WIND TURBINES. STANDARD OPERATING PROCEDURE S.O.P. No. Version 1.0

Transcription

1 WIND TURBINES STANDARD OPERATING PROCEDURE S.O.P. No. Version 1.0 DOCUMENT OVERVIEW: - To provide operational procedures and information for dealing with incidents involving WIND TURBINES CONTENTS Section Page 1. Introduction 2 2. Significant Hazards 5 3. Key Control Measures 9 4. Relevant Cross References Document History Risk Card Flow Chart 19 Standard Operating Procedure Page 1 of 19 Wind Turbines Issue date 15/01/2003 Reviewed 18/11/2009 Next Review 18/11/2012

2 1. INTRODUCTION 1.1 Large Scale Wind Turbines WIND TURBINES A wind turbine is essentially a sophisticated windmill. Domestic windmills may only be 10 to 15 metres high and have as many as 12 blades with a rotor diameter of 6 metres or so, whereas the average wind turbine tower may be more than 90 metres tall and be fitted with three blades, each 30 metres or more in length. These wind turbines may be situated along hilltops, on flat plains, or even at sea. Large wind turbines positioned in groups are called windfarms. The operating principles are basic. Wind blowing though the blades makes them rotate and turn the shaft of an electric power generator situated inside an elevated compartment, called a nacelle. Inside the nacelle are other controls such as brakes, rotor pitch controllers, gearboxes, and fire protection equipment. As the blades rotate, they produce energy, which turns the gears and reducers, which turn the generator s torque shaft. The generator produces energy, which is then transmitted from the tower to transformer stations through high-tension power lines for distribution. Most wind turbines have three blades which face into the wind. Wind turbines start operating at wind speeds around 10 mph and reach maximum power output at around 33 mph. At very high wind speeds, i.e. gale force winds, 50+ mph) wind turbines shut down. The blades rotate at anything between revolutions per minute at constant speed. However, an increasing number of machines operate at variable speed. 1. Blades 2. Rotor 3. Pitch 4. Brake 5. Low-speed shaft 6. Gear box 7. Generator 8. Controller 9. Anemometer 10. Wind Vane 11. Nacelle 12. High-speed shaft 13. Yaw drive 14. Yaw motor 15. Tower Figure 1 shows the interior of a wind turbine nacelle Standard Operating Procedure Page 2 of 19

3 Nacelle Rotor Platform Interior ladders and lifelines Transformer (in some models) Platform Lifeline Ground level connection closet Platform Cell disconnection Access door at ground level Ground Figure 2 shows the typical construction of a large scale wind turbine. 1.2 Domestic Wind Turbines There are two common types of domestic wind turbine: Pole mounted: these are free standing and are erected in a suitably exposed position such as a large garden or small holding and generate between 5kW to 6kW Building mounted: these are smaller than mast mounted systems and can be installed on the roof of a home or mobile home where there is a suitable wind resource. Often these are capable of generating around 1kW to 2kW. Standard Operating Procedure Page 3 of 19

4 Both types of domestic wind turbine create and store electricity and can be either linked directly to the National Grid, or they can store electricity generated in battery packs. Figure 3 A pole mounted wind turbine. Figure 4 A building mounted wind turbine. Standard Operating Procedure Page 4 of 19

5 2. SIGNIFICANT HAZARDS The potential for injury to personnel working with, or in the vicinity of wind turbines arises from the following factors: Access and egress Confined spaces Falls from height Fire Electricity Struck by flying/falling object Structural collapse Weather conditions Communication difficulties Moving machinery 2.1 Access and Egress Restricted access for vehicles may result in personnel walking long distances over rough terrain. It may also inhibit evacuation thus exposing personnel and appliances to the other risks. Movement of equipment and appliances over uneven ground may result in manual handling difficulties causing injury to personnel. 2.2 Confined Spaces Rescues from wind turbines may have to be made in confined or restricted areas. This may include entrapment within the machinery itself or because of the location of the area of work. The average tower diameters are approximately 4.5m at ground level, 3.6m at mid-height and 2.1m at the top where the nacelle is mounted. The interior dimensions of the nacelle vary however in general a typical nacelle is approximately 9m long 2.2m high and 2.8m wide. This area is greatly reduced due to the presence of the electricity generating equipment that is connected to the turbine blades. Fire service personnel may find it difficult to access such areas for rescue purposes. Working within a confined space or one with restricted access can result in significant risk of injury, due to not being able to conduct manual handling operations in an ergonomic way. Rescuers may also experience heat stress if wearing fire kit in a confined space for any length of time. For further information on confined spaces refer to Standard Operating Procedure No. 01 Confined spaces. Standard Operating Procedure Page 5 of 19

