The current technique of tunneling is based on the use of a tunnel-boring machines or TBM. The TBMs are equipped by cutting head tools that require special care. In pressurized TBM, the environment around the cutting wheel (TBM’s excavation chamber) is maintained at pressure higher than the atmospheric in order to offer a supporting pressure to the tunnel face, thus to ensure the tunnel stability, and the excavation process. Maintenance work is carried out in hyperbaric conditions, which represent a risk of decompression sickness and air embolism. Thus, the personnel in charge of the maintenance of the cutting wheel in hyperbaric environment should be not only qualified for the specific mechanic work but must be selected and trained to perform its duty in hyperbaric condition. All workers operating in compressed air environment are defined as CAWs (Compressed Air Workers) and must be selected after special physiological tests and qualification course. They must undergo periodic medical review, to evaluate their actual physical condition and predict any possible developing of dysbaric illness.
Since work in compressed air inside tunnels is becoming more common due to the abrupt expansion of pressurized mechanical tunnel boring techniques, this demands regulation and a specific manual for the managementsof activities, given the particular working conditions and risks the compressed air workers (CAWs) face performing their usual tasks, both they and the employers who hire them and the professionals who must ensure their physical and mental integrity.
The authors share the experience and knowledge of medical support, occupational health and safety, promoting technological advancement and ethical principles of practice in tunnel construction. Health prevention measures in times of pandemic receive special attention in this edition.