Overview
ISO 5485:1986 is an international standard established by the International Organization for Standardization (ISO) that specifies the technical requirements and primary dimensions for fixed steel deck stairs used on inland vessels. This standard ensures consistent safety, performance, and design quality of stationary steel staircases installed on the decks of river and inland waterway ships. It excludes indoor stairs, outboard stairs, emergency stairs, and specialized staircases.
Developed by ISO Technical Committee 8 (Shipbuilding and Marine Structures), this standard supports the inland navigation sector by providing practical guidelines that enhance vessel safety and operational efficiency.
Key Topics
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Scope and Application
ISO 5485:1986 applies exclusively to fixed steel deck stairs on inland vessels. It is not intended for interior vessel stairs, gangways, emergency stairs, or any special-purpose staircases.
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Design and Construction Requirements
- Stairs must facilitate effective drainage of water, snow, and ice to maintain slip resistance.
- Steel steps (treads) are fabricated either by stamping anti-slip metal sheets, grating forms, or smooth steel plates equipped with anti-slip strips on the front edges.
- Steps should have an inward inclination between 1° and 20° to promote water drainage, except for grated steps which need no inclination.
- Absence of rear protective plates on stair stringers (limons) allows for optimal installation on ship decks.
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Materials and Fixing Methods
- Stringers (limons) are made from steel profiles in U-shapes, I-shapes, or other approved cross sections.
- Steps are welded or bolted securely to stringers. The entire stair unit is firmly anchored to the deck with support feet or equivalent fixing means.
- When steps are attached directly to a superstructure wall or bulkhead with adequate strength, welding can be done without additional stringers. Reinforcements may be added at welding points if necessary.
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Safety Features
- Fixed steel deck stairs must be equipped with guardrails attached to the stringers.
- Where the stair is adjacent to a bulkhead or ship structure, only the exposed side requires a guardrail.
- For passenger vessels, guardrails must be installed on both sides of the stairs to enhance safety.
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Dimensions and Tolerances
ISO 5485 defines key dimensional parameters:
- Stair inclination angles of 45°, 50°, or 55°, with recommendations favoring 45° for passenger vessels.
- Stair widths typically range from 600 mm to 1000 mm, with the exposed part of the step (tread) dimensions adjusted according to inclination.
- Step spacing and dimensions have a maximum allowed tolerance of ±3 mm for consistent installation quality.
Applications
ISO 5485:1986 primarily serves naval architects, shipbuilders, and safety engineers within the inland waterway shipping industry. Its specifications ensure fixed steel deck staircases in cargo ships, passenger ferries, tugboats, and other inland vessels offer:
- Improved Safety: Anti-slip surfaces and proper guardrails reduce fall risk during onboard movement.
- Durability: Using steel and sound welding practices ensures longevity even in challenging riverine environments.
- Operational Efficiency: Consistent dimensions and construction methods simplify maintenance and replacement.
- Regulatory Compliance: Adhering to the international standard supports meeting national and regional maritime safety requirements.
Related Standards
For a comprehensive approach to shipbuilding and inland vessel safety, ISO 5485 should be considered together with other maritime standards, including but not limited to:
- ISO 3874 – Shipbuilding and marine structures - Single ladders, vertical ladders, and their tests.
- ISO 13857 – Safety of machinery - Safety distances to prevent hazard zones being reached by upper and lower limbs.
- National inland navigation regulations pertaining to vessel construction and passenger safety.
- ISO 14691 – Shipbuilding - Navigation signs and signals.
By integrating ISO 5485:1986 with complementary standards, stakeholders achieve higher safety and design consistency across inland vessel stair structures.
Keywords: ISO 5485, fixed steel deck stairs, inland vessels, shipbuilding standards, maritime safety, steel stair dimensions, deck stair design, passenger vessel stairs, inland navigation safety, ship structure standards.
