Filling out the paperwork for a sample of firefighting foam to send into Dyne for testing can be confusing if you are unfamiliar with some of the language or testing methods used in the firefighting foam business. One choice that must be made is if the sample must be tested to International Maritime Organization (IMO) or National Fire Protection Association (NFPA) specifications. IMO and NFPA have similar standards for firefighting foam testing except IMO stipulates a slightly more rigorous analysis.
Factors to consider when making this decision are detailed below.
When determining whether or not to test to IMO or NFPA specifications, the most important factor to consider is whether sea or fresh water is used to mix with the foam concentrate. IMO specifications must be used for any system using sea water. Most commonly, this applies to marine vessels. A report is required showing that the foam on board has been tested and is in compliance with IMO specifications before Coast Guard Type Approval is granted. Part of the reason there are different specifications for sea water and fresh water is because the dissolved salts in sea water can affect crucial components of the foam concentrate and system. Therefore, when using a sea water system, it is important to use a foam that is rated for use in sea water to avoid the possibility of its firefighting ability being impaired.
Both IMO and NFPA specifications mandate annual tests for appearance, refractive index, density, pH, expansion and 25% drain time (50% in the case of high expansion foams). Since sea water is primarily used in ship foam systems that do not have access to new equipment and foam concentrate for long periods of time, further criteria must be met. The first thing that must be done for a sample to be tested to IMO standards is for it to be conditioned in an oven at 60°C for 24 hours. This is done to simulate a year of aging. Since firefighting foam test results are valid for a year, this aging process theoretically ensures that the foam will maintain its integrity until the next annual test given it is stored in proper conditions.
A supplementary test that must be performed for IMO requirements is percent sedimentation. Samples are centrifuged so that any solid material mixed into the foam concentrate is pushed to the bottom of the container and can be measured. An excessive amount of sedimentation can result in poor results or even clog the proportioner. Although a pH reading is taken for both specifications, a very high or very low pH can cause a sample to fail when tested to IMO standards. If foam concentrates have a very high or very low pH, it can cause rapid degradation. This, again, is to help ensure the foam retains its effectiveness for the entire year following the test.
The decision of which standard to test to can not only save you time when trying to depart from port with proper documentation, but it can potentially save lives in the event of an emergency. At Dyne Technologies, we are committed to both with our fast turnaround rate and high technical quality. Our chemists are a great resource to use if you have any further questions on your specific situation—please call us at (800) 632-2304.