Pipes are designed to be used for structural applications only to the extent of withstanding normal soil loads and internal pressures up to their hydrostatic pressure rating. Therefore, any pipe supplying air, water, or steam, when exposed aboveground and in the interior of buildings must be supported adequately to prevent sagging. The weight of the pipes plus the weight of fluid contained in them may produce strained joints and breaks that can cause leaks in the valves. Figure 8-10 shows several methods of supporting pipe in both horizontal and vertical positions. On

water mains, standard thrust blocks (fig. 8-11), made of concrete or other applicable materials, are installed at all changes of direction to prevent pipe displacement caused by high water pressure.

Figure 8-11.-Uses of thrust blocks.