Consulting engineers who specify emergency power equipment understand that installations for mission critical facilities, such as hospitals and data centers, are required to comply with NFPA 110: Standard for Emergency and Standby Power Systems, in conjunction with NFPA 70: National Electrical Code. System designers must interpret the requirements of NFPA 110, ensure their designs follow them, and educate their clients about how the standard affects their operations. NFPA 110 provides performance requirements for emergency and standby power systems that supply reliable auxiliary power to critical and essential loads when the primary power source fails. The standard covers installation, maintenance, operation, and testing requirements as they pertain to the performance of the emergency power supply system (EPSS) including power sources, transfer equipment, controls, supervisory equipment, and all related electrical and mechanical auxiliary and accessory equipment.

1. Critical Power: NFPA 110: Standard
for Emergency and Standby Power
Sponsored by:
Join the discussion about this Webcast on Twitter at #CSENFPA110

2. Learning Objectives
•The audience will understand NFPA 110: Standard for
Emergency and Standby Power Systems; NFPA 70:
National Electrical Code; and how they work together
•Attendees will learn the changes from the 2010 edition of
NFPA 110
•Viewers will understand the criteria for EPSS
classification
•Viewers will learn how to minimize the impact of EPSS
testing

3. Tom Divine, PE,
Smith Seckman Reid Inc.,
Houston, Tex.
Kenneth Kutsmeda, PE, LEED AP,
Jacobs Engineering,
Philadelphia, Penn.
Moderator: Jack Smith,
Consulting-Specifying Engineer and Pure Power,
CFE Media, LLC
Presenters:

4. Critical Power: NFPA 110: Standard
for Emergency and Standby Power
Tom Divine, PE,
Smith Seckman Reid Inc.,
Houston, Tex.
Kenneth Kutsmeda, PE, LEED AP,
Jacobs Engineering,
Philadelphia, Penn.

5. Applicable NFPA codes and standards
associated with EPSS
• NFPA 70: National Electrical Code (NEC)
• NFPA 110: Standard for Emergency and Standby Power
Systems
• NFPA 99: Standard for Health Care Facilities.

6. Emergency power supply system (EPSS) is the total
system for distributing electrical power within a facility
when the normal power source is interrupted.
• Emergency Power Source (EPS)
• Transfer Switching Device
• Overcurrent Protection
• Control Systems

7. NFPA 70: National Electrical Code
(NEC)
Standard for the safe installation of electrical wiring
and equipment in the U.S.
• Article 700: Emergency Systems
• Article 701: Legally Required Standby Systems
• Article 702: Optional Standby Systems
• Article 708: Critical Operations Power Systems

8. NEC Article 700: Emergency Systems
Systems intended to supply illumination and
power to equipment essential for safety to
human life.
Examples:
• Egress lighting
• Life support systems
• Elevators
• Fire detection and fire alarm
• Fire pumps.

9. NEC Article 700: Emergency Systems
Requirements:
• Start and transfer automatically
• Dedicated transfer equipment
• Available for load in 10 sec
• Point of distribution must have physical
separation
• Emergency system wiring shall be
independent of all other wiring
• Selective coordination
• AHJ must witness testing.

10. NEC Article 700: Emergency Systems
Alternate source of power must be a storage
battery, generator set, UPS, separate
service, or fuel cell system:
• 2 hr on site fuel storage
• 90 min battery capacity
Additional requirements for assembly
occupancies over 1,000 persons or
buildings higher than 75 ft:
• Fire Protection for Feeder Circuit Wiring
• Fire Protection for Feeder Equipment

11. NEC Article 701: Legally Required
Standby
Systems intended to supply power to aid
firefighting, rescue operation, and control of
health hazards.
Examples:
• Smoke removal systems
• Communications systems
• Ventilation systems
• Sewage disposal systems
• Industrial processes that when stopped could
create hazards.

