In 2018, the California Photo voltaic Vitality Industries Affiliation (CALSEIA) rebranded to change into the California Photo voltaic and Storage Affiliation (CALSSA). Their justification was easy, it was a transfer that “acknowledges photo voltaic’s central function in the way forward for the U.S. electrical energy era combine whereas acknowledging its subsequent evolution is inextricably intertwined with the elevated use of power storage.” Different organizations and occasions have been fast to observe swimsuit. For instance, the annual Photo voltaic Energy Worldwide convention now goes by a extra nebulous identify, “RE+.”
Rebrands and identify adjustments explicitly acknowledged that photo voltaic’s worth to {the electrical} grid is absolutely realized when paired with power storage. A photo voltaic-plus-storage system is not constrained by intermittency: electrical energy generated throughout peak sun-hours could be saved regionally and exported to the grid during times of excessive demand and low provide. Clear energy from photo voltaic all of a sudden turns into accessible across the clock.
As battery prices decline and grid reliability points persist, attachment charges (the speed at which photo voltaic PV methods are put in with power storage) are going up. And as deployment will increase, so does the depth with which we scrutinize battery security. That brings us to the subject of this text, UL 9540, a security normal for the development, manufacturing, and efficiency testing of grid-tied power storage methods (ESS). UL 9540 is the measuring stick for ESS security within the U.S. Within the sections that observe, we’ll cowl how merchandise obtain UL 9540 certification, what’s included in the usual, and the main points of the 9540A take a look at course of.
What’s UL 9540 itemizing?
Underwriters Laboratories (UL) authors testing, certification, and inspection requirements. In 2016, UL launched the primary version of UL 9540 because the Commonplace for Security of Vitality Storage Methods and Tools. Since then, the Worldwide Hearth Code (IFC), Worldwide Constructing Code (IBC), and NFPA 1 and NFPA 855 fireplace codes have all required that electrochemical ESS be listed to UL 9540.
2023 NFPA 855
15.2 Tools Listings. ESS shall be listed and labeled in accordance with UL 9540.
The usual defines electrical, mechanical, fluid containment, environmental efficiency, and system security exams for power storage methods. Notice that it is a system-level normal, which means that every one elements that make up an ESS should be examined collectively. If an ESS have been comprised of a battery (listed to its component-level normal, UL 1973) and a battery inverter (listed to yet one more normal, UL 1741) packaged and designed to work collectively as an power storage system, they should be examined and listed as such. This ensures that security is retained at an built-in system degree.
To exhibit UL 9540 compliance, a producer should undergo one of many many Nationally Acknowledged Testing Laboratories (NRTLs). NRTLs which might be licensed to check elements to this normal can problem a certificates of compliance. All NRTLs should adhere to the UL 9540 normal when testing.
The second version of UL 9540, in impact since July 2022, added a number of new itemizing necessities.
- Listed ESS should be housed in a metallic enclosure.
- Itemizing acceptance standards should be mirrored in set up directions. The set up handbook should name out particulars equivalent to ESS unit spacing limitations and different parameters derived from take a look at outcomes.
- Listed methods should meet the efficiency standards of a brand new take a look at technique, UL 9540A, if the anticipated set up exceeds the capability or unit spacing limitations described within the UL 9540 normal. Extra on that within the following part.
The third version of UL 9540 was launched in April 2023 and can go into impact in September 2024. Since necessities are evolving, when and to which version an ESS was listed issues. Producers will typically present itemizing documentation on their web site and, most often, will share documentation upon request. NRTLs can even keep databases that embrace the specifics of the listings for numerous merchandise.
What’s UL 9540A testing?
UL 9540A is a take a look at technique to judge the hearth security hazards related to propagating thermal runaway inside battery methods. The exams set up {that a} storage know-how is able to reaching thermal runaway after which assess the hearth and explosion hazards of that know-how. Can we drive it into thermal runaway? In that case, then what occurs?
Thermal runaway happens when a chemical response has gotten uncontrolled and might not safely dissipate extra warmth. Thermal runaway could be brought on by inner short-circuits, overcharging, bodily harm to cells, or high- and low-temperature environments.
