How we score NYC parking buildings for EV battery fire risk
This tool scores approximately 6,200 parking buildings across New York City on a 0-100 risk scale. The score reflects how vulnerable each location is to an EV battery fire event in an enclosed structure — specifically, the factors that would determine whether a single-vehicle thermal runaway cascades into a multi-vehicle fire like the August 2024 Incheon, South Korea incident (140 vehicles destroyed, 23 hospitalized, 8 hours to extinguish).
"Parking buildings" is broader than "parking garages" as most people think about them. Only about 1,600 of the scored buildings are standalone parking structures (PLUTO class G). The other ~4,700 are residential, office, or institutional buildings with dedicated parking space inside them — the kind of ground-floor or basement garage that sits under apartments, under an office tower, or under a hospital. Most NYC parking exists this way. See Why garagearea, not just G-class below.
The score does not predict the probability of an EV fire occurring. EVs catch fire 20-60x less frequently than gasoline vehicles (~25 per 100,000 vs ~1,530 per 100,000). The score instead measures how bad it would be if one did occur at this specific location.
Earlier pre-v1 versions of this map scored only PLUTO building class G (dedicated garages) plus any non-G building that happened to match an EV charger location. That second category definitionally meant "has EV charger," which made the map biased — any "buildings with parking" number we reported was inflated by EV presence rather than actual parking capacity. It also meant any apartment building with a real parking garage but no EV chargers was invisible to the tool.
v1 replaces that with a more honest selection: a building is "a parking building" if it is either G-class OR has garagearea ≥ 1,000 sqft (roughly 3 or more cars) in PLUTO. PLUTO classifies buildings by their dominant use, so most NYC parking ends up inside buildings classified as something else:
Adding garagearea ≥ 1000 to the selection adds about 4,500 buildings the previous version missed, most of them in the exact "people sleeping above parking" configuration that makes battery fires dangerous at night. The Reims, June 2025 e-scooter fire — 4 dead in a social housing tower — happened in a building of this type.
Each garage is scored on five factors. Points are additive, capped at 100:
| Year Built | Points | Rationale |
|---|---|---|
| Before 1968 | 30 | Built under pre-modern NYC building code. Maximum structural deterioration time. Original fire safety standards were designed for lighter vehicles and different fire profiles. |
| 1968-2003 | 15 | Built under 1968 NYC Building Code but before IBC adoption. 50 psf design load standard. |
| 2004 or later | 5 | Built under International Building Code. Current 40 psf standard with modern fire safety requirements. |
| Unknown | 20 | No year recorded in PLUTO — treated as likely pre-1968. |
Why 1968? NYC adopted its first comprehensive modern building code in 1968. Garages built before this date were designed to varied and often undocumented standards. The 1968 code established uniform structural and fire safety requirements for the first time.
This factor measures how current a building's sprinkler system design is relative to evolving fire safety standards — not whether a system exists or whether it's been maintained. We use DOB sprinkler permits (installation and modification records, digital since ~1990) as the signal. A building with no DOB sprinkler permits may have a functioning, annually-inspected system — but if that system hasn't been modified since installation, its design predates current fire-load standards for vehicles.
Important distinction: DOB permits vs FDNY inspections. DOB sprinkler permits record installation and modification of systems. FDNY conducts separate annual inspections to verify existing systems work — but FDNY inspection data is not available as open data. A building with a 1985 sprinkler system that passes FDNY inspection every year would show "no sprinkler permit on record" in our data, because the system hasn't been modified. We cannot distinguish "well-maintained but old design" from "no system at all." What we CAN say: either way, the system was not designed for current fire loads.
In 2022, NFPA 13 reclassified parking garages from Ordinary Hazard Group 1 to Group 2, increasing the required sprinkler water discharge density by 33% (from 0.15 to 0.20 GPM/SF). This change was driven by the increased plastics and energy content in modern vehicles — including EV battery fire loads. A garage with a sprinkler system installed in 1985 — even if perfectly maintained and passing annual FDNY inspection — is delivering 33% less water per square foot than the current standard requires. San Francisco goes further, requiring double the OH2 density (0.40 GPM/SF) at DC fast charging spots.
| Status | Points | What we know |
|---|---|---|
| No sprinkler permits in DOB records | 25 | No sprinkler system was installed or modified in DOB digital records (post-~1990). Either no system exists, or the system's design predates 1990 — at minimum 32 years behind current NFPA 13 OH2 density standards. |
| Last sprinkler permit before 2010 | 15 | System was installed or last modified 12+ years before the 2022 NFPA OH1→OH2 reclassification. Design almost certainly below current vehicle fire-load density requirements. |
| Sprinkler permit 2010 or later | 0 | Relatively recent installation or modification — though even post-2010 work may not meet the 2022 OH2 standard unless the project specifically targeted the density upgrade. |
Can sprinklers stop an EV fire? No. Sprinklers cannot extinguish a lithium-ion thermal runaway — the fire happens inside a sealed battery pack. But full-scale testing (Fire Technology, 2024) found that sprinklers at adequate density prevent fire spread to adjacent vehicles, which is the difference between a single-car event and a 140-car catastrophe.
