1. ul singapore battery standards workshop 2021 final

1. May 2021 |Laurie Florence, Principal Engineer, Stationary & Motive Battery and ESS
UL and IEC Standards: A
Comparison in the Approach to
Safety of Energy Storage Systems

2. Introduction
Laurie Florence
Principal Engineer – Stationary/Motive Batteries, Fuel Cells and
Energy Storage
Energy & Industrial Automation, UL LLC
Corporate Fellow, William Henry Merrill Society
Background
Laurie Florence has over 30 years of experience in product safety. Laurie
represents UL on several battery and related standards committees for
various organizations, including UL, ANSI, IEC, ISO, CSA, NFPA, and SAE.
Laurie is the chair of IEC SC21A and convener for the IEC SC21A WG 5 for
industrial lithium batteries. In addition to UL 1974, Laurie is responsible for
UL 1973 for stationary batteries, UL 2580 and UL 2271 for electric and light
electric vehicle batteries, UL 9540 for energy storage systems and UL 9540A
the BESS large scale fire test method. Laurie is also responsible for the
certification categories related to these standards.
Laurie Florence
Principal Engineer – Stationary/Motive Batteries,
Energy Storage and Fuel Cells
Corporate Fellow, William Henry Merrill Society
Energy & Industrial Automation

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4. I. UL Standards Affecting Energy
Storage Systems (ESSs)
II. IEC Standards Impacting Energy
Storage Systems (ESSs)
III. A Comparison Between UL and IEC
Standards
IV. Future Trends
Agenda

5. UL Standards Affecting Energy
Storage Systems (ESSs)

6. Codes In the US Impacting Energy Storage
•NFPA 70, National Electrical Code (NEC) 2020
•Article 706
•NFPA 1, Fire Code 2021
•Chapter 52
•NFPA 855, Standard for Installation of Stationary Energy Storage Systems 2020
•ICC, International Fire Code (IFC) 2021
•Section 1207
•ICC, International Residential Code (IRC) 2021
•Section R328

7. BESS are required to
be Listed (3rd Party
Certification)
UL 9540 is a reference
standard for listing
The Fire, Residential codes
and Installation standard have
limitations on the system:
• Size (e.g. 50 kWh or 20 kWh)
• Separation distances (3 ft/0.9 m)
• Maximum allowable quantities in
the fire area (e.g. 600 kWh or 80
kWh)
• And other limitations to control a
potential fire event from the
BESS
These limitations
may be exempted
based upon large
scale fire testing (UL
9540A) and AHJ
approval
UL 9450A is referenced as
a LSFT method
Codes Impacting Energy Storage Systems

8. ANSI/CAN UL 9540, Energy Storage Systems and
Equipment
• Recognized as national standard in the US and
Canada
• Covers ESS that are either utility interactive,
standalone or a combination of both
• Multiple types of ESS covered:
• electrochemical, mechanical, chemical and
thermal
• Includes Construction Criteria
• References UL 1973 for battery system
requirements, UL 1741 for PCS, walk in system
criteria, FMEAand functional safety
• Includes Test Criteria
• Electrical Tests, Mechanical Tests, Environmental
Tests
UL Standards Affecting ESSs

9. UL 9540 2nd Edition which was under development in 2019 and published in February 2020
and includes the following major changes:
• Addition of reference of UL 9540A
• Updates to testing criteria
• Updates to instructions, etc. to better match up with codes
• Proposal to limit energy capacity unless large scale fire (LSF) testing conducted per codes
UL Standards Affecting ESSs

10. • ANSI/CAN UL 1973 is a major component
reference in UL 9540 for batteries
• ANSI/CAN UL 1973, Batteries for Use in Stationary,
Vehicle Auxiliary Power and Light Electric Rail (LER)
Applications
• Not exclusive of technology but includes specific
requirements:
• Secondary Lithium (e.g. Lithium ion)
• Secondary Nickel
• Lead Acid
• Sodium Beta (high temperature)
• Flow Batteries
• Electrochemical Capacitors
UL Standards Affecting ESSs

11. UL 1973 is recognized as national standard
in the US and Canada
Construction Requirements
• Materials, Enclosures
• Cell Criteria
• Electrical Safety Criteria
• FMEA, Functional Safety
• Instructions and Markings
Test Requirements
• Electrical Tests
• Mechanical Tests
• Environmental Tests
• Single Cell Failure Design Tolerance Test
UL Standards Affecting ESSs

12. ANSI/CAN UL 9540A, Test Method for
Evaluating Thermal Runaway Fire Propagation
in Battery Energy Storage Systems (BESS)
• Developed as a large-scale fire test method
for battery energy storage systems
• Provides data to validate BESS
installations including fire suppression and
deflagration protection necessary for BESS
installations
• Referenced in NFPA 855, ICC IFC and
NFPA 1 as the large scale fire test to use if
required per these codes
UL Standards Affecting ESSs

