Occasionally the originally American trend to fill breathing-air cylinders in safety filling boxes is being implemented in Europe, too.
If applied inexpertly, however, this way of filling scuba cylinders may entail far higher risks than the traditional way of filling with a filling panel. Personnel may be protected from flying parts, but most people do not consider the released compressed air.
In order to use a safety filling box safely the installation site (filling room) and the equipment of the filling box itself must meet certain requirements.
- Already when planning to buy a filling box you should do a hazard assessment which includes the filling box.
- The room in which you want to install the filling box must have a special venting device. When a breathing-air cylinder bursts up to 4.5 cubic meters (160 cubic feet) of air can be released within the fraction of a second. Where does this air go to? All web-published videos of presentations and tests several suppliers in the web and Youtube were shot outdoors. These videos show clearly how much air is released when a cylinder bursts.
- Certification of the filling box only means that the box itself can withstand the bursting of a cylinder. No tests were done, and thus no certification exists with regard to the chain reaction that can happen, if the individual cylinders are not separated by bulkheads in the box during filling. The amount of air released into a room was not taken into account and is therefore not included in the certification.
- Filling boxes must be securely anchored in the floor. Mind underfloor heating systems!
- Check the glass in the windows of the filling room: if it breaks when a cylinder bursts, its splinters could harm people passing by outside.
- Make sure the room has robust, inward-opening doors, so no one in the adjacent room can be hurt by the door flying open.
- It is crucial that the filling spaces in the box be separated by safety bulkheads. Otherwise a bursting cylinder could start a chain reaction.
- During the actual filling no one should be in the filling room, filling must be controllable from outside. Opening the filling room door during filling must stop the filling. A useful solution would be an unbreakable window between control unit and filling room, enabling you to monitor filling from there.
With all safety-mindedness we should not forget that hardly any accidents are caused by bursting cylinders. Most accidents were and are caused by handling errors. Certain filling boxes, however, have such a cumbersome handling that they almost call for a handling caused accident.
If you control the filling process from the adjacent room and install the above mentioned safety devices, a good modern and considerably cheaper filling panel with filling monitoring, recording and documentation in compliance with the Ordinance on Industrial Safety and Health is possibly more useful.