REVIEW OF CURRENT RESEARCH ON THE CORROSIVE EFFECTS OF FOAM CONCENTRATES AND THEIR WORKING SOLUTIONS ON FIRE SUPPRESSION SYSTEM COMPONENTS

Abstract

Problem statement. The problem of corrosion caused by aqueous firefighting agents remains highly relevant in the field of fire safety. When foam concentrates are used in fixed and autonomous fire suppression systems, metallic components (tanks, pipelines, nozzles, valves, sprinklers, etc.) are exposed to aggressive chemical interactions. Numerous studies have demonstrated that contact between foam solutions and metal surfaces initiates chemical reactions that form corrosion products, which in turn reduce equipment reliability and may even lead to system failure. Objective. This study aims to analyze recent research on the corrosive activity of foam concentrates and their working solutions on autonomous and fixed fire suppression systems, and to identify strategies to mitigate the harmful effects of corrosion, thereby improving the fire protection of facilities. Description of the material. The main experimental methods for assessing the corrosive activity of foam concentrates include immersing steel plates into foam working solutions followed by measuring mass loss. In addition to the gravimetric method, electrochemical analysis is employed to determine corrosion potential and corrosion current density. This approach enables a quantitative comparison of the corrosiveness of different types of foam concentrates. Notably, protein-based foams (including fluoroprotein foams) have shown the highest levels of corrosive activity in experimental conditions. In contrast, synthetic foams that include specialized stabilizers and corrosion inhibitors generally demonstrate lower corrosive effects. To reduce the corrosive impact of aqueous firefighting agents, a multi-faceted approach is recommended. First, corrosion-resistant materials should be used, avoiding unprotected carbon steel and zinc. It is common practice to protect the internal surfaces of tanks and fire extinguisher bodies with paints or polymer coatings. Second, corrosion inhibitors should be incorporated directly into the foam concentrate formulations. Third, water quality should be controlled by using softened or demineralized water to prepare working solutions, thereby avoiding salts and contaminants that increase electrical conductivity. Fourth, after fire suppression activities, systems should be promptly cleaned to remove residual foam and corrosion products. The international NFPA standard states that protein-based foam concentrates must include corrosion inhibitors, and that system components (e.g., piping, valves) must be made from materials compatible with the foam concentrate, such as brass, bronze, or stainless steel. For synthetic foams, material compatibility must be explicitly stated. Additionally, the standard regulates water supply conditions: the water used must be compatible with the foam concentrate and must not contain suspended particles or salts that could accelerate corrosion. Regarding Ukrainian standards, DSTU EN 1568 does not provide specific requirements regarding the corrosive properties of foam concentrates. This issue is mainly addressed in the manufacturer’s technical documentation, rather than being officially regulated with mandatory labeling. Another Ukrainian regulatory document, DSTU 3789:2015, requires that general-purpose foam concentrates exhibit low corrosive activity. Conclusions. Current practice indicates that the design and operation of fire suppression systems must take into account the corrosive effects of firefighting agents on system components, and operational guidelines must be defined accordingly. The analysis suggests that the most straightforward and cost-effective method of mitigating corrosion is the inclusion of corrosion inhibitors in foam concentrate formulations. However, further research is needed to evaluate the fire-extinguishing performance of such enhanced compositions. It is also necessary to revise regulatory documents concerning corrosion prevention in fire suppression systems, particularly regarding the use of protective paint or polymer coatings on the internal surfaces of fire extinguisher bodies.