scope:

This part of IEC 61400, which is a Technical Specifiation, establishes a guideline for the assessment of the risks which a wind turbine may pose to the general public.

Incidents in wind farms causing harm to the general public are very rare events. However, there are requirements to cover this topic in the permitting procedures of several countries. This document aims to facilitate a uniform scope and a uniform use of methods in wind turbine risk assessments.

This document covers harm to the general public. It does not cover occupational exposure, e.g. of personnel involved in the operation and maintenance of the turbine, since occupational risks are usually dealt with in occupational health and safety regulations. The risk of damage to structures or other objects is also not part of this document unless such damage in turn poses a risk to the public.

Harm according to this document can be direct harm or indirect harm via damage to buildings or infrastructure, e.g. gas pipelines, nuclear facilities, dykes, rail infrastructure or roads.

This document covers risk due to internal or external causes, such as technical failures, human errors, extreme wind conditions, turbine icing, lightning strikes, earthquakes, flooding, landslides or fire. However, the specific cause of an incident (e.g. an incident such as a turbine collapse) is irrelevant to the assessment of the consequences. The only relevant factor is the expected probability of occurrence for the incident considered.

In terms of transmission of the hazard to the people affected, this document describes tower collapses, shedding of the nacelle, blade failures, falling or throwing of ice pieces and fire spread.

This document does not cover risks from visual distraction and environmental risk such as noise or shadow flicker.

Wind turbines may pose a hazard to aviation through incidents such as collisions with aircrafts or disturbance of air traffic control radar. These hazards are not covered in this document. In order to mitigate the hazard of aircrafts colliding with wind turbines, aviation lights are installed on wind turbines as covered in IEC 61400-29[1]¹.

Risks connected to terrorist attacks and other malicious actions are not covered by this document.

This document covers only onshore wind turbines with a horizontal axis and a swept area greater than 200 m². Substations and other external structures are excluded. Other tall structures associated with a wind farm or wind turbine (e.g. temporary or permanent meteorological masts) also introduce risks related to their possible collapse or failure. Such structures are not covered by this document. Guidance on the risks can be inferred from the reliability classes of the tall structure as determined with reference to EN 1993 Eurocode 3: Design of steel structures [2], including the national annexes where local design requirements are specified.

As to the extent of the harm, this document is limited to the immediate, potentially lethal, physical harm. Non-lethal harm is indirectly covered as described in Clause 6.

This document describes risks during operation of the wind turbine including maintenance, idling and standstill. It does not describe risks during construction, civil works, crane operations, assembly or decommissioning.

Risks according to this document are assessed by prescriptive and/or risk-based methods.

In evaluating risk, the risk is first expressed as a localized risk. Along with the probability of people being present at the location, a risk of lethal harm per year will be used to quantify the risk of harm to people.

This document covers risk reduction measures that might be necessary to reduce risk to a tolerable level.

¹ Numbers in square brackets refer to the Bibliography.