Air Gap Required Distance for RPZ Drain

[ME27272727]

Anyone know where I can find a code reference to the minimum air gap required for an RPZ relief drain? Having a hard time tracking it down. Thanks.

 

[PEDARRIN2]

If this is in an International Plumbing Code enforced area, it is in chapter 8.

Typically, the distance is required to be 2X the size of the piping from the RPZ relief drain, i.e. a 1" drain ends 2" above the top of the drain/floor. I would also recommend the discharge pipe have a diagonal cut on the bottom to better direct the flow to the drain.

Another (sometimes) related issue is the size of the drain. Remember the RPZ can/will flow a lot of water if the valve fails. I have heard of 4" sanitary drains not being sufficient to handle the flow of an RPZ.

 

[trashcanman]

Normally, an RPZ already has an air gap between the body and the drain funnel. You do not need an additional gap at the termination of the drain.

 

[PEDARRIN2]

traschcanman;

You are entirely correct and I have seen that approach used. However, I have also heard of some jurisdictions stating the air gap on the rpz is part of the assembly so a "separate" air gap is required at the waste receptor. It is redundant in my mind, but sometimes it is less expensive if time and frustration just to add the second air gap.