Customer Service

Thesis

The fire suppression needs of the wind energy industry are myriad. However, the potential fire suppression solutions are few. Wind turbines represent remote and difficult industrial fire hazards that are stuck several hundred feet straight up in the air. Accessing the working compartments inside the turbine nacelle is difficult and dangerous. And, once a turbine fire starts, it is almost impossible to attack with standard strategies.

Representing the worst of this difficult scenario is the fact that once a million dollar turbine is lost to a fire, its ability to generate electricity – and therefore profits – is gone for good. It will take months to replace it with a new turbine, and the lost revenue stream means hundreds of thousands in lost profits to the wind farm owner.

Types of Fire Hazards

Three different areas within the wind turbine yield three different types of fire hazards:

Class A
The fiberglass superstructure of the turbine constitutes a Class A hazard.

Class B
The hydraulic oils and fluids within the nacelle constitute a Class B hazard.

Class C
The electrical circuitry and components within the nacelle constitute a Class C hazard.

Locations and Causes

Fires within the turbine nacelle are normally located within one of four areas:

The Brake
The disc braking system of a wind turbine is designed to slow or stop the turbine blades in the event of an emergency. These braking systems, though robust, can overheat under certain conditions and cause pieces of the disc brake material to slough off the rotor, and fall down into the bottom of the nacelle. When these types of conditions occur, hydraulics hoses can be ruptured by the red-hot braking material. Once the high-pressure hydraulics fluid is being released inside the nacelle, a potentially catastrophic failure is unfolding.

Hydraulic Oils and Fluids
Hydraulic pumps and connections can sometimes fail, causing fires when fluids within come into contact with hot surfaces.

Electrical Equipment – Up Tower
Electrical equipment such as capacitors and transformers can sometimes fail or catch fire in a lightning strike. These types of in-cabinet conditions can be relatively easily contained within the nacelle. Circuit overloads, while not common, can cause the loss of electrical equipment. Left unattended, they can eventually cause the loss of the entire nacelle.

Electrical Equipment – Down Tower
Down tower fires will be strictly a Class C problem. Transformers, SCADA controls and DCS controls can be susceptible to loss in the event of the failure of power supplies or perhaps lightning strikes.

Attacking the Hazard

The nacelle constitutes a very difficult fire suppression problem. Not only is the nacelle many hundreds of feet vertically upward, there is very little room within the nacelle for the location of tanks of fire suppressing fluids, gases or powders. Further, as a confined space, fire system designers need to think of the needs of tradesmen who might be working inside the nacelle: potentially releasing the fire suppressing agents in the vicinity of workmen might pose a problem for the health and well being of individuals inside the nacelle.

Because the nacelle is so remote from the ground, heavy tanks of gaseous, powdered or liquid fire suppressants cannot be easily lifted to the nacelle for installation. Further, many smaller and older nacelles are well-ventilated and will not allow the sustaining of the fire suppressing media in the vicinity of the hazard.

Therefore, because of these architectural limitations, dispensing of even small quantities of fire suppressants is difficult inside a wind turbine.

Fire Foe

A UL-listed solution for the Class C hazards in wind turbines (up-tower, or down-tower) is a small fire extinguishing cartridge that installs in mere minutes. Its simple design and snap-in installation assure that local site maintenance personnel will be able to install and service the device. Small, yet capable of yielding up to 130 cubic feet of coverage, the Fire Foe consumes a minimal amount of space for its fire kill capabilities.

Fire Foe™ uses a patented technology and specially formulated heat-intelligent nylon tubes. Because each unit has all-in-one technology there is no need for any external sensor system or power supply making Fire Foe™ the most cost effective automatic fire extinguishing system available on the market. The narrow tube profile and snap-on simplicity saves time and money when fitting or retro-fitting fire protection systems, minimizing down-time on plant and machinery.

Tubes are normally pressurized to 100psi at room temperature. Below 175°F (80°C) the Fire Foe™ tube remains robust and stable. The rugged construction ensures tubes are damage resistant. When a fire builds the heat in the affected space above 175°F (80°C) it triggers the heat-intelligent nylon tube which begins its activation countdown. The rising temperature of the fire softens the tube while increasing the internal pressure of Envirogel to the point at which the tube ruptures along a pre-designated strip, releasing the agent that floods the space. As soon as the Envirogel SB is released it reverts from gel to gas which instantly interrupts the combustion process, absorbing heat and chemically extinguishing the fire. The non-toxic and non-corrosive powder element travels with the gas, coating combustible material to prevent re-ignition and absorbing the dangerous Hydrogen Fluoride,( that is a normally an unavoidable by-product of HFC fire extinguishants), to levels that US Environmental Protection Agency have deemed safe for use in occupied spaces.

Fire Foe™ reacts to all fires, slow burning over time as well as flash fires. At 316°F (150°C) tubes will instantly discharge. The specially milled release strip provides a controlled and directional release to ensure maximum operational effectiveness. Tubes are 1.5" (3.8cm) in diameter and are available in various lengths from 8" - 32" (20.3 cm - 81.3 cm) sized according to the volume of the protected space.

Fire Foe™ tubes are easy and quick to install using the supplied instructions, brackets and hardware. Compact and self contained they provide ideal protection for virtually any enclosed space up to 130 cu feet (3.7 m³) that has an inherent risk of Type B&C fires. (Fire Foe™ can extinguish Type A surface fires).

Tubes are vibration and corrosion resistant, and are unaffected by low temperatures and will not activate before the pre-determined temperature has been reached (500 successful and sequential individual activation tests were initiated to secure UL approval).

Fire Foe™ is suitable for temporary or permanent installations. Where installation requires automatic machinery shut down and/or remotely sited discharge indicator, Fire Foe™ is available with an integral pressure switch for wiring to ancillary systems or connected to an optional LED indicator. Fire Foe™ tubes are fitted with integral pressure gauges for easy monitoring. Maintenance consists of a simple visual gauge check at room temperature and check-weighing at regular intervals.

Prices start at under $500.00 USD

• Fire Foe™ units are guaranteed for 5 years
• Self contained, compact, all-in-one heat-intelligent tube
• Self activated by temperature
• Snap-on simplicity
• No mechanical, electrical, battery systems required
• Rugged construction and maintenance free

A brochure is available at www.tilley-associates.com

Read More at www.quick-fire.com

Jeff R. Tilley, owner of Tilley and Associates, an independent manufacturers representative serving the Fire Suppression industry. Tilley has 30 years of experience in the fields of fire detection and suppression and has worked with some of the largest companies in the U.S. to bring best-in-class solutions for tough fire suppression problems. His experience also includes working on Department of Defense, U.S. Navy, U.S. Air Force and U.S. Army Corp of Engineers projects.

Article Source: ArticlesBase.com - A Guide To Class C Fire Suppression Strategies For The Wind Turbine Industry