Back Flow Preventor Hotbox/Above Ground Enclosure

[ClemsonVet]

we have a 6" back flow DCDA serving a single private fire hydrant. Will be installed above ground in an enclosure typically called a "hotbox".

question:
When do you need a heater? Is there a geographical way to determine when its not necessary? We're in SC and it does freeze a couple dozen times each winter, however i understand the box itself may provide enough insulation from the elements to keep the device from freezing. Additionally we see above ground back flow prevention devices around simply wrapped in insulation materials.

If i can be steered toward regulatory / industry standard type guidance on this I would appreciate the help!

 

[r13]

The linked article is posted on Portland Water Bureau website regarding DCDA installation requirement. in which it says "4. Backflow assemblies must be protected from severe environmental conditions (i.e. insulated enclosure and insulate exposed piping or provide a heat source). I think you shall check with SC Water Bureau for similar document. Link

 

[bimr]

When do you need a heater? Is there a geographical way to determine when its not necessary? We're in SC and it does freeze a couple dozen times each winter, however i understand the box itself may provide enough insulation from the elements to keep the device from freezing. Additionally we see above ground back flow prevention devices around simply wrapped in insulation materials.

You need ask around and see what is customarily furnished in the project location. Start with the AHJ in the building code department.

 

[ClemsonVet]

the water system doesn't do them often and doesn't seem to know. One of the water service PM's said no and the inspector said yes. I think its probably a design engineers judgement call based on the temperature. hoping to get steered towards some actual doctrine. i'll check with SC Department of healt and env services.

 

[PEDARRIN2]

Sounds like the water service PM and inspector need to get on the same page. Since, in my locale (Ohio), DCDA are commonly installed in pits which really do not have any freeze protection, we do not require a hot box. The only backflow we are required to put into a hot box are the RPZ type. Check with your local AHJ. If they do not require them, they are not required.