Gaskets spiral-wound

Spiral-wound gaskets are safer than fiber gaskets because, if the bolts work loose or are not tightened correctly, the leak rate is much lower. 

Low Leak Rate If friendly equipment does leak, it does so at a low rate, which is easy to stop or control. Examples already mentioned are spiral-wound gaskets, tubular reactors, and vapor phase reactors. 

Low leak rate Spiral-wound gasket Libre gasket... 

The leaks that lead to explosions in compressor houses are often not from a compressor but from other equipment, such as pipe joints. One such leak occurred because a spiral-wound gasket had been replaced by a compressed asbestos fiber one, probably as temporary measure, seven years earlier. Once installed, it was replaced by a similar one during subsequent maintenance [30]. 

The size and frequency of leaks can be reduced by using spiral-wound gaskets in place of compressed asbestos fiber ones. Screwed joints should not be used. 

Note For pumps with flange and pressure ratings in excess of the minimum values in 2.2.2, the gland stud size and circle may increase. Larger studs shall be furnished only if required to meet the stress requirements of Section VIII or Section II of the ASME Code, or to sufficiently compress spiral wound gaskets in accordance with manufacturer s specifications. 

If pumps with axially split casings are furnished, a sheet gasket suitable for the service is acceptable. Spiral wound gaskets should contain a filler matrial suitable for the service. 

Unless otherwise specified, the gland plate to seal chamber seal shall be a fluoroelastomer O-ring for services below 150°C (300°F). For temperatures 150°C (300°F) and above or when specified, graphite-filled austenitic stainless steel spiral wound gaskets shall be used. The gasket shall be capable of withstanding the full (uncooled) temperature of the pumped fluid. 

Spiral wound gaskets cost about four to eight times more than compressed asbestos gaskets, but are easily worth it if they can prevent blowouts and leaks. Also, they generally last considerably longer than compressed asbestos-type gaskets. Spiral wound gaskets can be made in virtually any metal and filler... 

Stage 4 Process change without recognizing need for new fastener type, e.g., a flammable liquid requires stronger fastener for spiral wound gaskets... 

Certification. Check that product description or part number matches purchase order. For spiral wound gaskets, verify that the manufacturer s stamped or inscribed name, pressure class, size and materials are in accordance with the appropriate ASTM productmarking requirements. 

Measure thickness to ensure conformance with purchase order. For sheet/envelope gaskets or spiral wound gaskets, measurements must be in conformance with ASME B16.21 and B 16.20, respectively. 

Figure 3-9. Color of imprint on spiral wound gasket outer ring indicates type of alloy or material.

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