Views: 0 Author: J-VALVES Publish Time: 2025-05-10 Origin: Site
In oil and gas pipelines, DBB ball valves are like "gatekeepers" controlling the flow of media. Especially within the wide pressure range from 150LB TO 2500LB, whether they can stably withstand pressure and comply with international standards is directly related to the safety of the pipelines. Today, let's talk about how to conduct a comprehensive "check-up" for BALL VALVES through pressure resistance testing and verification against the ASME B16.34 standard.
DBB BALL VALVES are short for "Double Block and Bleed Ball Valves". They have two core functions:
· Double Block Function: When closed, they can completely separate the media before and after the pipeline like two gates.
· Bleed Function: They can discharge the residual media inside the valve to avoid the danger caused by pressure accumulation.
For this reason, they are essential in high-pressure, flammable, and explosive oil and gas environments.
ASME B16.34 is an internationally commonly used industrial valve standard, just like an "exam syllabus", which stipulates all requirements for valves from design to testing. Especially in the pressure range from 150LB TO 2500LB, each grade has strict size, material, and performance indicators. Only ball valves that meet the standard can be used in global oil and gas projects.
1. PRESSURE RESISTANCE TESTING: To See if the Ball Valve Can "Withstand the Pressure"
· Shell Strength Testing: Pressurize the inside of the valve (usually 1.5 times the working pressure) and maintain it for 30 minutes. Observe whether the valve body deforms or leaks. This step is like testing whether a balloon will burst to ensure that the valve shell is strong enough.
· Seat Sealing Testing: Pressurize from both sides of the valve respectively, and use the bubble method or pressure drop method to check whether the seal is tight. Since DBB ball valves require bidirectional sealing, both the forward and reverse directions need to be tested to prevent the media from "escaping".
2. ASME B16.34 COMPLIANCE VERIFICATION: To See if the Ball Valve Is a "Standard Product"
· Dimensions and Tolerances: Measure the diameter, length, flange hole spacing, etc. of the valve. They must be completely consistent with the standard table, and the error cannot exceed the allowable range (for example, the flange outer diameter error of a 150LB ball valve cannot exceed ±1mm).
· Material Selection: Different pressure grades have different requirements for materials. For example, a 2500LB high-pressure ball valve requires high-strength alloy steel, and the seat may need wear-resistant hard alloy, and there must be material qualification certificates.
· Marking and Identification: The valve must be clearly marked with information such as the pressure grade (e.g., "2500LB"), specification (e.g., "DN100"), and manufacturer. It's just like an ID card, which is convenient for traceability and installation.
Pressure Grade | Key Points of Pressure Resistance Testing | Key Indicators of ASME B16.34 Compliance | Typical Application Scenarios |
150LB | Basic sealing detection, maintain pressure for 15 minutes, allow a small amount of leakage | Material: Carbon steel; relatively loose size tolerance (±2mm); only pressure grade is required for marking | Low-pressure gas pipelines, civil branch lines |
300LB | Bidirectional sealing test to prevent low-pressure back-pressure leakage | Sealing surface: Raised face (RF); materials need to resist slight corrosion; marking needs to include specification information | Urban gas transmission pipelines, small and medium-sized oilfield pipelines |
600LB | Shell deformation detection under medium pressure, maintain pressure for 20 minutes | Material: Alloy steel; tightened size tolerance (±1mm); material strength report is required | Refinery pipelines, high-pressure gathering and transmission pipelines |
900LB | Metal hard sealing test to prevent the leakage caused by the aging of sealing materials under high pressure | Sealing surface: Male and female face (M/F); materials need to pass high-temperature tests; marking includes material grade | High-temperature and high-pressure refining devices, offshore platform pipelines |
1500LB | Ultrasonic flaw detection of the valve body wall thickness to check internal defects | Material: Sulfur-resistant alloy steel; flange changes to ring joint face (RTJ); corrosion resistance certification is required | Sulfur-containing oil and gas fields, long-distance high-pressure trunk lines |
2500LB | Ultra-high-pressure zero-leakage test, allowable leakage amount ≤ 0.1ml/min | Material: Special alloy (such as Inconel); size is manufactured strictly in accordance with the standard; provide the whole process inspection report | Deep-sea oil and gas exploitation, ultra-high-pressure core hubs |
· Low-Pressure Scenarios (150 - 300LB): Choose carbon steel materials, focus on the reliability of sealing, and give priority to cost.
· Medium and High-Pressure Scenarios (600 - 2500LB): Choose alloy steel or special alloys, strictly check material certificates and size tolerances to ensure no leakage under high pressure.
· Key to Acceptance: Regardless of the grade, both the pressure resistance test report and the ASME B16.34 compliance certificate must be requested. Neither can be missing.
From the low-pressure branch lines of 150LB to the ultra-high-pressure trunk lines of 2500LB, every "qualified check-up" of the DBB BALL VALVE is a guarantee for the safety of oil and gas pipelines. Through pressure resistance testing and ASME B16.34 verification, it can not only avoid the risk of "working with defects" but also enable international projects to use it with confidence. Choosing the right BALL VALVE means choosing the right balance between safety and efficiency.
