4 Inch PVC Expansion Coupling

Expansion Joint Conduit Size: 4" Maximum Extended Length: 22.90" Maximum Retracted Length: 14.90" For every 100 deg. F change in temperature a 100' run of pipe will undergo a change of 3.6". When expansion joints are required the following steps should be taken 1.) Determine Number of Joints Required: Total Expansion = Total temp. change F deg. / 10 X Length of run in ft. / 100 X .36 The expansion joints should be installed at even intervals throughout the run. The Number of Joints = Total Expansion / 4 2.) Determine Piston Opening: Piston (in.) = max. temp. F - install temp F / temp change F X 4 Example: Assume a 200' run of conduit is being installed in an unheated building where the temperature will vary from 10 deg. F in the winter to 110 deg. F in the summer. The installation will be carried out when the temperature is 60 deg. F. Using step 1 we detemine the number of joints required: 100F / 10 X 200' / 100 X .36 = 7.2" 7.2 / 4 = 1.8 Note: Always round off to the next highest number. Therefore we see that 2 expansion joints are necessary in this run. Expansion joints should be placed at equal distances apart in the run. The center run should be firmly anchored in the middle to direct the movement evenly into both expansion joints. Using step 2 we determine the proper piston opening: 100F - 60F / 100F X 4" = 2" Therefore this piston should be opened 2" when the joints are installed. Note: Leave pipe staps loose to allow movement of the pipe.