13. From its start,
UL 9540A has
been a multi-
level test:
Cell Level
•Whether cell can
exhibit thermal
runaway
•Thermal runaway
characteristics
•Gas composition
and properties
Module Level
•Propensity for
propagation of
thermal runaway
•Heat and gas
release rates
(severity/duration)
•Flaming/deflagration
hazards
Unit Level
•Evaluation of fire
spread
•Heat and gas
release rates
(severity/duration)
•Deflagration
hazards
•Re-ignition hazards
Installation
Level
•Effectiveness of fire
protection system(s)
•Heat and gas
release rates
(severity/duration)
•Deflagration
hazards
•Re-ignition hazards
UL Standards Affecting ESSs

14. 1. BESS Installation Parameters
• Enables determination of separation distances between units to minimize
unit-to-unit fire propagation
• Enables determination of separation distances between units and
enclosure walls
• Enables determination of potential of fire spread to overhead cabling
2. Installation Ventilation Requirements
• Quantifies deflagration potential
• Quantifies heat generation
3. Fire Protection (Integral or External)
• Evaluates fire protection strategies
4. Fire Service Strategy and Tactics
• Characterizes magnitude of potential fire event
• Documents re-ignitions within a BESS unit under test
• Measures and documents gases generated
UL Standards Affecting ESSs
UL 9540AAddresses Key Fire Safety Concerns

15. IEC Standards Impacting Energy
Storage Systems (ESSs)

16. IEC TS 62933-5-1, Electrical energy storage (EES)
systems - Part 5-1: Safety considerations for grid-
integrated EES systems - General specification
• Scope - specifies safety considerations (e.g. hazards
identification, risk assessment, risk mitigation) applicable to EES
systems integrated with the electrical grid.
IEC 62933-5-2, Electrical energy storage (EES)
systems Part 5-2: Safety requirements for grid
integrated EES systems - electrochemical based
systems (recently published)
• Scope – safety Standard for electrochemical energy storage
systems (BESSs)
IEC Standards Impacting ESSs

17. IEC 62933-5-2 has requirements that include the following:
• References IEC TS 62933-5-1
• References battery standards:
IEC 62619, IEC 62485-2, -5,
IEC 62932-2-2, IEC 63056,
IEC 63115-2, IEC 62984-3-1
• Topics covered
• Hazard consideration for
BESS
• BESS System Risk
Assessment
• System Testing
• Guidelines and Manuals
IEC Standards Impacting ESSs

18. IEC battery safety standards referenced as normative in IEC 62933-5-2:
• IEC 62619, Secondary cells and batteries containing alkaline or other non-acid electrolytes - Safety
requirements for secondary lithium cells and batteries, for use in industrial applications
• IEC 63056, Secondary cells and batteries containing alkaline or other non-acid electrolytes - Safety
requirements for secondary lithium cells and batteries for use in electrical energy storage systems
(recently published)
• IEC 62485-5, Safety requirements for secondary batteries and battery installations - Part 5: Lithium-ion
batteries for stationary applications (under development)
IEC Standards Impacting ESSs

19. IEC battery safety standards referenced as normative in IEC 62933-5-2:
• IEC 62984-2, High Temperature secondary Batteries – Part 2:Safety requirements and tests of cells and
batteries
• IEC 62932-2-2, Flow Battery Systems for Stationary applications - Part 2-2 Safety requirements
• IEC 63115-2, Secondary cells and batteries containing alkaline or other non-acid electrolytes - Sealed
nickel-metal hydride rechargeable cells and modules for use in industrial applications - Part 2: Safety
(under development)
• IEC 62485-2, Safety requirements for secondary batteries and battery installations - Part 2: Stationary
batteries
IEC Standards Impacting ESSs

20. A Comparison Between UL and IEC
Standards

21. UL 9540 safety standard covers safety of electrochemical, chemical, mechanical
and thermal ESSs
IEC 62933-5-1 technical specification, covers general safety concepts for all
technologies (TS)
IEC 629335-2 safety standard, references IEC 62933-5-1 and covers safety of
electrochemical ESSs only
A Comparison of UL and IEC Standards