6 2.3 Working at Height Wind Turbines can be constructed to heights in excess of 90 metres. There are a number of situations that could involve the casualty being trapped at height in a wind turbine. Personnel when carrying out a rescue from within a wind turbine are at risk from falls from height due to for example poorly maintained internal ladders or step irons. For further information on working at height refer to Standard Operating Procedure No. 09 Working at Height. 2.4 Fire Due to the internal components of a large scale wind turbine ignition sources may exist from underground levels right up to the nacelle. Fuels can include electrical cables, plastics and even textiles any of which can be found at all heights in a wind turbine. Since the construction materials used in these towers and their components will invariably include plastics and possible some combustible metals (e.g. titanium and aluminium, among others) as well as easily deformable metallic structural and enclosure materials the consequences of a fire in a wind turbine can be disastrous. The origins of fires in wind turbines are numerous, a frequent cause of fires is the mechanical friction among the multiple moving parts of the turbine assembly, gears, shafts, brakes and other moving or rotating components that may provoke sparking. Since the average wind turbine may contain large amount of hydraulic fluid plus various quantities of other lubricants and similar combustible liquids there is no shortage of fuel. Electrical short circuits can occur in numerous locations anywhere from the turbines top to the base. Lightning does not necessarily lead to fire. Often when a wind turbine is struck by lightning it can simply lead to reparable damage however if a lightning bolt sparks a fire it becomes totally destructive. Susceptibility to lightning damage is heavily dependent on a wind turbines location and its size. A fire in a turbine assembly can spread to surrounding vegetation and produce a rural fire risk in addition to this a rural fire could pose a threat to a wind farm. Figure 5 Shows a typical fire in a nacelle. Note the large pieces of falling debris. Standard Operating Procedure Page 6 of 19

7 2.5 Electricity It is common for wind farms to produce over 2 mega watts. Cables are sometimes laid in plastic ducting up to 1m below the surface of the ground from the turbine to the transformer or substation. Personnel may be required to work in close proximity to, or in wind turbines a risk of electrocution as the result of contact with a live circuit exists. Due to the technical nature of the equipment involved within a wind turbine it will be difficult for personnel to determine which parts are still live therefore the attendance of an engineer to provide assistance will be required. On domestic wind turbines the isolation point may be located either on the main fuse board or near the inverter. The wiring to the inverter / fuse board from the wind turbine will remain live. For further information on electricity refer to Standard Operating Procedure No. 20 Incidents Involving Electricity. 2.6 Struck by Flying/Falling Objects Personnel attending incidents involving wind turbines are at risk from flying /falling objects due to: Falling debris Flying brands Dropped equipment Falling persons Falling debris Falling debris from a fire involving a wind turbine can range from small pieces of the structure to large assembly pieces such as rotor blades, even small pieces of the structure falling will accelerate to terminal velocity and can travel some distance away from the wind turbine. Structural failure and blade failure of a wind turbine may also result in large elements of the wind turbine and whole / pieces of a blade being thrown from the turbine some considerable distance. During periods of freezing weather there is a possibility ice being thrown / falling from the rotor blades of a wind turbine Flying Brands Flying Brands are the result of convection currents and direct burning. The up rush of heated air above the fire carries small pieces of flaming material, sometimes to a great height and considerable distances. Brands alighting on combustible material will ignite it. Standard Operating Procedure Page 7 of 19

