Multiplace Hyperbaric Chambers from ETC are developed to offer secure and productive clinical hyperbaric oxygen therapy (HBOT) and diagnosis for diving accidents. The chamber and its subsystems meet or surpass engineering design and fabrication standards as demanded by ASME PVHO-1 and NFPA 99, Chapter 14, Health Care Facilities. It is designed to offer treatment for many patients together. Its 6/2/6 and 12/2/6 two-compartment, 6-ATA systems are set to offer treatment for up to six or twelve patients respectively. When in the main compartment, the 6/2/6 system can be converted to hold two patients in lying face upwards position and the 12/2/6 system can be converted to hold four supine patients with supine position. Entry compartment acts either as a two-patient extension of the main compartment or as a personnel transfer lock. The large diameter inside the main compartment and rectangular doorway into the main compartment offers comfortable placement and simple access for patients and staff members. The chambers come with seats and bunks which can be modified rapidly to change inside design of the chamber to meet treatment requirements.