The following is a series of very informative discussions that took place during a recent email exchange between members when asked, “What do you do with training and working with the local fire department on handling a quench oil fire?” We thought it would be good to repost for all members to learn from:
Member #1 – Great Story and Lessons
Yes, we had an oil quench tank fire on Thursday, October 13, 1988. It quickly escalated to 6-alarm status that called over 250 total firemen to fight it. We had a 100% loss from this fire, and we were out of business for 17 months.
I know a lot of you remember this when my company burned to the ground.
The primary cause of this fire was human error, improper fire safety training, and an improperly engineered fire extinguishing system. The following are some keys we learned from this experience:
- There are 3 sides to the triangle that creates a fire;
- Oxidizer, or air,
- Fuel, something that is flammable,
- Heat, flame, spark, or anything that can combine with #1 and #2 to create a continuous fire. A basic understanding of this is important.
- If you COMPLETELY ELIMINATE any one side of this triangle you have no fire.
- We have a 12,000-gallon oil quench tank that is one third above ground, and two thirds below floor level in a large pit. This pit allows for a contained and controlled over flow of oil. NOTE: Oil will foam-up like the head of a beer if just a small amount of regular water gets in it, and it gets heated up from quenching!
- We have a 15,000-gallon oil dump tank that is 20' under ground, under the quench tank. It has a 16" diameter pipe at the bottom of the quench tank that has an automated butterfly valve on it.
- Our fire Extinguishing system is customized. ---There are six (6) thermocouples located both inside and outside the perimeter of the oil quench tank. These thermocouples are used to measure for an UNFRIENDLY FIRE. Obviously we have a fire when we quench a red-hot load in the oil until it is fully submerged --- no more air, no more fire!
- If there are more extensive flames than the usual 20 to 30 seconds, the thermocouples sense this and trigger two things;
- 400 lbs of sodium bicarbonate (baking soda) gets dispersed, both inside and out of the quench tank, extinguishing any fire there may be.
- Then the butterfly valve opens automatically, dumping the 12,000 gallons of oil (in 30 seconds) to the underground tank. This gets rid of the fuel, and the flames, two sides of the triangle, thus no fire.
This oil quench system is automatic and will go off on its own, even if we lose power. The system can also be manually activated. ------ We know the system works with 100% integrity, as we have activated it.
All the best automatic systems will do no good without proper fire safety training. Prevention is the greatest cure.
We also have installed a FIRE SUPPRESSION SYSTEM in this same oil quench tank. It is 100% manual. We know the nature of the oil quench load that we will be quenching, and temperature, so when we have a large square foot load, say over 1,000 square feet. As well as a high austenitizing temp. (1800 to 2000 degrees F), we know that we will get a HUGE oil and air flash column as high as 30'!
So 30 seconds before we quench, we discharge the first of 2 tanks of 75 lbs. of CO2. This displaces the air that is 4' down inside the tank, and replaces it with cold CO2. The results are a safe and amazing quench, with only 2' to 3' of flames that get extinguished immediately because we eliminated the oxygen. We actually have a second tank that we can discharge if needed as a back-up. There are two (2) activation switches at each end of the quench tank that allow the discharge of one, or both of these tanks, singly, or simultaneously. So we feel comfortable and safe when oil quenching at Donovan's.
All of these systems are tested twice annually, and a full cleaning and Preventative Maintenance Procedure is done annually.
We also have two (2) T/C's in the oil to measure its temperature. One of the T/C's is connected to an audible alarm that is set to go off at 320 degrees F, and then a flashing red light that is set to go off at 350 degrees F. We can set these alarms wherever we want, as it is crucial to know the flash-point of your quench oil. Our quench oil flashes at 375/380 degrees F.
I know I have provided a lot of information here, as our oil quench tank fire is an event I will never ever forget. Trust me, I do not hear fire sirens the same way anymore since that historic date 28 years ago. Some day I look to write a book about this significant event, as well as many others I have experienced as a 5th generation Heat Treater! Most of you reading this are the best of friends. Thanks to our trade association ties through the MTI --- or as I like to call it, my Heat Treating family, our business rebuilt and is thriving today because of those association connections.
As far as the "open oil tank" issues with insurance companies. We have been specific about the definitions of our tanks as follows:
- None of our tanks are considered storage tanks, because they are not that. Our open top oil quench tank is just that…a quench tank. By OSHA standards, if any open tank’s sides are not more than 3' above floor level, there must be a railing or guard to prevent persons from falling into the tank…no matter what is in the tank. Our quench tanks are 4' above floor level, railing is not required, and we can easily look into them without any threat of falling into them.
- Our 15,000 gallon dump-tank is just that, defined as a “dump-tank." It is not a storage tank, as OSHA has much more strict requirements for those. We have engineered a man-way access to get into the dump-tank if need be, and have a pump to get the oil back into the quench tank if need be.
If anyone would like more specifics about the engineering, or name of the company that helped us to custom design all of this, the information is:
Keystone Fire Protection
Mark Smith
267-464-1214
mark.smith@keystonefire.com
Other comments from members:
General Comment 1:
We hired a few guys who were also volunteer firefighters, we had them demonstrate and train all of our employees, including office staff in the proper use of fire extinguishers. One of these long-term employees was on our health and safety committee for a number of years. We also installed a street legal fire hydrant on our 26,000 gallon water quench tank that the local fire department have unobstructed exclusive excess to, which they test from time to time. We have a unique benefit of having the quench tank outdoors, which is heated or cooled as needed.
General Comment 2
With respect to training employees to put out fires, we have run into issues with OSHA. There is specific training if you have people on site who are expected to actually 'fight a fire' (anything outside of operating an extinguisher and calling 911...this makes them a 'fire brigade’) .... the local fire departments do not have issues, but OSHA training is extensive and for us, not realistic. We had a nitrogen suppression system on our open oil, which we have since had converted to polymer. Insurance companies hassled us relentlessly over the open oil system, even though we never had any incidents. Several refused to quote.
General Comment 3
We also do similar things. All of our IQ and pit furnaces are piped with “emergency nitrogen” that kicks on when power is dropped out. This was originally installed to protect customer’s work during a power outage…but also serves as a way to snuff out a fire should it start in the IQ vestibule. Our open oil quench tank is equipped with (2) CO2 heads tied to (2) 100 lb. tanks, which are supposed snuff out a fire. The pull station has just been relocated to an area away from the quench tank so no one has to be subjected to a fire to activate the system. This system is complimented with our other fire extinguishers, including large purple K units and several CO2 and ABC powder units.
In addition, we conduct annual fire extinguisher training with all employees (including office personnel). Training is done by our local fire department, whom we have an excellent relationship.
General Comment 4
Having suffered through two fires, one of our own doing, I can say for certain the fire departments want to help, but keeping them out is the safest policy. We now utilize a multi prone approach to deny the fire of oxygen, by use of a lid to tamp down flames, remotely activating an argon gas blanket and the use of “purple K” fire extinguishers. These are employed when a standard CO2 extinguisher or an ABC will not work. Ultimately the evacuation of the oil to a safe storage location that is activated by an independent thermocouple, set to below the open cap flash point, and run off a nitrogen operated diaphragm pump is where I want to go. This is the ultimate “non-human” safety measure, but requires capex and space considerations. I have been told by fire safety consultants and ex firefighters, that the best thing to do is prevent them from showing up. We had a fire that the response team, real firefighters, turned into a million dollar loss, cancellation by carrier, massive increase of premiums, to which I got a half-hearted unofficial apology.