8 2.6.3 Dropped Equipment Serious or fatal injuries could be sustained by operational personnel / members of public if struck by equipment falling internally within the wind turbine Falling Persons Serious or fatal injuries may be sustained by firefighters if struck by persons falling from height. 2.7 Structural Collapse Fires and/or gale force winds are known to contribute to the partial or total structural failure and collapse of wind turbines. Cordon sizes will be difficult to determine due to the size of a wind turbine and the weather conditions encountered at an incident. Figure 6 Shows a collapse of a wind turbine. For further information on collapsed structures refer to Standard Operating Procedure No. 05 Rescues from Collapsed Structures. 2.8 Weather Conditions Adverse weather conditions (cold, wet, windy) will affect the physical and mental capability of rescuers. Clothing and equipment will become wet and conditions will become hazardous, increasing the likelihood of falls from height of both personnel and equipment. Additionally hot and humid conditions may lead to personnel suffering heat stroke and fatigue. Electrical storms present an increased risk to personnel working at height. Operations may need to be suspended until the weather conditions improve. 2.9 Communication Difficulties Radio dead-spots may be encountered which will result in poor communication between personnel inside and outside the wind turbine Moving Machinery Even when machinery has been isolated personnel should be aware that there may still be movement in the wind turbines blades causing gearing mechanisms inside the turbine housing to move. Standard Operating Procedure Page 8 of 19

9 3. KEY CONTROL MEASURES 3.1 RISK ASSESSMENT (PLANNED) Operational personnel will need to consider the level of pre-planning that is required in order that their response, in terms of resources allocated, is proportional to the risk to Fire and Rescue Service personnel and the public Pre-planning Sites that have been developed as wind farms should be included in the districts 7.2.d Inspections programme. A majority of these sites will also involve, farming, rural areas etc. therefore the points mentioned in other specific S.O.P. s such as 05 Collapsed Structures, 09 Working at Height, 13 Fire in Rural Areas, 14 Farm Fires, 20 Incidents Involving Electricity, must be considered in addition to the points listed below: Availability of any on-site engineers with specialist knowledge Availability of any off-site engineers and contact details Safety features of the wind turbines Compensation for protracted attendance times Cordon locations Possible evacuation of nearby premises Contact details for advice etc Emergency responders should interact with the wind turbine operators to create, implement and maintain pre-emergency response planning Training Training in awareness of the hazards involved at wind turbines must form an on-going training theme at an operational level. In addition to this other areas to be covered are: S.O.Ps numbers A1, A2, A3, 05, 09, 13, 14 & 20 Extrication techniques Working at height Command and control Lifting/handling techniques The safe person concept Standard Operating Procedure Page 9 of 19

10 Districts should attend wind turbine sites to familiarise themselves with the facilities and develop simulation emergency exercises with the operators Pre-Determined Attendance The pre-determined attendance will vary dependant upon the incident, its location, what s involved and any information received by Fire Control. 3.2 Risk Assessment (Dynamic) Dynamic Risk Assessment The Incident Commander should follow the principles of the current national incident command system. On arrival a thorough, suitable and sufficient Dynamic Risk Assessment must be undertaken by Incident Commanders and crews in all cases, regardless of the incidents size and complexity. Immediate life saving actions must be carried out with due regard to the safety of all concerned but Incident Commanders and crews must resist the moral pressure to act applied by the colleagues or friends of casualties. In assessing the demands of the incident and reaching a decision regarding the application of control measures the Incident Commander must pay particular attention to the following: Whether the incident is a life risk and location of casualties Location of engineers / estimated time of arrival if not in attendance Consult and seek advice with site specialist engineers prior to commencing operations In those circumstances where there is no threat to life, the safest practice will be to await the attendance of a specialist engineer Firefighting options such as controlled burn or defensive only measures. Where possible or practicable, defensive firefighting is carried out from safe location(s) e.g. Upwind outside collapse range Location of the structure (tower number / map reference) The height and status (under construction / maintenance / stability) of the wind turbine The extent of the fire Locking / braking of the rotor blades or nacelle where possible (undertaken by engineer) Standard Operating Procedure Page 10 of 19

