By Arturo Arnalich
In the battle against climate change and carbon monoxide emissions, wind energy is playing a significant role. Wind turbines began to dot our landscape a few years ago, growing exponentially in number. Today, the United States ranks second worldwide for installed wind energy capacity; it has grown by an average of 29 percent per year over the past five years.
FIGURE 1. Wind Energy Use by Country
|Country||Total capacity 2012 (MW)|
Wind turbines must be considered industrial facilities subject to a full range of emergencies such as fire, entrapments, electrical accidents, falls, and even hazmat. Although the incident rate registered for an isolated wind turbine is low, given the total number of units installed, there is significant risk involved.
Education, training, and standard operating procedures (SOPs) stand as the proper way to face these newcomers to the firefighting scene. As firefighters, multiple reasons drive us to consider wind turbine emergencies, several of which follow:
- Scarce experience on real emergencies because of their recent development.
- A variety of wind turbine technologies mean that operating procedures between different wind turbines may vary significantly.
- Emergency scenarios taking place in high-rises involve extremely confined space and poor design for firefighting operations.
- There is no option for improvisation or applying “general” techniques; some of them may aggravate emergency scenarios.
- High risk of firefighters becoming trapped in the interior or running out of air during operation.
Guadalajara, a 5,000-square-mile province in central Spain with a population of 200,000 contributed greatly to early experiments and the development of wind energy in the early 2000s. CEIS Guadalajara Fire Department (GFD) developed specific firefighting SOPs and training for the full range of wind turbine emergencies, which have since been used as a guideline in several other fire departments throughout Spain.
Among all potential wind turbine incidents, a fully-involved fire at the nacelle (upper part) of a wind turbine is one of the most serious and risky a firefighting crew may face. A defensive strategy is common practice when it is confirmed that no victims are present; property damage will not be significantly reduced by firefighters’ operations.
In contrast, an offensive tactic is needed if you cannot confirm the absence of victims. The CEIS GFD responded to a fire call in the nacelle of a nearly 300-foot-high Gamesa wind turbine in April 2012. Luckily there were no victims in the interior, but it lead the crew to perform a search and rescue drill soon after, using the same model of wind turbine and assuming a trapped victim was inside.
The main goal of this drill was to gather accurate data on self-contained breating apparatus (SCBA) air usage during search and rescue operations in wind turbines more tan 250 feet high and to evaluate the use of positive pressure ventilation to improve interior conditions for victims and interior firefighting crews.
- Wind turbine model Gamesa G87, 2 MW, 270 feet high located at Los Guijos (Mazarete, Spain) Wind Farm.
- Fire seat located in the highest interior platform of the tower, 250 feet high.
- Maintenance operator working at the nacelle, 270 feet high, when fire is declared below his position.
- Smoke rapidly fills tower and nacelle.
- Maintenance operator is neither able to descend through tower nor exit through nacelle’s back exit due to heavy smoke conditions, sheltering himself in the wind turbine hub.
1 engine company (1 captain + 3 firefighters).
1 rope rescue team (1 captain + 3 firefighters).
1 incident commander (IC).
2 instructors—Captain Pablo Hitado and Battalion Chief Arturo Arnalich.
Wind farm operator (Eolia).
Wind farm maintenance service (Global Energy Systems).
1. The fire department receives an emergency call as described in drill setup.
2. En route to the scene, the IC calls Gamesa’s remote control center for exact GPS coordinates of the wind turbine and to confirm that it has been disconnected and de-energized. These two operations ensure that no electrical power should reach or come out of the damaged turbine. This step must occur prior carrying out any fire operations.
3. The engine company arrives on scene and performs a complete size-up, gathering essential information and again confirming that the wind turbine has no power. Ground level control panels allow to operate and check for disconnection and de-energization procedures.
4. The backup crew (two firefighters) set up a positive pressure ventilation (PPV) fan and being interior pressurization. The top end of tower and nacelle have plenty of open exhausts.
5. The attack crew (one captain and one firefighter) start to climb the interior ladder with a nozzle, termal imaging camera, hand tolos, and a victim rescue air pack while pulling a dry hoseline ready to be charged. Some specs include the following:
- Single hoseline layout: 1¾-inch from engine to wind turbine entrance, one-inch throughout interior ladder.
- Working pressure: 220 pounds-per-square-inch (psi) at engine outlet, 90 psi at fire seat, 250 feet high.
- Gallonage: 12-60 gallons per minute (gpm) nozzle.
- Total line dry weight: 45 pounds.
- Total line weight when in charge: 135 pounds. (Before asking for water, water line must be secured to ladder with strap.)
6. Positive pressure attack (PPA) rapidly improves interior conditions allowing firefighters to gain access to fire seat at the 250 foot high level.
7. Fire is controlled and extinguished.
8. PPV removes smoke and remaining water vapor, providing excellent conditions to perform victim search. Victim is located at wind turbine’s hub and given required medical attention.
9. Rope rescue team (one captain and three firefighters) accends wind turbine without SCBA;s ventilation provides necessary interior conditions.
10.Rope tescue team performs a standard victim evacuation through rear exit of the nacelle. One rescuer descends along with the victim and is in charge of tilting the stretcher while the rest of the crew uses a two-rope system to lower the victim and rescuer.
1. Burned Gamesa G87 wind turbine in Cantalojas (Guadalajara, Spain)
2. Ventilation from early stages removes smoke from interior providing safer conditions for firefighters and victims.
3. Firefighters climbing up the interior ladder with SCBA, hoseline, and rescue equipment.
4. One-inch water line working at 15 bars (220 psi) for fire control 250 feet up the tower.
5. Victim is rescued from the hub and evacuated using rear access door of the nacelle.
6. Crews remaining in the nacelle for rope control during descent have good air conditions due to early ventilation.
Accurate data regarding SCBA consumption was gathered yielding surprising values much higher than expected. This was because of the intense physical effort involved in gaining access and pulling the hoseline through a ladder, all in a space barely large enough for a firefighter with an airpack to move.
In our tests, climbing 270 feet and then descending the ladder fully equipped consumed around 80 percent of the air in 45-minute (66 cubic feet) SCBA bottles, leaving very little time for actual operations and putting firefighters in a risky situation.
The use of PPA from an early stage had a decisive and positive effect on the operation. At first, it provided visibility and better conditions for firefighters as they searched for and approached the seat of the fire. Shortly after fire knockdown, the flow path was cleaned, reducing time for search operations and providing a tenable atmosphere for both victims and firefighters.
Without PPA, firefighters must descend to ground level to change SCBA bottles as soon as the fire is extinguished. In constrast, PPA allows firefighters to continue search operations and remove SCBA as soon as gas detectors confirm air conditions are breathable.
Arturo Arnalich is the battalion chief of the CEIS Guadalajara in Spain. For additional information on this drill or wind turbine emergencies, contact Arnalich at email@example.com.