Can we get actual system specifications? Sprinkler engineering drawings filed with DOB are public records, obtainable through DOB BIS Options record requests (~$8/page) or FOIL requests. These would show the actual GPM/SF a system was designed for. This is not scalable to thousands of buildings but is a viable path for investigating individual high-scoring locations.
| Floors | Points | Rationale |
|---|---|---|
| 3+ floors | 10 | Multi-story enclosed structure — more vehicles, harder evacuation, heat rises to upper floors. |
| 2 floors | 5 | Partial enclosure risk. |
| 1 floor | 0 | Single-level structure. |
DOB violations are tiered by severity:
| Type | Points Each | Examples |
|---|---|---|
| Critical | 8 | Immediate emergency orders, unsafe building designations, structurally compromised buildings |
| High | 5 | Sprinkler deficiency violations (LL2604S) |
| Low | 1 (max 3) | Photoluminescent exit sign violations, emergency power violations |
Total violation points are capped at 20. We search for violation types: IMEGNCY (immediate emergency), UB (unsafe buildings), COMPBLD (structurally compromised), LL2604S (sprinkler), LL2604E (emergency power), and LL2604 (photoluminescent).
Garages with EV chargers concentrate vehicles that may be actively charging at high state of charge, which increases thermal runaway severity. DC fast chargers put more thermal stress on batteries than Level 2.
| Weighted Ports | Points | Calculation |
|---|---|---|
| 20+ | 15 | Weighted ports = L2 count + (DC fast count × 3) |
| 4-19 | 10 | |
| 1-3 | 5 | |
| None | 0 |
Why is charger presence a bonus, not a requirement? Roughly 56% of documented EV battery fires occur while the vehicle is parked and not charging. Any garage where EVs park is at risk — chargers just increase the concentration and add charging-related thermal stress.
The foundation of the analysis. PLUTO contains building-level data for all ~870,000 NYC properties including building class, year built, number of floors, building area, basement type, and — critical to v1 — garagearea (sqft of dedicated parking space within a building).
garagearea ≥ 1,000. See Why garagearea, not just G-class.bsmtcode field (1=full basement, 2=partial basement) combined with OpenStreetMap parking=underground tagsUsed in v1 for address-to-BBL resolution of AFDC chargers. Geosearch is a free, keyless API maintained by the NYC Department of City Planning's Planning Labs team, wrapping the Property Address Directory (PAD) — the authoritative NYC dataset for mapping every address, including aliases, to its BBL.
Used in v1 as fallback for chargers whose address doesn't resolve via Geosearch. Exposes tax lot polygons (not just centroids) so we can do true point-in-polygon queries.
Historical building permit records. We query for sprinkler permits (permit_subtype='SP') to determine fire suppression history.
Newer permit system (2021+). Queried separately because it uses different field formats (BBL as a single field, ISO dates).
work_type='Sprinklers' or job_description LIKE '%SPRINKLER%'Building code violations. We search for safety-related violation types only.
US Department of Energy database of EV charger locations.
/v1/nearest.json endpoint with 15 center points across NYC at 8-mile radius each, to ensure full geographic coveragefacility_type of PAY_GARAGE or PARKING_GARAGE onlyLimitation: AFDC is voluntary — operators self-register. Our count is a lower bound. Some garages with chargers may not be in the federal database. We checked PlugShare and Recharged.com for additional sources but neither offers bulk data access.
Community-edited map data. Queried via Overpass API for parking facilities tagged as parking=underground or parking=multi-storey within the NYC bounding box.
Connecting AFDC charger stations to specific NYC tax lots (BBLs) is the hardest data problem in this project. AFDC gives us the charger's coordinates plus its street address, but doesn't identify the building it's in. PLUTO tells us about buildings but not chargers. We need a reliable method to link them.
