This standard BS ISO 5894:2018 Ships and marine technology. Manholes with bolted covers is classified in these ICS categories:
47.020.10 Hulls and their structure elements
This document specifies requirements for watertight and oiltight manholes of the current types with bolted covers, for general shipboard use other than for pressure vessels.
It specifies the dimensions for the holes in the plating and the number, size and position of the fasteners.
It is applicable to manholes of raised coaming, surface mounted or recessed cover types.
The details of the manholes are at the discretion of the manufacturer.