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Basic Fire Fighting Concept Design

07/21/2015 2:47 AM

What is the basic fire fighting concept design to protect outdoor transformer in power plant?

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#1

Re: Basic Fire Fighting Concept Design

07/21/2015 9:19 AM
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#2

Re: Basic Fire Fighting Concept Design

07/21/2015 10:54 AM

The basic design concept is thermal detectors activating a deluge valve, and water spray nozzles arranged to "white out" the transformer.

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#4
In reply to #2

Re: Basic Fire Fighting Concept Design

07/21/2015 10:51 PM

Can water be used for electrical fire,quote codes.

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#7
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Re: Basic Fire Fighting Concept Design

08/24/2015 3:45 PM

NFPA 15 calls for water spray systems to protect transformers.

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#8
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Re: Basic Fire Fighting Concept Design

08/24/2015 7:28 PM

NFPA 15 is "Standard for Water Spray Feed Systems for Fire Protection". (1996 edition) http://gb.sa/basee/pdf/32NFPA-15%20Codes%20for%20water%20spray%20fixed%20system.pdf It is the standard for how to design, build and operate a Water Spray Feed System. It does not state that this system must be used for transformers. There are other preferred systems for this. It gives this system as an option for transformers and how the nozzles must be placed for that use, NFPA 15, 7.4.4 Transformers. The subject system is most often used for flammable chemical storage, temperature sensitive chemicals, gases, and to prevent a fire from heating the material stored to a point where it will explode the container. A well known and dramatic example of this is a "BLEVE", Boiling Liquid Expanding Vapor Explosion. https://www.youtube.com/watch?v=UM0jtD_OWLU

Use of this type of system on a fire of live electrical transformers and components will present a electrocution possibility and a rapidly expanding fire hazard. If this is used for transformers it should only be used if the electricity has been secured off and the primary and secondary's of the transformer(s) have been bonded and grounded.

Good Luck, Old Salt

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#9
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Re: Basic Fire Fighting Concept Design

08/24/2015 8:48 PM

For fire in electrical apparatus we used carbon tetreachloride, carbondioxide, halon,expandingfoam,silicon oil etc but some of these are now banned.Wht is the latest method/media used for extinguishing fire in electrical apparatus.

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#10
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Re: Basic Fire Fighting Concept Design

08/25/2015 12:11 AM

Carbon Tetrachloride is not used due to hazards with respiratory intake.

Halon depletes the Ozone layer.

Expanding foam contains water so it is out. Although very little water, it is better suited for class A or class B fires.

Silicon oils are a mess, take long to clean up and can damage equipment.

Carbon Dioxide and sometimes Nitrogen are usually used for flooding an area or container with a non-fire supporting material. Carbon dioxide is usually used due to it's low cost, numerous suppliers and ease in handling. It won't damage equipment unless the discharge for the carbon dioxide is directly in front of the equipment. Dry ice will form and make the equipment extremely cold,

Nitrogen is sometimes used if it is more available. Many chemical plants use this because they have liquid nitrogen available for use in processing, This is usually for blanketing and sparging so it is distributed to many parts of the plants.

Carbon dioxide and nitrogen are also the easiest to handle and distribute.

Good Luck, Old Salt

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#11
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Re: Basic Fire Fighting Concept Design

08/25/2015 12:39 AM

thank you

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#13
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Re: Basic Fire Fighting Concept Design

08/25/2015 10:45 PM

Can all these be used in both outdoor and indoor transformers and switchgears, won't gases like halon,CO2 be carried away by blowing wind??

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#12
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Re: Basic Fire Fighting Concept Design

08/25/2015 11:58 AM

I am currently engaged in 18 power plants in Saudi Arabia, 4 plants in Venezuela, 4 plants in Canada, 1 plant in Peru, and dozens in the US. Every one of these plants is currently using water spray systems on their yard transformers.

