Water Shuttle Operations

Topic: Water Shuttle Operations Teaching and Learning Domain: Cognitive Time Required: 2 hours Materials: Appropriate visuals and chalkboard or easel pad References: IFSTA Pumping Apparatus Driver/Operator (1st ed.), Chapter 14...


                                  GPM= 3,000 – 300

                                                12 minutes

                                  GPM = 2,700

                                                   12

                                  GPM = 225

F. What this means is that particular tanker able to supply 225 gpm over 1-mile shuttle route

G. Second method of evaluating tanker performance by using series of formulas originally developed by ISO

  1. Formulas used to rate water supply performance of fire departments that protect rural areas

  2. Formulas divide shuttle operation into two time elements: travel time and handling time

                                 Travel Time in minutes = 0.65 + (1 .7)(Distance in Miles)

H. Formulas include built-in factor for acceleration and deceleration times as tankers leave and approach fill and dump sites

  1. Assume average travel speed between fill and dump site of 35 mph

  2. If road conditions allow for faster speeds, formula adjusted accordingly

  3. Handling time computed as follows:

                                Handling Time = Fill Site Time + Dump Site Time

I. Fill site time includes time spent maneuvering apparatus into position, make and break times, and actual filling time

  1. For sake of calculation, flow rate that fill site pumper supplying established

  2. Each jurisdiction has to determine fill rate most likely to achieve

J. Dump site time includes time spent maneuvering apparatus into position and actual dumping time

  1. Each tanker dumps load at different rate

  2. Dumping time determined by actual testing or supplied by manufacturer

  3. NFPA 1901 specifies that tankers should be able to be dumped at minimum of 1,000 gpm

K. ISO allows 90 percent of tankers total tank capacity to be used for calculation

  1. 10 percent loss accounts for water spilled or remains in tank after dump valve closed

  2. Through testing, many departments found that their tanker actually only dumping 80 percent of load

  3. Modifications done to improve performance

L. One of the most accurate ways to measure amount of water left in tank after dumping to weigh apparatus on truck scale when completely full and again after tank dumped

  1. Difference in two weights accounts for amount of water actually dumped

  2. For example, suppose we wish to know how much water actually dumped from 2,000 gallon

      tanker

  3. After weighing apparatus both times, found to be 14,500 pounds lighter after water dumped

  4. Because we know that water weighs 8.34 pounds per gallon, we can determine 1,739 gallons

      (14,500÷8.34) dumped

  5. Would account for 87 percent of capacity of tanker

M. Once travel time and handling time determined, flow rate for tanker calculated using following formula:

                     Tanker Flow Rate = Tanker Water Tank Size (in Gallons) - 10%

                                                               Travel Time + Handling Time

 

Example 1

Determine flow rate for 2,500 gallon tanker shuttling water 3 miles in each direction. Assume fill and dump rates of 1,000 gpm. Also assume that maneuvering and make and break times at each site total 2 minutes.

Travel Time in minutes = 0.65 + (1 .7)(Distance in miles)

Travel Time in minutes = 0.65 + (1 .7)(3 miles)

Travel Time in minutes = 0.65 + 5.1

Travel Time in minutes = 5.75

 

Handling Time = Fill Site Time + Dump Site Time

Handling Time = (2 min. + [tank size/fill rate]) + (2 min. + [tank size/dump rate])

Handling Time = (2 min. + [2,500/1,000]) + (2 min. + [2,500/1,000])

Handling Time = (2 min. + 2.5 min.) + (2 min. + 2.5 min.)

Handling Time = 4.5 min. + 4.5 min.

Handling Time = 9 minutes

 

Tanker Flow Rate = Tanker Water Tank Size (in Gallons) - 10%