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Foam Testing Made Simple

2. Our Experience. TF Green Fire-Rescue purchased our meter in January 2003Dropped in my lap in December '03Began trying to figure out how conductivity testing works throughout December '03Because I'm lazy and hate math, wrote the Excel spreadsheet in January 2004Testing results stayed low for a

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Foam Testing Made Simple

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    1. Foam Testing Made Simple Down-and-Dirty Conductivity Testing of AFFF Solutions Thursday, October 9, 2008 LT/EMT-C Jeremy Souza - Presenter T.F. Green Airport, RI (KPVD)

    2. 2 Our Experience TF Green Fire-Rescue purchased our meter in January 2003 Dropped in my lap in December 03 Began trying to figure out how conductivity testing works throughout December 03 Because Im lazy and hate math, wrote the Excel spreadsheet in January 2004 Testing results stayed low for all 4 trucks

    3. 3 Our Experience, cont. Must be using the meter wrong keep testing. By April 04, we felt satisfied with our use of the meter, but the trucks were all low (1.8% to 2.7%) Brought in RI State Police to weigh the trucks to determine flow rates.

    4. 4 Our Experience, cont. Our Maintenance folks thought it was the plumbing rebuild all foam plumbing in our 97 T-1500 Snozzle Still low rates. In July of 2004, we had solved our foam testing problems the pump pressures were 5 psi too low. Dont let this happen to you! Learn from our mistakes!

    5. Enough of that. On to the class

    6. 6 Objectives Why test foam? Why conductivity? Describe the theory behind conductivity testing. Selecting and Using a Conductivity Meter. Correctly mix foams to a desired concentration. Collect a sample of foam from a fire stream. Accurately and precisely measure the percent concentration of a foam solution. Correctly use the Conductivity Testing spreadsheet.

    7. 7 Why Test Foam? Foam testing assures us that our apparatus are operating as they should be and will extinguish a flammable liquid fire. Teaches staff how the trucks operate whats going on behind that door? Allows staff to gain experience operating the truck

    8. How Often? I know, its pricey (~$730 per test for a 3000 gallon truck) The FAA says please see the applicable sections of NFPA 403, 2003 ed (A/C 150/5210-6D) NFPA 403 6.1.4 All foam producing ARFF vehicles shall be tested annually in accordance with NFPA 412 PVD tests each truck quarterly do you want to wait a year to find theres a problem? 8

    9. Well we use a refractometer. We *all* use Mil-Spec F-24385 foam (CertAlert 06-02, 8 Feb 06) If you dont, your foam cannot be refracted Mil-Spec foam has a chemical called Diethylene Glycol Monobutyl Ether (aka Butyl Carbitol) added to allow refracting* and to help dispersion in water Civilian AFFF does not have butyl carbitol Butyl Carbitol was what changed the refractive index of AFFF 9

    10. But They still dont work on Mil Spec AFFF What range is the refractometer measuring across? What is the high and low? Ever notice someone else gets a different number? Its too close for you to measure there arent enough lines Mil Spec AFFF at 3% should have a refractive index of 1.363 at 70F can you tell what 1.363 is? In short, conductivity is what works! 10

    11. 2% Solution 11

    12. 3% Solution 12

    13. 4% Solution 13

    14. 3% with Test Sample 14

    15. 15 Conductivity Theory Most liquids will allow electricity to pass through them. Pure water is an insulator electricity will not flow through it. The amount of impurities in the water will directly affect how much electricity will pass through. The temperature of the water will also affect how easily electricity will pass through.

    16. 16 Conductivity

    17. 17 Conductivity Theory This concept has been used for years in the water treatment industry to determine how clean a sample of water is. Because foam solutions are just water contaminated with another (conductive) product, it will work well for our needs to test foam. Remember were not testing foam, were testing contamination.

    18. 18 Conductivity Meters There are a number of conductivity meters on the market today. For our purposes, the best meters have a feature called Automatic Temperature Compensation (ATC). This adjusts the reading to what it would be if the sample was 70oF If you use a meter without ATC you must recalculate the results to bring it to 70oF

    19. 19 Using the Meter FOLLOW THE DIRECTIONS! Each meter will have its own peculiarities and differences, so read the instructions carefully. Remember to calibrate the meter according to the manufacturers directions before you use it.

    20. Starting the Test This begins with actually shooting foam make sure that white fluffy stuff comes out of the truck. For 3% AFFF, shooting from a turret, foam concentrations between 2.8% and 3.5% are acceptable. Less than 2.8% may knock down a fire, but will not suppress vapors. Greater than 3.5% will do a great job with the fire, but wastes concentrate. Upper limits of 4% are acceptable on handlines and undertrucks. 20

    21. 21 Mixing the Baseline Group The Conductivity Meter measures siemens, not foam percentages, so it only tells how conductive the solution is. 1 siemen = 1/ohm To convert this number to something useful (the percent concentrate), we need to establish a baseline of conductivity versus percent concentrate.

    22. 22 Establishing a Baseline Four measurements are needed: Sample of tank water from the vehicle being tested. 2%, 3%, and 4% concentrates mixed with water and foam concentrate from the vehicle being tested. To get these numbers, we need: Large sample (about gallon) of tank water. Sample of foam concentrate (about 30-50 mls)

    23. 23 Establishing a Baseline

    24. 24 Before Mixing the Baseline Before mixing the Baseline Group, you MUST take a conductivity reading of the tank water sample. Record this reading in the appropriate location on the worksheet.

