When can a ship's ladder be used instead of a regular stair?

OBC §3.4.6 (Stairs) permits steep-pitch alternative stairs only for specific limited-access situations — equipment access, low-occupancy maintenance platforms, and access to spaces not regularly occupied. The applicable use cases are spelled out in §3.4.6 sub-clauses (verify the current edition for your project). They cannot replace a code-required egress stair serving general occupant load. We confirm the use case at site measure before drawing.

What's the maximum pitch for a ship's ladder?

Industrial ship's ladders typically run 50° – 70° from horizontal; OBC and OSHA both define ranges where a steep-pitch ladder qualifies as an alternative to a stair. Above ~70° it transitions into a fixed ladder — see cage ladders .

Do ship's ladders need a guardrail?

Yes — both sides, with handrails sized for the steep pitch. Guards transition into the upper landing guard at the top, with no gap below 42" along the access path.

Ship's Ladders — Steep-Pitch Industrial Access

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.

Where they apply

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.

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

Ship's ladders. Steep-pitch access for equipment, platforms, low-traffic areas.