By a factor of how many times the full weight must lifting handles of portable gas containers withstand?

The correct answer indicates that lifting handles of portable gas containers must withstand a load that is five times the full weight of the container. This requirement is in place to ensure safety and reliability under various conditions that may occur during handling, such as dropping or jerking motions. The added factor accounts for dynamic forces that might be experienced beyond the static weight of the container when lifting or maneuvering it.

In the context of portable gas containers, this is especially critical as they can contain flammable liquids. Therefore, ensuring that the lifting handles can withstand a significant overloading factor helps prevent failures that could lead to spills or accidents.

While other options suggest different multiplying factors, five times the weight is established as a standardized safety measure across various guidelines and best practices in handling hazardous materials. This level of safety margin is typically adopted to provide greater assurance that the equipment will function safely even under unexpected conditions.