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Leader Spiral Wound Gasket Type SI


Designed more than 100 years ago, Spiral Wound Gaskets (SWG’s) are widely used as high integrity and sustainable gaskets. The sealing element is manufactured from preformed, v-shaped metallic windings with intermediate soft sealing fillers. As standard metallic material for winding and inner ring SS316L is used and for the soft fillers, graphite, PTFE or LeaderTHERM NXT 1000 (high temp. modified Phlogopite). Due to the gaskets construction, SWG’s offer high compressibility and recovery. Leader Style SI SWG’s are provided with an inner ring. The SI gaskets are suitable for ASME B16.5 tongue and groove or male / female (Spigot to Recess) flanges up


Product Data SheetMetallic materials


(Petro-) Chemical Industry, Steam, On- and Offshore exploration, pipeline systems, pressure vessels and exchangers.

Chemical Compatiblity

Spiral Wound Gaskets can be used in a wide variety of media, i.e. a pH range varying from 0-14. Application/ compatibility guide is available on request.

Delivery Options

Standard style SI gaskets are normally manufactured according to particular customer drawings, or by given sizes. Gaskets can be manufactured in a thickness of 2,5/3,2/4,5/6,4/7,2 mm. Different materials are available.


Spiral Wound Gaskets "SI" can be used in a wide variety of media, temperature acc. to used material(table of materials); standard SS316L - 100 °C up to 550 °C.


  • EN10.204 3.1

Sealing Characteristics

  • blow out safe
  • low leak rate
  • Firesafe
  • Design suitable for fluctuating temperatures and pressures
  • broad chemical resistance (pending on the metallic materials and filler)
  • wide seating stress range
  • non sticking to the flanges
Technical Data
max Temperature [°C]See material table below
max Pressure [bar]200
Minimum initial stress [DIN E 2505 part 2] [N/mm2]50
Maximum initial stress [DIN E 2505 part 2] [N/mm2]300
Y- Value [psi]10000
Gasket required flange roughness [Ra micron]3,2-6,3
Gasket required flange roughness [RMS]125-250
ROTT [Gb]926
ROTT [a]0.341
ROTT [Gs"]2.9
min Temperature [°C]See material table below
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