This guide is provided to assist you in the design of StormChamber systems.
1. EACH STORMCHAMBER PROVIDES 115 CUBIC FEET OF INSTALLED STORAGE.
The 100% void space in each StormChamber provides an internal storage capacity of 75 cubic feet. With the minimum stone requirement of 6″ above and 6″ below, each StormChamber will provide 115 cubic feet of installed storage. This is based on 40% void space in the stone.
2. ADDITIONAL STONE MAY BE ADDED TO INCREASE THE STORAGE CAPACITY OF THE STORMCHAMBER SYSTEM.
Additional stone may be added above/below the chambers, between rows, or to increase the one foot stone border which is required at the perimeter of the system.
3. MULTI LAYER CAPABILITY FOR SITES WITH SMALL FOOTPRINTS – UP TO 4 LAYERS.
StormChamber systems may be installed in up to four layers. Each layer is to be installed perpendicular to the layer above or below. Additional depth is required when using multi layers.
4. Replacing soil fill above the StormChambers with additional stone.
The minimum 6” of stone above the StormChambers can be extended up to the subgrade for the base of the pavement. This may be desirable where the excavated soil is required elsewhere or the excavated soil cannot meet compaction and other backfill specifications, or where it will facilitate pavement installation.
5. Lateral (side) pipe connections instead of header pipe manifold system.
The purpose of the lateral (side) pipe connections between the first chamber of the inflow and adjacent rows of StormChambers is to help ensure proper flow dynamics between StormChambers rows during high flow periods. These connections do not need to be water tight. Although the StormChambers all interconnect hydraulically through the surrounding stone, the pipe connections provide a flow path that can carry higher short duration flows comparable to an emergency spillway for a dam. Smooth walled (inside and outside) pipe of 8 or 10 inch diameter should be specified. Most often 8 inch PVC pipe is used. Corrugated pipe is very difficult to use in this application. Lateral pipe connections must be aligned directly across from each other, at the point where drain pipe feeds the StormChamber.
6. Detail sheet.
The detail sheet found under “Downloads” contains an AutoCad file with details that can be copied directly to your plans. Please include all this information on your detail sheet, along with anything else you feel will be of help to the contractor. The information we have provided reflects questions and concerns raised by the contractor on previous installations.
7. Sediment treatment and removal.
Sediment is easily managed with our patented SedimenTrap (see SedimenTrap under “Products.)” Also view the animated video “See how StormChambers provide water quality.” Under “Downloads” read “The StormChamber System as a water quality device.” We also recommend four foot sump in the upstream to help capture the heavier sediments. In combination with the BMP “Snout” (see below), expensive pre-treatment units can be eliminated.
8. Debris and oil treatment removal.
Grated inlet structures and debris trash racks for throated inlets can be used to prevent the larger debris from entering the system. It is highly recommended that a Snout, manufactured by BMP, Inc. be incorporated into the manhole(s) upstream from the StormChamber system. The snouts will prevent the smaller floatable and oil and grease from entering the StormChamber system. Click on “Downloads” for more information on the “Snout.”
9. Inflow alternatives.
Typically inflow is directed to the first chamber in the first row with the outflow out the last chamber in the last row. This provides for maximum retention time on the bio mat that forms on the underlying stone and soil, similar to the function of a septic drain field. Inflow can also be directed into the side portal of any chamber(s) of either outside row. The use of larger diameter pipes along the outside rows is accommodated for an inexpensive highly effective approach by eliminating one of the outer row chambers. Click on “Downloads” for StormChamber Detail Sheet. Surface drains can be directly connected vertically into a 12 inch riser pipe through the top portal, directly above a Sedimentrap.