- Author
- Arvidson, M. | Mansson, M.
- Title
- Utvardering av olika frysskyddsmedel for sprinklersystem. [Evaluation of Antifreeze for Automatic Sprinkler Systems.]
- Coporate
- Swedish National Testing and Research Institute, Boras, Sweden
- Report
- SP Report 1999:08, 1999, 30 p.
- Distribution
- For more information contact: SP Swedish National Testing and Research Institute, Box 857, SE-501 15 BORAS, Sweden. Telephone: +46 33 16 50 00, Fax: +46 33 13 55 02, Email: info@sp.se Website: http://www.sp.se/eng/default.htm
- Keywords
- sprinkler systems | evaluation | antifreeze | glycol | alcohol | salts | sprinkler activation
- Abstract
- ABSTRACT IN ENGLISH Where wet-pipe sprinkler systems are subject to freezing, an antifreeze can be used. This has become quite common in Sweden, especially within the saw mill industry. NFFA 13 recommends the use of glycerine, diethylene glycol, ethylene glycol, propylene glycol or calcium chloride. However, concerns have been raised whether or not some of these antifreezes contribute additional energy to an established fire upon sprinkler activation. This could potentially result in an excessive number of operating sprinklers. To investigate this a theoretical analysis and experimental study was initiated. In addition, questions regarding health, environmental issues, freeze point depression, corrosion, viscosity and cost were studied for a number of potential antifreezes. The following antifreeze solutions were selected for the experimental study: calcium chloride, ethanol, glycerine, methanol, potassium acetate, propylene glycol, urea. The fire tests were conducted in an intermediate scale. A burning wood crib was used as the fire source and the antifreeze solution was evenly distributed above it with spray nozzles. The heat release rate was measured continuously using oxygen depletion calorimetry. The results were compared to tests using water only. The conclusions were based on the total energy released over the ten minute period when water or antifreeze was applied. Two tests were conducted with each of the antifreeze solutions. The philosophy was to do one test with a mass concentration that provided for a freezing point of -15 deg C and another test with a mass concentration corresponding to -30 deg C. The exceptions from this philosophy were the tests with urea which were done at concentrations corresponding to -10 deg C and -l5 deg C, respectively, and potassium acetate where only one test was conducted at a concentration valid for at least -33 deg C. The results show that only two of the antifreeze solutions tested are comparable to or better than water only, namely calcium chloride and potassium acetate. The other antifreeze solutions tested resulted in a significant increase in heat release rate of the fire source. In some cases the energy released under the ten minute period of application was 1,5 - 2 times higher than that found when pure water was used. These results correlated well with the theoretical calculations. It is clear that these antifreeze cannot be recommended for use in sprinkler systems, unless the total amount (volume) is very limited. The report identifies areas where additional research are needed. These areas include, but are not limited to, an investigation of potential for corrosion and viscosity at low temperatures for potassium acetate.