???? ????? AWWA C509 ???? ?????? ?????? ??????? ?? ??????

?? ???? ??????? AWWA C509 ???? ????? ???? Shijiazhuang Deye Piping Industries Co., Ltd. ?? ???? ???? ?????? ???? ?????? ????????? ????????. ???? ??? ?????? ???????? ???? ?????? ????? ????? ?????? ?????????? ??? ???? ???????? ?????? ?? ????? ????? ??????. ?? ????? ???? ??????? ??? ???????? ???? ????? ??????? ??? ????? ??????? ???? ?????? ??????. ??? ????? ????? ???? ??????? ??????? ?????? ???? ??? ????? ??????? ??????? ?? ????? ?????? ?? ???????? ??? ?? ??? ?????? ?????? ????? ???????? ????????? ?????? ???? ??????? AWWA C509 ?????? ?????? ???????? ??? ?????? ??????? ?????. ?? ????? ??????? ??????? ?????? ?????? ?????? ?????? ??? ????????? ??????????. ?? ???? ?????? ????????? ??????? ???????? ??? ???? ??????? ??? ???? ??????? ?????? ?? ???? ??????? ?? ????? ?????? ?????? ?????? ????? ????? ?????? ?? ????????? ????????. ???? ???? ??????? AWWA C509 ?? ???? Shijiazhuang Deye Piping Industries Co. ? ???????? ?????? ??? ???? ?????? ?????? ?? ??? ??????? ?????? ?? ???????