Firefighting Suppression Foam: How to Measure Foam Concentration and Mixing Ratios with a Digital Refractometer

Firefighting foam is engineered to work at a specific concentration. Too little foam concentrate can reduce the effectiveness of the finished foam solution, while an incorrect proportioning rate can affect foam expansion, drainage, vapor suppression, and overall fire-control performance.

That makes foam concentration testing an important part of commissioning, inspection, maintenance, and troubleshooting for fire suppression systems.

One of the most practical field methods is the digital refractometer. A small sample of foam solution can be tested in seconds, providing a quantitative measurement that is far more useful than relying only on appearance, foam blanket characteristics, or equipment settings.

Modern digital refractometers from MISCO are particularly well suited to this application because they can measure refractive index with high resolution. A properly selected BOSS refractometer can also provide a practical, economical field-testing option for applications where a low-range Brix scale is appropriate.