Pre-v1 used a simple nearest-centroid approach: for each charger, find the PLUTO tax lot whose centroid is closest and call that the charger's building. This failed for two common cases:
v1 replaces that with a cascade of matching methods, in priority order:
We query NYC Planning Labs Geosearch with the charger's street address from AFDC. Geosearch is backed by the NYC Property Address Directory (PAD), which maps every address-and-alias in the city to its BBL. PAD handles the common NYC quirk that one BBL can have multiple addresses on different street frontages — which PLUTO doesn't expose.
Example: an AFDC charger at "377 E 33rd St" (the NYU Langone Garage H). PAD knows that address is an alias for BBL 1009390028, which is the luxury apartment tower whose primary PLUTO address is 347 E 33 Street. PLUTO alone has no record of "377 E 33rd" — PAD does.
We bias the query with the charger's own lat/lon (focus.point) and skip results whose returned coordinates are more than 1,000 ft from the charger, so fuzzy text matches like "251 New Jersey Avenue" don't get returned when we asked for "251 Avenue C."
When the AFDC address doesn't resolve cleanly (typographical errors, stale address strings, facility renamings), we fall back to geometry. The NYC ArcGIS MapPLUTO REST endpoint exposes every tax lot's actual polygon. We query with the charger's lat/lon and ask which polygon contains it. If the point is inside a polygon, we have an unambiguous match.
Points that are outside all polygons (curbside AFDC markers in the street) still usually have a building within a sidewalk's width. We use shapely to compute the distance from the charger to each nearby polygon edge and take the closest within 20 ft (approximately one sidewalk). More than 20 ft means the charger isn't adjacent to any building — usually a data error.
If all three steps fail, the charger is shown on the map as a "floating" dot with its AFDC street address label but no building association and no scoring effect. This is rare (typically 1 out of 264 chargers) and almost always due to AFDC data errors — e.g., a street address and a latitude/longitude that disagree with each other.
Match results are cached in charger_bbl_map.json between runs so we don't re-query external APIs unless the cache is cleared.
Every NYC tax lot where either (a) the PLUTO building class starts with G (dedicated parking/automotive use) or (b) PLUTO reports garagearea ≥ 1,000 sqft regardless of class. Approximate v1 counts:
| Category | Approx. count | Source |
|---|---|---|
| Standalone parking garages (G1/GU/GW) | 1,650 | PLUTO building class |
| Multi-story G0 residential garages | <50 | PLUTO class + numfloors > 1 |
| Under-residential (apartments, condos) | ~3,000 | PLUTO class D/C/R/A/B + garagearea ≥ 1,000 |
| Under-commercial (offices, retail, stores w/ apts) | ~780 | PLUTO class O/K/S + garagearea ≥ 1,000 |
| Institutional (hospitals, religious, schools) | ~145 | PLUTO class H/I/M + garagearea ≥ 1,000 |
| Other (warehouses, utilities, mixed) | ~630 | Other PLUTO classes + garagearea ≥ 1,000 |
| Total scored | ~6,300 |
Buildings with garagearea between 1,000 and 2,500 sqft (roughly 3-7 cars) are tagged with a small_garage flag. The scoring formula applies uniformly to them, but the flag exists so filtering and interpretation can distinguish small ground-floor parking from full multi-car garage operations.
garagearea field appears to exclude residential attached garages (class A), so the 1,000 sqft threshold naturally excludes them even without explicit filtering.garagearea for these (Hudson River piers historically had vehicle/warehouse space) but they are not parking garages in any meaningful sense for this analysis. Managed by Port Authority, Hudson River Park Trust, etc. with their own fire safety programs.garagearea in these is typically vehicle maintenance space, not public/commercial parking.The formula — age + sprinkler maintenance + floors + violations + charger presence — was originally designed for standalone G-class parking garages. In v1 we apply it uniformly to non-G buildings (apartments, offices, institutional) with embedded parking. The factors still matter, but the "no sprinkler permit on record" penalty (+25) is particularly prone to misinterpretation for non-G buildings: an older apartment building may have never filed sprinkler work in DOB digital records for its ground-floor garage specifically, while the apartments above have sprinklers that the building data doesn't expose to us. Buildings in the "under_residential," "under_commercial," and "institutional" categories should be read with this caveat. This is a known calibration gap we expect to address in a future revision by either distinguishing per-level sprinkler maintenance or adjusting the penalty by class.
