Views: 0 Author: Site Editor Publish Time: 2026-07-28 Origin: Site
For high-pressure fluid transmission systems including urban gas pipelines, long-distance oil & gas trunk lines and thermal heating networks, the sealing performance of industrial valves under fire conditions directly determines explosion prevention and hazardous medium leakage control. As core shut-off equipment for buried pipelines, fully welded ball valves with auxiliary vent pipes face higher structural complexity and greater fire failure risks.
API 607 and API 6FA are two globally recognized fire safety standards to evaluate fire resistance of industrial ball valves. There are major gaps in test protocols, applicable valve types and acceptance thresholds between the two standards. Optimizing valve body structures against both specifications can effectively reduce fire hazards for vent-integrated fully welded ball valves.
API 607 is designed for ball valves, butterfly valves fitted with non-metallic soft seats such as PTFE, nylon and rubber. The standard simulates continuous external flame exposure on valve bodies for 30 minutes. After polymer soft seats melt under extreme heat, secondary metal seals must block medium flow. Minor external leakage is permitted within limited values, while internal leakage must stay below standard limits.
This certification is widely applied to ordinary fully welded ball valves for medium & low-pressure municipal gas pipelines. It only inspects the main flow channel of valve bodies without special fire resistance tests for extended vent stems, drain branches or bypass pipes, acting as a basic fire safety qualification.
API 6FA is a mandatory fire resistance standard for high-pressure oil & gas pipelines, covering metal-to-metal seated ball valves, globe valves from Class 150 to Class 2500 pressure classes. It implements 30-minute flame exposure with higher burning temperature, and requires synchronous leakage inspection for all auxiliary pipes including vent, drain and bypass branches.
The standard prohibits obvious shell leakage during the entire fire exposure process. After flame cooling, valves must still perform normal opening and closing to cut off medium supply. Its strict requirements on welding seams, stem packing and small pipe connections far exceed API 607, making it an essential certification for high-risk long-distance industrial pipelines.
Comparison Items | API 607 | API 6FA |
Applicable Seat Type | Non-metallic soft seats | Metal hard seats, compatible with dual metal-soft seating |
Flame Exposure Duration | 30 minutes | 30 minutes with higher flame temperature |
Test Coverage | Only main valve flow path | Valve body + all auxiliary vent/drain branch pipes |
Leakage Acceptance Rule | Minor external leakage allowed, focus on post-fire sealing | Strict internal & external leakage control during fire, functional performance required after cooling |
Typical Working Conditions | Medium/low-pressure municipal gas & water pipelines | High-pressure long-distance oil & gas lines, refinery hazardous medium stations |
Certification Level | Basic fire safety standard | Mandatory standard for high-risk industrial pipelines |
Most traditional fully welded ball valves only obtain single API 607 certification. Without fire-resistant design for vent branches and extended stems, auxiliary pipe connections will suffer packing failure and medium leakage during pipeline fires, triggering secondary explosion accidents.
Split cast valves with flange joints generate gaps under thermal expansion and contraction during fire exposure. Ordinary welded ball valves with thin welding seams will form micro-cracks under continuous flame burning, leading to flammable medium leakage and fire escalation.
Extended vent stems and small vent branches use standard non-high-temperature resistant packing and threaded connections. Non-metal packing carbonizes rapidly under extreme heat, making vent pipes the weakest leakage point during pipeline fires. This critical flaw restricts single API 607 certified valves from serving high-pressure hazardous pipelines.
J-VALVES fire-safe series vent fully welded ball valves adopt integrated forged A105 / WCB steel monolithic bodies with seamless full welding technology, eliminating flange splicing gaps. Reinforced welding seams and high-temperature anti-corrosion coating pass strict API 6FA shell penetration tests with zero cracking or seepage under flame exposure.
To resolve failure risks of vent stems and branch pipes, our valves are equipped with metal wound graphite composite high-temperature packing. Metal hard seal gaskets are installed on all vent branch flanges. All small pipe joints undergo full API 6FA auxiliary pipe fire tests to eliminate weak fire leakage points of traditional vent ball valves.
The valve seat combines metal hard sealing and PTFE soft sealing structures. Soft seats achieve bubble-tight sealing under normal temperature; once soft polymer melts in fire, metal hard seats instantly take over medium shut-off function. The dual-seat design successfully completes full fire tests of both API 607 (soft seat) and API 6FA (metal seat), acquiring dual fire safety certifications.
Founded in 2009, J-VALVES delivers complete industrial valve solutions for global pipeline projects. All vent integrated fully welded ball valves hold dual API 6FA and API 607 fire safety certifications, together with API 598 factory hydrostatic test, ISO9001 quality management system and SIL safety integrity level approvals.
Our fire-safe ball valves serve wide applications: long-distance natural gas trunk pipelines, buried high-pressure urban gas networks, refinery fluid transmission pipelines and high-temperature thermal heating systems. Custom solutions including underground extended stem type, dual vent discharge structure, full bore / reduced bore bodies are available to adapt to extreme working conditions from cryogenic low temperature to high-temperature fire scenarios.
Low-pressure municipal gas branch lines: Soft-seated fully welded ball valves with API 607 certification are acceptable.
High-pressure long-distance oil & gas trunk lines and refinery hazardous medium pipelines: Select monolithic fully welded ball valves with dual API 6FA + API 607 fire certifications, with vent branches specially optimized for fire resistance.
When purchasing buried ball valves with vent functions, request full third-party fire test reports from manufacturers to confirm auxiliary vent pipes are included in fire test scope and avoid hidden fire safety risks.
