In the State of Mississippi, State law stipulates that Backflow IS NOT required on Low Hazard Connections and specificially lists wet and dry pipe sprinkler systems as being exempt from backflow requirements. It does require them if there is nonpotable cross connections such as antifreeze loops and pumps taking suction from non potable sources. State Law went a step further and prohibited any political subdivision in the state from adopting or enforcing any law or policy that is more stringent than the State Law thereby negating IPC requirements for Backflow on wet and dry pipe sprinkler systems.

I am not a big fan of these devices as you may have noticed. They do have their place but my experience with these devices is that they never are maintained and tested for the use they are intended to serve and they are unreliable when connected to fire sprinkler systems and especially so when placed on lines serving fire hydrants.

We had one installed on a resort complex and when we went to do annual fire pump testing we could not achieve light hazard flow from the system. The connection was one block away from the city’s well.

We had another one installed on private fire service mains and could not achieve 4 head criteria on a 13R system nor could we achieve any usable fire flow from the hydrants serving the apartments. The city main serving this private system system was at a 10 inch/12 inch circulating main crossroads.

So I am not a big fan of these and this article is good in that it points out the need is positively there to not only install the testing means, but fire inspectors do need to enforce the testing provisons of these devices.

12.6.2 Testing.

12.6.2.1* All backflow preventers installed in fire protection system piping shall be tested annually in accordance with the following:

(1) A forward flow test shall be conducted at the system demand, including hose stream demand, where hydrants or inside hose stations are located downstream of the backflow preventer.

(2) A backflow performance test, as required by the authority having jurisdiction, shall be conducted at the completion of the forward flow test.

A.12.6.2.1 The full flow test of the backflow prevention valve can be performed with a test header or other connections downstream of the valve. A bypass around the check valve in the fire department connection line with a control valve in the normally closed position can be an acceptable arrangement. When flow to a visible drain cannot be accomplished, closed loop flow can be acceptable if a flowmeter or sight glass is incorporated into the system to ensure flow.

12.6.2.1.1 For backflow preventers sized 50.8 mm (2 in.) and under, the forward flow test shall be acceptable to conduct without measuring flow, where the test outlet is of a size to flow the system demand.

12.6.2.1.2 Where water rationing shall be enforced during shortages lasting more than 1 year, an internal inspection of the backflow preventer to ensure the check valves will fully open shall be acceptable in lieu of conducting the annual forward flow test.

12.6.2.1.3 Where connections do not permit a full flow test, tests shall be completed at the maximum flow rate possible.

12.6.2.1.4 The forward flow test shall not be required where annual fire pump testing causes the system demand to flow through the backflow preventer device.

12.6.2.2* All backflow devices installed in fire protection water supply shall be tested annually at the designed flow rate of the fire protection system, including required hose stream demands.

A.12.6.2.2 The tests required by 12.6.2 typically test only for operation of the device under backflow conditions. Forward-flow test conditions are required by other portions of this standard.

12.6.2.2.1 Where connections do not permit a full flow test, tests shall be conducted at the maximum flow rate possible.

12.6.3 Maintenance.

12.6.3.1 Maintenance of all backflow prevention assemblies shall be conducted by a trained individual following the manufacturer’s instructions in accordance with the procedure and policies of the authority having jurisdiction.

12.6.3.2 Rubber parts shall be replaced in accordance with the frequency required by the authority having jurisdiction and the manufacturer’s instructions.

For folks who follow the 2008 version of NFPA 25 it is in chapter 13.6.2.