How much should manhole covers weigh to require tools for opening?

Manhole covers typically need to weigh a certain amount to ensure safety and security, as well as to prevent unauthorized access. A weight of 100 lbs is significant enough that it generally requires the use of tools—such as a lift or hose— to facilitate safe handling. Covers of this weight can be cumbersome and difficult for a person to lift manually without risk of injury.

The rationale for designating 100 lbs as the benchmark is based on ergonomic considerations; it is heavy enough that it poses potential outweighing risks for manual lifting by an average person. Lighter covers, such as those weighing less than this amount, may be manageable for individuals without assistance, whereas heavier covers would likely necessitate tools or additional equipment to ensure safe opening and closing.

In the broader context, ensuring that manhole covers weigh at least 100 lbs helps to prevent vandalism, unauthorized entry, or accidental dislodging, thus contributing to the safety and integrity of our infrastructure.