22. Classification of Systems:
UL 9540 Does not formally classify in a table,
but requirements differ based upon
Installations, size and use
A Comparison of UL and IEC Standards
UL 9540
Use Residential, Non-residential
(commercial),
Utility
Technology Electrochemicial,
Mechanical, thermal,
chemical
Size (energy
content)
≥ 50 kWh
Location Outdoor: Remote or near
exposures
Indoor – Dedicated use Bldg.
Mixed use Bldg.
IEC 62933-5-2 Classifications
Features Categories Comments
POC Volt V-L <= 1 kVac or 1.5 kVdc
V-H > 1 kVac. or 1.5 kVdc
Energy Cap. S-L ≤ 20kWh
S-H > 20kWh
Site
Occupancy
S-O Occupied
S-U Unoccupied
Chemistry C-A non-aqueous electrolyte
C-B aqueous electrolyte
C-C High temperature
C-D Flow
C-Z Other

23. UL 9540 Battery Requirements
• UL 1973
IEC 62933-5-2 Battery
Requirements
• IEC 62619, IEC 63056, IEC
62485-5 (lithium ion)
• IEC 63115-2 (nickel metal
hydride)
• IEC 62485-2 (lead acid)
• IEC 62932-2-2 (flow battery)
• IEC 62984-2 (sodium high temp)
A Comparison of UL and IEC Standards

24. Power Conditioning Systems:
UL 9540:
• UL 1741, Inverters, Converters,
Controllers and Interconnection System
Equipment for Use With Distributed
Energy Resources or
• UL 62109-1, Power Converters
for use in Photovoltaic Power
Systems - Part 1: General Requirements
IEC 62933-5-2
• IEC 62477-1, Safety Requirements
for Power Electronic Converter
Systems and Equipment - Part 1: General
(safety of converter systems but not
specific to grid application)
A Comparison of UL and IEC Standards

25. Safety Analysis:
UL 9540:
• Requires safety analysis consisting of
risk analysis and risk assessment,
which can be in the form of an FMEA,
FTA, etc. be conducted
IEC 62933-5-2
• Requires a risk analysis be conducted
using tools such as FMEA, FTA, etc.
A Comparison of UL and IEC Standards

26. UL 9540 – FS and EMC
• If electronics and software are determined
critical to safety must comply with FS standard
(e.g. IEC 61508, UL 991/1998, UL 60730-1)
• Includes EMC testing to address controls (IEC
61000-4-2. -4-3, -4-4, -4-5, -4-6, -4-8)
IEC 62933-5-2 – FS and EMC
• Mentions IEC 61508 as guidance but not
requirement
• Appears to be conducting functional safety
evaluation of controls as end system evaluation
tests.
• Includes normative EMC criteria to evaluate
controls (IEC 61000-1-2, IEC 61000-6-7)
A Comparison of UL and IEC Standards

27. Remote Monitoring Systems:
IEC 62933-5-2 includes requirements for monitoring
systems that provide information to the operator
• Off specification conditions (e.g. overcharge,
overdischarge, overcurrent, over temperature)
reported to operator
• Temperature of system provided to operators
• Toxic or flammable gas detection provided to
operators
• Communication interface required
UL 9540 currently does not specifically address this or
require that there be the capability for remote monitoring
• An early warning communication system task
group established in 2021
• To be developed for proposal to UL 9540 in
2021.
A Comparison of UL and IEC Standards

28. UL 9540 Electrical Safety
• NFPA 70 (NEC) for connections and wiring
• Electrical Spacings, insulation criteria & grounding, Wiring
(UL 60950-1, UL 62368-1, IEC 60664-1, etc.)
• Certification of electrical components (e.g. PCS to UL 1741
or UL 62109-1) to safety standards
• Functional Safety requirements
IEC 62933-5-2 Electrical Safety
• Reference IEC 60364 series (Low-voltage electrical
installations,
• IEC 60664-1 (insulation coordination),
• IEC 61936-1 elect. Installs. > 1 kVac
A Comparison of UL and IEC Standards

29. Markings and Instructions:
UL 9540:
• Markings and signage: nameplate, cautionary markings, code required
markings
• Instructions: Electrical safety instructions, installation operating and
maintenance instructions.
• Compliance with code criteria on information provided (e.g. NFPA 855,
IFC ICC, NEC)
IEC 62933-5-2:
• Information for End User, Operation and maintenance, IEC 62933-5-1
• Information for end users
• Operation and maintenance
• Operation and maintenance plan
• Preventive maintenance
• Includes information that are part of NFPA 855 criteria for
commissioning and de-commissioning
A Comparison of UL and IEC Standards