I have worked in many hundreds of power plants world wide for the past 25 years, and the vast majority used water spray systems on their transformers. The plants that did not use water spray systems, elected to provide no protection at all.

My statement was not that they must be used on transformers, but that NFPA 15 defines the concept.

What are the "preferred systems" for transformers.

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#14
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Re: Basic Fire Fighting Concept Design

08/26/2015 12:03 AM

To me at least, the statement "NFPA 15 calls for water spray systems to protect transformers" denoted that NFPA 15 stated that water spray systems are the only method of extinguishing transformer fires since no other methods were given nor that there are other acceptable extinguishing methods.

As for the statement that all those power plants use water spray systems I can't verify that. I can state that I have worked several transformer fires at a local transformer yard with input supplies of 1ea 500KV and 2ea 250KV transmission lines and 3ea of the same output transmission lines, there is no water spray protection system on any of the transformers. We were told by the yard engineers that putting straight water on live transformer insulators and wires would possibly cause an electrical originated fire and possibly an explosion/fire (or maybe electrocuting us). NFPA 15 only gives a few choices on how build and set up the water spray equipment, it doesn't say how to operate this equipment. During each transformer fire we were (correctly) delayed while the power in and out of the transformer was disconnected. Burning Mineral Oil and sprayed with water can't be put out with a live system unless you want the fire to spread and become much larger.

Preferred system-- no protection. If the unit begins to burn or explode disconnect power and drown it with a long and heavy stream of foam and water till the fire goes out.

Good Luck, Old Salt

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#15
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Re: Basic Fire Fighting Concept Design

08/26/2015 7:52 AM

Well I don't know what credentials these yard engineers had, but any transformer located in a yard has a rating of at least NEMA 3R and is always subject to rain without an issue.

Google "transformer deluge system" and see what images you pull up.

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#16
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Re: Basic Fire Fighting Concept Design

08/26/2015 11:48 AM

As a firefighter and an engineer with electrical experience, I would no sooner put water on a burning live transformer than to put water on a 500KV high voltage. With all due respect to them they could KILL ME. If a transformer has caught fire there has been a rupture or leak that has allowed the insulating oil to leak out of the enclosure. In almost all cases if the oil leaks out the water can leak in.

One of the most basic rules of fire fighting is that water and electricity do not mix. This is the same reason for the basic lock out/tag out procedure. Also, the "Yard Engineers" are EE's and Technicians have AA or AS's.

NFPA 15 is not a rule book. NFPA develops and publishes standards which they feel are the best on the topic subject. They are not rules or law until a governing body adopts them for law. After the governing body has adapted standards as law it is then the law of the area of that governing body.

Good Luck, Old Salt

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#17
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Re: Basic Fire Fighting Concept Design

08/26/2015 9:07 PM

Well I am a Navy veteran firefighter (as all sailors are), an electronic technician, and a Degreed Fire Protection Engineer who has spent 35 years designing all types of fire systems.

And I can see that I am wasting my time trying to convince you that a deluge water spray system is the most widely accepted and utilized system for power plant yard transformers.

And as I stated earlier, google "transformer deluge systems" and check out the images.

Anything else is I guess just me blowing smoke.

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#18
In reply to #17

Re: Basic Fire Fighting Concept Design

08/26/2015 11:59 PM

You are not wasting your time and not blowing smoke. My experience, my discussions with others more familiar with this subject, my knowledge in various subjects (which we both have) and my experience as both a fire fighter (Ex-Chief) and over 40 years as a Haz Mat responder for some incidents involving transformers makes me conclude a different answer than you. Yes, a deluge system will work many times but there are safer, more ecologically friendly, simpler systems than the deluge. As listed previously, shut off the power, extinguish with a water and foam mixture, have separation walls between transformers and clean any mess up. A lot of that is based on working with transformer yard personnel, electric company engineers, having been the Incident Commander at several transformer fires, safety practices and much research including goggling and other sources.

http://www.usbr.gov/power/data/fist/fist3_32/fist3-32.pdf

Facilities Instructions, Standards, and Techniques

Volume 3-32 Transformer Fire Protection

Fire suppression water should NOT be discharged on an energized transformer, nor should it be used as a cooling method. Water contains contaminants that if used extensively, will damage transformer external components and possibly cause flashover. The transformer should automatically be deenergized prior to water being discharged.

