Anti-pressure valve - what is it and is it needed in a home installation?

What is an anti-surge valve?

Anti-contamination valve is a special type of check valve, the main task of which is to protect drinking water from secondary contamination. It acts like a one-way guard on the pipe - it allows water to flow only in the direction to the building, but in the event of an attempted reverse flow (backflow), it automatically blocks its path. This will ensure that contaminated water from the indoor system does not back up into the water mains or into other parts of the home system.

The mechanism of operation of the anti-squeeze valve is based on simple principles of physics. Under normal conditions, the valve remains open and does not interfere with the flow of water. However, when there is a sudden drop in network pressure (e.g., due to a malfunction, a burst pipe or a large water intake in the area), there is a risk that water from the home system will be sucked back into the network. In such a situation, the anti-contamination valve will react immediately: it will close the backflow through a flap or plug mechanism, and often additionally open the air supply to the system, interrupting the vacuum. In other words, this valve eliminates the siphon effect - it does not allow, for example, water from household appliances (already containing soap, detergents, rust deposits or bacteria) to back up into the drinking water pipeline.

Is an anti-drain valve needed in a home installation?

Definitely yes. The anti-contamination valve is now a standard component of a safe water system in residential buildings. Its installation in a single-family home ensures the protection of the health of the household members and those using the same water supply system - because it prevents contamination of the common drinking water through backflow of contaminants. In emergency situations, such as a drop in network pressure, backflow could cause water from a domestic system containing harmful admixtures to be drawn into the water supply system.

What's more, Polish building regulations require the use of anti-siphoning valves in new buildings. According to PN-EN 1717 and the Decree of the Minister of Infrastructure, each new internal water supply system must have protection against backflow - most often just in the form of an anti-contamination valve. Regulations mandate the installation of such a valve after the main water meter. This means that if you are building a new house or upgrading the installation, the installation of an anti-drain valve is not optional, but mandatory.

The benefits of having an anti-squeeze valve at home:

- Health and drinking water protection
- Compliance with the law
- Installation safety

Types of anti-surge valves

Various types of anti-contamination valves are available on the market, adapted to the nature of the installation and the level of risk of contamination. Each type is assigned a letter designation (according to the standard) and a slightly different design. Among the basic ones are:

• Type EA - basic anti-pressure valve used in simple domestic installations.
• Type BA - advanced anti-contamination valve with so-called reduced pressure zone.
• Type CA - anti-drain valve also protecting against backflow of water, but without the possibility of supervision.
• Type HA/HD - special anti-contamination valves for hoses and temporary connections.

The selection of the appropriate type of anti-siphoning valve depends on the so-called category of fluid with which the drinking water could potentially mix.

Installation and operation of the anticontamination valve

In order for the anti-corrosion valve to fulfill its role, it is necessary to install it in the right place and ensure proper working conditions. The optimal installation location is the section just behind the main water meter. In the case of a branched installation, each circuit (e.g., garden watering, admittance to C.O.) should have its own valve. Installation should be carried out by the installer, and the valve must be installed according to the direction of flow and left in a place easily accessible for inspection. It is recommended to check it periodically - preferably once a year.

Summary

The anti-drain valve is a small but key component of any modern water supply system. Its role is to ensure the safety of drinking water by preventing the backflow of contaminated water into the network. In this era of high sanitary standards, the installation of such a valve has become a necessity and a legal obligation in new buildings. For the homeowner, this means health protection, regulatory compliance and peace of mind about the quality of water in the taps.