Overview#
NFPA 110 (Standard for Emergency and Standby Power Systems) defines the minimum equipment requirements for any Emergency Power Supply System (EPSS). This matrix maps every required and recommended component to the NFPA 110 section that mandates it, the compliance level (Level 1 vs Level 2), and the component category in our equipment library.
Use this page as a cross-reference when specifying, auditing, or maintaining NFPA 110-compliant generator systems.
Equipment Matrix by NFPA 110 Section#
Chapter 7 — Emergency Power Supply (EPS)#
The EPS is the generator itself and its directly coupled components.
| Component | NFPA 110 Section | Level 1 | Level 2 | Notes |
|---|---|---|---|---|
| Prime mover (engine) | 7.2.1 | Required | Required | Diesel, natural gas, or bi-fuel. Must meet local emissions. See our engine component library. |
| Generator (alternator) | 7.2.1 | Required | Required | Sized for full emergency load plus starting inrush. See alternator components. |
| Engine cooling system | 7.2.2 | Required | Required | Radiator or remote radiator. Antifreeze for freeze protection. See radiator components. |
| Engine starting system | 7.3 | Required | Required | Battery starting with automatic cranking cycle. |
| Starting batteries | 7.3.1 | Required | Required | Minimum two independent sets for Level 1. Battery charger required. See battery components. |
| Battery charger | 7.3.2 | Required | Required | Automatic float/equalize charger sized per NFPA 110, 7.3.2.1. |
| Block heater (engine jacket water) | 7.2.3 | Required | Recommended | Maintains engine block at operating temperature for fast starts. Required for Level 1 in climates where ambient drops below engine manufacturer's minimum. See block heater components. |
| Exhaust system | 7.8 | Required | Required | Piping, flexible connectors, and silencer rated for backpressure limits. See silencer components. |
| Fuel system (on-base tank) | 7.9.1 | Required | Required | Sub-base or day tank. Must store fuel for minimum run duration per 7.9.2. See fuel system components. |
| Fuel system (bulk storage) | 7.9.3 | Conditional | Optional | Required when on-base tank cannot hold the mandated fuel reserve. |
| Governor / speed control | 7.2.4 | Required | Required | Electronic isochronous governor for frequency stability. |
| Voltage regulator | 7.2.5 | Required | Required | Automatic voltage regulator (AVR) maintaining +/-2% at steady state. |
Chapter 6 — Transfer Equipment (EPSS)#
| Component | NFPA 110 Section | Level 1 | Level 2 | Notes |
|---|---|---|---|---|
| Automatic transfer switch (ATS) | 6.3 | Required | Required | Must transfer within 10 seconds (Level 1) or 60 seconds (Level 2). See ATS components. |
| Bypass-isolation switch | 6.3.4 | Required | Recommended | Allows ATS maintenance without de-energizing the load. |
| Transfer switch controller | 6.3.5 | Required | Required | Time delay settings per NFPA 110. See controller components. |
Chapter 7.4 — Control and Monitoring#
| Component | NFPA 110 Section | Level 1 | Level 2 | Notes |
|---|---|---|---|---|
| Generator controller | 7.4.1 | Required | Required | Automatic start/stop, engine protection, load management. See controller components. |
| Remote annunciator | 7.4.2 | Required | Recommended | Visual and audible alarms at a continuously attended location. |
| Remote monitoring system | 7.4.3 | Recommended | Optional | Cellular or IP-based monitoring for unmanned sites. See monitoring components. |
Chapter 8 — Routine Maintenance and Operational Testing#
| Component | NFPA 110 Section | Level 1 | Level 2 | Notes |
|---|---|---|---|---|
| Load bank (portable or permanent) | 8.4.2 | Required | Recommended | Annual load bank test at rated nameplate kW. Monthly loaded testing acceptable if building load is sufficient. See load bank components. |
| Exhaust aftertreatment (DPF/SCR) | 7.8.2 | Conditional | Conditional | Required for Tier 4 Final diesel engines. Requires periodic regeneration. See aftertreatment components. |
Chapter 7.9 — Fuel Supply#
