Safety of urban rooftop wind systems

1. Safety of urban rooftop wind systems Bruce Lipscombe I Want Energy Pty Ltd

2. Lesson: 1 What can go wrong will go wrong • Any machine that involves moving parts can fail. • Managing the damage and issues are the biggest problem. • A risk analysis of the installation, reviewed by piers is invaluable. • Design systems for a worst case scenario.

3. Lesson: 2 get it right the first time. • Plan, plan then plan some more. • Be prepared to invest in the best equipment. • Train you staff. • Chances are the supplier has no idea of all the issues, don’t rely on them, its your neck!

4. Lesson: 3 Do it once do it right. • Don’t be pressured into getting a job done in a time that makes you rush! • Take time to check and double check. • Most building top turbines are high profile, be aware of getting it right.

5. System Design. • Who is responsible for what? • Structural Engineer. • A structural engineer is responsible for the design and evaluation of anything that supports or carries a load. A structural engineer must be registered and have appropriate insurance. • Building surveyor. • A building surveyor is a professional trained in understanding and interpreting building law. He or she is authorised to assess building plans with a view to ensuring they are compliant with the Building Regulations. In addition to having recognised qualifications, a building surveyor must be registered and must have appropriate insurance. • Builder. • Builders or building contractors manage and coordinate the project, manage the purchase and delivery of materials coordinate the work of tradespeople involved in the project.

6. System Design. • Who is responsible for what? • Supplier. • Provides the machine along with associated data, data such as loads etc will normally be passed to the builder then to the surveyor and structural engineer for approval or design. • Building owner. • Supply of plans (may be held by others) • Applications • Insurances on turbines.

7. Design considerations • Worst case • Maximum winds in the area • Multiply x 4 • Blade impact area for horizontal turbine. • 10 x blade diameter at ground level. • Add .5 x for each 10m in height. • So a 5m diameter turbine at 50m has a blade impact area of up to 175m!

8. Design considerations • Vertical turbine. • Can blade separation be controlled (mechanical) • A Darrieus turbine blade when separated usually falls straight down but will be blown by the wind, but will not “Fly” • A Savonius blade can “Fly” for some distance.

9. Design considerations • What happens in the event of failure. • How do you stop a turbine? • Cataclysmic braking. • When something fails, a mechanical action causes the turbine to come to a halt, it usually results in turbine destruction but can save lives. • Tangle systems. • A web of nylon netting can be deployed from a pack that is attached to the support pole, it will tangle the blades and cause the turbine to stop.

10. Design considerations • Access to the turbine for maintenance. • You WILL need to get to it one day. • What tools will be needed. • Safety training, height management etc. • Removal of heavy objects, how?

11. Design considerations • Electrical design. • What are you doing with the power? • Net or Gross feed in, back to main meter panel. • 3 phase is the system capable of supporting the produced power? • Turbine feed. • May need to be armoured. • Ensure it is larger than the required size as it may on occasions (Dump Load) be under near short conditions.

12. Design considerations • Electrical design. • Inverter selection. • Ensure the inverter curve matches the turbine power curve. • What happens in event of power failure? • Dump load temperatures. • Adequate ventilation. • Vermin nests.

13. Design considerations • Emergency plan. • When it goes wrong everything will happen at once. • Power out. • Access difficult. • Have an emergency kit ready at the site. • Flashlights. • Rope. • Tangle nets.

14. Design considerations • Remember life is more important than a piece of machinery. • Try to bring the situation under control. • If you can’t then who do you call?

15. Design considerations • When the turbines are installed. • Remember to work with the fire department who will set up a plan for themselves. • Do you need to shutdown the turbines if the fire alarm goes off? – How?

16. Work within your limitations • Be prepared to walk away. • The risks associated with doing something you don’t understand is far greater than the monetary gain. • Its easier to face your limitations than it is to face a coroner.