Stair (ISO 14122-3)

Straight steel stair after ISO 14122-3: UPN channel stringers with level-cut feet on anchored cleats, bar-grating treads with yellow chequer nosings and bolted end plates, even risers near 180 mm with the going set by the pitch, an intermediate landing on posts for every 3 m of rise, and handrails with knee rails on both sides. Foot (first riser) at the origin on y = 0, climbing along +X; the upper floor edge is at x = run = (round(rise/0.18) − 1) × going per flight, plus landingLength per intermediate landing. Optional free-standing top landing.

Installation

Copies structure/stair.tsx and the shared lib/ into src/components/deck-twin/. Needs three, @react-three/fiber and @react-three/drei. See installation for the manual route.

Usage

import { Canvas } from '@react-three/fiber'
import { OrbitControls } from '@react-three/drei'
import { Stage } from './components/deck-twin/lib/stage'
import { Stair } from './components/deck-twin/structure/stair'

export default function Scene() {
  return (
    <Canvas shadows camera={{ position: [8, 5, 9], fov: 35 }}>
      <Stage>
        <Stair />
      </Stage>
      <OrbitControls makeDefault />
    </Canvas>
  )
}

Props

P&ID

Plan view: a rectangle filled with parallel tread lines and an arrow along it labelled UP (or DN), often with a break line half-way.

Layout plan convention (structural / plot plan drawings); ISO 14122-3

Rungs at close spacing with a circle around them is a caged ladder seen in plan. Not on P&IDs.

Typical suppliers

Fabricated to project specification. The geometry is generic and sized from public standards. It is not vendor CAD.

For agents

Machine-readable entry with props, ranges, defaults and ports:

Or fetch /r/stair.json, or copy a ready-made instruction:

Add the Deck Twin "Stair (ISO 14122-3)" component to this project. Run `npx -y https://decktwin.com/cli/deck-twin-0.2.2.tgz add stair` (it copies the file and the shared lib into src/components/deck-twin/), then `npx -y https://decktwin.com/cli/deck-twin-0.2.2.tgz info stair` for its props, ranges and ports. Render <Stair /> inside a React Three Fiber <Canvas shadows>, wrapped in <Stage> from src/components/deck-twin/lib/stage. Set props from my data (metres, NPS in inches, ASME class) and leave the rest at defaults. Install three, @react-three/fiber, @react-three/drei and @types/three if they're missing. Full guide: https://decktwin.com/skill/SKILL.md