Step 13. Cover shelter with earth mound.
Cover the shelter with a minimum of 3-feet of granular soil. Mound the soil around the vent pipes. Stack several extra sandbags at the entrance to each shelter along with a pile of loose soil. This loose soil will be used in sealing the shelter entrances.
The granular soil must be compacted to 95% Proctor level. Compacting can be done using a whacker tamper. A quick test of this level is to slam your heel into the compacted earth. If it barely leaves an imprint, you are at the 95% compacted level.