In wet fire protection systems like certain types of sprinklers and standpipes, a large volume of water never moves until it flows from an activated sprinkler head or a broken sprinkler pipe. When water sits, it becomes stagnant. Bacteria can grow, transforming the sprinkler water into a thick, smelly, black oily sludge that could potentially cause serious issues if it reverses into the drinking water supply.

Would you or your family want to drink it? I think not. Let’s look at a couple instances where proper backflow preventors were not in place.

Backflow Case History #1: Burned in a Shower

A resident of a small town in Alabama jumped into the shower at 5 a.m. one morning in October, and when he got out, his body was covered with tiny blisters. “The more I rubbed it, the worse it got,” the 60-year-old resident said. “It looked like someone took a blowtorch and singed me.”

He and several other residents received medical treatment at the emergency room of a local hospital after the water system was contaminated with sodium hydroxide, a strong caustic solution.

Other residents claimed that, “The water was bubbling up and looked like Alka-Seltzer. I stuck my hand under the faucet and blisters came up.” One neighbor’s head was covered with blisters after she washed her hair, and others complained of burned throats or mouths after drinking the water.

The incident began after an 8-inch water main that fed the town broke and was repaired. While repairing the water main, one worker suffered leg burns from a chemical in the water and required medical treatment. Measurements of the pH of the water were as high as 13 in some sections of the pipe.

An investigation into the cause of the problem led to a possible source of contamination from a nearby chemical company that distributes chemicals such as sodium hydroxide. The sodium hydroxide is brought to the plant in liquid form in bulk tanker trucks, transferred to a holding tank, and then pumped into 55-gallon drums.

When the water main broke, a truck driver was adding water from the bottom of the tank instead of the top, and sodium hydroxide back-siphoned into the water main.

Backflow Case History #2: Human Blood in Water Supply

Health department officials cut the water supply to a funeral home located in a large southern city after it was determined that human blood had contaminated the fresh water supply. The chief plumbing inspector had received a phone call advising that blood was coming from drinking fountains within the building.

Plumbing and county health department inspectors went to the scene and found evidence that blood had been circulating in the water system within the building. They immediately ordered the building cut off from the water system at the meter. City water and plumbing officials said that they did not think the blood contamination had spread beyond the building. However, inspectors were sent into the neighborhood to check for possible contamination.

An investigation revealed that the funeral home had been using a hydraulic aspirator to drain fluids from the bodies of human “remains” as part of the embalming process. The aspirator was directly connected to the water supply system at the faucet outlet located on the sink in the “preparation” room. Water flow through the aspirator creates suction that was utilized to draw body fluids through a hose and needle attached to the suction side of the aspirator.

The contamination of the funeral home potable water supply was caused by a combination of low water pressure in conjunction with the simultaneous use of the aspirator. Instead of the body fluids flowing into a sanitary drain, they were drawn in the opposite direction—into the potable water supply of the funeral home.

Here is a case history where water pressure from fire trucks overwhelmed the city’s drinking water supply lines, causing fire suppression foam to backflow into the water supply. These are just a few cases.

Fire protection systems must be considered non-potable systems due to the poor quality of the water.

If backflow from these systems should occur, the hazard will vary from a low health or aesthetic concern to a high health hazard. Most fire protection systems will have a fire department pumper connection. In these cases, the pumper connection must be installed downstream of the backflow prevention assembly.

For fire sprinkler system water supply protection and as per NFPA 13 backflow preventor regulations, all fire protection systems that are connected to the water purveyor’s potable water system, either directly or indirectly on the property side of a potable water service, should be isolated with an approved backflow prevention assembly. With backflow preventers in fire protection systems, the level of protection should be commensurate with the degree of hazard.

A fire protection system without any chemical additives is considered a low hazard. If there are additives like anti-freeze, foam concentrates, or water from auxiliary water supplies, then it is classified as a high hazard. The approved backflow prevention assembly must be installed as per the local water purveyor.

The fire protection assemblies are Double Check (low hazard) and Reduced Pressure (high hazard). There are many others for plumbing and domestic water systems—testable and non-testable.

Which brings us to testing of the assemblies.

Not only is it the law to have backflow prevention assemblies installed in your building, but the law also requires that these assemblies be tested and certified at least once per year by a certified backflow tester technician.

Along with NFPA fire protection backflow requirements, it should also be noted that after backflow prevention assemblies are tested, a full-flow main drain test must be performed as per NFPA-25 to ensure the water supply has been returned to service. The code also requires a system demand full-flow water test to be conducted to assure the sprinkler demand can be met through the assembly.

Oliver Fire Protection and Security has many fire protection backflow certified tester technicians on staff who are trained to perform complete NFPA-25 inspections at the same time as backflow tests.