By Author(s): Paul Shapiro 
Published Sunday, May 17, 2009
| From the May 2007  Issue of FireRescue 
We all know why a quick knockdown on a fire especially by first-in companies is important: It minimizes destruction. A blitz attack can be accomplished whether your first-due company has five firefighters or two but smaller crews require creative techniques to accomplish a blitz attack. In this article I'll discuss a specific weapon of choice for a blitz attack that's ideal for minimum staffing: the 1 ? handline.
Four key factors contribute to the overall positive performance of a blitz attack handline:
- Ease of deployment from the hosebed and while advancing;
- The required flow;
- Stream performance; and
- Nozzle- and hose-handling techniques.
Let's examine each of these techniques and how a 1 ?" line measures up to a standard 2 ÃÂ«" blitz line for each of them.
Ease of Deployment
Just like fully staffed companies minimum-staffed units must be able to deploy and deliver large-flow lines quickly. The standard 2 ÃÂ«" high-flow handline provides the most efficient means for delivering high handline flows when it comes to the required engine speed (rpm) and pump discharge pressure (PDP). Example: Based on actual flow tests a 200-foot 2 ÃÂ«" blitz line pre-connected to the rear 2 ÃÂ«" discharge can deliver flows ranging from 250-500 gpm with an automatic nozzle.
Chart 1 shows the flows and their corresponding PDPs both in the standard 100-psi base-pressure mode and the low base-pressure mode.
Although the PDP and flow range are quite efficient for the 2 ÃÂ«" the trade-off-heavy hose to pull-can greatly hinder its deployment especially with a low-staffing scenario. A charged 200-foot 2 ÃÂ«" blitz line weighs approximately 533 lbs.; a charged 50-foot 2 ÃÂ«" weighs approximately 133 lbs. Realistically you can expect to extend at least 50-100 feet of the line during fire attack once it has cleared the bed. Again this can be difficult for a low-staffing operation.
The 1 ?" hose provides a realistic alternative. It's a lot easier to pull from the hosebed and extend when charged. A charged 50-foot section of 1 ?" hose weighs 71 lbs.; a charged 200-foot section weighs approximately 284 lbs. Depending on the mode of operation one to two firefighters can easily work the line.
When a high-flow handline is required for an interior attack the 2 ÃÂ«" line can work providing there's sufficient manpower usually four to six firefighters. Note: No matter the flow the weight of the 2 ÃÂ«" line remains the same but flexibility especially at the nozzle diminishes as the flow range increases.
If you lack sufficient manpower for a 2 ÃÂ«" line you can deploy a 1 ?" high-flow line as easily as an interior standard-flow attack line (120-180 gpm). Does a high-flow high-pressure 1 ?" handline become rigid and hard to work with? Is the flexibility diminished? To see for yourself try a simple test. Charge a 1 ?" handline and throttle up to 250 PDP but do not flow water. Next drag the line through an obstacle course such as the burn tower fire station or other realistic environment. You will notice little rigidity at the nozzle; the firefighter's stream-directing capabilities should not be affected. The rest of the line should be just as easy to drag through the hallway and around corners as if it were pumped at a common interior-attack handline pressure.
The Required Flow
Since we are looking to replace the 2 ÃÂ«" handline with the 1 ?" handline should we expect to get 2 ÃÂ«" flows? The answer is yes to a certain degree. But before we discuss flow capabilities of the 1 ?" handline we must take a closer look at the available types of 1 ?" hose. Hose that's 1 ?" means just that: The hose has an inside diameter of 1 ?" or 1.75 inches right? Well here is where it gets interesting. For some reason not all brands of 1 ?" hose have a diameter of 1.75 inches; some brands actually have a larger inside diameter such as 1.85 inches or 1.88 inches. They are still called 1 ?" and purchased as 1 ?". And they have the same weight as the standard 1 ?" hose.
Why is this allowed to happen? I don't know. In fact I don't care. What I do care about: The larger inside diameter 1 ?" hose has far superior flow capabilities over the standard 1 ?" hose. I like to call it the 1 ?" "super hose." The super hose flows more water at a lower PDP than the standard hose while maintaining the same basic weight and maneuvering capabilities. Tip: To obtain a super hose ask the manufacturer for the actual inside diameter.
Using a 200-foot 1 ?" high-flow handline and a 250 PDP the following flows are capable:
HoseÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ Inside DiameterÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ GPM
1 ?"ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ 1.75 inchesÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ 250
1 ?"ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ 1.88 inchesÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ÃÂ¿ 345
The goal of a fire stream delivered from a high-flow handline nozzle is to put a large volume of water on a high-volume burning fire; in essence to achieve an overwhelming knockdown as quickly as possible. This requires a stream with a high gpm capability and the velocity to reach the fire. Most standard interior-attack combination and smooth-bore nozzles used for low-flow interior-attack operations can also be used in a high-flow scenario. The trade-off for the higher flows is a higher PDP. Pressures ranging from 200-300 psi will need to be obtained. I know this sounds like a lot but this elevated pressure is well within the hose manufacturer's maximum allowed working pressure and with proper hose handling techniques will be safe and efficient to handle.
Chart 2 lists several nozzles both smooth-bore and combination their rated flows and a corresponding nozzle base pressure and/or a nozzle exit pressure (also known as nozzle pressure). Note: All flows in the left column were obtained with 1.75" inside diameter 1 ?" hose. All flows in the right column were obtained with 1.88" inside diameter 1 ?" hose.
Nozzle- & Hose-Handling Techniques
There's no question that the high-flowing 1 ?" handline can be difficult to handle unless certain techniques are used. The traditional standing position is the most difficult method to use. It's important to realize that the full flow of the nozzle will not be obtainable while advancing. This is where nozzle control by the firefighter comes into play. Only flow as much as you safely can. A minimum of two firefighters is recommended.
If the firefighters are using a high-flow handline there's a good chance the fire will be high in volume and intensity and will probably require them to be down low to avoid the heat. A common 2 ÃÂ«" hose-handling technique is a stationary sitting position on the line at the nozzle. This allows the nozzle reaction to be stopped if you will at the point where the firefighter's body meets the hose and ground. This technique has always been done with a Keenan loop for stability but flow tests have proven that the loop doesn't need to be used.
The same sitting technique can be used on the 1 ?" handline as well usually with only one firefighter but in some cases two. A modified version of this operation utilizes a kneeling technique. The firefighter drops to both knees straddling the line perpendicular (facing it) with the hose going under the rear leg and over the front leg. I like this technique the best because the firefighter can get into and out of the position quickly while advancing the line.
No matter which technique is used there will be a slight tendency for the hose to kink right behind the nozzle due to the nozzle reaction. Being aware of this problem and using proper technique to correct the kink is all that's needed to rectify the problem: Simply push against the kink with one hand.
A Final Word
Being progressive keeping an open mind and continually evaluating equipment and techniques produces new possibilities for blitz attack. You won't find most of what you read in this article in the standard fire stream books in circulation today. Does that mean that using 1 ?" handlines is not an acceptable way to deliver high flows? In my opinion it does not. At no time do any of the above-mentioned flows nozzle combinations nozzle pressures or techniques go against what the manufacturers say their equipment can do.
If you like what you've read don't implement it tomorrow-first practice practice practice. Feeling comfortable and confident is the key to success.
Comment Now: Post Your Thoughts & Comments on This Story