DS Pipe and Steel Supply

Vacuum Breakers

Vacuum breakers are mechanical devices used to prevent the collapse of a vessel or piping system due to a vacuum or negative pressure. They are essential components in piping systems to protect against potential damage or hazards caused by vacuum conditions. Vacuum breakers allow atmospheric air into the system when a vacuum occurs. This prevents the formation of a vacuum, which could lead to equipment damage, implosion, or other hazards. The vacuum breaker typically consists of a valve mechanism that remains closed during normal operation but opens automatically when a vacuum condition is detected, allowing air to enter the system and equalize the pressure.

Types of Vacuum Breakers

Different types of vacuum breakers are designed for various applications and operating conditions. Some common types include:

  • Pressure Vacuum Breakers (PVB): These are typically used in water supply systems to prevent backflow contamination. They contain a spring-loaded check valve that opens to admit air when a vacuum occurs.
  • Atmospheric Vacuum Breakers (AVB): These are simple, cost-effective devices used in non-pressurized systems, such as irrigation systems and hose bibs. They rely on gravity and atmospheric pressure to prevent backflow.
  • Thermal Vacuum Breakers: These are used in steam systems to prevent vacuum conditions that could lead to steam traps malfunctioning or collapsing. They use a temperature-sensitive element to open and allow air into the system when the temperature drops and a vacuum forms.


Vacuum breakers are widely used in the piping industry for various purposes, including:

  • Water Distribution Systems: In water supply systems, vacuum breakers are installed at high points or points of potential vacuum formation to prevent the collapse of pipes or water heaters due to negative pressure. They also prevent backflow of contaminated water into the potable water supply.
  • Steam Systems: In steam piping systems, vacuum breakers prevent the formation of a vacuum that could lead to steam traps malfunctioning or condensate lines collapsing. They ensure the efficient and safe operation of steam equipment.
  • Chemical Processing: Vacuum breakers protect vessels and piping systems from collapse due to vacuum conditions that may occur during processes such as distillation or evaporation.
  • HVAC Systems: Vacuum breakers are employed in HVAC systems to prevent the formation of a vacuum in chilled water or hot water piping, which could cause damage to pumps, coils, or other components.