Jason Estep - Excerpts from article written from experience
Morrisvale VFD, West Virginia
Understanding Fire Service Vacuum Apparatus and Comparisons to Conventional Apparatus. There have been many strides made in fire fighting technology in the past 100 years. At the beginning of the 20th century fire fighting equipment consisted of a steam powered piston pump pulled to the scene of a fire by a team of horses. Once the apparatus arrived on scene some type of water source had to be secured in order to effectively fight the fire. Modern day apparatus have evolved into high horsepower, high volume pumping machines that have tremendous advantages over earlier apparatus. However, one thing remains the same, once arriving on scene a water source still has to be established in order to properly extinguish the fire.
Since the majority of the United States is rural, many communities are not blessed with water systems and if they are it is often a weak system. Regardless of the reason for a feeble water supply the fire department is still charged with the responsibility of properly controlling fires within their community. This has caused most fire departments in rural America to depend on streams, ponds, lakes, rivers, etc. to provide water for fire fighting operations. The only problem is to get it from the source to the fire. In order to do this tanker shuttle operations are set up. A tanker shuttle consists of individual trucks, usually with large tanks, transporting water from point A to point B.
The flow rate of a tanker shuttle is dependent on two variables: dump time and fill time. The ISO formula travel time in a two mile shuttle is a constant 35 mph. In order to increase flow rates departments began to try to lower the fill and dump time. Lowering the dump rate was easily accomplished by placing 10" Newton gravity dumps on trucks. The problem is you can not dump what you have not first loaded. In order to decrease fill times, large quantities of manpower, hose, and at least one 1250 pumper must be committed to fill a tanker. As a rule of thumb the fill site pumper will only be operating at 70% efficiency. Combine that with the fact that most conventional tankers have only one 2.5" direct tank fill and you can see the difficulty in lowering the fill times. Now, examine the amount of manpower needed to fill the conventional tankers. You must have a fill site pump operator, at least one person per tanker (in a large shuttle) to connect the hoses, one person tending to portable pumps/drafting operations,a driver for each tanker and in a large shuttle more fill site pumpers to reduce wait time.
Next, let's examine the set up time for a fill site operation. A drafting operation has to be set up, whether it is directly from a water source or from a dump tank being supplied by portable pumps. In the event that portables are used, time must be taken to set them at the water source, stretch the lines, and get the dump tank set. Once the drafting operation is established fill lines must be laid out along with any adapters, appliances need to fill each tanker in the shuttle. This all has to be done while the attack crews are fighting the fire and needing the water the most: at the beinning. There is no doubt that after everything is setup, with enough manpower and trucks that an efficient shuttle can be established, it is usually well into the fire suppression effort that it is established. Most of the time our tankers do not meet the needed fire flow, but the fire burns down to the flow rate provided by our tanker shuttle before it is extinguished.
If there was a tanker that could cut the manpower required at the fill site by more than half, fill itself without a pumper, and double the flow rate of an ordinary tanker. Sounds impossible? If a tanker like that was available it would revolutionize the fire service. This tanker does exist in the form of a vacuum tanker. It works using a very simple, yet efficient system that requires little maintenance and is easy to operate. Vacuum was introduced into the fire service market in the mid-1980's by Firovac. Although vacuum had been used for years in the industrial field, it had never been engineered for the fire service until 1980.....................
As tested, a Firovac tanker can create and maintain flow rates close to the 250 gpm required by ISO by itself. It can self load at approximately 1000 gpm (usually more, but 1000gpm is a safe "average" number for Firovac) and self unload at 1250 gpm. It can load from available water sources (ponds, creeks, portable tanks etc.), from remote locations through 48' of hose or more (limited in a horizontal lay only by the hose carried: and vertical lifts of 28'.
Now remember that it was stated earlier that you will normally only get 70% efficiency from the fill site pumper. To prove the 70% efficiency, think about a normal fill site. The pumper usually has 2 or 3 fill lines running at the same time. As a basic rule figure 250-275 gpm per line. That is 750-825 gpm that the pumper is producing. Let's be generous and go with the highest number, 825 gpm/1250 gpm capacity x 100% = 70%. What about the other 30 percent, or 375 gpm that is being "wasted"? (Although this formula has never been published, if you refer to many articles previously written by various authors, and have observed many tanker shuttles, the figures hold true. Another rule of thumb derived from the same criteria used above is, each conventional tanker has the capacity of supplying 100 gpm ISO calculated sustained flow rates.)
This is how Firovac can enhance a conventional tanker shuttle. It wants that extra 30%. Set a dump tank at the fill site pumper and pump that extra 30% of unused capacity into it while the Firovac is gone. In approximately 5 minutes there will be enough water to fill a 2000 gallon tank. When the Firovac tanker returns, the dump tank is full and he can self fill from it. Most of the time, under actual fire conditions, a Firovac tanker will find a water source closer to the fire than the main fill site, that would be unattainable by conventional units. There have been instances such as this where a Firovac has delivered 3 to 4 loads of water before a conventional has returned with his first load.
How does vacuum work? Vacuum works simpsly by extracting air from a closed container which causes a negative pressure in the container, allowing water to replace it. This movement of air is caused by a vacuum pump. There are several types of vacuum pumps. They are rotary vane and piston or displacement pumps. The two most accepted rating stndards for vacuum pumps in the United States are CFM (cubic feet per minute), which is when the displacement capacity of the pump is measured in expanded air at 15 column inches of mercury. (Vacuum degrees are measured in inches of Mercury. As a vacuum pump reduces the atmospheric pressure on top of the calibrated column on Mercury, a measurement can be taken) The other accepted rating standard is SCFM (standard cubic feet per minute) when the displacement capacity of the pump is brought back to normal atmospheric pressure and measured at free air. Care should be taken to make certain that the comparison of pumps is done by the same rating standards. It should be done at 15" of Mercury so as to show the pumps efficiency at working levels of vacuum. In conjunction, it should be judged for its maximum vacuum capacity. If properly constructed, the vacuum pump will be just one part of a system that allows the vacuum tanker to meet its performance and safety requirements...................