The UL 9540A take a look at technique begins on the cell degree and regularly builds to the set up degree over 4 steps. If an ESS know-how meets the efficiency standards of any of the primary three exams, there is no such thing as a requirement to proceed testing the next ranges. If not, it strikes to the following degree.
Cell-Stage Checks
Checks begin on the smallest degree attainable. Per UL, only a few applied sciences meet the cell-level efficiency standards: can the cell be pushed into thermal runaway after a number of makes an attempt with a number of strategies? The testing stops right here if there is no such thing as a observable flaming, smoke, or gasoline venting.
Module-Stage Checks
Cells are assembled into modules and retested. Now, the purpose is to drive propagation between a number of cells throughout the module and search for exterior flaming, smoke, or warmth launch. Any gasoline merchandise are collected and analyzed. As with cell-level exams, it is a excessive bar to clear. Typically, an ESS will transfer to the following degree.
Unit-Stage Checks
The ESS unit is put in with none fireplace suppression system in place except one is built-in throughout the ESS. Many indoor and out of doors mounting configurations are examined. Efficiency standards differ for every configuration and for residential vs. nonresidential methods. Residential methods should meet efficiency standards at this degree since we can’t assume that every one houses have fireplace suppression. Nonresidential ESS that fail at this degree proceed to the ultimate take a look at.
Set up-Stage Checks
Set up-level and unit-level take a look at strategies are very comparable, however the effectiveness of fireside suppression brokers is now analyzed. ESS that present no indicators of detonation, deflagration (combustion that propagates via a gasoline), flaming, or reignition after preliminary fireplace suppression will meet the efficiency standards. The remainder will fail and should change their know-how or set up earlier than retesting.
As soon as a know-how meets the efficiency standards, a UL 9540A take a look at report is issued with particulars of the take a look at setup, technique, and outcomes. Producers will not be required to make take a look at reviews available, however can voluntarily put up some or all of their outcomes to a free UL 9540A database maintained by UL. It is a good spot to start out if you happen to’re in search of pattern take a look at reviews.
Check outcomes shall be offered to the hearth code officers per fireplace code necessities. Due to this fact, if the producer has not publicly posted these outcomes, they might want to present them upon request.
UL 9540 ≠ UL 9540A
UL 9540 defines a system-level itemizing normal. UL 9540A defines a particular take a look at methodology. Regardless of how comparable their names are, the 2 issues will not be the identical and shouldn’t be conflated. There isn’t any certification for UL 9540A. Certification to UL 9540 requires UL 9540A testing if indicated by the codes your AHJ follows.
Bear in mind, totally different editions of the UL 9540 normal have totally different necessities. Most notably, ESS listed below the primary version of UL 9540 weren’t required to finish UL 9540A testing. Most ESS producers will checklist compliance with UL 9540 and UL 9540A on datasheets to keep away from confusion.
Information from the exams is used to find out whether or not an ESS can bypass the baseline security and set up necessities ascribed by NFPA 855. For instance, ESS models listed to UL 9540 that meet UL 9540A efficiency standards could, in some circumstances, be put in nearer collectively than non-tested models.
2023 NFPA 855
15.3.1 ESS Spacing. Particular person ESS models shall be separated from one another by a minimal of three ft (914 mm) except smaller separation distances are documented to be sufficient primarily based on fireplace and explosion testing complying with 15.13. (UL 9540A)
For a extra detailed take a look at UL 9540A testing to bypass NFPA 855 necessities, take a look at our self-paced on-line workshop 2023 NFPA 855 and Hearth Codes for ESS.
Conclusion
The photo voltaic trade is rapidly turning into the photo voltaic-plus-storage trade. In the meantime, most power storage producers promote built-in ESS (battery plus cost controller plus inverter, and so forth.) as a substitute of standalone batteries. System-level itemizing requirements like UL 9540 are proof of idea for AHJs and installers to belief that the various elements that type an ESS will work collectively safely. System-level exams like UL 9540A outline any further fireplace suppression or set up necessities for ESS models.
