Fairmount
Fire Company
Water
Transfer Exercise
9/24/2013
About a week and a half ago a good friend invited me along to observe a series of tests of the potential to transfer water using jet siphon devices. The following results are our non-scientific data that were collected. It was a great opportunity to get some baseline data on a topic that has little published information.
The Fairmount Fire Company protects a portion of Washington Township, in Morris County NJ. Their response district includes some areas with hydrants, but is largely unhydranted. The company operates two engines a tender and a support rig. You can learn more about them at www.34fire.org
The goals of this drill were to;
- Test the potential flow rate of jet siphon devices using one and two devices
- Test the potential to transfer water up a grade through a jet siphon device
The setup for the
first part of the test included;
- (1) 3500 Gallon folding tank (Tank #1)
- (1) 2000 Gallon folding tank (Tank #2)
- (1) Kochek “JS60” power jet siphon device connected to (2) 15’ x 6” suction hose
- (1) Kochek “JS60 power jet siphon device connected to (2) 10’ x 6” suction hose
- Clamp-on hose bracket with (2) 2 ½” hose connection elbows on the 3500G tank
Preparation for tests #1-4
- Two tanks were set up approx 3-4 feet apart, on flat asphalt, with a slight incline
- The 3500 gallon tank sat on the “downhill” side
- The 2000 gallon tank sat slightly “uphill” from the larger tank
- E34-62 pumped its 1000 gallons of booster tank water into the 3500 gallon tank through the clamp on hose bracket.
- Once the booster tank had been emptied, a mark was made on the sidewall of the tank indicating the 1000 gallon water level
- Using a tape measure, corresponding marks were added for 500, 1500 and 2000 gallons along the tank sidewall. It should be noted that the 3500 Gallon tank was only able to hold about 2000 gallons due to the pitch of the parking lot
- (2) 15’ sections of hard sleeve were connected together and the Kochek jet siphon was attached. The intake for the siphon was placed at the lowest “downhill” point in the 3500 gallon tank
- 50’ of double jacket-rubber lined hose was connected from the pump panel discharge of Tender 34 to the jet siphon
- A stopwatch was set to 00:00
- After each test, water was pumped back into tank #1 by E34-62, utilizing the clamp-on 2 ½” hose connection bracket.
- Time was recorded at each 500 gallon interval
- 3500 Gallon tank on the "downhill side"
- 2000 Gallon tank on the "uphill side"
- 50' of 6" hard sleeve with an approximate 7' elevation
Test #1
Objective:
Determine flow rate of water from nozzle of jet siphon at different pump
pressures through 50’ of 1 ½” hose.
The “JS60” Siphon
used
The
jet siphon was evaluated and noted to have a single ¾” nozzle orifice with a 1
½” NH hose connection. It has 6” male NH
thread to connect to the hard sleeve hose.
A check of a smooth bore discharge chart shows the ¾” nozzle listed and
therefore we can deduct the measurements taken with the handheld pitot gauge
are generally accurate.
 |
| Water transfer back to original tank |
The
jet siphon was held by a firefighter and aimed into the portable tank. The handheld pitot gauge was used to measure
the pressure of the stream exiting the nozzle.
Results of Test #1
The
flow test resulted in the following performances.
- PDP - 75 PSI = 50 PSI nozzle pressure or approximately 120 GPM
- PDP - 100 PSI = 70 PSI nozzle pressure or approximately 140 GPM
- PDP of 125 PSI = 80 PSI nozzle pressure or approximately 150 GPM
- PDP of 150 PSI = unknown nozzle pressure – not tested
It
should be noted that the sharp 90 degree bend of the nozzle pipe in the device
results in a very broken stream, with fluctuations on the pitot gauge. The values measures represent a good “average
assessment” while holding the pitot gauge in the stream for approx 10-15
seconds.