.............In summary, if properly constructed, vacuum tankers can supply more water to a fire with less personnel and expense because:
1. They load from available water sources and do not have to return to town or a hydrant system to get water.
2. Set up time is quick and easy using minimal personnel.
3. Self load times are quick and easy.
4. Vacuum tankers can provide twice the water at the same distance, in the same time period as a conventional.
5. Vacuum tankers can utilize all the pumper's capacity.
6. It pressure unloads all water in the tank quickly, recognized as a "zero loss" tanker by ISO.
For the complete article contact Jason Estep at email@example.com or Firovac
Vacuum Vs Conventional
Jason Estep - Morrisvale VFD
Since mankind began fighting fire, through all the advances of technology, one thing has remained common in the fight: water. Rural departments around the country have always felt the need to conserve water on the fire ground due to the lack of sufficient water supplies. I understand these problems first hand with no hydrants in the fire district. One day our Chief picked up a magazine where a company claimed a tanker could fill itself (2000 gallons) in about a minute and a half. We were skeptical so we told him to "prove it". Once we watched the trucks operate we realized we found something that would help solve some of our problems. After receiving our trucks we realized immediate benefits from this. Now instead of committing the entire department to water supply operations, we now sent 2 people in the tanker to supply the fire ground with a sufficient water supply.
In 2002 at the Lincoln County Fire School we compared conventional tankers to vacuum tankers. We had 2 conventional tankers and a class A 1250 GPM pumper to fill them and 2 vacuum tankers. The only area we focused on was the fill time, since most tankers can dump at about the same rate and travel time is constant. We see the fill time as the only area that can be improved in order to maximize the flow rate of a shuttle.
Filling the conventional tankers in a efficient manner took quite an effort. One 1250 GPM pumper, two 2500 gallon dump tanks, two float pumps, 20' of 6" suction hose, a 5" hard suction used as a transfer tube between dump tanks and hose ranging from 2.5" to 5". Twelve people had to be committed to the water shuttle in order to make it run smoothly. Since the stream had a good water flow, but was very shallow we had to construct a makeshift dam in order to utilize the water. Two float pumps were set in the stream with one 3" line coming into three 2.5" to 5" hose manifold. The 5" hose was then run to the second dump tank. A siphon was connected to a piece of 5" hard suction and a 1.5" line from the pumper was connected to the siphon. This setup was used to transfer water from tank 2 to tank 1. Once both tanks were full we began to fill the conventional tankers with two 3" lines and quick connect fittings to save connection time. The pump operator was then instructed to pump the fill lines at no more than 100 PSI due to the manufacturer warranty on most tanks.
The two Firovac vacuum tankers go up stream from the conventionals and lay all 88' of 6" suction hose from the two trucks. No dam was constructed. Instead a Firovac low flow strainer was used in approximately 4" of water. A total of 3 people operated the vacuum shuttle, the 2 tanker drivers and a helper to connect and disconnect the suction hose. Each tanker filled in 2 minutes and 24 seconds (2000 gallons each through 88' of suction hose. That is a flow rate of over 1666 gallons per minute for the 2 tankers.
The advantages of using a Firovac tanker are obvious: superior fill and flow rates using less tankers, less people involved which means more people on the fire ground fighting the fire, less equipment involved which means cheaper maintenance and more equipment on the fire ground and the fill pumper now becomes the backup pumper on scene.
For questions contact firstname.lastname@example.org
Chief Ken Becker - New Pittsburg VFD
Everyone talks about increased flow rates with a vacuum unit. While this is true, we have two Firovacs because of the personnel savings, which is critical to our rural department.
Assistant Chief Alan Altoff - Bear Branch VFD
The useable water sources in our fire district went from 17 to 95 with our Firovac unit. It is such a simple system that fits into rural water supply perfectly.
"Exceeded Our Expectations"
Gary Pullen - Former Fire Chief Cherry Grove Fire Dept.
When a fire department buys a new piece of equipment, and expressly if it is something different than most have, you do so with some apprehension.
After spending time, and putting to the test the Firovac Vacuum Tender, it has exceeded our expectation.
Supplying Water Without a Hydrant
Chief Butch Speelman - Fredericksburg VFD
" I admit I was not for a vacuum unit but some of my guys were. Within 2 weeks of the delivery of our Firovac we had a barn fire. The closest hydrant was 3 miles away. The Firovac unit went to a creek closer and supplied four 1800 Gallon Loads of Water, (7200 Gallons), before another load could be supplied by any other unit."
No Hydrant, No Problem
Chief John Lovejoy - Mud River VFD
We were called for a tanker assist to a structure fire in a rural area. Upon arrival we unloaded our Firovac tanker into the drop tank. Within about 600’ we found a shallow water hole to load from. All the other guys had to drive 3-4 miles to a hydrant...
We hauled all the water to the fire after that.
"Wouldn't Trade It For Anything"
Jack Conklin - Decatur VFD
A majority of the members in our department were skeptical of the Firovac apparatus at first, but now, they wouldn’t trade it for anything! Our Firovac will outperform any other apparatus in our area, two to one.
"Excellent Fire Truck"
Chief Jim Delman - Sunset Heights VFD
The Firovac is an excellent fire truck. It made our part simple. We didn’t have to worry about having an engine to fill us.
Chief Dick Glessner - Sterling VFD
Thank you for servicing our Firovac unit so quickly. We have put nothing into this truck since purchase (6/05), so, I don’t mind spending some now (8/12).