In 2018, the California Photo voltaic Vitality Industries Affiliation (CALSEIA) rebranded to change into the California Photo voltaic and Storage Affiliation (CALSSA). Their justification was easy, it was a transfer that “acknowledges photo voltaic’s central function in the way forward for the U.S. electrical energy era combine whereas acknowledging its subsequent evolution is inextricably intertwined with the elevated use of power storage.” Different organizations and occasions have been fast to observe swimsuit. For instance, the annual Photo voltaic Energy Worldwide convention now goes by a extra nebulous identify, “RE+.”
Rebrands and identify adjustments explicitly acknowledged that photo voltaic’s worth to {the electrical} grid is absolutely realized when paired with power storage. A photo voltaic-plus-storage system is not constrained by intermittency: electrical energy generated throughout peak sun-hours could be saved regionally and exported to the grid during times of excessive demand and low provide. Clear energy from photo voltaic all of a sudden turns into accessible across the clock.
As battery prices decline and grid reliability points persist, attachment charges (the speed at which photo voltaic PV methods are put in with power storage) are going up. And as deployment will increase, so does the depth with which we scrutinize battery security. That brings us to the subject of this text, UL 9540, a security normal for the development, manufacturing, and efficiency testing of grid-tied power storage methods (ESS). UL 9540 is the measuring stick for ESS security within the U.S. Within the sections that observe, we’ll cowl how merchandise obtain UL 9540 certification, what’s included in the usual, and the main points of the 9540A take a look at course of.
What’s UL 9540 itemizing?
Underwriters Laboratories (UL) authors testing, certification, and inspection requirements. In 2016, UL launched the primary version of UL 9540 because the Commonplace for Security of Vitality Storage Methods and Tools. Since then, the Worldwide Hearth Code (IFC), Worldwide Constructing Code (IBC), and NFPA 1 and NFPA 855 fireplace codes have all required that electrochemical ESS be listed to UL 9540.
2023 NFPA 855
15.2 Tools Listings. ESS shall be listed and labeled in accordance with UL 9540.
The usual defines electrical, mechanical, fluid containment, environmental efficiency, and system security exams for power storage methods. Notice that it is a system-level normal, which means that every one elements that make up an ESS should be examined collectively. If an ESS have been comprised of a battery (listed to its component-level normal, UL 1973) and a battery inverter (listed to yet one more normal, UL 1741) packaged and designed to work collectively as an power storage system, they should be examined and listed as such. This ensures that security is retained at an built-in system degree.
To exhibit UL 9540 compliance, a producer should undergo one of many many Nationally Acknowledged Testing Laboratories (NRTLs). NRTLs which might be licensed to check elements to this normal can problem a certificates of compliance. All NRTLs should adhere to the UL 9540 normal when testing.
The second version of UL 9540, in impact since July 2022, added a number of new itemizing necessities.
- Listed ESS should be housed in a metallic enclosure.
- Itemizing acceptance standards should be mirrored in set up directions. The set up handbook should name out particulars equivalent to ESS unit spacing limitations and different parameters derived from take a look at outcomes.
- Listed methods should meet the efficiency standards of a brand new take a look at technique, UL 9540A, if the anticipated set up exceeds the capability or unit spacing limitations described within the UL 9540 normal. Extra on that within the following part.
The third version of UL 9540 was launched in April 2023 and can go into impact in September 2024. Since necessities are evolving, when and to which version an ESS was listed issues. Producers will typically present itemizing documentation on their web site and, most often, will share documentation upon request. NRTLs can even keep databases that embrace the specifics of the listings for numerous merchandise.
What’s UL 9540A testing?
UL 9540A is a take a look at technique to judge the hearth security hazards related to propagating thermal runaway inside battery methods. The exams set up {that a} storage know-how is able to reaching thermal runaway after which assess the hearth and explosion hazards of that know-how. Can we drive it into thermal runaway? In that case, then what occurs?
Thermal runaway happens when a chemical response has gotten uncontrolled and might not safely dissipate extra warmth. Thermal runaway could be brought on by inner short-circuits, overcharging, bodily harm to cells, or high- and low-temperature environments.
