Matching the Right Sprinklers to the Job

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.

Boil-Over Prevention

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.

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.