Fig. 28.—Forms for concrete work—how to use them.
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1. Make the forms as shown and to the dimensions required by [fig. 25] and the table on [p. 37]; nails to be driven from the inside and left projecting for drawing with a claw hammer.
2. Excavate to lines 6 or 8 inches, as may be required, outside of the forms and to the depths required for both chambers.
3. Pour settling chamber floor and place form thereon.
4. Pour settling chamber walls to level of siphon chamber excavation, inserting submerged outlet pipe at the proper height.
5. Block siphon trap and connected branch and short pipes to correct line and grade, and fill with concrete around the trap.
6. Pour siphon chamber floor, and place the form thereon.
7. Continue pouring all walls to their full height, inserting the inlet pipe when the concrete reaches that elevation.
8. Do not remove forms till the concrete is hard; with favorable weather, forms for walls only may be removed in 1 to 2 days; forms supporting a cover slab should remain 1 to 2 weeks.