Expansion Joint Flange Assembly With Fire-Rated Dual-Seal Gasket
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Solution Overview
Problem
Conventional glass-lined flanged fittings fail to meet the NFPA 30 standard and API Specification 6FB fire test for flammable and combustible liquids, and expansion joint fittings connected to non-metal lined equipment often do not meet these safety standards.
Innovation Solution
A flange joint assembly comprising a flanged fitting with a fire-rated annular flange extension and an annular gasket that includes a radially inner gasket segment for a liquid-tight seal and a radially outer gasket segment for a fire-rated seal, along with a radially outer annular inlay for enhanced corrosion resistance and fire protection, ensuring the assembly passes the API Specification 6FB fire test.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional glass-lined flanged fittings are used, then corrosion resistance is improved, but fire safety compliance deteriorates (fails NFPA 30 and API 6FB fire tests)
Solution Approach 1:
The flange assembly uses a composite structure combining glass-lined fittings (for corrosion resistance) with metal flanges and fire-rated gaskets (for fire safety). The glass lining provides chemical corrosion protection while the metal components and fire-rated materials ensure compliance with NFPA 30 and API 6FB fire tests.
Solution Approach 2:
A fire-rated gasket acts as an intermediary element between the glass-lined fitting and metal flange, enabling the combination of corrosion-resistant and fire-safe components. This intermediary component ensures fire safety compliance while allowing the glass-lined fitting to maintain its corrosion resistance.
2Adaptability or versatility
If expansion joint fittings connected to non-metal lined equipment are used, then flexibility and expansion capability are improved, but fire safety compliance deteriorates (fails to meet NFPA 30 and API 6FB standards)
Solution Approach 1:
The expansion joint fitting uses a composite construction with metal bellows (for expansion capability) combined with fire-rated materials and gaskets (for fire safety). This composite structure maintains the flexibility and expansion capability of the bellows while ensuring compliance with NFPA 30 and API 6FB fire tests through the fire-rated components.
Solution Approach 2:
Fire-rated gaskets and sealing elements act as intermediaries between the non-metal lined expansion joint and connected equipment, enabling the expansion joint to maintain its flexibility while achieving fire safety compliance through the fire-rated intermediary materials.
3Device complexity
If a single-material gasket is used, then device complexity is reduced, but performance deteriorates (cannot provide both liquid-tight seal and fire-rated seal)
Solution Approach 1:
The gasket is segmented into multiple functional zones: an inner sealing surface that provides liquid-tight sealing and an outer fire-rated portion that provides fire safety compliance. This segmentation allows each zone to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different portions of the gasket have different material properties tailored to their specific functions: the inner portion has sealing qualities for liquid-tight performance while the outer portion has fire-rated material properties. This local differentiation of material qualities enables both sealing and fire safety performance.
Data Source
AI summary
An expansion joint fitting for conveying liquid includes a radially inner bellows defining a liquid-conveying passage for conveying liquid between the first and second longitudinal ends of the expansion joint fitting. A radially outer bellows is disposed radially outward from and extending around the radially inner bellows. An annular plenum is defined between the radially inner bellows and the radially outer bellows.