Could you let me know the maximum allowable velocity in pipe in your country?

I wonder the allowable maximum velocity in pipe in other countries. In Korea, the maximum velocity is 3.0m/sec but I guess it can be increased when we use erosion resistant materials like steel or PVC. I found some countries like Hong Kong, some states in US allow more than 3.0m/sec (ex: 4.5 or 6.0m/sec) It will be very appreciated all of you let me know the allowable maximum velocity in pipe. If possible, send me your design standard document to my e-mail. e-mail: yscatfish96@gmail.com or yscatfish@hanmail.net Thanks in advance. Best regards, Yongseok CHOI