Pinning the Line
1996 was the year I entered the fire service as a volunteer, this was also the first year I read an article by Andy Fredericks. In his 1996 2 ½” Handline article for Fire Engineering Andy laid a foundation of support for an incredibly efficient weapon which at the time and in years following was largely falling out of favor in the American fire service. I would encourage you to revisit his piece as it bears repeating and expands on those topics which he explains much better than I could.
Within that article Andy presented not only reasons but also techniques for making the 2 ½” handline a more readily available weapon for your engine company and one of those techniques was “pinning the line”. As I am sure anyone who has had to have the 2 ½” handline debate, staffing is one of the first hurdles to overcome.
When you move up from an 1 ¾” attack line with the 15/16” tip and a flow of 185 GPM at 50 PSI (nozzle reaction of 66lbs) to the 2 ½” attack line with a 1 1/8” tip and a flow of 266 GPM at 50 Psi your nozzle reaction is also increased to around 96lbs. This jump in nozzle reaction force of about 30 pounds theoretically requires 3 firefighters on the line to manage those forces. This theory is based on the works of Paul Grimmwood on the abilities of firefighters to manage nozzle reaction. Since most handlines in the American fire service are being operated by two firefighters this becomes a quick ticket out on the big line……”we don’t have the staffing”
The first time I saw the technique of “pinning the line” was in that 1996 article in this photo by Matt Daly. Andy explains the method as the backup man pinning the hose to the ground using his hands and knees which allows the nozzle man to “freely operate and move the nozzle without the undue stress of the nozzle reaction.”
“Pinning the line” is a method to direct the nozzle reaction forces into the ground or walls instead of the muscles and frame of the firefighters. By applying this method we can counter reaction forces with technique instead of man power.
328 GPM from the 1 1/4″ Tip managed by a single firefighter
Over the years I have learned various forms of this technique. In 2005 while in Boise Idaho, Jay Commella and Daryl Liggins of the Oakland Fire Department presented a technique of pinning the line as a single firefighter by using your knee in place of the backup man. The key is ensuring that you maintain plenty of hose in front of you so small movements at the base (you) will keep the now common foundation and operator solid while getting maximum stream movement and use. After sharing this technique with several crews and groups I began to hear chatter that the knee on the hose method was “fine for the outside but not for the interior firefight”.
To counter that argument I present the fact that my overall profile in using a knee on the hose or traditional stance with the line is relatively the same, however if you insist on traditional stream positioning you can still utilize methods of pinning the line to absorb reaction forces.
Here the stream is maintained upward and the line directly behind so that energy is transmitted down the line and into the ground.
Finally we are back to the most traditional of attacks, two on the line pushing in. The backup man supporting directly behind the nozzle position by taking the nozzle reaction to the friction and collection point of the ground. All the while 250 to 325GPM is being thrown as far as 60’ ahead of this two person crew.