Installation Guide

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22121 REV 19
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335
ESP Safety Shelter Foundation
Inspection / Anchoring
Concrete Foundation Inspection
The following concrete slab requirements and inspection criteria are based
upon the engineering specifications specific to the ESP Safety Shelter. To
maintain Near Absolute Protection any variations from these specific
recommendations must be reviewed and approved by a structural engineer.
Minimum Slab Thickness must be an average 5 inches:
• To test for thickness drill several holes concentrated around area of installation;
the drill bit selected must be able to drill a minimum of 5 1/2” deep.
o Take a piece of stiff wire and bend a small “L” on the end. The “L” must be
small enough to fit through the drilled hole and will be used to hook on the
underside of the concrete.
o Once the wire has been inserted into the hole, pull up on the wire so the “L”
catches on the underside of the concrete and mark the wire at the top side
of the concrete.
o Remove the wire from the hole and measure the distance from the “L” hook
to the mark on the wire to obtain the concrete thickness. This process will
be repeated with each hole and the measurements noted.
• If there is any doubt that the average thickness is less than 5 inches, a plan
should be put into place to cut out existing section of concrete and re-pour with
proper reinforcement.
• Concrete should also extend beyond (overhang) the ESP Safety Shelter the
minimum distance as described in the Installation Section of the Owner’s
Manual.
Minimum Concrete Reinforcement:
• No. 4 (1/2”) rebar at a maximum spacing of 24” on center, in two perpendicular
directions.
o If you are not sure if your concrete reinforcement meets this requirement,