On August 27, Morrisvale (WV) Volunteer Fire Department Chief Engineer Jason Estep presented “Rural Water Delivery,” a Webcast on efficient rural water delivery for suppressing fires in small town USA (Watch the archive HERE). Below are some of his answers to questions posed by students during the presentation. Sponsored by Kochek Co., Inc.
Q. Should a 3,000-gallon tender have a 3,000-gallon drop tank, or 2,000?
A. I believe in carrying as big a dump tank as possible on your truck. I would recommend at least a 3,000-gallon dump tank on a 3,000-gallon tanker. I actually prefer to size the dump tank 5,000 gallons, or larger than the tank capacity. This is helpful in the event that the dump tank is unlevel, allowing you to still hold your 3,000 gallon capacity.
Q. With 12,650 gallons on the first-due assignment, comment on scenario that would transition to drop tanks. Assuming about a three-mile fill site.
A. The best practice that my department follows is that the first-arriving tanker will establish dump tank operations. This allows the transition to dump tank operations to occur early on in the incident, which is when we need our water and higher flow rates the most. Knowing that you are front loaded with 12,650 gallons on the first-due should allow you to sustain 500 gpm for more than 20 minutes and working from the dump tank will allow you to flow higher flow rates (750-1,000 gpm) for short periods of time. It will also allow you enough cushion to establish a fill site operation and have tankers return before the dump tank runs dry.
Q. What’s your opinion on best method for tank-to-tank transfer–jet siphon or drain-to-drain?
A. I think jet siphons are much more effective than drain-to-drain. The goal is to keep your primary drafting tank as full as possible, which is hard to do in a drain-to-drain setup since the water level will equalize between the tanks. The jet siphons will allow you to control the rate at which you transfer water into the primary tank.
Q. What is the longest distance that you can pull a draft through hard suction?
A. I have personally drafted through 132 feet of hard suction using the vacuum tanker. We have performed vertical lifts of 27 feet at about 850-900 foot elevation.
Q. Does the United States have a water tanker shuttle accreditation system for fire departments? We use this system in Ottawa.
A. In the United States, We use the ISO 2 hour tanker shuttle exercise, which is very similar to the Canadian system.
Q. We are on pipe line, use all 5-inch line, but our engine, piped for 3-inch, uses a 5-inch gated 5X5X5 valve.
A. Have you ever considered a scenario where the water system fails? I agree that 5-inch is very effective on hydrant systems, but what is the backup plan?
Q. How fast can the vacuum tanker fill itself?
A. Typical fill rates are 1,000-1,350 gpm. In extreme vertical lifts, the fill rate will reduce to about 700 gpm, but in many cases it allows you to access water that you would have previously driven by, so you are still saving time. We normally fill our 2,000-gallon tankers in about a minute and a half to two minutes.
Q. Is the vacuum tanker able to draft a higher capacity and height than a pumper?
A. The vacuum tanker is able to draft at a higher height than a pumper and can fill at rates of 1,000-1,350 gpm. The tanker can also fill through long lays of suction hose (I have filled a 2,000-gallon vacuum tanker through 132 feet of 6-inch hard suction in two minutes and 24 seconds, for a fill rate of 833 gpm). The other advantage is that if it sucks air, it will not cavitate like a normal pumper; this allows operations from shallow streams that would otherwise be unusable. Putting all this together, the vacuum tanker will make water available that previously was unattainable in your area. You are basically only limited by the amount of suction hose you carry on your truck. We carry more than 70 feet on each of our tankers, but the greatest advantage of a vacuum tanker is that the fill site pumper and the fact that the staffing required to operate it is eliminated!
Q. Our department responds a 2,000-gallon pumper tanker as its first-due apparatus. In our own district, the next arriving apparatus are an engine with 1,000 gallons and a quint with 300 gallons. The department with the quint also has a 5,000-gallon tanker, but limited staffing didn’t always allow it to respond. With this first-due mix, what is your suggestion to maximize initial flow? As an additional complication, our pumper tanker only carries a frameless dump tank. Do you have any suggestions for to maximize its use?
A. Would it be possible to ask the department with the 5,000-gallon tanker to staff it before staffing the quint? With no water supply, the pumping capacity and aerial waterway on the quint will be of little use. Assuming that the 1,000-gallon engine is responding from the same station, could you consider it as a first-due piece and the pumper tanker as second-due and establish a dump tank operation on arrival? This would give you 8,000 gallons on the initial alarm, which means a sustained flow rate of 500 gpm for about 16 minutes, with the ability to hit higher flow rates for short periods of time while from the dump tank.
The frameless dump tank does complicate matters some. They work pretty well on level ground once they are full. Getting them full initially can be a battle at times, often spilling valuable water that we need at the start of an incident. Would it be possible to add a rigid tank carrier to your truck? Could you carry one on a rack in your hosebed above the hose? I encourage you to practice a few different scenarios with the departments involved to see what would be the most effective.
Q. We have 1,000-gallon soft round drop tanks. What is the advantage to rigid frame? Ours fit into a duffel bag, but are at a disadvantage on unlevel ground.
A. The advantage of the rigid frame tank is that is more forgiving on unlevel ground, as you mentioned. The other reason I prefer the rigid tanks is that you can use all of your water on the initial fill. I have experienced situations where a good deal of the water is “spilled” trying to get the self supporting tank filled the first time. Since our greatest need for water is at the beginning of a fire, I feel this is a big disadvantage for the soft tank. I think the soft tanks can be an option for longer-term incidents, especially wildland-interface operations, where you have a little more time to establish water supply.
Q. Are you not worried about the long distances for supply hose friction loss in the vacuum tankers? Most information I have read says not to exceed 20 feet lift and 30 feet length for drafting operations.
A. That is correct for a centrifugal fire pump. The great thing about a vacuum tanker is you are basically only limited by the amount of hose that you carry for a long hoselay. We carry a minimum of 72 feet of hose on each of our vacuum tankers (see above answer for filling time and rates). We have filled our vacuum tanker through a vertical lift of approx 27 feet at a fill rate of 700 gpm. While these flow rates are reduced from the normal fill rate of 1,300 gpm, it is a much better option than driving another mile to find a suitable fill site. This capability of the vacuum tanker enabled our department to take advantage of many water sources that we had driven by in previous years.
Q. Please review the formula for needed dump tanks on scene.
A. A rule of thumb I use for the number of dump tanks needed is to take the tank capacity and divide by 10. So I figure that a 3,000-gallon tank is good for 300 gpm. If I estimate that I will have a sustained flow rate of 800 gpm, it is reasonable to assume that it will take the capacity of three tanks to achieve this during a sustained tanker shuttle.
- Water Supply: The Great Debate
- WATER TANKER SHUTTLES: 10 RULES FOR SUCCESS
- ESTABLISHING A WATER SUPPLY
- ENSURING A CONTINUOUS WATER SUPPLY
- Prepare to Ensure a Sufficient Water Supply
Jason Estep is Chief Engineer of the Morrisvale (WV) volunteer fire department with 21 years of service. He has a Mechanical Engineering Degree from Fairmont State university, and is currently employed as a senior maintenance planner for a major coal company.