DCDA-II & RPDA-II – Type 2 backflow devices; how do you record test results?

Posted by:

DCDA & RPDA Type 2 devices are the first major change in backflow devices in a lot of years.

The USC approved RPDA-II and DCDA-II to be installed back in 2004. However, we still aren’t seeing that many of them in the field yet. But we’re starting to, and without a doubt they’ve raised one common question – how do you record their test results?!

Differing Opinions

It turns out there are a lot of differing opinions on the subject.

Here’s a quick review of the Type 2 assemblies if you haven’t seen one in the wild yet.

A common DCDA has two devices: a big one, and a small one – the bypass device. You test both devices separately and record their results on separate test forms. Easy enough.

The type two assemblies do away with the first check on the small device and instead use the first check on the larger device. Instead of two distinct first check assemblies they are a single shared one. The second checks are still separate though.

Backflow Direct has made a couple youtube videos on how the type two devices differ – they’re extremely useful in seeing the difference. Since the videos put my drawings to shame, I’ve linked them here: DCDA-II RPDA-II

When we first had a tester ask us how to handle the entry we reached out to our local AWWA chapter. The Pacific Northwest AWWA chapter maintains the most common test report form we see in the PNW. That form has had a Type 2 assembly on it for a number of years.

We quickly got back a few different answers. We actually brought it up at a backflow sub-committee meeting to see how each of the water purveyors preferred it.

Some wanted to treat the detector assembly on a type 2 as a single check on a separate report. Others wanted the first check and the type 2 second check on one report and the main device on another report (similar to a standard DCDA.) Still others wanted to see it done on one report with a place for the type 2 check result to be indicated.

How we’re handling Type 2 Devices

We’ve since had testers from across the country ask us how it’s ‘normally’ done and we’ve had to tell them there isn’t a normal yet!

Our initial thought was to treat it as a single device. Why? The USC approval is for a single ‘device’ rather than a double check and an additional second ‘single’ check. It gets confusing though, with no clear ruling on how to treat them. Since backflow test resultss are important to us, we want to make sure we’re giving our customers the best advice on how to report on the devices, but in the end, we err on the side of the water purveyor to decide how to receive the info.

How do you track type 2 assemblies? Has there been any confusion in your area regarding them? Let us know!

0

Add a Comment