DOB digital records begin around 1990. A building showing "no sprinkler permits" may have a functional system installed before records went digital. We cannot distinguish "no system" from "no digital record." However, any pre-1990 system without subsequent upgrades is almost certainly below the 2022 NFPA OH2 density standard (33% higher than the previous requirement). The scoring reflects this: buildings with no evidence of recent fire suppression activity are at higher risk regardless of whether an older system exists, because that system was not designed for modern vehicle fire loads. Actual system specifications (GPM/SF) are available through DOB record requests but are not in any bulk dataset.
The garagearea field on PLUTO is populated during Department of Finance assessment and reflects what the city has on file. Some ground-floor garages may be under-reported; some "garagearea" values may conflate parking with storage or service space. The 1,000 sqft threshold filters the most obvious noise (single-car residential) but the exact size of the captured set will shift quarterly as PLUTO updates.
PLUTO basement codes + OSM identify approximately 200 underground garages. The true number in Manhattan alone is likely much higher — virtually every large residential or office building built since the 1960s has below-grade parking. The INRIX parking API has a "Subterranean" classification for 350K+ facilities globally but requires enterprise licensing.
AFDC is voluntary and self-reported. Our ~264 NYC garage stations likely undercount the true number. Smaller operators and recently installed chargers may not be registered.
The v1 PAD-plus-geometry cascade resolves almost every AFDC charger to the correct BBL, but rare cases remain where AFDC's street address and coordinate disagree with each other — one or both is wrong. Those chargers appear as unmatched "floating" dots on the map with no building association.
A high score means a building has risk factors — it does not mean the building is unsafe or will have a fire. Only a licensed engineer can assess structural integrity, and only an on-site fire safety inspection can determine actual suppression capability. The 57 Ann Street collapse investigation took two years to determine the actual cause.
A building with extensive DOB records will have more data points to score against. Absence of violations may mean a clean record or may mean the building hasn't been inspected recently.
This project began as an investigation into whether heavier EVs were stressing old parking structures. The engineering evidence says no: even a worst-case scenario with every spot filled with a 9,063 lb GMC Hummer EV produces only ~38.7 psf — still under the 40 psf IBC design minimum (Pankow Foundation, 2024). The weight concern was amplified by the April 2023 Ann Street garage collapse, where officials initially blamed vehicle weight. The actual cause (revealed two years later) was unauthorized removal of a load-bearing masonry pier.
EV battery fires differ fundamentally from gasoline fires: they burn at ~5,000°F vs ~1,500°F, last 60-90+ minutes vs ~30 minutes, can reignite days later, and produce toxic hydrogen fluoride gas. Roughly 56% of documented EV battery fires occur while the vehicle is parked. The primary causes at rest are manufacturing defects in battery cells (torn anode tabs, folded separators, metal particle contamination) that can lie dormant for months before triggering thermal runaway.
After the Incheon fire, South Korea mandated retroactive sprinkler upgrades in existing garages, battery chemistry disclosure, state-of-charge limits for underground parking, and mandatory fire liability insurance. The US has none of these. NFPA actively voted to remove EV charging provisions from NFPA 30A in 2024. Meanwhile, NYC Local Law 55 (2024) requires 20% of commercial parking spaces to be EV-ready — with no fire safety conditions attached. More chargers in old garages, no sprinkler upgrades required.
Sprinklers can contain an EV fire but cannot extinguish it. However, there is a window for earlier intervention: lithium-ion cells emit hydrogen gas during the early stages of thermal runaway, 16-26 minutes before flames (Energy Material Advances). A single venting cell produces over 1,000 ppm of hydrogen outside the battery pack — roughly 1,000x the indoor background level of ~1 ppm — easily detectable with existing sensor technology.
This is not theoretical. China mandates thermal runaway warning systems in EV battery packs (using the vehicle's onboard BMS). NFPA 855 (2026 edition) requires hydrogen detection for stationary energy storage systems — the shipping-container-scale battery banks at solar farms and data centers. Commercial products exist for this: Li-ion Tamer (now Honeywell) detects thermal runaway off-gassing for battery rooms, and H2Scan's HY-GUARD is designed specifically for battery room safety.
But this technology has not been applied to parking garages or residential battery storage. No US fire code requires gas detection in parking structures. No building code addresses thermal runaway detection in e-bike storage rooms. The same chemistry that NFPA considers dangerous enough to require hydrogen monitoring in a grid battery installation receives zero detection requirements when it's in a vehicle parked in a basement or a bike stored in an apartment.
This project is not anti-EV. EVs catch fire 20-60x less frequently than gasoline vehicles. The problem is not the technology — it's that our fire safety infrastructure hasn't caught up to the reality that lithium-ion batteries are now everywhere, in vehicles of every size.
