The multi-place hyperbaric chambers allow the simultaneous treatment of multiple patients, on-site medical assistance, use of diversified equipment.
Pressurization is carried out with air and oxygen is administered to the patient through special devices.
Multiplace chambers of varying sizes are in use, capable of allowing simultaneous treatments from two to twelve patients; in particular pressurized environments, it is even possible to perform surgery.
The newer models in use consist of two separately compressible chambers:
- a "main room", which allows the upright position, the introduction of at least one patient on stretcher and comfortable assistance to patients;
- an "airlock" or "sentry box", which allows, by equalizing the pressure between the two chambers, the transfer of people in and out without interrupting the pressurization in the main chamber.
The main room and the sentry box are separated by a closing door.
The fundamental structure of a hyperbaric chamber consists of a metal cylinder ("hull"), closed at the end by convex or flat doors which generally house the access openings to the interior.
These openings are often circular, more recently they have been built rectangular to allow entry to stretchers or wheelchairs.
All the chambers are equipped with an "object pass" consisting of a cylinder passing through the hull wall, welded to it and equipped with two hatches, one outside and one inside the chamber.
The doors can be fixed to the cylindrical body with various methods and each of them has a small valve that allows to balance the pressure present on the opposite interface of the door.

The principle of use is very similar to that of the sentry box, in fact, it is possible to generate the pressure present in the chamber and the pressure of the external environment inside the glove box.
Other structural elements of the hull are the closing doors of the access passages, with autoclave seal, in the sense that, opening towards the inside of the hull, it is the same pressure that keeps them firmly in the closed position by pushing them against the appropriate impact surface equipped with rubber gasket.
There are also portholes that allow visual communication and possibly the necessary lighting. In addition to the porthole, the lighting can be brought inside by optical fibers, or similar elements, deriving from sources located outside.
The control panel or panel is the structure that houses all the equipment necessary for the use of the room. Generally it is similar to a metal cabinet, on the front there are the maneuvering devices and the control instruments.
The main operating organs of a hyperbaric chamber are the air shut-off, delivery and discharge valves.
They regulate the necessary flow rate of fluid both in compression (pressurization) and in decompression (depressurization) in the main chamber and in the sentry box.
The calibrated opening of these valves allows, during the pressurization phase, the entry of compressed air, coming from the storage tanks, and in decompression it allows the exit until the desired pressure is reached.