11625 AIRPORT RD BASE FILE 2018-01-01 MF Import

� � Meg Haley �Gl!� �U`� From: Bill Bruce Sent: Friday, November 02, 2007 3:34 PM To: Kirk Brooks; Tom Thetford; Mark Sadler; Meg Haley; Loren Postma ��, Bob Keller: Gordon Witcner Sub�act�. . 11625 Airp�rt Rd. To All, There are some importani eleTents to keep m mind when retrofitting 11625 Airport Rd. These elements may generalty be applied ro all retrofitting; but, each facility is a unique situation that needs the cooperetion of all parties tha!need to be involved. All fireservices with Single Check Device(SCD) need to be eventually upgraded to a State approved backflow preventer appropriate to the degree of hazard.. A L.uble Check Valve Assembly(DCVA) may be dsed inside provided that the Ciry of Everett's sp�cifications are met. In the case of the DCVA, the SCD must remain because of the need for a metec It is slso preferable that an engin2er approve the arrangement to assure that there is not too much head loss.. However, it is preferable that a Double Check Detector Assembly(OCDA)be used whether it is inside and the SCD is taken out or the SCD is replaced with a DCDA outside in a vault. The consensus seems to be that if the building is further than 70 feet from the water main,the DCDA should always be outside in a vault. I am writing this because the ratrofitting of fireservices is the most controversiat in cross-connection because of the perceived low health risk and high cost. It is important though, because according[o the American Backflow Prevention Association(ABPA) 1999 survey, 43%of reporting systems had backflow incidents relating to fire systems I am more than willing to have comments and additions to this email and thank you for your attention. Bill Bruce, CCS i