grid.

Schedule a consultation with us today.[/vc_column_text][/vc_column][/vc_row]

Comments are closed.