ISO 12133:2021

Overview

ISO 12133:2021 - Small craft - Carbon monoxide (CO) detection systems and alarms - specifies requirements for the design, construction, performance, installation, marking and instructions for marine CO detectors and CO alarms on small craft (recreational boats up to 24 m). The standard also includes Annex A, which provides essential educational material on carbon monoxide hazards and recreational boating recommendations to reduce CO exposure.

Key Topics and Requirements

• Scope: Applies to CO detection and alarm systems for craft with enclosed accommodation compartments and sleeping spaces.
• Design & construction
  • Detectors shall meet relevant national standards (e.g., UL 2034, EN 50291-2:2019).
  • Audible alarm required; mute function limited (max 6 minutes) and protected from casual use.
  • No power switch on the detector; visual operation indicator required (LED/LCD).
  • Self-check circuitry with alarms for defective sensors or low battery; test procedure/switch required.
  • Environmental protection: IP rating 42 (drip proof) per IEC 60529.
  • Power: craft electrical system or self-contained battery.
• Performance
  • Detector performance tested against a beta (β) COHb curve (β ≤ 10%); alarm must occur within the illustrated beta curve region.
  • Operating temperature range: -40 °C to 70 °C.
• Installation
  • CO detection required for all craft with enclosed accommodation compartments and in each sleeping space separated by solid bulkheads.
  • Detectors must avoid areas of physical damage, dilution or poor circulation.
  • Hardwired detectors (no self-contained battery) must be powered from the continuously energized side of the battery switch; circuit breakers must resist inadvertent shut-off.
• Instructions & Markings
  • Provide installation/operation instructions, recommended testing frequency, manufacturer's service policy, and actions when alarm sounds (evacuate, ventilate, investigate, corrective action).
  • Mark with “Marine carbon monoxide alarm”, certification body name (if certified), and a replace-by date or lifespan statement.

Applications and Who Uses It

• Boat manufacturers and OEMs specifying on-board safety systems.
• Marine electrical installers and shipyards performing CO alarm installation and wiring.
• Detector manufacturers designing marine-grade CO sensors and alarms.
• Certification bodies, surveyors and regulators assessing compliance with marine safety standards.
• Recreational boat owners/operators seeking guidance on CO safety and detector placement.

ISO 12133:2021 is essential for improving onboard CO safety, ensuring consistent boat CO detection performance, and reducing the risk of CO poisoning in recreational boating.

Related Standards

• ISO 13297:2020 - Small craft electrical installations (AC/DC)
• IEC 60529:2013/Corr1:2019 - Degrees of protection by enclosures (IP Code)
• National detector standards such as UL 2034 and EN 50291-2:2019

Keywords: ISO 12133:2021, carbon monoxide detection, CO alarms, small craft, marine CO detectors, boat CO detection, recreational boating, installation requirements, performance specifications.