ISO 5779:1987

Overview

ISO 5779:1987 - "Shipbuilding - Ordinary rectangular windows - Positioning" specifies allowable positions for ordinary rectangular windows (as defined by ISO 3903) on passenger and cargo ships intended for international voyages. The standard defines geometric and strength-related limits, provides a formula for calculating the required design pressure (Annex A) and supplies simplified graphs for window positioning (Annex B). It is intended to ensure window placement meets load-line, freeboard and structural-safety requirements.

Key topics and technical requirements

• Scope: Applies to ordinary rectangular windows on passenger and cargo ships; annexes A and B are integral parts of the standard.
• Positioning rules:
  • Windows must not be installed below the freeboard deck or in the first tier of superstructures/deckhouses whose sides are within 1.2 m of the ship’s side.
  • Additional restricted zones are defined relative to curves derived from Graph No. 1 (Annex B).
  • Position depends on ship length (L), sill height above the Summer load line (y), and wall orientation (fronts, sides, aft ends).
• Strength limits:
  • The lowest permissible sill position is governed by the design pressure borne by the window vs. the window’s maximum allowable pressure (table of allowable pressures is provided for ISO 3903 window sizes/types).
  • Windows that cannot withstand calculated design pressure must be positioned higher or protected.
• Shutters and protection:
  • First-tier deckhouses providing access to spaces below the freeboard deck require permanently attached shutters.
  • Second-tier windows giving direct access to first-tier superstructures or below-freeboard spaces must be protected by shutters (portable shutters may be permitted if approved).
• Design-pressure calculation:
  • Annex A gives the calculation method (formula) including factors for height (a), longitudinal distribution (b), probability (f) and breadth (c), using ship parameters (L, block coefficient, breadth).
• Graphical method:
  • Annex B provides Graphs 1–4 for quick determination of minimum sill heights for ISO 3903 window types E and F, using a scale drawing and plotted ordinates.

Applications and users

ISO 5779:1987 is used by:

• Naval architects and ship designers for window placement and structural compliance
• Shipyards and outfitting engineers specifying window installations
• Classification societies and regulatory authorities assessing conformity with IMO load-line rules
• Window manufacturers and suppliers verifying allowable window types and required protection
• Ship owners and ship managers planning retrofits or safety upgrades

Related standards

• ISO 3903 - Ships’ ordinary rectangular windows (window types, sizes, glass thickness)
• IMO - International Convention on Load Lines (1966) - referenced for Summer load line and freeboard
• IACS Requirement S3 - Strength of end bulkheads (source of adopted pressure formula)

Keywords: ISO 5779:1987, shipbuilding, rectangular windows, positioning, ISO 3903, design pressure, freeboard, shutters, load line, Annex A, Annex B.