Manhole vs. Manway — What's the Difference?

Manholes are primarily designed for accessing and maintaining underground public utilities like sewers, electrical, and telecommunications. They are typically found on roads or sidewalks, featuring heavy covers that can withstand traffic and protect pedestrians. These covers are often made from materials like cast iron or reinforced concrete to ensure durability and safety. On the other hand, manways are access points used for entering closed vessels or tanks, often found in industrial or chemical plants. Unlike manholes, manways are designed to allow workers to access the interior of tanks, reactors, or other large containers for maintenance, cleaning, or inspection purposes.

The design of manholes allows utility workers to enter the underground infrastructure for inspection, maintenance, or repair work. The size and shape of manholes can vary, but they are generally round to prevent the cover from falling into the hole. Manways can be found on the sides or tops of these vessels and are equipped with covers that can be bolted or clamped shut to ensure a tight seal. This is crucial in controlling the internal environment of the vessel, whether to maintain pressure, prevent leaks, or ensure safety against hazardous materials.

While both manholes and manways serve as entry points for maintenance and inspection, their applications and settings significantly differ. Manholes are associated with underground public utilities, requiring specific designs to accommodate traffic and pedestrian safety. In contrast, manways cater to the needs of industrial sectors, focusing on providing secure and controlled access to the interiors of vessels and tanks. The design considerations for each reflect their distinct functions, with manholes prioritizing accessibility and safety in public spaces, and manways emphasizing sealing and pressure control in industrial environments.

Another key difference lies in the regulatory and safety standards that apply to manholes and manways. Manholes must comply with municipal and transportation regulations, considering factors like load-bearing capacity and accessibility. These regulations ensure that manholes are safely integrated into public infrastructure. Meanwhile, manways must adhere to industrial safety and quality standards, which can include pressure ratings, material compatibility, and sealing requirements. The standards for manways are often dictated by the specific needs of the industries they serve, such as chemical processing, oil and gas, or food and beverage production.

The terminology and specificity of use further distinguish manholes from manways. The term "manhole" is widely recognized and used in the context of municipal and public utility access. In contrast, "manway" is a more specialized term, familiar within industrial and manufacturing circles, highlighting the sector-specific nature of its application. This linguistic distinction underscores the different worlds in which manholes and manways operate, from public streets to private industrial complexes.