The
following table lists the flow data collected
PDP Flow Friction Loss (Hose) Approx. Tip PSI Device
Loss (estimated)
75
PSI 120 GPM 34.6 PSI/100’ or 17.3 PSI/50’ 50 PSI Tip 7.7
PSI
100
PSI 140 GPM 47 PSI/100’ or 23.5 PSI/50’ 70 PSI Tip 6.5 PSI
125
PSI 150 GPM 54 PSI/100’ or 27 PSI/50’ 80 PSI Tip 18 PSI
150
PSI 160 GPM 61.4 PSI/100’ or 30.7 PSI/50’ 100 (estimate) 19.3 (estimate)
Test #2
Objective:
Determine flow rate of single jet siphon to transfer 1000 gallons of water from
one folding tank to another at 100 PSI pump discharge pressure.
The
3500 Gallon tank was marked at 500 gallon intervals with the top mark being
2000 gallons.
The
stopwatch was started when the discharge valve was opened. The water level started at the 2000 gallon
mark. When the water level reached the
1500 gallon mark the time was recorded.
It was recoded again at the 1000 gallon mark.
The
jet siphon was attached to (2) 15’ sections of 6” lightweight suction hose
Tank Markings made using a tape measure and a measured quantity of water (1000 Gallons)
Results of Test #2
With
a pump discharge pressure of 100 PSI the following results were achieved.
Water
level at the 1500 Gallon mark (500 gallons transferred): 1:27
Water
level at the 1000 Gallon mark (1000 gallons transferred): 3:22
Average
flow rate for 1000 Gallons 4.95
Gallons/second or 297 GPM
Average
flow rate for first 500 Gallons 5.74
Gallons/second or 344 GPM
Average
flow rate for last 500 Gallons 4.34
Gallons/second or 260 GPM
 |
| The discharge gauge readings between the main pump and the line gauge were virtually identical at the 100 PSI test |
Summary of Test #2
It
appeared that the first 500 gallons of water transferred at a higher flow rate,
while the last 500 gallons of the test transferred at a lower rate. The difference in flow between the first and
last 500 gallons was an 84 GPM decrease.
We felt that because the siphon action does not use the advantage of
positive pressure that as the water level in the tank lowers that it requires
more energy to raise the water up the suction hose, thus showing the decline in
flow.
The
average flow of 297 GPM also did not account for “prime time” of the siphon, so
the actual true flow rate might be slightly higher
Because
the known flow of the jet siphon nozzle at the 100 PSI pump pressure is
approximately 140 GPM, the average net flow rate of the transfer device is
actually 157 GPM. This could be considered the flow rate of
a single 1 ¾” handline
Test #3
Objective:
Determine the flow rate of two jet siphons to transfer 1000 gallons of water
from one folding tank to another at 100 PSI Pump discharge pressure
The
3500 Gallon tank was marked at 500 gallon intervals with the top mark being
2000 gallons.
The
stopwatch was started when the discharge valve was opened. The water level started at the 2000 gallon
mark. When the water level reached the
1500 gallon mark the time was recorded.
It was recoded again at the 1000 gallon mark.
The
first jet siphon (#1) was attached to (2) 15’ sections of 6” lightweight
suction hose. The 50’ section of 1 ½”
hose was connected to the pump panel discharge of Tender 34, shown below.
The
second jet siphon (#2) was attached to (2) 10’ sections of 6” lightweight
suction hose. The 50’ section of 1 ½”
hose was connected to the rear discharge of Tender 34. The discharge is located to the lower right
of the dump chute.
The photos show the
piping and location (lower right) of the rear discharge on T34
Results of Test #3
With
a pump discharge pressure of 100 PSI the following results were achieved.
Water
level at the 1500 Gallon mark (500 gallons transferred): 1:02 (62s)
Water
level at the 1000 Gallon mark (1000 gallons transferred): 2:12 (132s)
Average
flow rate for 1000 Gallons 7.57 Gallons/second
or 454 GPM
Average
flow rate for first 500 Gallons 8.06
Gallons/second or 483 GPM
Average
flow rate for last 500 Gallons 7.14
Gallons/second or 428 GPM
Summary of Test #3
It
appeared that the first 500 gallons of water transferred at a higher flow rate,
while the last 500 gallons of the test transferred at a lower rate, as in test
#2. The difference in flow between the
first and last 500 gallons was a 55 GPM decrease. We felt that because the siphon action does
not use the advantage of positive pressure that as the water level in the tank
lowers that it requires more energy to raise the water up the suction hose,
thus showing the decline in flow.