| Requirement | NFPA 110 Section | Level 1 | Level 2 | Notes |
|---|---|---|---|---|
| On-site fuel storage duration | 7.9.2.1 | Class X: varies | 2 hours min | Level 1 Class 96 = 96 hours, Class 48 = 48 hours. Sized for full rated load fuel consumption. |
| Fuel quality maintenance | 7.9.7 | Required | Recommended | Annual fuel testing. Polishing system recommended for stored diesel. See fuel system components. |
| Day tank with automatic transfer | 7.9.4 | Conditional | Optional | Required when bulk tank is remote from generator. Automatic float-controlled pump. |
| Leak containment (double-wall) | 7.9.6 | Required | Required | Per EPA/state environmental codes. Secondary containment for all fuel storage. |
Classification Quick Reference#
NFPA 110 classifies systems by Level (how critical) and Class (how long):
| Level | Max Transfer Time | Typical Applications |
|---|---|---|
| Level 1 | 10 seconds | Hospitals, high-rise egress, fire pumps, 911 centers |
| Level 2 | 60 seconds | Data centers, commercial standby, water/wastewater |
| Class | Minimum Run Duration | Notes |
|---|---|---|
| Class 0.083 | 5 minutes | UPS bridge only |
| Class 0.25 | 15 minutes | Short-duration emergency |
| Class 2 | 2 hours | Minimum for most installations |
| Class 6 | 6 hours | Common commercial standby |
| Class 48 | 48 hours | Healthcare, critical infrastructure |
| Class 96 | 96 hours | Hospitals (per CMS/Joint Commission) |
| Class X | User-specified | Mission-critical, military, custom |
Equipment Sizing Considerations#
Fuel Storage Calculation#
Fuel tank size is driven by Class designation and full-load fuel consumption:
Required fuel (gallons) = Full-load consumption (GPH) x Class hours x 1.15 safety factor
For a 500 kW diesel generator consuming ~36 GPH at full load:
- Class 48: 36 x 48 x 1.15 = 1,987 gallons
- Class 96: 36 x 96 x 1.15 = 3,974 gallons
Battery Sizing#
NFPA 110, 7.3.1 requires batteries capable of a minimum cranking cycle. For Level 1:
- Minimum 3 cranking attempts of 15 seconds each, with 15-second rest intervals
- Battery capacity must account for worst-case ambient temperature
- Two independent battery sets recommended for Level 1 redundancy
Transfer Switch Rating#
The ATS must be rated for:
- Full emergency load (amps) with appropriate withstand and closing ratings
- Voltage class matching the distribution system
- Short-circuit current rating (SCCR) coordinated with upstream protective devices
Maintenance Requirements by Component#
NFPA 110, Chapter 8 mandates specific maintenance intervals:
| Component | Interval | NFPA 110 Reference | Action |
|---|---|---|---|
| Engine oil and filters | Per OEM schedule | 8.3.4 | Replace per manufacturer intervals |
| Coolant | Annually | 8.3.4 | Test concentration, pH, inhibitor levels |
| Fuel filters | Per OEM or annually | 8.3.4 | Replace; sample fuel for contamination |
| Batteries | Monthly | 8.3.7 | Check voltage, specific gravity, connections |
| Transfer switch | Monthly | 8.4.1 | Exercise under load; verify transfer timing |
| Load bank test | Annually | 8.4.2 | Run at rated load for minimum 2 hours |
| Exhaust system | Semi-annually | 8.3.4 | Inspect for leaks, backpressure, corrosion |
| Block heater | Monthly | 8.3.4 | Verify operating temperature, check for leaks |
| Fuel storage | Annually | 8.3.8 | Test fuel quality; inspect tank integrity |
OnPoint Service Notes#
OnPoint Generators provides full NFPA 110 compliance programs for commercial and healthcare facilities across the central California coast. Our generator maintenance contracts include all Chapter 8 testing intervals, documented per NFPA 110 record-keeping requirements (Section 8.3.1).
For facilities requiring NFPA 110 Level 1 compliance, we provide:
- Monthly loaded transfer tests with documented results
- Annual load bank testing at rated nameplate capacity
- Fuel quality testing and polishing services
- Battery load testing and replacement programs
- Full compliance documentation for AHJ inspections
Contact us for a compliance assessment of your emergency power system.