5.2 Blast condition
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Offshore Units, July 2022 - Part 10 Ship Units - Chapter 2 Loads and Load Combinations - Section 5 Accidental loads - 2 Blast condition

5.2 Blast condition

5.2.1  Global loads.
  1. The blast condition is to be assessed for the following load combinations of blast pressure and global loads:
    1. Blast pressure + Permissible still water hogging bending moment for the operational condition.
    2. Blast pressure + Permissible still water sagging bending moment for the operational condition. Loading conditions where there is no risk of blast loads need not be included in the calculation of the permissible still water bending moments for the blast assessment.

    Environmental loads need not be considered. See also Pt 4, Ch 3, 4.16 Accidental loads.

5.2.2  Pressure.
  1. Generally, the blast pressure is a rapidly propagating pressure or shock-wave in the atmosphere, with high pressure, high density and high particle velocity.
  2. The design blast pressures are to be defined by the Owners/designers and are to comply with National Regulations.
  3. Design calculations are to be submitted which may be based on elastic analysis or elastoplastic design methods.
5.2.3  Assessment.
  1. Assessment of the potential fire loadings and blast pressures are to be based on the specific hazards associated with the general layout of the unit, production and process activities and operational constraints. For assessment of the post accident condition, the static loads may be reduced if damage control or recovery measures are implemented, see Pt 4, Ch 3, 4.3 Load combinations 4.3.1.
  2. The blast load case is applicable primarily to the upper deck, deck-house and turret boundary. The pressures acting on the opposite side of these structures to the blast load (ballast water pressure, inert gas pressure, etc.) may be ignored when assessing the local scantlings but the hull girder stresses (due to shear and bending) are to be included. The amount of damage to the structure following a blast is to be considered in the assessment.
5.2.4  Boundary bulkheads and main decks.
  1. Particular consideration is to be given to the potential effects of fire and blast impinging on exposed boundary bulkheads of accommodation spaces and main decks. Where boundary bulkheads and main decks can be subjected to blast loading, the scantlings are to comply with Pt 4, Ch 3, 4.16 Accidental loads 4.16.9.
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