What NFPA 855 covers
NFPA 855 is the installation standard that fire officials in the US — and many other markets that adopt NFPA codes — use to approve battery energy storage. Its main areas:
- Listing of the system to UL 9540, with UL 9540A data where the code relies on it.
- Size and separation: default limits on unit energy and spacing between units and to walls, which can be changed only with test data.
- Fire detection and suppression appropriate to the installation.
- Explosion control to NFPA 68 or NFPA 69.
- Hazard mitigation analysis for failure modes.
- Large-scale fire testing to show what happens if a unit is fully involved in fire.
How we help
| Need | What we provide |
|---|---|
| Test data | UL 9540A cell, module, unit and installation tests; large-scale fire tests; deflagration tests |
| Explosion control design | NFPA 68 vent sizing and NFPA 69 ventilation analysis, verified by simulation |
| Compliance | Code interpretation, gap analysis and remediation, AHJ communication; P.E. stamping through Summit and Jensen Hughes |
Frequently asked questions
Does NFPA 855 require UL 9540A?
NFPA 855 requires energy storage systems to be listed to UL 9540, and uses UL 9540A test data to justify exceeding its default limits — for example larger unit sizes or reduced spacing.
What does NFPA 855 say about explosion control?
Where a battery system can release flammable gas, NFPA 855 requires explosion control: deflagration venting designed to NFPA 68, or gas concentration control (ventilation) designed to NFPA 69 — unless test data shows the hazard is not present.
Can you help with an AHJ submission?
Yes. We combine test data, gap analysis and simulation into the documentation the AHJ reviews, and North American P.E. stamping is available through our partners Summit and Jensen Hughes.