Biogas installations and occupational health and safety law. We are seeing it more and more often: digesters being closely scrutinised by the inspectorate when it comes to safety and health. Entirely understandable, but not always pleasant. In this article BaSystemen explains briefly and clearly:
- Hazards at biogas installations
- Dutch regulations on lone working and gas detection
- Solutions from practice
Hazards at biogas installations
The main hazard: gas. That can mean explosive gas (methane) or toxic gas (hydrogen sulphide/ammonia/carbon dioxide). The risks involved here are regularly compared with those in the petrochemical industry. We are not here to judge whether that is justified or not, but to share knowledge and to help with solutions. Gases that occur around biogas installations:
| Gas | Molecular formula | Percentage |
| Methane | CH4 | 30-80% |
| Carbon dioxide | CO2 | 35% |
| Hydrogen sulphide | H2S | 0-2% |
| Ammonia | NH3 | 0-2% |
| Water vapour | H20 | 0-2% |
In addition to the risk of explosion, narcosis and asphyxiation, staff at biogas installations also frequently have to deal with confined spaces. And all of that possibly in combination with lone working.
Lone working
Waste for digestion is scarce and expensive, which does not do the profitability of such an installation any good.
Sometimes the choice is therefore made to run (evening or weekend) shifts single-handedly, which adds an extra item to the risk inventory and evaluation (RI&E): lone working.
Even when several colleagues are nearby, but it is not unusual for people to be out of each other’s sight for hours on end, this falls under ‘lone working’ and proper follow-up must be in place in the event of an emergency.
The Dutch Working Conditions Act (Arbowet) does not set out any special requirements for lone workers. There is, however, one proviso. Employers are responsible for a safe and healthy working environment for their employees. As mentioned earlier, for lone workers this means:
- Make sure that proper follow-up is in place in the event of an emergency.
In practice this can mean:
- Work with several people who have each other in sight as much as possible
Should that not be possible:
- Give every ‘‘lone worker’’ a man down device with an emergency button. It goes into alarm when the emergency lever is pulled, when a fall has been detected or when no movement at all has been detected over a long period.
Gas detection
As mentioned earlier, hazardous gases are present at a biogas installation, which brings risks with it. It is therefore mandatory to move around with gas detection that has at least the following sensors:
- Oxygen (O2)
- LEL (explosive gases including CH4)
- Carbon monoxide (CO)
- Hydrogen sulphide (H2S)
- A possible addition to this is ammonia (NH3)
Solutions from practice
At BaSystemen we have been able to provide numerous biogas installations with a solution that also satisfied the inspectorate. To tackle the above problems in one go, we often recommend the Blackline G7c. This is a device that detects the above gases and at the same time has built-in man down functionality for emergencies. If you have any questions, please contact us.
A great feature is that, by means of a so-called heat map, the device gives insight into the high-risk areas. Green dots indicate low readings, while red dots characterise high gas values.
