ISO 9785:2002 PDF

Overview

ISO 9785:2002 - Ships and marine technology: Ventilation of cargo spaces where vehicles with internal combustion engines are driven - specifies methods to calculate the theoretical outdoor airflow required to dilute vehicle exhaust in ship cargo spaces (e.g., RO‑RO and ferry decks) down to accepted occupational exposure limits (OELs). Annex A provides representative pollutant emission values (CO, NOx, HC, etc.); Annex B gives good‑practice guidance. The standard is aligned with IMO guidance (MSC/Circ.729) and requires simultaneous compliance with applicable statutory and class rules.

Key topics and technical requirements

• Airflow calculation criteria: choose the higher of (a) minimum air changes required by statutory rules or (b) outdoor supply necessary to maintain OELs.
• Per‑vehicle airflow model: required supply per operating vehicle is derived from pollutant emission rate, dilution factor and the OEL. The standard distinguishes calculations for normally polluted and highly polluted outdoor air.
• Pollutant data (Annex A): average emission rates for typical vehicle types (passenger cars, small/large trucks, coaches, diesel/spark engines) for CO, NOx, HC and NO2 under defined operating cycles (idling, transport, acceleration).
• Factors of dilution: recommended default dilution factors (e.g., 0.8 for general cargo, 0.4 for car carriers) to account for mixing and distribution of contaminants in the cargo volume.
• Volume definition: cargo space volume is gross internal volume (no deductions for fittings); use inside lining dimensions if present.
• Normative vs informative content: Annex A is normative (data for use); Annex B is informative (guidance and best practice).

Practical applications and who uses it

ISO 9785:2002 is used by:

• Naval architects and ship designers sizing ventilation systems for RO‑RO decks and vehicle decks
• HVAC and marine ventilation engineers performing airflow calculations
• Ship operators, terminal managers and safety officers preparing operational ventilation procedures
• Classification societies and flag states evaluating compliance with health and safety requirements
• Port authorities and consultants assessing on‑board air quality risks

Practical steps for application:

• Identify vehicle mix and expected simultaneous operation.
• Use Annex A emission values (or supplier data) to compute per‑vehicle pollutant generation.
• Select appropriate dilution factor and OEL, then calculate required outdoor supply airflow.
• Verify against statutory air‑change requirements and IMO MSC/Circ.729 guidance.

Related standards and guidance

• IMO MSC/Circ.729 - Guidelines and recommendations for ventilation systems in RO‑RO cargo spaces (referenced)
• National occupational exposure limit (OEL) regulations and ship‑specific statutory rules

Keywords: ISO 9785:2002, ventilation of cargo spaces, RO‑RO, airflow calculation, occupational exposure limit, CO, NOx, dilution factor, marine ventilation.