Pipes become rougher as they age. In some cases pipes become much rougher than common literature recommendations for aged pipe. Age related changes in pipe roughness are particularly important because of the ubiquity of iron based pipe. For this study, it was found that the headloss due to friction in seven pipes ranging from 30 to 50 years old increased 200%-2400% as compared with the new condition. This unique set of aged pipe friction data shows that Darcy’s f for the tested aged pipes ranged from 0.06 to 0.22. A ratio of the effective aged pipe diameter to the new pipe diameter was also calculated for each pipe. Plotting Darcy’s f versus the diameter ratio revealed correlation between the two terms. The seven aged pipes were chosen for testing because they had visible age degradation and are not necessarily representative of pipes in this age class.
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