You may know them by one of their various names: sill cock, wall hydrant, spigot, garden hose faucet, lawn faucet, wall tap, hose bibb, yard hydrant, etc. It can all seem a bit confusing. Regardless of what you call it, it’s defined as a supply fitting, generally used outdoors, which is connected to a single water line with hose end threads to attach a hose. Here forward, I will refer to these as hydrants as “devices.” [Note: there are hydrants plumbed to both hot and cold water currently on the market.]
With the connection of a hose to these devices, it is important to note that there is a possibility for backflow to occur. It is conceivable that the hose, when attached to the fitting, could be left submerged in a non-potable reservoir. Depending on the circumstances, the contaminate in the reservoir could be lethal. Just think about a chemical dispenser that is attached to a hose and dispenses fertilizer or weed killer on your lawn. Should an event occur that causes the upstream pressure to drop, the contents of the reservoir can be backsiphoned into the potable water supply.
For this reason, backflow protection is an important feature of these devices. In fact, the plumbing codes require these devices to have backflow protection. Hence, standards that establish the minimum requirement for the inclusion of backflow protection with these devices have been developed and published.
There are five different ASSE product performance standards for these types of devices. Just as the multiple naming conventions of hydrants creates confusion, the existence of the five standards for (seemingly) the same product is often misunderstood. I will attempt to add clarity to the differences and explain why five different standards were created.
I will begin with the ASSE 1011 and ASSE 1052 standards. These standards cover the backflow protection components added to hydrants that do not have integral backflow protection. These devices are intended to be non-removable and are non-testable.
The ASSE 1011 device (Hose Connection Vacuum Breaker) uses a single check valve to prevent backflow and uses air ports to prevent back-siphonage. To prevent backpressure, the device uses the check valve and relieves the backpressure through the air ports.
The ASSE 1052 device (Hose Connection Backflow Preventer) is similar to the ASSE 1011 device, except it uses two check valves — one check valve holds the pressure in the hose. There is an intermediate chamber between the check valves, which vents to atmosphere.
Plumbing codes specify these devices for protection of low and high hazard backsiphonage. Both devices are not for use in continuous pressure. Continuous pressure is defined as “under pressure for more than 12 hours in a 24 hour period.”
The ASSE 1019 device (Wall Hydrant with Backflow Protection and Freeze Resistance) is the most familiar. This hydrant has an integral backflow protection device consisting of a check valve to prevent backpressure, and an air inlet to prevent backsiphonage. ASSE 1019 devices also have a feature to minimize the danger of the freezing valves at low temperatures. The device also includes a shutoff valve.
Plumbing codes specify these devices for protection against low and high hazard backsiphonage. These devices are not for use under continuous pressure.
The ASSE 1053 device (Dual Check Backflow Preventer Wall Hydrants – Freeze Resistant Type) is a wall hydrant with an atmospheric vent between two check valves. The check valves are biased in the open position and the device is testable. These hydrants require a special detachable key or handle to operate.
There are two types of ASSE 1053 devices. The Type A device will drain water automatically when the valve is closed and the hose is removed. This is to prevent damage due to freezing. The Type B device will automatically drain water regardless of whether the hose is attached or not.
Plumbing codes specify these devices for protection against low and high hazard back-siphonage. Both devices are not for use under continuous pressure
The last device to discuss is the ASSE 1057 (Freeze Resistant Sanitary Yard Hydrants with Backflow Protection). As the name implies, this device is not attached to a wall; the valve is attached to a pressurized standpipe to supply water.
There are five types of yard hydrants. The differences being a combination of one or two check valves, and freeze protection with or without a hose connected (Types 1-4). The fifth type is one in which the backflow prevention device is removable and designed so that a hose cannot be connected to the device when the backflow protection device is removed.
Plumbing codes specify these devices for protection of low and high hazard back-siphonage. These devices are not for use under continuous pressure.
As you will have noticed, all of these devices are similar in their protection capability and internal design. However, the applications are distinct, and in some cases, the requirements are slightly different based on the accepted applications. For these reasons, it was necessary to have separate standards for each. However, since these devices are so similar, there are ongoing efforts to harmonize the test methods and language where it makes sense. The goal of this activity is to further reduce the confusion, to help clarify the methods, and to better distinguish the differences between the devices.
The new revisions of these standards are expected to publish by ASSE International over the course of the next year.
