What type of loading arms are not permitted for LHGs?

Pressurized loading arms are not permitted for liquefied hazardous gases (LHGs) due to the potential risks associated with safety and environmental hazards. In the context of handling LHGs, using pressurized systems can increase the likelihood of leaks and catastrophic failures, especially when dealing with substances that have low boiling points and can vaporize rapidly at atmospheric conditions. This risk is particularly critical during loading and unloading operations, where rapid changes in pressure can exacerbate the danger of leakage.

In contrast, other types of loading arms, such as gravity loading arms and those with flexible joints, are typically employed because they can mitigate some of these hazards rather than increase them. Gravity loading arms utilize the weight of the liquid to transfer product without the need for pressurization, thereby reducing the risks associated with high-pressure systems. Loading arms with flexible joints can accommodate movement and shifts in positioning of the vessel during loading while ensuring a secure connection, reducing the potential for strain and breakage that could lead to leaks.

The allowance of other types of loading arms reflects a commitment to safety in handling LHGs and avoidance of high-risk systems whenever possible.