The
average flow of 454 GPM also did not account for “prime time” of the siphon, so
the actual true flow rate might be slightly higher
Because
the known flow of the jet siphon nozzle at the 150 PSI pump pressure is
approximately was not tested, the average net flow rate of the transfer devices
is estimated at 174 GPM. This could be considered the flow rate of
a single 1 ¾” handline.
After
reviewing the piping on Tender 34, we noted that the rear discharge contains
several sharp bends, and that the pressure gauge line is affixed close to the
pump. It can be deducted that because of
this, that jet siphon #2 was somewhat underpowered due to pressure loss in
piping. In addition, due to the
difference in length of the two hard suction lines it can be deducted that
there may have been a slightly lower level of efficiency in the longer of the
two lines. There were (4) 90 degree
elbows and (2) 45 degree elbows identified within the pump house. It is assumed once the piping reaches the
last visible bend that it runs straight to the rear along the frame, but this
was not certain.
The
flow rate of approximately 280 GPM (140 GPM ea.) is required to support the two
jet siphon devices, and thus makes this water unavailable for the fire
site. This must be considered in the
pumps total capacity, especially since operating at draft as well as the
required pump pressure (100 PSI) to achieve the flow.
Test #4
Objective:
Determine the flow rate of one jet siphons to transfer 1000 gallons of water
from one folding tank to another at 150 PSI pump discharge pressure
The
3500 Gallon tank was marked at 500 gallon intervals with the top mark being
2000 gallons.
The
stopwatch was started when the discharge valve was opened. The water level started at the 2000 gallon
mark. When the water level reached the
1500 gallon mark the time was recorded.
It was recoded again at the 1000 gallon mark.
The
jet siphon (#1) was attached to (2) 15’ sections of 6” lightweight suction hose. The 50’ section of 1 ½” hose was connected to
the pump panel discharge of Tender 34
Results of Test #4
With
a pump discharge pressure of 150 PSI the following results were achieved.
Water
level at the 1500 Gallon mark (500 gallons transferred): 1:11 (71s)
Water
level at the 1000 Gallon mark (1000 gallons transferred): 2:18 (138s)
Average
flow rate for 1000 Gallons 7.24 Gallons/second
or 434 GPM
Average
flow rate for first 500 Gallons 7.04 Gallons/second
or 422 GPM
Average
flow rate for last 500 Gallons 7.46
Gallons/second or 447 GPM
Summary of Test #4
It
appeared that the first 500 gallons of water transferred at a lower flow rate,
while the last 500 gallons of the test transferred at a higher rate, as
compared to the other tests. This
represents an inverse result to the previous pattern. The difference in flow
between the first and last 500 gallons was a 25 GPM increase. As stated, this is the opposite result of
previous tests. We can theorize that the
higher velocity of water from the jet may have impacted this result, but have
no other data to explain this difference.
The
average flow of 434 GPM also did not account for “prime time” of the siphon, so
the actual true flow rate might be slightly higher
The
estimated flow of the jet siphon nozzle at the 150 PSI pump pressure is
approximately 167 GPM, the average net flow rate of the transfer devices is
actually 267 GPM. This could be considered the flow rate of
a single 2 1/2” handline or two 1 ¾” handlines.
Test #5
Objective:
Determine the flow rate of one jet siphon to transfer 1000 gallons of water
from one folding tank to another at 150 PSI Pump discharge pressure up an
approximate 7’ elevation.
The
3500 Gallon tank was marked at 500 gallon intervals with the top mark being
2000 gallons.
The
two tanks were 3500 gallons each. The
lower tank was filled to capacity; the upper tank retained its water level
markings.
