This article is inspired by two recent books. “Fastest Water” is a term cited in Billy Goldfeder’s new book Pass It On, The 2nd Alarm. The term itself comes from the National Fire Sprinkler Association’s work toward providing sprinklers in private dwellings. The idea is that the fastest way to get water on dwelling fires is residential sprinklers. And of course making sure sprinklers are properly designed, maintained, and are not defeated by the fire service is the overall objective of this column.
The second is Sun Tzu and the Art of Fire Service Leadership by Arron Johnson, an Aircraft Rescue and Firefighting (ARFF) trained firefighter. It’s all about preplanning, knowing the enemy, and knowing your own strengths and weaknesses.
This two-part article will address five topics: 1) Boil-Over Prevention, 2) Attacking airport tank fires with ARFF apparatus, 3) Fastest sprinklers for warehouse fires, 4) Structural blitz attack, and 5) Large industrial monitors.
For as long as I have known David White, Industrial Fire World Publisher, he has stated that the only way to prevent a boil-over1 is to put the fire out. Putting the fire out therefore is a race against time. Everything that can be done to have resources in place will help win that race. Unplanned gathering of resources is likely to take more time than is available and the race will be lost. Sun Tzu would not have faced such a fire but his ancient methods of preparation would apply today.
Attacking airport tank fires with ARFF apparatus
Conventional wisdom is that tank fires, or any flammable liquids fire for that matter, should not be attacked until enough foam resources and other resources are on the scene. The primary rationale is that the foam supply is a limited resource and if an attack is not successful because it cannot be sustained for long enough, then the foam has been wasted and foam resupplies might not be sufficient to mount another attack.
Consider an 80 foot (24.4 meters) diameter jet fuel tank with a full surface fire. The NFPA required foam supply is 1266 gallons (nearly 4800 liters) of 3% AFFF2 for extinguishment. Most experts recommend that this amount be doubled for post- extinguishment security. This is based on a flow rate of 804 GPM (3043 l/min). This flow is well within the range of most ARFF vehicles turrets3; therefore the foam and water supply is the limiting factor. Both foam and water can be resupplied but staffing levels at many airports may result in a delay in establishing resupply.
Although not stated in NFPA 11, the 50 minute duration assumes a pre-foam application burn time that likely significantly exceeds the response time of ARFF apparatus. Prolonged burning causes tank shell fold-in and creates super-heated metal that foam may have difficulty sealing against.
If two or three ARFF apparatus can begin attack in a few minutes and apply foam at a significantly higher rate than required, should they do so? It might be possible to attack the fire while it is more like a pit fire and less like a tank fire that has been burning for a long time. We hope to get comments on this. Please contact me at the e-mail address below, or else to the editor. The responses will be the topic of a future article.
The author was assigned to one facility where the plan was to try to quickly overwhelm the fire with a mass application attack from ARFF vehicles. We would try to establish water and foam resupply quickly enough to sustain the attack. If that failed, we still had enough foam to mount a more conventional attack as envisioned by NFPA 11.
This is a decision that should be made in advance. It can be adjusted for the fire ground conditions but an adjustment cannot be made to a non-existent plan.
Items 3-5 will be addressed in part 2 of this article.
Feel free to contact the author at [email protected] C
John Frank is Senior Vice President of the XL Catlin’s Property Risk Engineering / GAPS Loss Prevention Center of Excellence, where he is involved in loss prevention research and loss prevention training. XL Catlin’s Property Risk Engineering / GAPS team provides property loss prevention consulting and delivers individually tailored solutions to protect and enhance property, production, and profit. With approximately 220 engineers and consultants in 18 countries, the team brings clients occupancy specific experience as well as deep knowledge of specific hazards across industries. The XL Catlin insurance companies offer property, casualty, professional, financial lines and specialty insurance products globally. Businesses that are moving the world forward choose XL Catlin as their partner. To learn more, visit xlcatlin.com.
1 According to NFPA Standard 30, Flammable Liquids Code, a boil-over is defined as “an event in the burning of certain oils in an open top tank when, after a long period of quiescent burning, there is a sudden increase in fire intensity associated with expulsion of burning oil from the tank”. Boil-overs have been discussed extensively in this magazine and elsewhere. A reader not already familiar with the devastation that boil-overs can cause is urged to research the topic further.
2 NFPA 11, Foam Systems, requires 0.16 gpm/ft2 for 50 minutes for Jet A fuel plus 100 gpm for supplementary hose steams for 20 minutes. In SI units 6.5 mm/min are needed plus 380 l/min for supplementary hose. NFPA 11 does not allow monitors (turrets) as a primary means of protection; however, monitors are commonly used. Further, airport tanks are typically floating roof tanks so turret use for full surface fires would be considered a secondary scenario.
3 The new USAF Ultra High Pressure Turrets are not considered here.