The following tests are conducted by our laboratory depending on the particular type of foam concentrate sample.
Physical Property Tests
The physical properties of the foam concentrate are tested to the manufacturers published specifications. Typically, the following tests are performed on each foam sample received in our laboratory:
| Appearance – We visually examine your foam concentrate noting the color, whether it is opaque or clear, its thickness, whether there are two phases or any contaminants. |
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| Density – Our laboratory measures the density of your foam concentrate sample. The density is the weight of a given volume of foam concentrate and is typically measured in grams per milliliter. The density of the foam concentrate can indicate the type of foam concentrate. If the density is either above or below its specification, it can indicate either evaporation, dilution with water, or mixing with a different type of foam concentrate. |
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| Refractive Index – The refractive index of a liquid is a measure of the angle that light bends as it travels through the liquid. The refractive index can be used to measure the concentration of a foam solution and is also used to determine if a foam concentrate has been inadvertently diluted with water. |
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| pH – The pH measures the acidity or alkalinity of the foam concentrate on a scale of 1 to 14. Most foam manufacturers will define an acceptable pH value for their foam concentrates. Generally a neutral pH (7) is preferred to minimize the corrosion of foam concentrate tanks. |
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Viscosity – The viscosity of alcohol resistant foam concentrates are measured to ensure they meet the foam manufacturer’s specifications. A reduction in the viscosity can be an indication of foam dilution. An increase in viscosity can result from aging. If the viscosity is either above or below its specification, it could prevent accurate proportioning.
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Performance Tests
After analyzing the foam samples as described above, we run the following tests, which indicate how your foam will perform in actual use.
| Foam Expansion Ratio (Low Expansion Foams) - The foam expansion ratio is the ratio of the weight of a given volume of expanded foam to the weight of that same volume of unexpanded foam solution. In order to measure the expansion ratio the foam concentrate must be mixed with water at its nominal concentration. Dyne Technologies uses the equipment and procedures described in NFPA 11, Standard for Low-,Medium and High-Expansion Foam, 2002 edition, Annex (Section C.1 Procedures for Measuring Expansion and Drainage Rates of Foams) for measuring the expansion ratio of the mixed foam solution. A minimum expansion ratio of 5:1 is required for all types of foams. |
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Foam Expansion Ratio(High Expansion Foams) – The foam expansion ratio is the ratio of the weight of a given volume of expanded foam to the weight of that same volume of unexpanded foam solution. In order to measure the expansion, the foam concentrate is mixed with water at its nominal concentration. In testing high expansion foams, Dyne Technologies use the equipment and procedures described in NFPA 11, Standard for Low-Medium- and High-Expansion Foam, 2002 edition, Figure .2(a) High-Expansion Foam Quality Test Generator.
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| 25% Drain Time – The 25% drain time, measured in minutes and seconds, is the time it takes for 25% of the expanded foam to drain back to foam solution. The 25% drain is measured on low, medium and high expansion foam. |
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| Film Formation and Film Sealability – Film-forming foams such as AFFFs and FFFPs must form an aqueous film on flammable liquids. Dyne requires film-forming foams to pass a film formation and film sealability test on cyclohexane. |
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Surface Tension – The surface tension is a measurement to predict the ability of the solution to wet a surface or substrate. The surface tension is measured on wetting agents to meet the requirments of NFPA 18 Standard on Wetting Agents. The wetting agent concentrate is mixed with water at is nominal use concentration prior to this measurement. The units of measurement for surface tension are dynes per square centimeter.
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Sediment – The percentage of sediment is measured on the foam concentrate and is required by the United States Coast Guard and the International Maritime Organization. The concentrate is placed in a large centrifuge and spun at rapid rotations per minute in order to concentrate and quantify the sediment in the sample.
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