Other major benefits of precast refractory shapes are related to simplified installation and repair logistics, which can reduce costs and down times. Using precast shapes eliminates forming labor, materials, equipment costs, actual placement time and expense, and associated costs during form removal, curing, and cleanup. It shifts these costs back to the manufacturer of the shape, who can absorb them much efficiently by spreading them over the overall production capacity.
Refractory installation contractors have begun to consider precast refractory shapes much like they do any other pre-manufactured item such as block insulation, ceramic fiber blanket, anchors, etc. These items can be bought and then re-sold as a component of their installation projects. Whenever any portion of refractory repair work can be completed prior to crews being on site, costs are automatically reduced. Installation contractors have also found that the use of precast shapes can often give them a substantial advantage in competitive bid situations.
With the use of precast shapes, crew sizing can be minimized. Speed of installation is another obvious benefit to both the installer and the owner, resulting in reduced costs due to shorter job duration. Material usage is also reduced, when compared to other installation methods such as guniting, where as much as 45% of extra material is required to compensate for rebound and other job losses. Environmental hazards such as dusting and tripping hazards associated with equipment and hoses are also reduced substantially, if not eliminated. Future repairs also become much more economical and quicker to accomplish. Repair areas can be isolated to just the immediate wear area within the boundaries of a shape. Anchor attachment points can typically be reused. Replacement shapes, purchased early and kept as spare parts on site, can be easily installed in a fraction of the time required for conventional repair methods. The initial bake-out of a new refractory lining on site can be a very expensive and time-consuming component of a refractory repair project. The use of precast and prefired refractory shapes can sometimes reduce or even eliminate the need for an extensive initial bake-out. If an entire repair is made with a prefired system, then normal furnace start up schedules can be used, without the fear of steam spalls or other damage during the initial heating. Bake-out of multi-component linings, which may include a combination of precast shapes and other materials placed in the field, can often be reduced by the pre-firing of the castable shapes, particularly if that material would have been the critical item determining the bake out schedule. This can have a positive impact on not only job costs, but in reducing down time as well.