Sino Forged Steel Ball Valve


» Blog

What is DBB Valve: Double Isolation and Bleed Valves or Double Block and Bleed Valves(2)

November 12, 2017

In the previous article we talked about the introduction and definition of DBB valves, please see 

What is DBB Valve: Double Isolation and Bleed Valves or Double Block and Bleed Valves(1)

In this article we will continue with application of DBB valves.


DIB and DBB valves are used in applications where crucial isolation is needed to make sure that leakage doesn’t occur. Based upon the program and type of service, a wide range of choices and DBB or DIB valve types are available to match certain needs. 

The mechanical wedge activity of a double plug valve hammering both the upstream and the downstream seals firmly requiring no assistance to affect a positive seal. Double block and bleed ball valves, which can be used a great deal from the transmission and storage markets, supply consistent and provable zero leakage of fluids that are various. 

Both DBB and DIB valves conserve space, decrease the demand for multivalve systems, and offer zero capabilities from upstream to downstream. The valve allows for an integrity test of chair seals. In addition, both valves may be utilized in goods transmission lines, natural gas procedures, manifold and mainline valves in liquid pipelines, and a variety of markets and applications, including transmission, petrochemical, LNG and storage. 

Applications and Advantages of DBB and DIB Another program where DIB and DBB valves are used is your meter calibration market. Every closed valve at the meter system needs to seal drop tight. A tiny leak will cause errors in the meter calibration and the meter factor that is wrong will last until the demonstrating operation. This will cost end users quantities of money. Choosing the correct API verified DBB or DIB valve can help ensure correct calibration almost every moment. 

“When I teach our sales force and clients about double block-and-bleed, I use the API 6D definition,” says Technology director, Wilia Wu. “In my presentations, I clarify that a DBB valve is a valve with two seats and when closed, will shield against pressure from the ends of the valve permitting the body cavity to be bled.”


The following table will be part of an Informative Appendix in the next edition of API 6D that’s currently out for ballot. The table was fortified with a column revealing where the valve types comply with OSHA regulations. “When determining whether to use a DBB or DIB valve and which definition to follow, API or OSHA,” says Wilia Wu, “it is important to get a clear comprehension of the similarities and differences between these types of block-and-bleed valves and the particular program the valve will perform in. Furthermore, it’s necessary that the features required for isolation are fully tested during factory acceptance testing of the valve.” Since DIB and DBB are very such generic terms in the business, it is very important to take the program, networking, and various environmental issues when deciding upon the proper solution and valve type.

Maybe you like also