1 REQUIREMENTS
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Circulars - Maritime Safety Committee - MSC.1/Circular.1515 - Revised Design Guidelines and Operational Recommendations for Ventilation Systems in Ro-Ro Cargo Spaces - Part 1 - Design Guidelines for Ventilation Systems in Ro-Ro Cargo Spaces - 1 REQUIREMENTS

1 REQUIREMENTS

1.1 Definition of exposure limits and flammability limit

An exposure limit value means the highest acceptable average concentration (time-weighted mean value) of a substance or, in some cases, of a mixture of substances in the air breathed by the occupants. The concentrations are usually given in parts per million (ppm) or mg/m3. An exposure limit value refers either to a long-term exposure level or a maximum limit value. Short-term exposure level is also used.

Long-term exposure level, means the exposure limit value for exposure during the entire working day (normally 8 hours).

Maximum exposure level means the highest concentration reached.

A short-term exposure level means the time-weighted mean exposure value over a short period of 10 or 15 minutes, dependent on the national occupational exposure standards.

Lower Explosion Limit (LEL) means concentration of flammable gas, vapour or mist in air below which an explosive gas atmosphere will not be formed. Also known as Lower flammability limit.

1.2 Pollutants of interest

The exhaust gases generated by internal combustion engines contain hundreds of chemical substances. The main part of them are nitrogen (N2), carbon dioxide (CO2), oxygen (O2), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2) aldehydes such as formaldehyde, polyaromatic hydrocarbons such as benzo(a)pyrene and organic and particulate bound lead.

Among the pollutants emitted in the exhaust gases of petrol and diesel engines, CO is generally of the most significant concern for petrol engines and NOx for diesel engines. Lead, particulate matter (PM) and benzo(a)pyrene are also of a significant concern.

Knowledge of the effects of other pollutants to the health is at present insufficient. However, considerable research is being undertaken.

Monitoring of occupational hygiene should be planned and its results should be assessed by a qualified expert, with special training in this field. The studies should be carried out in cooperation with the monitoring staff, the management of the ship concerned and the relevant Administrations.

1.3 Rate of air change

Regulations II-2/19.3.4 and 20.3 of the 1974 SOLAS Convention, as amended, provides requirements for rate of air changes which are intended to limit maximum concentration of pollutants during loading and unloading and also to prevent a build-up of hazardous and flammable gases in the ro-ro cargo spaces when the ship is at sea with a cargo of motor vehicles. These regulations provide the minimum acceptable standards for ventilation.

Parent topic: Part 1 - Design Guidelines for Ventilation Systems in Ro-Ro Cargo Spaces
Copyright 2022 Clasifications Register Group Limited, International Maritime Organization, International Labour Organization or Maritime and Coastguard Agency. All rights reserved. Clasifications Register Group Limited, its affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as 'Clasifications Register'. Clasifications Register assumes no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant Clasifications Register entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.