Ship's ladders. Steep-pitch access for equipment, platforms, low-traffic areas.
When floor space is tight and the destination doesn't carry general occupant load — equipment platforms, mezzanine maintenance access, low-traffic upper levels — a steep-pitch ladder is the right tool. Code-defined as an alternative to a stair, not a substitute, with specific use-case limits we confirm at site measure.
- Pitch (angle)50° – 70° from horizontal
- Width24" – 36" (600 – 900 mm)
- Treadsopen, grip-strut / bar-grate
- Handrailsboth sides + pivot-arm at top
- CodeOBC §3.4.6 alt-stair · OSHA 1910.25
Full breakdown in the ship's ladder dimensions & angles guide.
Alternative-stair use cases.
OBC §3.4.6 treats ship's ladders as alternative stairs for limited-access situations only. They are not interchangeable with code-required egress stairs — see egress staircases for general-occupant-load exits. Where a ship's ladder is appropriate, the floor-space saving over a 35° stair is significant.
Ship's ladder vs stair vs fixed ladder
The deciding factor is pitch — the angle from horizontal — and who uses the access. The steeper the pitch, the smaller the footprint, but the narrower the allowed use.
| Type | Pitch | Use case | Code |
|---|---|---|---|
| Standard stair | ≈ 30° – 38° | General occupant egress, routine traffic | OBC §3.4.6 |
| Ship's ladder | 50° – 70° | Equipment / maintenance access, no general occupant load | OBC §3.4.6 alt-stair · OSHA 1910.25 |
| Fixed ladder | 75° – 90° | Vertical access — tank tops, roofs, silos | OSHA 1910.23 · cage rules |
Approved use cases
- Equipment-platform access — service access to a single platform for maintenance.
- Mezzanine maintenance access — secondary access to an unoccupied mezzanine deck for pick / restock or service.
- Low-traffic upper levels — spaces not regularly occupied, where a full stair isn't justified.
- Tank-top or process-equipment access — typically paired with a cage ladder for the upper segment.
What they don't do
- Code-required egress — ship's ladders cannot serve general occupant load.
- Public access — buildings open to the public require code-compliant stairs.
- Frequent traffic — steep pitch is fatiguing; for routine multi-trip-per-day traffic, a real stair is better.
Detail options
- Tread surface — grip-strut by default; bar-grate where water shed matters.
- Pivot-arm rail — handrail extends past the top tread for hand-over-hand transition; we detail it on every ship's ladder.
- Pitch — 50° – 70° typical; specific pitch tuned to floor space and code requirement.
- Width — 600 mm – 900 mm depending on use case.
Typical parameters
- Pitch50° – 70° from horizontal
- Rise range3 ft – 18 ft
- Width600 mm – 900 mm
- Treadgrip-strut / bar-grate
- Handrailboth sides, with pivot-arm extension
- Live load4.8 kPa + 1.3 kN concentrated
- Finishshop primer / galvanized
- Lead time3 – 5 weeks from sign-off
- All steel stairs & industrial stair systems
- Cage ladders — for vertical access above ~70°
- Egress staircases — when occupant-load egress is required