FAQ

The international crew of HydroWork GmbH has extensive practical experience in carrying out a wide variety of tasks in overpressure, underground on tunnel construction sites; even at high pressures.

• Worldwide support of tunnelling projects with specially trained personnel for any overpressure work
• Provision, design and construction of personnel and patient locks
• Customer-specific equipment of mobile treatment chambers
• Medical chamber maintenance
• Maintenance, refurbishment, and equipping of existing airlocks for personnel in tunneling
• Provision of mobile oxygen systems
• Provision of technology and first aid accessories
• Provision and delivery of equipment for work in overpressure
• Training courses

Our Equipment
We provide the right equipment for every project. Of course, our hyperbaric tunnel workers are equipped with state-of-the-art equipment. HydroWork also has the appropriate equipment to suit the customer’s requirements

All employees are qualified and have operational experience and can show current medical compressed air examinations. Our crew includes:

• Compressed air supervisors with a certificate of competence in accordance with the Compressed Air Ordinance (Hyperbaric Supervisors)
• Lock keepers and lock operators
• Compressed air technicians (Hyperbaric Technicians)
• Compressed air technicians for MixGas applications
• Diving work in bentonite
• Tunnelling personnel for TBM (tunnel boring machine) and AVM (overburden boring machine)

• Cutting wheel cleaning on the tunnel boring machine (TBM)
• Changing the cutting wheel tools of the TBM
• Welding work on the cutting wheel
• Diving in Bentonite
• Working with mixed gas at high pressures

Read more about our tunneling support

Our equipment
We supply special equipment for all underground work in compressed air worldwide:

• Mobile medical/ pressure chambers:
  • 40-foot container hyperbaric chambers (up to 6 places in main chamber, 2 in antechamber including doctor’s room)
  • 20-foot Container pressure chambers (Mobile Medical Chamber)
  • Hyperbaric chamber with round doors in a 20-foot container
• Oxygen emergency kit
• Oxygen Sensors
• Mobile Respiratory Oxygen System MSS 100
• Mobile breathing system for welding work
• Renovation of TBM locks
• Saturation systems
• Fire extinguishing systems
• Safe diving work in bentonite
• All diving equipment

We have projects in Germany, Europe, America and Asia. HydroWork is equipped for operations worldwide.

Are you interested in our previous tunnelling projects? On our homepage you will find a world map with our previous locations.

In tunnel construction, the working area in front of the machine is pressurized to create a counterpressure against soil and water pressure. This improves the stability of the tunnel face and reduces the inflow of groundwater.

How is compressed air generated?
Compressed air is generated by compressors that suck in air and reduce its volume. The pressure increases according to the physical relationship between volume and pressure.

Working under hyperbaric pressure means that people are in an environment where the ambient pressure is above atmospheric pressure. This requires special safety and decompression procedures.

Who is allowed to carry out compressed air work?
This special work may only be carried out by qualified and certified personnel. Staff must meet certain requirements and undergo regular occupational health check-ups. For example, G31 suitability (working under overpressure) is required. This certificate confirms that the persons are medically suitable for such activities. They also have recognised training and relevant experience, for example in the field of professional diving

There is a special and obligatory hierarchy for an optimal organization of compressed air work:

• The compressed air Supervisor. He is the reference person for the customer, colleague and doctor; he organizes everything related to compressed air as well as the commissioning and maintenance of the compressed air technology required on site
• The Lock Operator. He is the person in charge of controlling the Working Chamber, where people are channelled in and out, assisting the pneumatic workers and keeping in constant contact with them through a communication system.
• The Hyperbaric Tunnel Worker . They work in the compressed air environment at the TBM (tunnel boring machine). Their work consists of TBM sanitation and maintenance.
  They are responsible for the TBM cutting tools (repair, maintenance, spare parts). Normally, three compressed air workers are employed per shift. Three people in case something unexpected happens, such as an injury or fall, and then the other colleagues can help quickly.

The main risks include

• decompression sickness
• physiological stress due to increased gas partial pressures

These risks require controlled pressure profiles and medical monitoring. To avoid risk, there are legal requirements.

A hyperbaric chamber is a pressure-tight system designed to treat decompression sickness. It is mainly used to treat decompression accidents.

A medical hyperbaric chamber must be accessible within 30 minutes and available 24/7.
It is the only system to deal with sudden health emergencies in the compressed air environment. It has specific requirements and it is managed by the supervisor or another smuggler keeper in COLLABORATION with the medical staff.

This process usually takes only a few minutes. However, the exact duration depends on the individual sensitivity of the pneumatic workers. In most cases, a few minutes are enough to perform the compression safely.

Does the same time principle apply to the decompression phase?
No! The decompression phase is much more complex and takes considerably longer. During this phase, the lock operator closely monitors every minute. Various pressure levels and time intervals must be strictly adhered to. Everything depends on the working pressure and the duration of the stay under pressure. In most cases, the supply of oxygen—provided by a portable oxygen unit—also plays a crucial role.

How are the pressure levels controlled in the decompression phase?
There are special tables that determine the duration of the decompression phase based on the working pressure and the length of stay under pressure.

These tables are drawn up by a specialist doctor as part of the risk assessment. They are regulated by special institutions. In Germany, for example, they are set by the BG Bau. There are also American and French tables, which are very well known and are used worldwide.

• Only from a working pressure above 4,5 bar is a saturation system appropriate.
• Definition: A saturation system, also known as a saturation system, is a containerized system for tunneling that functions as a complete self-supporting unit. The saturation system is independent of other systems
• The TBM (tunnel boring machine) must be suitable for docking the transport shuttle (see below)
• HydroWork designs custom-made, customer-specific saturation systems
• Container of a saturation system.
  As a rule, a saturation system consists of:
  • a living chamber
  • a control container
  • Equipment/Storage-Container
  • Gas storage-Container
  • Medical Chamber
  • Hyperbaric transport shuttle to transport compressed air personnel from the living area directly to the TBM without pressure change

Read more about the saturation system

The oxygen system is mandatory during the decompression phase in the hyperbaric chamber. Inhalation of oxygen is necessary to avoid decompression sickness.