Quality criteria

Adhesion is required for foam to apply its cooling, insulating and wetting properties, even on vertical surfaces and bulky incendiary matter.

Ageing behaviour

This is gauged on how long the foam solution contained in the foam is retained, or how slowly/quickly the foam dehydrates. The unit of measurement is the water drainage time.

Combustion resistance

Combustion resistance refers to the foam’s ability to withstand flames and thermal radiation. Compatibility of foams for immediate use Foams generated from different concentrates are compatible with all other expanded fire extinguishing foams. Different foam concentrates must not be mixed.

Film formation
Film formation is differentiated by:
• Polymer film • Aqueous film

Fire performance
Fire performance largely depends on the criteria contained in this section. To determine this, fire tests are carried out using calibrated testing equipment in accordance with recognised standards, e.g. DIN EN 1568 part 1-4.

Flowability is the capacity of the foam to rapidly spread across a fire surface. Good flowability ensures a fast, successful firefighting operation.

The gastight foam cover seals and suppresses flammable gas on extinguished or preventatively covered flammable liquids. Gastight foam prevents burn-back and reduces fire risk.

Powder compatibility
STHAMER fire extinguishing foams are suitable for combined use with foam compatible dry chemical powders.

Seawater resistance
This is a requirement for foams used on maritime vessels, at ports, or in the off-shore sector. The excellent extinguishing properties of these foam agents are unaffected by use of salt, brackish, or treated industrial water.

Water drainage time
Water drainage time specifies the time in which e.g. 25% or 50% of foam solution contained in the foam is drained.

Environmental properties
These are particularly important, as foam is often used on unpaved surfaces, from which it can enter the environment. Our fluorine-free products are 100% biodegradable. Our fluorine-containing products are easily biodegrade, with the exception of the fluorinated components.

Frost resistance
Frost resistance is required where freezing temperatures are expected during longer operations or storage.

The pH-value may indicate a change in quality, e.g. if there is a sharp drop, premature ageing and a loss of fire extinguishing efficiency may occur.

Physiological properties
Dr. STHAMER foam concentrates are physiologically safe. Adverse health effects are not expected, when used as intended. For further details see the safety data sheets.

Dr. STHAMER products may be stored over a long period of time in the sealed original containers and in compliance with the storage recommendations. Storage temperatures range from the indicated lowest temperture for use to +50°C. Temporary freezing at temperatures below the specified frost resistance limit will not affect the quality.

Local authorities are to be consulted for information on foam disposal. Foam solution runoff into groundwater must be avoided.

Viscosity is important for ensuring a constant proportioning rate at low temperatures and for specifying foam concentrate pumps in fixed fire extinguishing installations. Depending on the application temperature, pump-supported induction may be necessary for highly viscous foam concentrate.

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