Nowhere is this clearer than with e-bikes. NYC recorded 279 e-bike battery fires in 2024, with 18 deaths in 2023. FDNY officials consistently identify uncertified batteries in fire investigations — "Many times, I'd look at the battery and see there was no certification on it" (John Orlando, former FDNY Lithium-Ion Battery Task Force). No fire from a genuinely UL 2271/2849 certified battery has been documented in public records.
NYC is addressing the root cause through practical legislation: Local Law 39 (2023) requires UL certification for all e-bike batteries sold in the city, and battery exchange programs are replacing uncertified batteries with certified ones. This is evidence-based policy addressing the actual problem.
But many NYC buildings have responded with blanket bans on all e-bikes and lithium batteries in common areas — regardless of certification status. This creates a paradox: a UL-certified 500 Wh e-bike battery is banned from a building's bike room, while 119 NYC garages are hosting EV chargers (50,000-100,000 Wh batteries) with no evidence of fire suppression maintenance.
The argument for detection is not that it makes bad batteries safe — it doesn't, and uncertified batteries need to be removed from circulation. The argument is that certified batteries + hydrogen detection creates a safety profile that makes blanket bans unnecessary. An e-bike battery is 150x smaller than an EV battery. With early detection providing minutes of warning, a 500 Wh battery event in a monitored space is survivable and manageable. A 500 Wh battery event with zero warning while someone is sleeping is how people die. The technology to bridge that gap exists, is proven, and is already required in other contexts. It just hasn't been applied here yet.
Pankow Foundation. "Safe and Sustainable Parking Garage Live Loads in the Age of the Electric Vehicle." Report RGA-05-24, 2024. Link
Springer / Fire Technology. "Full-Scale Fire Testing to Assess the Risk of Battery Electric Vehicle Fires in Underground Car Parks." Vol. 61, pp. 4133-4163, 2025. Link
NFPA. "Parking Garages and EVs." July 2024. Link
EV FireSafe. "EV Battery Fire Data." Global incident database, updated continuously. Link
ICCT. "Clearing the Air: EVs Could Bring Lower Fire Risk." October 2024. Link
MDPI / Fire. "Risk Assessment of Toxic Gas Dispersion from Electric Vehicle Fires in Underground Apartment Parking Garages Using Numerical Analysis." Vol. 8, Issue 3, 2025. Link
Wen, Y.K. and Yeo, G.L. "Design Live Loads for Passenger Cars Parking Garages." ASCE Journal of Structural Engineering, Vol. 127, No. 3, 2001.
Gothamist. "Deadly Manhattan parking garage collapse tied to unsafe demolition, structural neglect, city report finds." April 28, 2025. Link
Fortune. "Exploding Mercedes-Benz EV prompts parking garage bans in South Korea." August 7, 2024. Link
NFSA. "Fire Protection for Parking Garages." April 2024. Link
SF Fire Department. "Sprinkler Protection Requirements for Parking Spaces Associated with Electric Vehicle Charging Stations." Information Sheet 429. Link
NYC Local Law 55 (2024). EV charging infrastructure requirements for commercial parking. Analysis
Energy Material Advances. "A Critical Review of Thermal Runaway Prediction and Early-Warning Methods for Lithium-Ion Batteries." Gas signals provide 16-26 minutes of advance warning. Link
Journal of Energy Storage. "Hydrogen gas diffusion behavior and detector installation optimization of lithium ion battery energy-storage cabin." H2 detector warned 145 seconds before thermal runaway; 1,493 ppm H2 measured outside pack. Link
NFPA 855, 2026 Edition. Standard for the Installation of Stationary Energy Storage Systems. Mandates combustible gas detection including hydrogen. Analysis
NFPA Journal. "Lithium-Ion Battery Fire Learnings from FDNY." August 2025. Link
FDNY Commissioner Robert S. Tucker. Statements on uncertified lithium-ion batteries. October 2024. Link
CPSC. Warning on Rad Power Bikes batteries (non-UL-certified). 2026. Link
NYC Local Law 39 (2023). UL certification requirements for e-bike batteries. Link
UK Office for Product Safety and Standards. "Fires in E-bikes and E-scooters 2024." 45% from aftermarket conversion kits, 20% from factory-built. Link
NYC DOT. E-Bike Trade-In Program. 2025. Link
Last updated: April 2026. Data snapshot reflects NYC Open Data as of query date. Source code and data on GitHub.