Pressure Vessel for Human Occupancy
The American Society of Mechanical Engineers defines a Pressure Vessel for Human Occupancy as a container that is intended to be occupied by one or more persons at a pressure which differs from ambient by at least. Since 1977, the ASME's PVHO committee has published standards governing the construction of a number of PVHO applications. The current design standard is PVHO-1-2023. The current code for maintenance and operation guidances is ASME PVHO-2-2019. Similar standards are published by a range of national and international standards organisations.
List of PVHO types
Types of pressure vessels for human occupancy include:- diving chambers
- decompression chambers
- closed diving bells, also known as dry bells or personnel transfer capsules
- high altitude chambers
- hyperbaric chambers
- hyperbaric stretchers
- medical hyperbaric oxygenation facilities
- recompression chambers
- submarines
- crewed submersibles
- atmospheric diving suits
- pressurized tunnel boring machines
Section 1-3 "Exclusions" specify nuclear reactor containments, aerospace cabins, caissons are not considered under the ASME PVHO-1 code. This is because each of those types of occupied pressurized chambers are under other jursidictions and therefore under other design codes. It is noted while "caissons" are under other applicable rules depending on the specific application, the Occupational Safety and Health Administration specifies the chambers in pressurized tunnel boring machines are under ASME PVHO-1 and any chamber used to decompress tunnel workers must meet ASME PVHO-1.