    25. 25 Mixing the Baseline Group Use 3 plastic cups (or graduated cylinders) and two syringes (a 10ml and a 60 ml). Accuracy is everything when mixing the Baseline Group Place EXACTLY! 98 mls, 97 mls, and 96 mls water in each cup/cylinder. Add EXACTLY! 2 mls, 3 mls, and 4 mls of foam concentrate in the respective cylinders to make 100 mls of foam solution. The concentrate should disperse through the water all by itself.

    26. 26 Mixing the Baseline Group Mixing the 2, 3, and 4 percent foam solutions.

    27. 27 Measuring Conductivity

    28. 28 Measuring Conductivity Measuring the 3% baseline foam.

    29. 29 Measuring Conductivity Measuring the conductivity of the 4% baseline foam.

    30. 30 Verifying the Baseline Group Once the Baseline Group is mixed, run the results through the Spreadsheet to see if the baseline was correctly mixed, then head outside to get the foam samples from the truck. Well talk about the Spreadsheet later

    31. 31 Collecting Foam Samples Obviously, if we are going to test the foam that comes from the discharges, we need to collect the foam coming from the discharges to test them. NFPA 412 specifies a collection device to capture pure, aerated foam samples to perform all applicable foam tests on (not just % concentrate).

    32. 32 Collecting the Sample The NFPA 412 sample collection device. From NFPA 412, 1998 ed

    33. 33 Collecting the Sample At Green, we didnt have the time or resources available to build the NFPA 412 device. When starting the foam testing process, we used a high-tech device to collect discharged foam solution.

    34. 34

    35. 35 Foam Collection Since the foam tube, we have moved towards an even more high-tech solution collecting device

    36. 36

    37. Beer Cups Cheap Packaged in quantity Available anywhere Clean* You can write on them Allows sufficient depth for the meter to read * Make sure they stay clean before you put foam into them! 37

    38. 38 Foam Collection You are looking for the liquid solution, not bubbles. Wait for good foam to flow, which can be from 3 to 45* seconds. Stop flowing Collect the drippings from that discharge Works best on Snozzles in low-attack, bumper turrets, and aspirated roof turrets. DO NOT collect foam from drain tubes!

    39. 39 Collecting the Foam According to NFPA 412, Oshkosh, and E-One, when testing foam, you need to start from the lowest flowing discharge and move up to the highest flowing discharge

    40. General Flow Rates 40

    41. 41 Collecting the Sample Once the sample is collected in the cup, set it aside and collect the other samples. Make sure no contamination enters the samples as they sit. If your meter does not have Automatic Temperature Compensation, let all of the samples reach the same temperature first.

    42. Undertrucks 42

    43. 43 Handlines

    44. 44 Standard Bumper Turret

    45. Snozzle Piercing tip 45

    46. 46 Roof Turret

    47. 47 Snozzle, low attack

    48. High Volume, Low Attack Bumper Turret 48

    49. Drain Tubes Do not use drain tubes! Dirt and dust in the drain tubes can add contamination. 49

    50. Collection Caveats You MUST only flow from your tank no hydrant connections If you have to refill your water tank: You have done something wrong, and You need to make new baseline samples with the new tank of water If you have to refill your foam tank, something very wrong has taken place! You should be able to do the test on tank of water 50

    51. Adjustment Dial Before testing your foam, make sure the foam proportioner adjustment dial is set to 0 Setting the dial to 3 does not mean 3% foam! 51

    52. 52 Measuring Conductivity Once all of the samples are collected, test their conductivity according to the meters instructions. If the meter is not temperature compensated, let all of the samples reach 70oF (unless you are going to recalculate the results, which I dont recommend).

    53. 53 Measuring Conductivity Measuring the conductivity of a foam sample. Make sure there is enough depth for the dip tube to measure.

    54. 54 Recording the Results Dont forget to record the readings in microseimens on the Foam Testing Worksheet for all samples; including plain water, baseline foams, and discharges.

    55. 55 Using the Spreadsheet Once you have tested all of the apparatus that will be tested for the day, enter the results into the Foam Testing Spreadsheet to calculate the results. The spreadsheet uses the Baseline Group to calculate percent concentrates from the conductivity. This can also be done by hand, but it is much more time consuming and less accurate.

    56. 56 Entering Results

    57. 57 Viewing Results

    58. 58 Viewing Results

    59. 59

    60. 60 Foam Results Once information is entered on the spreadsheet, save the sheet as appropriate for your department. Saving each test with a different name will allow prior tests to be examined, so a trend can be tracked across different tests or different apparatus.

    61. Any Questions? On to the demo.. 61

    62. Special Thanks: Chief Jim Nilo, Richmond, VA Airport Fire Rhode Island Airport Corporation RI State Police Commercial Vehicle Enforcement Unit Leo Sedlemeyer, Dane County Airport, WI Jim Cottrell, Cottrell Associates, Inc 62

    63. Further Questions? Email JSouza@pvdairport.com 401-691-2268 (fire station) 63

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