Spectacle Flange

• Design: A spectacle flange, also known as a spade and spacer flange, is a type of flange assembly used to isolate sections of piping or equipment. It consists of two components: a "spade" (or "blade") and a "spacer" (or "spectacle"). The spade is a solid flange that blocks flow, while the spacer is a blank flange that allows for future flow when removed. The two components are mounted together on the same flange assembly, and the design looks somewhat like a pair of spectacles, hence the name.


• Applications: Used to isolate a section of a pipeline or equipment for maintenance, inspection, or modification. Common in systems where frequent changes in flow direction or flow isolation are needed, such as in chemical processing or oil and gas industries.


• Installation: The spectacle flange assembly is installed between two other flanges in the piping system. The spade blocks the flow, while the spacer can be replaced or removed to allow flow when needed.

Chemical and Mechanical Properties Table

Material	Grade	Chemical Composition (wt%)	Yield Strength (MPa)	Tensile Strength (MPa)	Elongation (%)
Carbon Steel	ASTM A105	C: 0.35 max, Mn: 0.60-0.90, P: 0.035 max, S: 0.035 max	205 - 250	420 - 550	20
Stainless Steel	ASTM A182 F304	C: 0.08 max, Cr: 18.0-20.0, Ni: 8.0-10.5	205 - 310	510 - 720	40
Stainless Steel	ASTM A182 F316	C: 0.08 max, Cr: 16.0-18.0, Ni: 10.0-14.0, Mo: 2.0-3.0	205 - 310	510 - 720	40
Alloy Steel	ASTM A234 WP22	C: 0.12-0.20, Cr: 1.0-1.5, Mo: 0.4-0.6	205 - 275	485 - 620	20
High-Temperature Alloy	ASTM A182 F91	C: 0.05-0.15, Cr: 8.0-9.5, Mo: 0.85-1.05	415 - 485	620 - 825	20

Notes:

• Chemical Composition: Reflects the alloying elements present in the material. For example, ASTM A182 F304 and F316 stainless steels include chromium and nickel for corrosion resistance.


• Yield Strength: The stress at which the material begins to deform permanently.


• Tensile Strength: The maximum stress the material can withstand while being stretched or pulled before breaking.


• Elongation: Indicates the material's ability to stretch before breaking, which helps in assessing ductility.