1. Material
Lumber for staves and bottom shall be clear all heartwood, dense, sound well seasoned redwood, free from shakes, splits, sapwood, rot, knots, and unsound birdseye, or any other defect which would be detrimental to strength, water tightness or durability of the tank. Lumber shall have a moisture content of 20% or less.

Lumber grade shall conform to specifications for "Clear All Heart" and "Tank Stock" Par #103 & Par #304 of the "Standard Specifications for Grades of California Redwood Lumber" as adopted by the Redwood Inspection Service, the latest edition.

2. Dimensions
Tank is to be straight sided (without taper), and all tank dimensions are outside measurements unless otherwise specified.

3.Bottom
Bottom boards shall be 4" to 12" nominal width, nominal 2" thick surfaced four sides, cut the to proper circle with edges chamfered (top and bottom) to make a snug fit with the croze in the staves. Bottom planks 20' or less shall be furnished as one piece; over 20' shall be spliced with a stainless steel spline or finger-jointed.

4. Staves
Staves shall be milled to the true outside tank diameter and edges shall be beveled to the true radial lines to insure a water tight joint between staves. Staves shall be crozed in such a manner as to provide a water tight fit with the bottom chamfered edges. All staves shall be furnished in one piece (to 20' length) and are cut 1" less than nominal length.

5. Hoops
Steel tank hoops shall be of hot rolled mild steel conforming to A.S.T.M. A-36 specifications with minimum tensile strength of 58,000 P.S.I., minimum yield strength of 36,000 P.S.I., and elongated of 20% in 8 inches. Each hoop section shall have a standard button head on one end and 8 inches of cold rolled upset thread and a heavy hexagon nut on the other end. The thread shall equal or exceep the hoop body. Hoop diameter, spacing, and count shall be recommended by the manufacturer (based on standard hydrostatic calculations for 1.0 specific gravity contents, and a four to one safety factor). The hoop sections shall be hot dip galvanized after fabrication.

6. Lugs
Hoop sections shall be connected by straight pull, canopy type, malleable iron tank lugs. The lugs shall be manufactured of the highest quality malleable iron, A.S.T.M. A-47 Grade 32510 (USA) with a minimum tensile strength of 50,000 P.S.I., minimun yield strength of 32,500 P.S.I., and elongated of 10% in 2 inches so shaped to produce a straight pull on the hoop section without torsion of side binding. The lugs shall be hot dip galvanized.

7. Chime Joists
Chime joists shall be manufactured of sound 4" x 6" Construction Heart Redwood, be sufficient to provide proper support, clearance between staves and concrete slab. Standard Maximum Spacing is 18" O.C.

8a. Flat Roof
Flat roof shall be constructed with construction heart or better lumber grade; rafters, segment rings, support blocks, beam(s) and post(s). Standard sheathing is 1" T&G select heart or better, hatchway, perimeter ventilation with stainless steel screening. Standard design 25 P.S.F. live load. Other live load and wind load are available.

8b. Plain Conical Roof
Self supporting conical type roof with adequate perimeter and peak ventilation. Framing is construction heart grade lumber or better, hatchway. Standard sheathing is 1" T & G select heart or better. Standard design is 25 P.S.F. live load. Other live load and wind load are available.

9. Interior Ladders
Redwood ladders are constructed from clear all heart 2" x 6" rails and 2" x 4" rungs, fastened with glue, galvanized nails and rail faces are fastened with nails and bolts. Fasten at the roof structural framing and tank bottom.

10. Exterior Ladders
Redwood ladder with 2" x 6" rails from clear all heart and 2" x 4" rungs from clear all heart or better attached with galvanized nails, bolts, and brackets. The rails extend 3'-6" above the top rung as a walk through. Anti-climb panel of 1" T&G redwood, galvanized hinges and hasp, the panel covers the first ten rungs or all on shorter tanks.

11. Register
Standard indicator shall consist of a 1" x 4" target board painted white, attatched to the tank, full height of tank, wood float (epoxy sealed), cast iron or mild steel target (painted red), and stainless steel flexible cable. Numerals (in black) shall be at one foot intervals.

12. Fittings
Galvanized tank nipples 3/4" to 2"and Flanges 1 1/2" to 6" in stock. Stainless steel, steel (specify coating), and PVC are available.



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