11 Ground conditions Adequate lighting Observe any warning signs / information on the structure etc. Ground type (peat, soil, rocky areas etc.) Establishing cordons and cordon control Requesting the attendance of the specialist rescue team for rescues from height etc Isolation of electrical supplies to and from the wind turbine Limit number of personnel in the hazards area Fully brief crews on tactics to be employed and specific hazards Appointment of safety officers Welfare or personnel, refreshments and reliefs are established, particularly where operations are arduous or protracted Establishing regular and effective communications between all personnel Ensure all personnel are wearing correct PPE. (ear defenders, eye protection, BA) The provision of clear information, instruction and supervision to all personnel Refer to other specific risk cards for identified hazards i.e. Electricity, Height, Collapsed Structures, Confined Spaces A plan should be formulated as soon as possible based on information received and the Dynamic Risk Assessment. All crew members must be briefed and understand the overall plan. The Incident Commander if faced with a rescue must prioritise the immediate course of action. Based on the skills and equipment immediately available the Incident Commander may choose to either: Rescue - Make an immediate attempt at rescue (e.g. low level) using available equipment already in attendance. Stabilise - Make interventions to stabilise the situation (e.g. request isolation of power) but await the arrival of specialist equipment, officers or teams to complete the rescue or contain the fire. Prepare - Make preparations for the arrival of specialists, teams or others such as the Specialist Rescue Team. Standard Operating Procedure Page 11 of 19

12 On arrival at the scene of operations the Incident Commander may be faced with a fire with person reported at the top of the wind turbine. The following considerations must be borne in mind: Is there saveable life? Isolation of power How long has the fire been burning? What is the integrity of the turbine? Does the risk outweigh the benefits if a rescue was attempted? Can I safely deploy crews to the risk area? Can a safe system of work be put in place? Can a water supply be provided for crew safety? Do I have a back-up plan? The Incident Commander must consider the above in a Dynamic Risk Assessment if they are to commit personnel to save saveable life Cordon for Fires The inner cordon should be shaped to include: The total height of structure (including blades) should the structure fail and fall over The risk of material being ejected from a failing blade or ice being thrown off a blade (in line with the current direction of the rotation) The strength and direction of wind (causing burning debris to fall in the wind direction) Distance dependant on wind strength and direction Possible Debris Field Distance dependant on blade rotation and travel extent of thrown items Distance dependant on height of structure Standard Operating Procedure Page 12 of 19

13 3.2.3 Cordon for Rescues The inner cordon should include the immediate area around the tower base. Where an external fall hazard also exists, a fall zone exclusion area should be established beneath the hazard, which should extend to at least 1/3rd of the working height Safety Officers The early appointment of one or more Safety Officer(s) will help ensure that risks are either eliminated or reduced to an acceptable level. The Safety Officers must be briefed regarding the nature of the incident, the allocated task and prevailing hazards and risks. The Incident Commander should confirm that the Safety Officer understands: Their role and area of responsibility Allocated tasks Lines of communication Those undertaking the Safety Officer role should: Be competent to perform the role Review the appropriate risk information Complete an Analytical Risk Assessment (ARA) Ensure personnel are wearing appropriate personal protective equipment Ensure any equipment used is set up in a safe manner and is appropriate for the task and environment Ensure safe working practices are adopted and implemented Monitor the physical condition of personnel and/or general or specific safety conditions at the incident, in accordance with their brief Take any urgent corrective action required to ensure safety of personnel Update the Incident Commander or senior Safety Officer regarding any change in circumstances Not be engaged in any other aspect of operations, unless this is required to deal with a risk critical situation Ensure emergency procedures are initiated An evacuation signal must be agreed and understood by all persons actively engaged in operations (including non-fire service personnel). Under normal circumstances the Standard Operating Procedure Page 13 of 19

