RPZ Enclosures

A designer may specify one of 2 types of backflow prevention devices. First, the Double-Check Valve Assembly. This is often shortened to DC and is typically thought of as the appropriate solution for low hazard conditions. Second, the Reduced Pressure Zone Valve Assembly, often shortened to RP or RPZ, is thought of as the appropriate solution for high hazard conditions. If you came here from our DC vs RPZ backflow preventers blog post, you already know all about the differences between the valves as well as why the RPZ provides a higher level of protection to the water supply.

Because the RPZ provides the highest level of protection for your water supply, many areas are now requiring their use on all domestic and fire service lines. Now that they are becoming so prolific, you may need to know where to install them. You basically have two options - inside in a mechanical room, or in an RPZ enclosure. Because of their propensity to flood while operating as intended, an RPZ is better off outside the building. There is a big difference between the work, headache, and money involved in a situation where a mechanical room floods, and when water pours out of an RPZ enclosure like in the video shown below.

RPZ ENCLOSURE MODELS

Below you'll find standard details showing a backflow preventer assembly drawn inside it's corresponding enclosure. We chose to show you the three most commonly specified sizes of RPZ from the most popular backflow manufacturers. If you need to find the right RPZ enclosure for your device, you can use our sizing guide tool to find the correctly sized enclosure for nearly any RPZ valve. You'll be able to specify whether it has a strainer or not, what type of valve shut-offs it has, and of course which make and model the valve is. These RPZ enclosures are designed with the RPZ in mind. They have the proper drainage to allow discharged water to flow out of the box, are insulated for valve frost protection, and keep thieves away from the device's valuable metal.

watts 4 inch 957 nrs.jpgWatts

To the right you'll see a typical standard detail for a 4" Watts 957 model RP backflow preventer inside of an RPZ enclosure. You can click on the image to enlarge it. Below are direct links to drawings for the rest of the most popular models of Watts backflow preventers inside an RPZ enclosure.

 

6" Watts 957

8" Watts 957

 watts 6 inch 957 osy watts 8 inch 957.jpg

 

Wilkins

wilkins 4 inch 375 NRS

To the right you'll see a typical standard detail for a 4" Wilkins 375 model RP backflow preventer inside of an RPZ enclosure. You can click on the image to enlarge it. Below are direct links to drawings for the rest of the most popular models of Wilkins backflow preventers inside an RPZ enclosure.

 

Wilkins 6" 375 Wilkins 8" 375
wilkins 6 inch.jpg wilkins 8 inch 375 osy

 

apollo 4 inch rp4a nrs.jpgAPOLLO

To the right you'll see a typical standard detail for an Apollo 4" RP4A model RP backflow preventer inside an RPZ enclosure. You can click on the image to enlarge it. Below are direct links to drawings for the rest of the most popular models of Apollo backflow preventers inside an RPZ enclosure.

6" Apollo RP4A

8" Wilkins RP4A
apollo 6 inch osy wilkins 8 inch 375 osy