Ground Supported Flat Bottom Storage Tank (FB)

Reservoir (RES) when diameter is larger than height or Standpipe (SP) when diameter is smaller than height

DEFINITION: A welded carbon-steel cylindrical water storage tank built at grade-level on a steel-reinforced concrete foundation.

Positive Uses (when it's best)

  • Welded steel ground storage tanks are low cost, flexible in a seismic event or foundation settlement, and can easily be modified or retrofitted
  • Quickest style to construct and works well at higher ground elevations
  • Standpipe designs can achieve additional pressure in the water system (especially for power outages)
  • Reservoir designs can increase storage capacity in the water system (especially for fire protection)

Highlights & Advantages (over other styles)

  • Smaller ground storage tanks are easier to disguise (harder to find) and can easily be painted specialty designs and attractive logos
  • New epoxy and polyurethane coatings provide long life and require very little maintenance
  • Four different styles of typical roofs: Ellipsoidal, Sphericone, Dome, Low Pitched Cone
  • These reservoirs can accept a light-weight aluminum geodesic dome type of roof

Special Features (bonus part of asset)

  • Typically, Ground Storage Tanks are the most economical way to provide simple long-term water storage.
  • Tank diameters and heights are varied to meet customer requirements.
  • Ornamental pilasters or other architectural treatments can be added for a unique and beautiful structure.
  • Easiest style to self-maintain because many people are afraid of heights and no specialized equipment is necessary for maintenance.

Standard Sizes (others available but may be at a premium)

  • Normal capacity ranges are from 25,000 to 6,300,000 gallons with endless dimensional possibilities

Standard Accessories
American Water Works Association (AWWA D100 & D102)

  • Steel frost-proof pressure/vacuum relief vent designed for maximum protection
  • (1) 24" diameter roof manhole with hinged cover and hasp
  • (1) 24" diameter roof hatch bolted for attachment of exhaust fan
  • (1) 24" diameter bolted shell manhole with a hinged cover
  • (1) 30" diameter bolted shell manhole with a hinged cover
  • Purchaser-specified inlet/outlet connections
  • Tank shell supported overflow pipe to grade level with concrete splash pad
  • Exterior tank ladder for access to roof hatches and vent
  • Grounding for minimizing lightning damage
  • OSHA compliant safety climb devices on all tank ladders
  • Sand pad supporting tank floor plates

Elective Accessories
Collective in the Water Tank Industry

  • Alternate designs using Section 14 of AWWA D100-05 (alternate design basis for standpipes and reservoirs)
  • Tank drain for washouts
  • Larger diameter manholes and hatches
  • Baffles or other chlorine retention measures
  • Complete internal seal welding
  • Non-freeze drain valve at base of tank shell
  • Overflow flap valve
  • High water elevation/pressure gauge
  • Roof handrail
  • Aluminum or custom roof vent
  • Cellular antenna supports and provisions
  • Painted logo, lettering, and custom graphics
  • FAA lighting
  • Locking ladder gates
  • Ladder cages and/or platform landings
  • Architectural treatment such as pilasters
  • API flush-mount clean out
  • Additional security or ornamental lighting
  • Specialty trim or customized design

Specifications & Standard Tank Drawing

Caldwell Drawings & Specs

Surveys from Actual Caldwell Tank projects

Case Studies for Actual Caldwell Tank projects

Caldwell Connect