50
total feet of hard sleeve were connected together (2) 10’ and (2) 15’ sections
E34-62
was connected to a 6’ low level strainer in tank #2 (uphill tank) and had
approx 500 gallons of on board tank water.
The level of water in tank #2 was at the top of the opening to the
strainer, and unsuitable to draft at the start of the test.
The
stopwatch was started when the discharge valve on E34-62 was opened.
Test #5
Results of Test #5
Water
was discharged from the 6” hard sleeve into tank #2 (uphill), but it was noted
to have a low volume, and did not fill the entire hose coupling opening.
After
exhausting approximately 500 gallons of remaining tank water, E34-62 was unable
to establish an effective transfer and the operation stopped.
Summary of Test #5
The
test failed.
While
attempting to prime the siphon, E34-62 operator increased pump pressure to near
200 PSI, with no appreciable results. It
was also noted that tank #1 (downhill) began to overflow, leading us to believe
that the tank water from E34-62 was simply being exhausted into this tank and
backflowing out of the siphon. A small stream of water exited the uphill end of the suction hose, but never gained enough water to establish a draft with the low level strainer.
We
believe that the action of the jet siphon is limited to very slight elevation
differences. It would seem logical that
because the action of the siphon it requires more energy to “prime” itself and
flow than if the water were being pumped through the hard sleeve. With that conclusion, we felt that dump site
setup is critical when elevation is a factor and that the following options
exist in such a situation;
- Portable pumps
- Drafting out of tanks directly and pumping back into other tanks
Overall Conclusions
After
running the previous tests, we came to a few conclusions, which are listed
below. Understanding that without
additional test gauges and more precise testing parameters, that the results
have a known “approximation” built in, however, we can still consider the data
is fairly consistent to use for “real world” purposes.
- Regarding the pressure to pump the jet siphons at, we felt that the best results were at the 150 PSI PDP and that a flow of 125-150 PSI PDP will yield best results in most cases
- Regarding how many jet siphons to use for water transfer, we felt that no less than two should be used as a standard practice between each tank
- Regarding the hose supplying the jet siphons, we used 1 ½” hose, 1 ¾” hose may yield better performance due to lower friction loss
- The use of the primary fireground supply pumper for water transfer beyond 2-3 jet siphons will impact its ability to deliver higher volumes to the fire scene. With a flow of 160+/- GPM per siphon, this can add up quickly. The operator should consider the flow of a jet siphon as equivalent to a typical 1 ¾” handline when factoring in total water supply. Also, this water being used in each siphon is “recirculated” and never delivered to the fire, hence why we mentioned the “net” flow of each siphon.
- Using a separate pumper for water transfer may be a preferable option at large scale fire events, to allow the primary supply pumper to flow its best possible capacity to the fire site.
- When elevation is an issue, water can be transferred downhill, but not uphill beyond slight elevations when using jet siphons. Dump site setup should consider this factor
- The discharge end of the hard sleeve must remain above the static water line in the folding tank, failure to maintain this position will result in high likelihood of back flow, as when the flow stops from the jet, the transfer will tend to reverse itself and return the water back to the original tank.
- Portable tanks on uneven ground will not hold their capacity, and additional tanks may need to be deployed on inclines to compensate for the lowered overall capacity
- You can mark the liquid level of folding tanks, but doing so must be done on level ground and there must be an understanding that if the tank is uneven that the level will be inaccurate. One way to make this issue more apparent is to mark opposite sides and compare the levels. If nothing else, it serves to indicate an approximate liquid level, as most fires don’t happen on flat, level ground.
- Water supply officers have a dity to collect additional suction hose, strainers and jet siphon devices from tanker and engine companies assigned to the operation, in order to be able to build an effective dump site. Be familiar with thread size of hose and appliances used by mutual aid companies.
Fairmount
Fire Co. should be commended for quickly unloading and setting up all the
required equipment and taking the time out of their evening to run these tests. -Mike G.