14 standard fire and rescue service signal will suffice (repeated short sharp blasts on an Acme Thunderer type whistle). To avoid fatigue and loss of concentration the Safety Officer should be relieved at frequent intervals. When relieved a thorough briefing must take place before the role of Safety Officer is exchanged. The role of a Safety Officer can be carried out by any of the fire service roles, but the complexity of the task, size of the incident and scope of responsibility should be considered by the Incident Commander when determining the supervisory level required. 3.3 Operational Considerations For this incident type, the early implementation of an RVP is essential to ensure the control of resources. The Incident Commander must nominate a RVP and inform fire control as soon as the exact incident location has been determined. Fire control must also be informed of the best access route to the incident at the earliest opportunity. Access to technical expertise may be gained on site from liaison with the: Site engineer Site contractor Land owner Power supply company The hazards and difficulties present at a wind turbine fire are so significant that offensive firefighting will not be possible. The normal tactics to be employed when dealing with a wind turbine on fire is to arrange for the power to be isolated to the affected structure whilst allowing a controlled burn. In remote locations this will restrict operations to maintaining a safe cordon whilst watching for any fire spread to surrounding grassland. Where wind turbines are located in built up areas that could affect other property, the Incident Commander should put systems in place to evacuate and then protect adjacent properties without undue risk to firefighters. Where above ground rescues are required from inside or above the structure, only specialist rescue team members are trained to undertake such rescues and understand the risks associated with such interventions. A rescue may not be possible whilst fires are still burning. The normal tactics to be employed when dealing with a rescue from height in or around a wind turbine is to arrange for the power to be isolated to the affected structure whilst preparing for the arrival of the specialist rescue team. Prior to commencing work inside the tower, specialist rescue teams must consider: Isolation of lift mechanisms Isolation of power supplies Standard Operating Procedure Page 14 of 19

15 Braking / locking of rotor blades Suitable and secure anchor points The use of fall protection systems already engineered in place Because of the high voltages generated by the turbines, only a site engineer may isolate the power to a given structure. As many towers are constructed in series this may be accomplished from the adjacent tower or from the substation linked to the site. Crews must never attempt to isolate the power in a wind turbine or associated substation. Such actions may prove lethal even if the isolation method looks simple. There is a chance that fires may spread from the structure to adjacent property and grassland. The Incident Commander should appoint observers who should attempt to attack any subsequent fires quickly to prevent fire development (where safe to do so). Particular attention must be paid to downwind areas where fire spread is more likely to occur. When positioning the appliances at fires involving wind turbines, the Incident Commander must consider avoiding: The combined height of the tower and blades should the structure fail The rotational direction of the blades (in case of blade failure or ice throw) Wind direction and strength This document sets out the Standard Operating Procedure for incidents of this nature. However, it is recognised that no two incidents will be the same and therefore in some circumstances the dynamics of the incident may make it necessary to take actions that deviate from this procedure. Before taking any action outside of this procedure, a thorough Dynamic Risk Assessment must be undertaken, alternative appropriate control measures implemented, and any subsequent actions must be justifiable. Once this has been done, every effort must be taken to return to the Standard Operating Procedure as soon as practicable given the ongoing dynamic assessment of risk. Standard Operating Procedure Page 15 of 19

16 4. RELEVANT CROSS REFERENCES 1. Standard Operating Procedures No 01 Confined Spaces No 05 Collapsed Structures No 09 Working at Height No 13 Fire in Rural Areas No 14 Farm Fires, No 20 Incidents Involving Electricity 2. Technical Information Document 3. Others 4. Reference Documentation Home Office Guide to Operational Risk Assessment Home Office Technical Bulletin 1/97 Breathing Apparatus Fire Service Manual Volume 2 Incident Command Fire Service manual Volume 2 Electricity Home Office Guide to Operational Risk Assessment Brigade Written Safety Policy Electricity at Work Regulations 1989 Fire and Rescue Manual Volume 2 Incident Command 3 rd Edition 2008 Standard Operating Procedure Page 16 of 19

17 5. DOCUMENT HISTORY Version No. 1.0 Replaces Summary of changes New Document Author WM T Robinson Department Corporate Services Approved by Version Date Modified by Changes Review Period This Standard Operating Procedure will be reviewed in December 2015 Standard Operating Procedure Page 17 of 19