Double Check Assemblies are backflow prevention device used to protect the clean water from contaminants. They do that by employing two check valves so water can’t go the other way. This device is appropriate for low risk environments.
A Double Check Assembly is a series of two check valves placed in line. And each valve includes a spring, which helps close it when water moves toward it in the wrong direction. Both valves would otherwise remain open so water could flow freely. If the water pressure reverses, the valves seal to prevent reverse flow. This double protection ensures that if one valve gets compromised, the other can immediately kick in to prevent backflow.
Where Is It Used?
There are low risk common uses for Double Check Assemblies. Some typical uses include:
Fire Sprinkler Systems
Many buildings have fire sprinkler systems connected to the water supply. Even if one part of the system has issues, the Double Check Assembly ensures that contaminated water cannot enter the clean water line.
Lawn Irrigation and Landscaping
Outdoor watering assemblies, such as those used for lawns and gardens, also use these assemblies. They do not require more expensive devices and thus are a practical use case for backflow prevention.
Commercial Pools and Recreational Areas
Double Check Assemblies are also used for pools and other water features to prevent water containing chemicals or debris from returning to the main supply.
Food Service Equipment
Kitchens can get protection from contamination that occurs through water-utilizing equipment. The device is designed to prevent any water used for washing or cooking from contaminating the clean supply.
Industrial Processes
Some manufacturing and processing plants use these assemblies to prevent process water from entering the main water supply, especially when potential contamination does not pose a high health risk.
Benefits of Double Check Assemblies
Double Check Assemblies offer several advantages:
- Cost-Effective: They are cheaper when to compared for complex devices. Because the protection offered is adequate for low-risk applications, these assemblies allow to save money.
- Easy to install: They are easy to install due to their simple design. These can be positioned horizontally or vertically based on how the water system is constructed.
- Simple Maintenance: The assembly comes with built-in test ports and shut-off valves that let the technician test and service it. Regular checks also make sure that the valves are functioning properly and that water quality is not compromised.
- Reliable Backup System: The assembly utilizes two valves which provide added peace of mind. If one valve fails, the other will prevent backflow. This means this system becomes super reliable in low-hazard scenarios.
- Meets Regulations: Backflow prevention devices are required in many local building codes. For low-risk applications, double check assemblies provide these desired features which can help facilities comply with safety regulations.
Installation and Testing Guidelines
For the double check assembly to function as desired, proper installation and periodic testing are imperative.
1. Follow Manufacturer Instructions
To ensure a proper installation, technicians should always follow the manufacturer’s guidelines. This ensures the assembly is configured correctly and will work.
2. Correct Orientation
While the assembly can be installed there in various positions, the correct orientation is critical. Valves function properly when water flows in the right direction.
3. Use of Shut-Off Valves
Placing shut-off valves in both the inlet and outlet sides makes it easy to isolate the device for maintenance. This rule makes it possible to conduct testing safely without compromising the entire water supply system.
4. Regular Testing
A certified professional should try the assembly at least once a year. The testing is done by measuring the pressure differentials across the test ports to ensure both check valves operate correctly to close under the conditions they need to close under.
Maintenance Considerations
Regular maintenance is crucial to keeping the double check assembly in working order.
Periodic Inspections
Scheduled inspections also catch issues before they grow. Certified technicians can inspect for signs of wear or small leaks before issues become serious.
Cleaning and Component Replacement
Over time, particle or mineral build up can impact the valves. Cleaning or adjusting parts when they wear out maintains a tight seal and dependable function.
Record Keeping
Detailed documentation of any inspections and tests is essential. This documentation serves the purpose of maintaining the device’s functionality and keeping up with the maintenance schedule.
Timely Repairs
Repairs should be made immediately if any component exhibits signs of wear or failure. Servicing to keep the prompt system up to date decreases the chances of contamination so the water system is complied.
Comparing Double Check Assemblies with Other Devices
It is helpful to know how double check assemblies are compared to other types of backflow prevention devices.
Reduced Pressure Zone (RPZ) Devices
RPZ devices are meant for higher risk scenarios. They have a relief valve that releases water to prevent backflow. They offer a higher level of protection but are more complicated and costly. On the other hand, double check assemblies are well suited for low risk environments.
Pressure Vacuum Breakers (PVB)
Pressure vacuum breakers are primarily for irrigation systems, and are less complicated than the RPZ devices. But they cannot provide the same level of backup protection as double check assemblies.
Air Gaps
Air gaps are the most straightforward backflow prevention type and require no moving parts. While these are some of the most efficient gas capture methods, they're also not always viable in scenarios with limited space, or systems where water pressure is a crucial metric. Double check assemblies provide a small, simple and reliable option in situations where this is required.
Conclusion
The double check assemblies are a proven, economical means of backflow prevention in low hazard applications. This ensures that no contaminated water passes back into the clean water supply. These fittings see use in fire sprinkler systems, lawn irrigation, commercial pools, food service equipment, and industrial processes.
Double check assemblies are approved for use where the safety requirements in local codes demand, with easy installation, maintenance, and regular testing. They are designed for use in applications where the possible contamination is not life threatening but still needs protecting.