The Duration of ventilation when gas releases in containers is difficult to predict

Many people do not realize that dangerous gases are released from goods inside of sea containers. For Arjen van Perk, Operations Support Coordinator at EWS Gas Measurement, this is a daily routine. How much dangerous gas will be release in a sea container cannot be predicted, but accidents and damage can be prevented. Arjen explains how.

The first question is how these dangerous gases actually arise. “A little knowledge of physics and chemistry is useful, Arjen warns. “In the production of goods, there is a frequent use of solvents”. As the temperature in a sea container increases, the speed of the molecules of these solvents increases and will escape from the product. This is called “desorption”. There is very little ventilation in a sea container so these molecules will accumulate in gaseous form. The concentration will possibly increase during transit.

Limit value
Due to progressive insight, limit values ​​of various substances are regularly adjusted downwards. After extensive research at European level, limit values are set for additional gases. A common gas that has been found in recent years, for example, is ethylene oxide (EtO). This substance is often used to sterilise medical products.

The gases in a closed sea container will release when the container is unloaded. These potentially dangerous concentrations of gas can be inhaled by logistics personnel who have to unload the containers. In the long term, this can be very harmful to health. The gases can adversely affect fertility and cause hereditary changes and / or cancer. This certainly applies to the so-called CMR substances. The gases found in containers that have been “fumigated” with Methyl Bromide, Phosphine and Sulfuryl difluoride against insects can even result in instant death. “The concentrations of gases cannot be predicted, so measuring and ventilating when the concentration is to high is the best option to prevent damage to health,” says Arjen.

It is difficult to predict how long ventilation will take. It has to do with the level of the gas concentration at the start of the ventilation, the temperature and how the cargo is loaded inside the sea container. When a sea container is full of boxes, it is still difficult to achieve efficient air circulation with a fan. Goods that are composed of fiber material and glue such as chipboard, will continue to evaporate gases even after ventilation for a longer period of time. “If it appears that ventilation of the container has no effect, we can unload the container for the customer with the use of  respiratory protection” , says Arjen.