What is the appropriate percentage of foam to use on petroleum fires?

The appropriate percentage of foam to use on petroleum fires is typically 3%. This concentration is effective because it allows for adequate coverage and suppression of flammable liquids. At this concentration, the foam can create a stable blanket over the flammable liquid, effectively preventing vapors from escaping and reducing the likelihood of ignition. The foam works to smother the fire while also cooling the surface, which is crucial in the case of petroleum products.

Using foam at this concentration balances effectiveness and resource usage, as a higher concentration may not provide additional benefits proportionate to the increased amount of foam needed. Lower concentrations may not adequately suppress the fire or prevent re-ignition. Therefore, 3% is recognized in firefighting protocols as the standard for addressing petroleum-based incidents.