12. NEC Article 701: Legally Required
Standby
Requirements:
• Start automatically
• Available for load in 60 sec
• 2 hr on-site fuel storage
• AHJ must witness testing.
NEC indicates that generators used for
emergency and legally required systems
shall not be solely dependent on public source
(gas line) for fuel supply unless where
acceptable to the AHJ.
=

13. NEC Article 702:
Optional standby systems
Systems intended to supply power to prevent physical
discomfort, interruption of an industrial process,
damage to equipment, or disruption of business.
Examples:
• Refrigerators/freezers
• Data processing
• Farms
• Commercial buildings
• Carnivals.

14. Requirements:
• Manual or automatic start
• No available for load time requirements
• No on-site fuel storage requirements
Portable generators are acceptable to be connected to
an optional standby power system.
NEC Article 702:
Optional standby systems

15. Emergency/legally required:
Designed to safely evacuate people and
prevent hazards by keeping portions of the
system operating for a certain period of
time.
Critical operations/mission critical:
Designed to keep the entire facility or
critical components operating for the
complete extent of the outage.

16. • Availability: System must function when required (24x7)
• Reliability: System must not fail. If a failure occurs, the
system must respond and recover quickly.
• Security: System must provide protection against an attack,
either human or naturally caused.
“A mission critical system is a system that is essential to
the survival of a business or organization. When a mission
critical system fails or is interrupted, operations are
significantly impacted.”

17. Types of mission critical facilities
Private: business continuity
Attributes defined by the business based on its
business case
• Business enterprise data centers
• Financial data centers and trading
Public safety
Attributes defined by code and governed by the
agency having jurisdiction (AHJ)
• Emergency call centers
• Police and fire stations
• National security.

18. Private business continuity
Facilities where the levels of
availability and reliability are dictated
by the business case.
• Acceptable level of risk
• Downtime for maintenance
• Required degree of redundancy
• Protection against failures.

19. Private business continuity
• Low tolerance for risk
• No downtime
• High level of reliability.
Redundant components/generators
(N+1, N+2, or 2N)
Allows for one of the components or
generators to be taken offline for
maintenance or failure of one
generator without affecting the
operation of the facility.

20. Public safety facilities
Facilities where the levels of availability and
reliability are required to protect the public
safety, public health, and national security.

21. NEC Article 708: Critical Operations
Power Systems (COPS)
• Addresses homeland security issues for mission critical
facilities.
• Provides requirements for the installation, operation,
control, and maintenance of electrical equipment
serving critical operation areas that must remain
operational during a natural or human caused disaster.
• Critical operations power systems are installed in vital
facilities that if incapacitated would disrupt national
security, public health, and public safety.

22. • Provide an alternate power supply
• Alternate power shall have on-site fuel capacity to
operate for 72 hr
• Generator can’t be dependent on public utility gas for
fuel
• Redundant equipment is required, or at minimum, the
means, to connect roll up equipment
• Equipment must be located above the 100 yr flood plain.
NEC Article 708: Requirements for
standby power

23. • COPS system wiring shall be independent of all
other wiring
• Fire protection for feeders
• Selective coordination
• Documented commissioning
• Documented maintenance plan.
NEC Article 708: Requirements for
standby power

24. Examples of facilities that would
use COPS:
• Police and fire stations
• Emergency management centers
• Emergency call centers
• Government facilities involved with
national security
• Financial facilities involved with
national economic security
• Hospitals.

25. NEC Article 517: Scope
• Scope: Health care facilities for humans
• Special requirements
– Wiring, protection, grounding, x-ray, operating rooms
• “Essential electrical system”
• Amends requirements of other articles,
particularly Article 700.

26. NEC Article 517: Key definitions
• Essential electrical system:
– Alternate source, usually standby generator
– Plus distribution and ancillary equipment
• Structure under NEC 2010
– Emergency system
• Life safety branch
• Critical branch
– Equipment system

27. NEC Article 517: Structure
• Life safety branch: 517.32
– Getting out of the building
– Plus a couple of other things
– Prescriptive and proscriptive
• Critical branch: 517.33
– Patient care
– Effective hospital operations
– Less restrictive that life safety branch

28. NEC Article 517: Structure
• Equipment system: 517.34
– Delayed connection
– Some equipment required, some optional
– In practice, mostly HVAC.

