- Author
- Hiraga, S.
- Title
- Investigation of Antifreezing Method of a Hydrant. [ABSTRACT ONLY]
- Journal
- Report of Fire Research Institute of Japan, No. 79, 85, 1995
- Keywords
- fire hydrants | weather effects | insulating materials
- Abstract
- [ABSTRACT IN ENGLISH] In the cold region, the water in a hydrant is stopped by the freezing of the main valve of a water pipe which exists at about 1.5 meter below the ground surface in depth. The water in the vertical part of the pipe between main valve and hydrant is alwasy exchanged with air. The most important problem is the obstructions due to frozen water in the main valve. Therefore, the transient thermal conduction of two dimensions around a hydrant is numerically analyzed on the purpose of development in an antifreezing method of the main valve. According to the numerical analysis, the most effective and practical method is proved that the heat insulating board (3,3 by 0.1 meters in sizes) is to be horizontally buried at 0.5 meter in depth in the ground. The 5397 hydrants in total which were set up by this method in Ashikawa city have never caused the obstruction since their establishments. This analysis gives that the conventional protection method, that the vertical part of the hydrant is covered by the insulating materials, causes the obstruction more than no protection. The reason is that the heat conduction from the earth to the vertical part of hydrant is stopped by insulating materials. This fact has already been found by experiments at Asahikawa city.