Saturday, October 27, 2012

Diversity in hose lines: a simple key for success

I am well aware that this is a topic that will often get the guys emotions going. I also know that not every run is the same. So why do we have hose lines that are the same length and size on the same truck? Why are we not diversifying our loads to give more variety in selection? If your company has thought outside of the box and diversified your hose lays, I applaud you. 

I give this example to illustrate the concept.

A cop pulls up to a bank robbery. He pulls his 9mm handgun. The bank robber drops his handgun and pulls out a shotgun. The cop runs to his cruiser and opens the trunk, and pulls another 9mm handgun. A second bank robber emerges and is holding a rocket launcher. The cop calls for SWAT backup. They arrive with 9mm handguns.

See a trend here? We all know that the police carry a variety of weapons with them for quick, preset solutions and choice.

Taking a guess and assuming that the majority of fire departments have two cross lays that are the same size and length, a larger hand line off the rear of the truck that is maybe a little longer and supply line. You might even have a front jump line, booster line, or a trash line off the back.
A common crossly set up. Two 200' or identical pre connected lines.
A common front bumper "trash" line
A common large diameter handline and supply line
My question for you is, why don’t we have more of a preconnected solution at our fingertips? Why don’t we take a plunge into the new and pack several different length lines to give us a quick choice on the fireground.

For the sake of this article, lets assume we all ride a truck that has a front jump line, a booster line, two cross lays, and the possibility of 2 preconnected hose lines off the rear. A solid attack line setup recommendation would be:

150' 1.75" line off the front bumper
250' 1.75" line on the front crosslay
300' 1.75" line on the rear crosslay
300' 2.5" line off the rear
400' 1.75" line off the rear
The 2.5” line can be easily used for a courtyard long lay situation, but have the 3” option ready to go if needed. I am  fan of the courtyard long lay and I feel that it has it's place; but I have to think on a three man staffed truck, is having longer preconnected lines quicker and more versatile than setting up the courtyard. By courtyard, I am speaking of using a 2” or larger line to a gated wye with 1 or 2 attack lines supplied by the 2”or larger line.

DISCLAIMER: I am NOT saying you shouldn’t be proficient in the courtyard and preconnected lines. Any set up possible on your truck is your job, and when the boss calls for it, you better know your job.

Lets look briefly at the friction loss of my above scenario:

Front jump (150’ 1.75” line flowing 150 from a fog, rule of thumb 35 per 100): 152.5 PSI

Front crosslay (250’ 1.75” line flowing 150 from a fog, rule of thumb 35 per 100): 187.5 PSI

Rear crosslay (300’ 1.75” line flowing 150 from a fog, rule of thumb 35 per 100): 205 PSI

Large rear line (300’ 2.5” line flowing 250 from a fog, rule of thumb 15 per 100): 145 PSI

Long rear line (400’ 1.75” line flowing 120 from a ¾” smooth bore, rule of thumb 23 per 100): 142 PSI

In regards to the friction loss used, some rule of thumb charts may vary. Here is how the above is figured.

1.75” line flowing 150 gpm: 34.9 PSI actual loss, rule of thumb 35 PSI
1.75” line flowing 120 gpm: 22.3 PSI actual loss, rule of thumb 23 PSI
2.5” line flowing 250 gpm: 12.5 PSI actual loss, rule of thumb 15 PSI

Are all of the above friction loss scenarios possible for your truck to pump? I would think so. This whole idea is such a simple idea, but a major change for many companies. Lets run through it from the eyes of the right seat. Lets assume that your crew is so well trained that all you have to do is call the lay and it comes off perfect.

You pull up on a residential fire and see you have to cross the yard next door and you will need to enter on the Charlie side. You call for the long rear lay. The 400 is run and you end up only needing 250’.

Do you have enough? If you need to regroup or advance, is there enough to quickly change tactics? Both of the answers are yes.

Supply line is territory specific. Know what your territory calls for, what your mutual aid companies will be using, and what each type and size of supply line can offer your company.

When it comes to hose, I would rather have more than enough. Coming short solves nothing. Keep yourself open to new ideas, use the ones that work for your company, and create your own ways. Never let yourself become satisfied with the “way things are” because that is the “way they have been”.  Just this week, I was driving my vollie engine company to a first due working residential fire. We arrived on the bravo side, with an attack line stretch difference of 100’ to the front door. Most would have grabbed a shorter line, say 150’ or 200’. We pulled the 250’ and moved anywhere in the house the line needed to go.  Think “enough”, not “easiest”. Stay safe out there. 

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