Which type of tanks are characterized as non-pressure or low-pressure tanks?

The correct answer identifies non-pressure or low-pressure tanks as those rail cars with exposed fittings. These tanks are designed to carry liquids, typically hazardous materials, that do not require internal pressure to contain them safely. The design features of exposed fittings allow for easier access and transfer of materials but also indicate that these tanks are not built to withstand high internal pressures, which distinguishes them as low-pressure systems.

In this context, rail cars with exposed fittings generally transport materials such as fuel oils or chemicals, which are compatible with lower pressure containment. This characteristic is fundamental in the handling and emergency response for hazardous materials, as it influences how first responders approach potential leaks or spills.

The other options, such as the MC 306/00T 406 tanks, intermodal containers, and ISO tanks, are designed with varying degrees of pressure tolerance. The MC 306/00T 406 tanks, for example, are often used for carrying flammable liquids and are typically constructed to be capable of withstanding some level of pressure or vacuum, thus not classifying as low-pressure tanks. Similarly, intermodal containers and ISO tanks are built for shipping across different transport modalities and can be designed to handle both pressure and non-pressure contents.

Understanding these distinctions is crucial for effective emergency