New York already opens hydrants in heat waves — 1,000 gallons a minute, pressure drops, DEP warnings. Mr. Palm Tree crowns the hydrant instead: a 3D-printed palm that mists a 20-foot canopy on about 1% of a spray cap's water, shades the sidewalk, and lifts off in 15 seconds when FDNY needs the hydrant.
Every design decision serves the one constraint that matters: a fire hydrant must stay a fire hydrant. The tree is a guest on FDNY's hardware.
Street pressure (30–90 psi, verified) lives in off-the-shelf brass at the outlet: swivel adapter → ball valve → 200-mesh filter → regulator at 40 psi → backflow preventer. The regulated line runs inside the structural riser. A printed part failing is a dribble, not shrapnel. The whole connector is now modeled in the CAD and shown in the 3D viewer.
The collar hangs on the bonnet flange above both hose outlets. The operating nut sits under a 70 mm wrench window. Pull one lynch pin, twist 25°, lift — the whole tree is off in under 15 seconds, no tools. Our feed unthreads like any hydrant cap.
NYC runs several hydrant castings across eras. Every dimension is a parameter in one OpenSCAD file; the only precision interface — the 2.5" New York Corporation thread — is a purchased brass part, never printed. EPDM foam absorbs the rest.
A physics test bench runs the whole system virtually: self-consistent hydraulics from street main to the frond-tip nozzles, and a Lagrangian droplet simulation — drag, evaporation, gusty urban wind — for the mist itself. First-order engineering physics, honestly labeled (not CFD), field-calibrated by design.
Drag street pressure, wind, temperature, and humidity. Watch a few thousand droplets respond in real time — and watch the readouts: nozzle pressure, flow, evaporate/land split, latent kilowatts, canopy ΔT, wet footprint.
One diagram carries the argument: the mount never blocks an outlet or the operating nut, printed parts never see street pressure, and the whole canopy rides the hydrant — the sturdiest anchored object on the block.
About a dozen unique printable parts (PETG for the body, ASA for the sun-baked load path — PLA is banned; it sags on exactly the day this matters) plus hardware-store brass. The trunk is one screw-together ring you print as many times as your height needs — a 6-ft minimum, taller by the ring. Full settings in the print guide below.
Mount set in ASA (collar ×2, legs ×4, hub plate, riser sleeve) — ~12 h. Trunk + crown in light-color PETG: the trunk base, a stack of identical screw-on rings (~10 for the 6-ft minimum), a crown adapter, then the crown. 0.6 mm nozzle, 0.3 mm layers.
EPDM-lined halves bolt around the bonnet flange with four M5s — load bears on the casting shoulder, above both hose outlets. Line stays paint-safe.
Four pivoting legs straddle the dome to the hub plate; clevis pivots self-align to any hydrant's dome angle. The 70 mm wrench window lands over the operating nut.
Base onto the bayonet, then hand-spin rings on one at a time (coarse thread, under a turn each — no tools) until you hit your height, 6 ft minimum. Feed line runs up the open core. Crown adapter, then crown hub with fronds, manifold, and topper.
Tree drops into the bayonet socket, twists 25°, lynch pin locks it. That pin is the FDNY quick-release — and the printed lugs are the designed sacrificial fuse.
Flush the hydrant 30 s → swivel adapter → valve → filter → regulator at 40 psi → backflow preventer → feed line up the riser. Open the valve (permit holder only) — mist on.
Core build (recommended): the rings stack in compression over a thin metal tension core (½" EMT or an M10 rod) that pre-loads the stack into a rigid mast; the feed line runs inside the core. Add rings for true toolless height. Sleeve build: the same rings are cosmetic screw-on sleeves over a cut-to-length 1-1/4" PVC riser that carries the load — lowest risk, height capped by the pipe you cut. The FDNY bayonet quick-release lives at the base and is independent of ring count — a taller tree lifts off exactly the same.
Pull lynch pin → twist tree 25° → lift off (<15 seconds, no tools). Wrench passes through the hub window onto the nut. Our feed adapter unthreads like a hydrant cap. Both outlets were never blocked to begin with.
| Claim | Value | Basis |
|---|---|---|
| Water use (street 30–90 psi, regulated) | 0.20–0.25 GPM | [SIM] hydraulics solve, flat across the verified band |
| DEP spray cap, for comparison | 20–25 GPM | [VERIFIED] NYC DEP |
| Illegally opened hydrant | 1,000+ GPM | [VERIFIED] NYC DEP |
| Latent cooling power | ~30 kW (≈10 window ACs) | [SIM] evaporated mass × latent heat |
| Spray that evaporates in NYC heat-wave air | 78–80% | [SIM] 95°F · 55% RH; the rest lands as felt mist |
| Felt mist reaching the occupied zone (3 m/s) | ~21% (+50% vs the crown ring) | [SIM] v0.4 frond-tip downspray |
| Canopy cooling, calm air | 7–8°C | [SIM] mixed-box; dilutes <0.5°C above 3 m/s wind |
| Street main pressure, NYC | 30–90 psi | [VERIFIED] location/time dependent |
| Hydrant thread | 2.5" New York Corporation (not NST) | [VERIFIED] buy the brass adapter, never print threads |
[SIM] = first-order physics bench (sim/mist_sim.py), constants field-calibrated via the catch-cup protocol before any number goes in a contract. [VERIFIED] = sourced in the project research file.
The whole design is parametric OpenSCAD — measure your hydrant, set a few numbers, export. Set trunk_mode (core or sleeve) and min_trunk_height (6 ft default); the trunk is one screw-on ring you print as many times as your height needs. The pack is the v0.5 defaults (placeholder hydrant dimensions; test-fit before batch printing).
The city already sanctions hydrant cooling: FDNY firehouses hand out spray caps every summer, and NYC Parks' Cool It! program is actively adding cooling elements — including hydrants adapted as misting features. Mr. Palm Tree productizes the city's own program line, at roughly 1% of the water.
| Buyer | Why them | Speed |
|---|---|---|
| Business Improvement Districts | Private budgets, control plazas, love photogenic amenities — pilot under a DEP hydrant-use permit | Days–weeks |
| NYC Parks | Cool It! NYC already adapts hydrants into misting features — this is shovel-ready product for their line | Weeks |
| NYC DEP | Owns street hydrants + the spray-cap program; the water math is their headline | Months |
| Council / Participatory Budgeting | Visible, district-level, equity-mappable cooling (Heat Vulnerability Index targeting) | Budget cycle |
| NYCEM heat emergencies | Emergency procurement moves fast when a heat emergency is declared — be pre-piloted and pre-priced | Event-driven |
A pilot pack — three trees, install, removal, season maintenance, and a data report — prices under NYC's $20,000 micro-purchase line: an agency can buy it with a signature, no competitive bid. The Partner page lays out the tracks for agencies, BIDs, and makers.