29. NEC Article 517: Special rule
• Generators are sized for demand load –
517.30(D)
• 700.4 and 701.4 require sizing for
connected load
• Potential for generator damage from light
loading: wet stacking.

30. NEC Article 517: Wet Stacking

31. NFPA 110: Standard for Emergency and
Standby Power Systems
• Describes requirements for performance
• Doesn’t drive requirement for system: 1.2.1
– Building codes
– NFPA 70: NEC
– NFPA 99: Health Care Facilities Code
– Operational requirements

32. NFPA 110: Scope
• Installation: location, equipment, accessories
• Maintenance: inspections, frequency, records
• Testing: installation and maintenance
• System characteristics: transfer switches, fuel
system
• Scope ends at load terminals of transfer
switches.

33. NFPA 110: Key abbreviations
• Emergency power supply: EPS
– Source, usually generator
• Emergency power supply system: EPSS
– Everything between the generator and the
load terminals of the transfer switches.

34. NFPA 110: Inspection and testing
• Installation testing: EPSS
• Weekly inspection: EPSS
• Monthly load testing: EPSS
• Transfer switches operated monthly
• More extensive requirements for level 1 EPSS

35. Code changes: NFPA 110 - 2013
• 6.1.6: Permits electrically interlocked
circuit breakers as transfer switch for
medium-voltage mechanical equipment
• 8.1.2: Requires consideration of portable
generator when type criteria can’t be met
• 8.4.8: Requires that only “qualified
persons” perform maintenance, changed
from “a properly instructed individual.”

36. Code changes: NFPA 110 - 2013
Annex: Not exactly code
• A.7.9.1.2: Added description of fuel
testing
• A.7.13.4.3: Added description of standby
and prime generator ratings
• A.8.4.2: Requires a permanent record of
the generator rating to be readily available.

37. Code changes: NEC 517 - 2014
• Definition of “emergency system” deleted
– Essential system composed of three
branches: life safety, critical, equipment
– In practice, has little effect
• Defines selective coordination requirement
at 0.1 sec
• Purpose: Harmonization with NFPA 99,
which no longer uses the term.

38. NFPA 110: Standard for Emergency and
Standby Power Systems
Defines how emergency and standby power systems are to be
installed and tested. It contains requirements for energy
sources, transfer equipment, and installation and
environmental considerations.
NFPA 110 divides emergency power systems into three
categories:
• Type
• Class
• Level

39. The type refers to the maximum time that an emergency power
system can remain unpowered after a failure of the normal source.
NFPA 110: Standard for Emergency and
Standby Power Systems

40. The class of an emergency power system refers to the
minimum time, in hours, for which the system is designed to
operate at its rated load without being refueled or recharged.
NFPA 110: Standard for Emergency and
Standby Power Systems

41. The Level of an emergency power system refers to the level
of equipment installation, performance, and maintenance
requirements.
NFPA 110: Standard for Emergency and
Standby Power Systems

42. NFPA 110: Testing requirements
Installation testing
• Start system and record performance
• Full-load test: 2 hr
– 30% of nameplate kW for ½ hr
– 50% for ½ hr
– 100% for 1 hr
• Engine crank and battery tests
• Detailed records.