30. A Comparison of UL and IEC Standards
UL 9540 Tests IEC 62933-5-2 Tests
Electrical: impulse, dielectric voltage, earthing
and bonding, UL 1973, UL 1741, FS testing
Electrical: Short circuit, Overcharge, High current
charge and earth fault, Impulse, Dielectric voltage,
Earthing & bonding, Anti-islanding, and Part 1 tests
Mechanical: kinetic energy tests, leakage and
overpressure, seismic, enclosure tests
Mechanical: Enclosure impact, static force, seismic
Explosion: UL 9540, UL 1973, UL 9540A, USA
installation codes
Explosion: Specification of flammable gas, gas
detection, ventilation
EMC: FS testing, IEC 61000-4-2, etc. EMC: IEC 61000-1-2, IEC 61000-6-7
Some of the testing for UL 9540 is covered in the major
component standard such as UL 1973

31. A Comparison of UL and IEC Standards
UL 9540 Tests IEC 62933-5-2 Tests
Fire: UL 9540A (if required per code) Fire: (future)
Temperature: Normal Operations, FS testing, UL
1973
Temperature: Verify TCs operation, abnormal
operation of venting systems, temperature and
normal operations
Chemical: UL 1973, fluid containment, hazardous
warnings, leak detection, material compatibility,
etc.
Chemical: specification of toxic fluids, fluid
detection, Protection from hazardous fluids
Environment: Salt fog, Ingress/IP rating Environment: moisture ingress, marine
environment, IP
Some of the testing for UL 9540 is covered in the major
component standards such as UL 1973

32. Production Testing and Quality Control
UL 9540:
• Dielectric Voltage Withstand, Grounding & Bonding
• Check of safety controls,
• Production quality control
• Components have their own production requirements
IEC 62933-5-2:
• Factory Acceptance Tests:
• Dielectric voltage, Anti-islanding, Gas detection, Ventilation, Propagation
• Fluid detection, Protective measures against fluid hazards
Site Acceptance Tests in IEC 62933-5-2
• Overcharge, high current charge and earth fault protection
• Dielectric voltage
• Insulation resistance
• Earthing and bonding system check
• Anti-islanding
• Earthquake impact and vibration
• Gas detection / off-gas detection
• Ventilation
• Fire hazards (propagations)
• Verification of thermal control operation
• Abnormal operations of subsystems for
• Ventilation
• Temperature under normal operations test
• Fluids detection
• Protective measures against hazardous fluids
• Hazards arising from auxiliary, control and communication system malfunctions
UL 9540 does not specifically include site acceptance tests.
NFPA 855 has commissioning criteria that would include site acceptance tests necessary to
commission the system
A Comparison of UL and IEC Standards

33. A Summary
• The general approach has many similarities
• The differences are in the details
UL 9540 2nd edition published in 2020
• Some major changes were proposed
including some based upon code
requirements
IEC 62933-5-2 published in in 2020
A Comparison of UL and IEC Standards

34. Future Trends

35. NPPA 855 is under revision for the 2023 edition
• Include a scope
• Some changes for different chemistries
• Address explosion protection
NFPA 70 (NEC) is under revision for the 2023 edition
• Changes to art 480 (standby batteries) and art 706(ESS)
ICC IFC, ICC IRC and NFPA 1 2021 editions recently out.
Future Trends
Code updates

36. UL 9540 is in the process of receiving proposals
• Explosion protection
• Updates based upon changes to codes
• Addition of criteria for thermal energy storage systems
• Updates for lead acid and nickel cadmium batteries
• Updates to tests and functional safety criteria
• Updates to functional safety criteria
• Early Warning Communication System Task Group
• Working on proposals for this type of system
UL 1973 is going through a major standards revisions
• Updates to functional safety criteria
• Inclusion of all lithium ion cell criteria into standard
• Addition of high rate charge and overload discharge tests
• Inclusion of lead acid and nickel cadmium test program
• Update to clarify electrical spacing criteria
UL 9540A is in the process of receiving proposals
• Updates to cell and module test methods to improve clarity
• Provide further clarification for testing of different installations
including container systems at unit level
• Method to test lead acid and nickel cadmium batteries
Future Trends
UL standards impacting ESS are currently under major updating

37. There are a lot of updating and new standards efforts in the IEC:
1. IEC 62933-5-2 is open for revisions within IEC TC 120 MT 7
2. IEC 62933-5-1 will be open for revisions within IEC TC 120 MT 8
• Will be revised and turned into an IS
3. IEC 62933-5-3, Electrical Energy Storage (EES) Systems - Part 5-3:
Safety requirements for electrochemical based EES systems
considering initially not-expected modifications - partial replacement,
changing application, relocation and reusing/repurposing battery
• Is under development in IEC TC 120 WG 5
4. IEC 62933-5-4, Electrical energy storage(ESS) systems Part 5-4 –
Safety test methods and procedures for grid integrated EES systems –
Lithium ion battery-based systems
• Is currently under development IEC TC 120 WG 5
Future Trends

38. Laurie Florence
laurie.b.florence@ul.com
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