=187. Rate of Progress.=—In a general way it can be assumed that the laying of 1,000 bricks will require 3⅓ hours of the time of one mason, 10 man-hours for helpers and laborers, 2 barrels of cement, 0.6 cubic yard of sand, and about 10 feet board measure of centering. One thousand bricks will make about 2 cubic yards of brickwork. To the costs, as estimated on the basis of materials and labor, must be added about 15 per cent for overhead and an additional amount for the contractor’s profit. The number of bricks required in various size sewers is shown in Table 67. A mason can lay more bricks per hour in a large sewer than in a small one as there is a smaller percentage of face work, there is more room to work, and it is easier to lay the bricks radially. The number of bricks laid and the rate of progress on various jobs are shown in Table 68. TABLE 67 BRICK MASONRY IN CIRCULAR SEWERS. CUBIC YARDS PER LINEAR FOOT (From H. P. Gillette) ─────────────────┬─────────────────┬─────────────────┬───────────────── Diameter, │ One Ring │ Two Ring │ Three ring Feet and Inches │ (4½ Inches) │ (9 Inches) │ (13½ Inches) ─────────────────┼─────────────────┼─────────────────┼───────────────── 2 0│ 0.103│ 0.240│ 2 6│ 0.125│ 0.280│ 3 0│ 0.147│ 0.327│ 3 6│ 0.169│ 0.371│ 4 0│ 0.191│ 0.415│ 4 6│ 0.213│ 0.458│ 5 0│ 0.234│ 0.501│ 0.802 5 6│ 0.256│ 0.545│ 0.867 6 0│ 0.278│ 0.589│ 0.933 6 6│ │ 0.633│ 1.000 7 0│ │ 0.677│ 1.063 7 6│ │ 0.720│ 1.128 8 0│ │ 0.763│ 1.193 8 6│ │ 0.807│ 1.260 9 0│ │ 0.851│ 1.325 9 6│ │ 0.895│ 1.390 10 0│ │ 0.938│ 1.456 ─────────────────┴─────────────────┴─────────────────┴───────────────── CONCRETE SEWERS