Overview
ISO 5894:2018 - Ships and marine technology - Manholes with bolted covers - specifies requirements for watertight and oiltight manholes with bolted covers for general shipboard use (excluding pressure vessels). The standard defines nominal sizes, dimensional details for openings, and the number, size and position of fasteners for common manhole types (raised coaming, surface-mounted and recessed covers). It also covers material, manufacturing quality, gasket requirements and interchangeability of components.
Key topics and technical requirements
- Scope and types: Applicable to manhole types AO, AE, BO, BE, CO, DO (raised coaming, surface mounted, recessed).
- Dimensions and nominal sizes: Clear opening sizes (l × b) and associated dimensions are given in the standard’s figures and tables for each type and nominal size; dimensions are in millimetres.
- Fasteners and coordinates: Number, size and positioning of bolts/nuts are specified, with recommended fastener coordinates listed (see Table 7). Threaded fasteners follow ISO 262 metric thread selection. Examples in the standard reference M20 fasteners (hole Ø23 mm) and auxiliary fastener sizes.
- Material and strength: Cover plate, ring/coaming, bolts and nuts must be marine-approved material with a minimum yield strength of 235 N/mm². Corrosion-resistant equivalents are permitted.
- Gasket requirements: Gasket materials must be suitable for oil, seawater and freshwater service and free from asbestos.
- Manufacturing and quality: Surfaces must be flat, free from pitting and safe to handle; dimensional accuracy (cover, gasket, hole spacing) must ensure interchangeability. Marking, handles and jacking-up bolts details are included for practical use.
- Designation: Standardized designation format (e.g., “Manhole cover ISO 5894 - AO - 600×400-8”) is provided.
Applications and who uses it
ISO 5894:2018 is used across the maritime sector wherever standardized, watertight or oiltight manholes are required:
- Shipbuilders and shipyards for fabrication and outfitting
- Naval architects and marine designers specifying access openings
- Manhole and gasket manufacturers ensuring interchangeability
- Classification societies and regulatory bodies referencing dimensional and material criteria
- Ship operators and maintenance crews for repair, replacement and inspection guidance
Benefits
- Ensures interchangeability of covers, gaskets and fasteners
- Improves safety and watertight integrity in shipboard compartments
- Provides clear manufacturing and inspection criteria to reduce field rework
Related standards
- ISO 262 (metric screw threads - selected sizes for screws, bolts and nuts) - referenced for fastener threads.
- Note: Classification society rules and regulatory conventions may require higher material thickness or additional requirements; consult applicable class rules.