The UL 9540A take a look at technique begins on the cell degree and regularly builds to the set up degree over 4 steps. If an ESS know-how meets the efficiency standards of any of the primary three exams, there is no such thing as a requirement to proceed testing the next ranges. If not, it strikes to the following degree.
Cell-Stage Checks
Checks begin on the smallest degree attainable. Per UL, only a few applied sciences meet the cell-level efficiency standards: can the cell be pushed into thermal runaway after a number of makes an attempt with a number of strategies? The testing stops right here if there is no such thing as a observable flaming, smoke, or gasoline venting.
Module-Stage Checks
Cells are assembled into modules and retested. Now, the purpose is to drive propagation between a number of cells throughout the module and search for exterior flaming, smoke, or warmth launch. Any gasoline merchandise are collected and analyzed. As with cell-level exams, it is a excessive bar to clear. Typically, an ESS will transfer to the following degree.
Unit-Stage Checks
The ESS unit is put in with none fireplace suppression system in place except one is built-in throughout the ESS. Many indoor and out of doors mounting configurations are examined. Efficiency standards differ for every configuration and for residential vs. nonresidential methods. Residential methods should meet efficiency standards at this degree since we can’t assume that every one houses have fireplace suppression. Nonresidential ESS that fail at this degree proceed to the ultimate take a look at.
Set up-Stage Checks
Set up-level and unit-level take a look at strategies are very comparable, however the effectiveness of fireside suppression brokers is now analyzed. ESS that present no indicators of detonation, deflagration (combustion that propagates via a gasoline), flaming, or reignition after preliminary fireplace suppression will meet the efficiency standards. The remainder will fail and should change their know-how or set up earlier than retesting.
As soon as a know-how meets the efficiency standards, a UL 9540A take a look at report is issued with particulars of the take a look at setup, technique, and outcomes. Producers will not be required to make take a look at reviews available, however can voluntarily put up some or all of their outcomes to a free UL 9540A database maintained by UL. It is a good spot to start out if you happen to’re in search of pattern take a look at reviews.
Check outcomes shall be offered to the hearth code officers per fireplace code necessities. Due to this fact, if the producer has not publicly posted these outcomes, they might want to present them upon request.
UL 9540 ≠ UL 9540A
UL 9540 defines a system-level itemizing normal. UL 9540A defines a particular take a look at methodology. Regardless of how comparable their names are, the 2 issues will not be the identical and shouldn’t be conflated. There isn’t any certification for UL 9540A. Certification to UL 9540 requires UL 9540A testing if indicated by the codes your AHJ follows.
Bear in mind, totally different editions of the UL 9540 normal have totally different necessities. Most notably, ESS listed below the primary version of UL 9540 weren’t required to finish UL 9540A testing. Most ESS producers will checklist compliance with UL 9540 and UL 9540A on datasheets to keep away from confusion.
Information from the exams is used to find out whether or not an ESS can bypass the baseline security and set up necessities ascribed by NFPA 855. For instance, ESS models listed to UL 9540 that meet UL 9540A efficiency standards could, in some circumstances, be put in nearer collectively than non-tested models.
2023 NFPA 855
15.3.1 ESS Spacing. Particular person ESS models shall be separated from one another by a minimal of three ft (914 mm) except smaller separation distances are documented to be sufficient primarily based on fireplace and explosion testing complying with 15.13. (UL 9540A)
For a extra detailed take a look at UL 9540A testing to bypass NFPA 855 necessities, take a look at our self-paced on-line workshop 2023 NFPA 855 and Hearth Codes for ESS.
Conclusion
The photo voltaic trade is rapidly turning into the photo voltaic-plus-storage trade. In the meantime, most power storage producers promote built-in ESS (battery plus cost controller plus inverter, and so forth.) as a substitute of standalone batteries. System-level itemizing requirements like UL 9540 are proof of idea for AHJs and installers to belief that the various elements that type an ESS will work collectively safely. System-level exams like UL 9540A outline any further fireplace suppression or set up necessities for ESS models.
