Larger primary devices (and transitions) that do not readily fit into a standard precast manhole barrel, either a larger barrel or a concrete vault must be used which adds cost. Packaged metering manholes, on the other hand, can integrate primary devices that are larger than the manhole barrelwith any portion that doesn't fit inside the manhole barrel extending upstream or downstream as necessary. Those portion that extend upstream / downstream of the barrel are manufactured with integral covers and laminated into the manhole structure. It is this ability to incorporate primary devices larger than the manhole barrel allows packaged metering manholes to be equally if not less expensive than a precast manhole or vault.