Some facilities were constructed with the capability to trap and contain spilled transformer insulating oil and fire suppression water in sumps or other containment structures. This reduces the risk of oil being discharged into the adjacent waterway

Operation of the fire suppression system should deenergize the transformer to prevent water from discharging onto an energized transformer.

Activation of the suppression system should stop transformer fans and oil pumps that might feed the fire.

if it is appropriate to retain the deluge system, improvements must be made to avoid potential contamination problems. Adequate water-oil containment and control of discharge into waterways is essential.

Water mist systems (low volume at high pressure) have been proven to be effective in suppressing transformer fires in certain situations

"Deluge water spray system is the most widely accepted and utilized system" but there are much simpler and especially safer methods of transformer fire extinguishment than this older method with water and energized transformers.

My priorities in fire firefighting have always been: #1 Life safety of the firefighters; #2 Life safety of the victims' and #3 Properties. Working with live circuits is a high risk when using water to extinguish transformer fires. THE LIFE YOU SAVE MAY BE YOUR OWN!

Good Luck, Old Salt

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#3

Re: Basic Fire Fighting Concept Design

07/21/2015 11:40 AM

Suitable overload protection devices would do it. They are called "fuses".

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#5

Re: Basic Fire Fighting Concept Design

07/21/2015 11:04 PM

A water spray system similar to a sprinkler to envelope the property to be protected. The activation could be via several types or multiple types of detectors with an alarm valve to activate flow. There does need to be specific pressure and distance from the property for electrical safety purpose. This is an old school approach but I'm sure the NFPA code covers this occupancy. Check with them for specifics.

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#6

Re: Basic Fire Fighting Concept Design

07/22/2015 12:57 AM

Basic Fire Fighting Concept: Don't Let It Happen. Prevention is the key to firefighting.

Avoidance: if possible construct cement walls separating adjacent transformers. Also place them in shallow diked areas for retention of materials if a fire should occur. Equip with oil/water separators and pumps

Detection: visual human monitoring; irregularity detection on inlet electrical system and outlet electrical systems; IR monitoring of unit temp.; smoke detectors; and numerous other possibilities.

Preparation: shut down all cooling oil (usually vegetable oil) connections and break connections between storage tanks and transformers. Remove all unnecessary personnel and equipment (autos, construction equipment, etc.). Set up hydrants and pumps/fire trucks to handle large quantities of water and foam. Even better to use CAFS (compressed air foam system). Shut off all adjacent equipment and overhead electrical lines which could cause problems to the fire fighting personnel and equipment.

Extinguishment: Large quantities of either aspirated foam/water or CAFS applied at high rates onto the transformer from several directions if necessary. Apply the highest volumes of water and foam available. Extinguishment is achieved by the foam changing the surface tension of the oil and the large quantities of water cooling and eliminating oxygen to the burning material. May be necessary to do this several times. Have plenty of foam available. Prepare for a long time period if necessary. Fire out!

Also's: Plan for large volumes of smoke. Plan for highways to clog and delay arrival of equipment. Make extra police available if necessary. Plan on temporary/mobile facilities for rest and rehab of firefighters. Plan on having a basic life support unit(s) on hand and ready to perform their duties. Plan on sources at odd hours for coffee, donuts, pizzas, fast type food, soda/pop, and of course the porta-john.

EXTREMELY IMPORTANT! No water in any form should be applied to the unit until all power is shut off and verified that it is off by both the power company and the Incident Commander.

Fought one like this 2 years ago. Prevention and pre-incident planning are what prevents this type of problem from occurring. No need for firefighting if there is no fire!

Good Luck, Old Salt

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