43. Monthly load testing
• Requirement covers entire EPSS
• Run generator under load
– Special requirements for diesel units
• Exercise transfer switches
– Round trip to emergency position and back.
NFPA 110: Testing requirements

44. • Monthly load testing – diesel generators
– 30 min minimum
– Recommended exhaust temperature, or 30%
of nameplate kW rating
• Otherwise, annual test with supplemental
load, for ½ hr at 50%, 1 hr at 75%
• Level 1: 100% test for lesser of Class
duration or 4 hr, every 3 yr, at 30% and at
recommended exhaust temperature.
NFPA 110: Testing requirements

45. Monthly load testing – diesel generators
• 30 min minimum
• Recommended exhaust temperature, or
30% of nameplate kW rating
• Otherwise, annual test with supplemental
load, for ½ hr at 50%, 1 hr at 75%
• Level 1: Annual 100% test for lesser of
Class duration or 4 hr.
NFPA 110: Testing requirements

46. NFPA 110: Testing strategies
• Transfer less sensitive load, if adequate
• Manage mechanical systems to increase
load for test
– Let chilled water temperature drift upward
before load testing
• Complete normal power system shutdown
• Load bank: start with facility load,
supplement with load bank.

47. Because of the dependency on the generator to keep the
facility operating, all generator systems for mission critical
facilities are fully tested and commissioned before they are put
into service.
Factory witness testing
Site acceptance testing
• Load steps
• Transients response
• Heat run
Integrated system testing
• Test all system together
• Pull the plug.

48. Maintenance recommendations
• Implement a facility preventive
maintenance program
• Follow NETA recommendations,
perform maintenance and testing of
generators every 12 mo
• Exercise the generator regularly
• Load test generator
• Keep an inventory of spare parts
• Properly train all operators
• Periodic analysis of lube oil and fuel
oil.

49. During Hurricane Sandy there were many facilities in the
Northeast that relied on their standby power systems for
multiple days to keep the facility operating.
Lessons learned:
• Locate above the flood plain
• Adequate on-site fuel supply
• Means to change filters while
operating.

50. Locate generators and other standby power system
distribution equipment above the flood plain.
• Generators, transfer switches, and electrical equipment
can’t operate if under water
• During Hurricane Sandy, areas did see flooding above 100
yr flood plain.
• Recommend locating standby equipment above the 100 yr
flood plain or above the 500 yr flood plain, if possible.

51. Have adequate supply of
on-site fuel storage
• Water subsided in about a day but the debris
and damage made it difficult to deliver fuel
(even for those facilities with emergency
contracts)
• On average, it was about 3 days before
facilities could get fuel delivered
• Recommend minimum of 72 hr fuel storage.

52. Provide means to change filters
out while operating
• Fuel that was delivered was
contaminated with water and debris
• Facilities operators were changing
filters every couple of hours to keep
the systems from clogging
• Recommend installing dual-header
filter systems with transfer valve that
allows for filter replacement while
engine is operating
• Consider fuel polishing system.

53. Classification summary
Emergency and Level 1 are systems
essential to the safety of human life.
Legally required and Level 2 are
systems less critical to human life, but
if stopped could create hazards or
hamper rescue and fire fighting
operations.
Critical systems have a requirement to
remain operational under all conditions
and demand a higher level of reliability
and availability.

54. Overall goal of emergency and
standby power systems is to
provide power when there is a
loss of utility.
• NFPA 70: National Electrical
Code (NEC)
• NFPA 110: Standard for
Emergency and Standby Power
Systems
• NFPA 99: Standard for Health
Care Facilities

55. Codes and Standards References from
Today’s Webcast
• NFPA 70: National Electrical Code
• NFPA 99: Health Care Facilities Code
• NFPA 110: Standard for Emergency and Standby
Power Systems

56. Tom Divine, PE,
Smith Seckman Reid Inc.,
Houston, Tex.
Kenneth Kutsmeda, PE, LEED AP,
Jacobs Engineering,
Philadelphia, Penn.
Moderator: Jack Smith,
Consulting-Specifying Engineer and Pure Power,
CFE Media, LLC
Presenters:

57. Webcasts and Research
• Critical power: Generators and generator system
design
• Critical power: Integrating renewable power into
buildings
• Critical power: Circuit protection in health care facilities
• Critical power: Standby power for mission critical
facilities
• 2013 Electrical and Power study

58. Critical Power: NFPA 110: Standard
for Emergency and Standby Power
Sponsored by:
Join the discussion about this Webcast on Twitter at #CSENFPA110