If the drop rod length required is too long for the installation, DST Ball Hangers or DST Hemispherical Cups and Washers can be used to increase the movement, but decrease the drop rod length. Further advice can be given by one of our Technical Sales Engineers.
Drop Rod Calculation Example
Calculation of Drop Rod Length = Δ / Tan 5°
To calculate the drop rod length required for a length of 50nb pipe expanding 35mm
Expansion in mm = 35 / Tan 5° = 400mm to centre line of pipework
Therefore drop rod length will be:
400mm – 1/2 of 60mm (outside diameter of 50nb)
400mm – 30mm = 370mm
Drop Rod length (minimum) = 370mm
