In case of steel (MS) to steel (MS) contact between the pipe and support respectively, the coefficient of friction generally taken is 0.3.In one of the projects the client is suggesting to use the value as 0.5 as the surrounding environment is not so clean and the piping is low grade MS with rough finish. In addition to the industry practice of using the value of 0.3 is there any backup to substantiate the value considered for specific cases with varying site conditions?