ISO 23780-1:2023

Overview

ISO 23780-1:2023 - Ships and marine technology: Procedure for testing the performance of continuous monitoring TRO sensors used in ships - Part 1: DPD sensors - specifies laboratory test methods and requirements to verify the performance of continuous Total Residual Oxidant (TRO) sensors that use the N,N‑diethyl‑1,4‑phenylene diamine (DPD) colorimetric method. The standard addresses shipboard environmental challenges (high salinity, vibration, humidity and temperature variation, sea conditions) and is intended for use prior to installation in Ballast Water Management Systems (BWMS) or other shipboard locations.

Key technical topics and requirements

ISO 23780-1:2023 defines the test scope and procedures, including:

• Measurement procedure determination and instrument calibration using defined standard and span solutions.
• Preparation for tests: confirmation of effective chlorine concentration, preparation and verification of chlorine standard solutions, and reagent validity testing.
• Interference assessment for shipboard and marine waters, including:
  • Salinity effects
  • Manganese compounds
  • Colour and turbidity (shadowing/particle effects)
  • Dissolved oxygen and temperature influences
• Pre-test checks and method/specification checklists (abnormal water level, sample temperature).
• Performance tests such as:
  • Linearity, zero drift, and span drift
  • Method detection limit (MDL) and repeatability
  • Response time and total performance under varying conditions
• Environmental tests for shipboard suitability: vibration, humidity/temperature cycling, Ingress Protection (IP) testing, and explosion-atmosphere considerations (IEC 60079 referenced).
• Documentation and test reporting requirements for conformity demonstration.

Practical applications and users

ISO 23780-1:2023 is practical for organizations involved in ballast water treatment and onboard oxidant monitoring:

• BWMS manufacturers - validate TRO sensor performance before system integration.
• Sensor manufacturers - pre‑qualification and type-approval evidence for DPD TRO sensor units.
• Testing and calibration laboratories - perform standardized laboratory tests consistent with ISO/IEC 17025 competence.
• Ship owners and operators - verify that installed TRO sensors will perform reliably for oxidant dosing at uptake and neutralization at discharge to meet operational and regulatory requirements (e.g., IMO BWM Convention compliance).

The standard helps ensure reliable, real-time TRO monitoring in marine environments where salinity and other interferences can affect DPD colorimetric measurements.

Related standards

Relevant normative references cited in ISO 23780-1:2023 include:

• ISO 7393‑2 (colorimetric DPD method)
• IACS UR E10 (type approval)
• IEC 60529 (IP Code)
• IEC 60079 (explosive atmospheres)
• ISO/IEC 17025 (laboratory competence)

Keywords: ISO 23780-1:2023, TRO sensors, DPD sensors, ballast water management system, BWMS, total residual oxidant, sensor performance testing, marine salinity, IMO compliance.