ISO 23152:2021

Overview

ISO 23152:2021 specifies a standardized methodology for computational physical modelling of ultraviolet (UV) reactors used in ballast water management systems (BWMS). The standard addresses how to simulate UV reactor performance for scaling purposes - comparing a scaled reactor to a validated base reactor - and how to calculate the reduction equivalent dose (RED) using organism-specific dose–response data. ISO 23152:2021 supports manufacturers and verifiers in producing validated and verified computational fluid dynamics (CFD) models for UVBWMS (UV ballast water management systems) so untested treatment rated capacities (TRCs) can be justified for type approval.

Key topics and requirements

• Model validation and verification: Models must be verified against empirical data and validated to ensure they reflect physical constraints and perform as intended. The IMO requires validation of computational models used for scaling.
• RED calculation: Procedures to compute the UV RED from CFD dose distributions combined with organism UV sensitivity (biodosimetry or collimated-beam dose–response curves).
• Modelling elements:
  • Geometric modelling and meshing of the reactor domain.
  • Turbulence modelling options (RANS, LES, DES, DNS are defined concepts in the standard).
  • Radiation modelling and solving the radiative transfer equation (e.g., discrete ordinates approaches).
  • Dose calculation methods: Lagrangian particle tracking and Eulerian reacting tracers are described for residence time and dose integration.
• Scaling procedure and metrics: Steps and metrics for comparing REDs between base and scaled reactors, defining system design limitations (SDL), and identifying vulnerable scaled models for shipboard testing.
• Terminology and test organism specificity: REDs are organism-specific (e.g., MS2 phage, Tetraselmis sp.) and depend on lamp spectral output, water optical properties, and reactor hydraulics.

Applications and who uses this standard

• BWMS manufacturers: To justify TRC scaling claims and prepare documentation for type approval.
• CFD engineers and reactor designers: For developing validated computational models of UV reactors.
• Testing laboratories and biodosimetry labs: To link collimated-beam dose–response data with reactor simulations.
• Regulatory authorities and certifying bodies: For assessing model-based scaling evidence submitted for IMO/BWMS Code compliance.
• Shipyards and naval architects: When evaluating BWMS selection and integration based on validated performance across TRCs.

Related standards and guidance

• IMO BWMS Code (MEPC 72/17/Add.1 Annex 5) - type approval testing framework.
• IMO Guidance on Scaling of BWMS (BWM.2/Circ.33/Rev.1).
• IMO Ballast Water Management Convention Regulation D-2 (performance standard).

Keywords: ISO 23152:2021, ballast water management systems, BWMS, UV reactors, UVBWMS, RED, computational modelling, CFD, scaling, validation, verification, TRC.