22.5< to ≤ 45, use 3 pieces
45 < to ≤ 67.5, use 4 pieces
67.5 < to ≤ 90, use 5 pieces
A) The larger the O.D. of the fitting, the more competitive a mitered fitting will be. Because of the ultimate use, most fittings 54″ and larger can be fabricated and will provide that competitive edge.
B) AWWA C208-96 elbows are made from miter cut pieces of pipe. The mitered pieces that make up the elbow are called gores. In a 5-piece elbow, there are two end gores and three middle gores. The dimensions of the end and middle gores are determined based upon formulas provided by AWWA on page 7 of C208-96.
C) AWWA C208-96 recommends 2 and a half X diameter as an optimum radius, (centerline radius), for mitered elbows with 1 X diameter as the minimum. Due to industry standards for elbows of other specifications, (e.g. A234 WPB), we set the normal radius at 1 and a half X diameter.
D) However, other standards set the “center-to-face,” or the line originating 90 degrees from the plane of the face of one end of the elbow to the center line of the other end as equal to the center-line radius. AWWA C208-96 DOES NOT FOLLOW THIS PRACTICE! In the AWWA spec, the “radius” is a calculation based upon the formulas mentioned above. The AWWA spec states the radius of a 60″ elbow is 90″. The “center-to-face” is 92.065″.