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Pedesphere Elevated Storage Tank (PED)

Water Storage Tank

Pedesphere Elevated Storage Tank (PED)

DEFINITION: An elevated, welded, carbon-steel, spherical water storage tank; supported by a single cylindrical carbon-steel support pedestal with a flared conical base.

Standard Sizes: PED

Capacity (US Gallons)
Head Range (Feet)
Tank Diameter (Feet)
Shape
50,000
21'3"
24'
Sphere
75,000
25'6"
27'
Sphere
100,000
25'6"
30'
Sphere
125,000
29'6"
32'
Sphere
150,000
32'3"
34'
Sphere
200,000
28'3"
41'
Spheroid
250,000
31'
43'8"
Spheroid
300,000
33'
46'6"
Spheroid
400,000
35'6"
51'6"
Spheroid
500,000
37'6"
55'6"
Spheroid
600,000
38'6"
60'
Spheroid
750,000
40'
66'
Spheroid
1,000,000
40'
66'
Spheroid
1,000,000
40'
74'
Spheroid
1,250,000
40'
80'
Spheroid
1,500,000
48'
84'
Spheroid

Specifications & Standard Tank Drawing

  • Caldwell Tanks adheres to all American Water Works Association (AWWA) standards for our potable water PED style tanks
  • Caldwell Tanks follows the National Fire Protection Agency (NFPA) 22 Standard, as applicable
Download Plans & Specifications

Special Features

  • The slender single support column, which does not contain water, securely encloses the access ladders and connects piping to the tank.
  • In larger sized PED's, the base provides lockable storage for pumps, piping, controls, or extra storage.
  • Some believe this to be the most aesthetically pleasing tank style, because of its simple, contoured shape, its small ‘sky-print' (the equivalent of a footprint in the sky), and its small ground silhouette (shadow on the ground).

When It's Best

  • Sleek design reduces surface area and future maintenance costs 
  • Largest selection of standard tank sizes
  • To gain additional storage capacity in the water system (especially for fire protection)
  • To gain additional pressure in the water system (especially for power outages)

Highlights & Advantages

  • Caldwell's Pedesphere Tank is sphere-shaped in capacities from 25,000 gallons to 150,000 gallons and is spheroidal-shaped for larger capacities
  • Attractive, sleek, simplistic appearance
  • Beneficial in specific types of soil and seismic conditions
  • Smooth, continuous exterior surface and reduced overall surface area offer future maintenance benefits
  • Interior ladders and piping protect against weather and vandalism; and easily allow for pipe insulation
  • The pedestal shaft and flared base cone diameters are varied to suit individual design requirements and owner conditions

Standard Sizes

  • Reference the table 50,000 to 1,500,000
American Water Works Association (AWWA D100 & D102)

Standard Accessories

  • Steel frost-proof pressure/vacuum relief vent designed for maximum protection
  • (1) roof hatch with hinged cover and hasp
  • (1) roof hatch bolted for attachment of exhaust fan
  • (1) access tube roof hatch
  • (1) manhole in base of access tube
  • (1) painter hatch at top of pedestal
  • Purchaser-specified inlet/outlet piping with expansion joint
  • Pedestal-supported overflow pipe to grade level with concrete splash pad
  • Base cone, pedestal, and access tube ladders with OSHA compliant safety climb devices
  • Platform landing at top of pedestal
  • Painter's rings near top of pedestal
  • Interior lighting in pedestal and in access tube
  • Grounding for minimizing lightning damage
  • Condensate ceiling (steel with a drain to the overflow pipe)
  • Personnel door in base cone
  • Gravel floor inside base

Elective Accessories

  • Tank drain for washouts
  • Larger diameter manholes, hatches, and access tube
  • Intermediate rest platforms
  • Complete internal seal welding
  • Roof handrail or exterior ladder up the pedestal
  • Aluminum or custom roof vent
  • Cellular antenna supports and provisions
  • Painted logo, lettering, and custom graphics
  • FAA lighting
  • Insulated and/or heat traced tank piping or stainless steel piping
  • Piping in base cone - bypass lines, altitude valve, etc.
  • Overflow flap valve
  • High water elevation/pressure gauge
  • Concrete floor inside base
  • Instrumentation, control room, & cathodic protection
  • 8' or 10' wide overhead door
  • Solar powered or other type of mixing system
  • Additional security or ornamental lighting
  • Specialty trim or customized design