Hydropower stations can pose significant safety risks to those who work in them, but there is no excuse for injury or death in our workplaces. Developers, owners and operators of hydropower plants all need to make a strong commitment to workplace health and safety.
Some of the hazards at hydropower stations differ from those at thermal power stations or commercial installations. Hydropower stations typically have limited access and no natural lighting. Lower floors are often below the outside water level, and many are underground.
1. Designing safety into hydropower stations
When designing and implementing a new hydropower scheme, or when upgrading an existing station, we need to carefully consider the required standard of workplace health and safety, and the scope of work necessary to achieve that standard.
This means understanding the relevant legislation, building codes and the requirements of the insurer. We also need to be clear about how responsibilities are shared between all the parties involved – the designer, developer, owner, contractors, and so on.
But while standards, codes and guides are a good starting point, the final solution needs to be tailored to the particular circumstances and level of risk at the station in question. Safety systems for hydropower plants can be complex and sophisticated, but simple systems can also be robust – it all depends on the specific requirements of the facility in question.
2. Planning ahead to control risks
A general approach taken to minimise workplace risks involves planning ahead to prevent workplace accidents, injuries and illnesses. We do this by ensuring that systems of work are safe and that equipment is properly maintained. Employees must receive health and safety information, training and appropriate supervision.
This approach is usually expressed through a hierarchy of controls:
3. Safety upgrades for older hydropower stations
Typically, new hydropower stations are well designed and comply with appropriate safety standards and local building codes. Larger hydropower stations can have safety systems as complex and thorough as those in modern multi-floor commercial buildings. However, older plants were often designed with little regard to safety, and now need urgent attention to comply with modern workplace health and safety standards.
While safety facilities are readily incorporated into new hydropower schemes, they may be more difficult to retro-fit into existing stations. The scope of work will need to take into account the interfaces with existing facilities and the tailoring required to suit the specific site and location.
4. Station evacuation
Whatever the nature of the crisis, people must be able to get out of a hydropower station safely. All stations should have at least two independent ways to exit. If one route becomes inaccessible, an alternative emergency escape route should always be available. Adequate lighting is essential for emergency escapes.
Safety at hydro stations involves more than simply having the correct equipment or hardware present at the site."
The primary consideration should be to provide safety facilities to get personnel out of a hydropower station safely before conditions inside become dangerous. The second consideration should be providing facilities to get people out safely after conditions become dangerous. Only then do we think about safety facilities to prevent damage to the plant itself.
5. Flood protection
Hydropower stations can and do flood. Failure of drainage pumps can lead to a slow increase in the water level and eventual flooding of the station. Alternatively, a plant failure and leakage that drainage pumps cannot manage can cause rapid flooding of the station. This makes water-level, flood and evacuation alarms an absolute necessity.
Flood protection schemes can be implemented to automatically close intake gates or hilltop valves and keep turbines operating to attempt to drain the headworks and penstocks of water to control flooding, and to automatically stop the hydro plant before the water levels become critical.
6. Fire and smoke control
We need to detect fires as early as possible, prevent them from spreading, alert all personnel, and provide safe and well-lit means of evacuation as soon as possible.
Smoke control and ventilation are also extremely important. Fire will rapidly fill a hydro station with thick, black, acrid smoke, which is often a far greater hazard to personnel than the fire itself, as it obscures vision (preventing occupants from finding safe escape routes, as well as hindering search and rescue operations). It can also asphyxiate or poison people well before the temperature of the fire or smoke causes injury.
A holistic fire protection system needs to attend to the full range of passive measures (e.g. fire-rated construction materials and methods), active measures (e.g. sprinklers, venting, fire-fighting equipment) and operational measures (e.g. plans, systems and training for fire prevention and response).
7. Emergency and crisis management
Safety at hydro stations involves more than simply having the correct equipment or hardware present at the site. It involves an ongoing commitment by the owner, management, operator and employees to provide and maintain a safe and healthy work environment.
This commitment should be documented in writing and form part of a workplace health and safety policy supported by safe work systems and documentation. These should include a written risk control program and fire protection program, hazard register, site induction procedures, attendance boards, permit to work systems, local safety teams, and a detailed crisis and emergency plan.
You can read more about hydropower safety here.
You can read more about Entura's work on hydropower here.