Overview
ISO 8861:1998 - Shipbuilding: Engine-room ventilation in diesel‑engined ships specifies design requirements and calculation methods for ventilation of engine rooms on diesel‑engined ships under normal conditions. The standard defines design assumptions (e.g., ambient air +35 °C and a maximum engine‑room temperature rise of 12.5 K), gives formulae for required airflow and heat‑load calculations, and includes an informative Annex A with guidance and good practice for ventilation layout.
Key topics and technical requirements
- Design conditions
- Outside ambient air temperature assumed +35 °C.
- Maximum temperature rise from intake to casing entrance 12.5 K.
- Ventilation must supply combustion air, maintain comfortable working conditions and protect heat‑sensitive equipment.
- Total airflow (Q)
- Q must be at least the larger of:
- Combustion airflow (qc) + airflow for heat evacuation (qh)
- 1.5 × combustion airflow (i.e., combustion airflow plus 50%)
- Airflow for combustion
- Calculated per machinery group (main propulsion, diesel generators, boilers) using service standard power, air‑fuel mass ratios and air density r = 1.13 kg/m3 (at +35 °C, 70% RH).
- Guidance values for air requirement m_ad: 0.0023 kg/(kW·s) for 2‑stroke and 0.0020 kg/(kW·s) for 4‑stroke engines when manufacturer data are unavailable.
- Airflow for heat evacuation
- Based on summed heat emissions from engines, generators, boilers, pipes, electrical installations, exhausts, tanks and other components.
- Formula uses a factor 0.4, specific heat c = 1.01 kJ/(kg·K) and ΔT = 12.5 K.
- Heat emission calculations
- Engine heat: f = P × Δh / 100 (Δh = percentage heat loss).
- Boiler and exhaust heat: given formulae and reference curves; values for fuel heating value and fuel consumption are referenced when manufacturer data are missing.
- Annex A guidance
- Air distribution recommendations (approx. 50% delivered near top of main engines/turbocharger inlets).
- Maintain slight positive engine‑room pressure (normally ≤ 50 Pa).
- Separate exhaust for purifier/fuel‑oil separator rooms.
Applications and who uses this standard
- Used by naval architects, shipbuilders, marine HVAC designers, marine engineers, classification societies and regulatory compliance teams to:
- Size ventilation fans and ducting for engine rooms.
- Verify combustion air supply and heat‑removal capacity.
- Ensure crew comfort and protection of heat‑sensitive equipment.
- Support design reviews, equipment specification and certification.
Related standards
- ISO 31 (Quantities and units), ISO 3046‑1 (reciprocating engine performance), ISO 3258 (air distribution vocabulary) are normative references cited in ISO 8861:1998 and should be consulted where detailed unit conventions and engine performance data are needed.
Keywords: ISO 8861:1998, engine‑room ventilation, diesel‑engined ships, ventilation design, airflow calculation, heat emission, shipbuilding standard, marine HVAC.