VIP are recognised as the leading global manufacturers of Tyton-SIT® self restrained gaskets for ductile iron pipe and as a result, our Tyton-SIT® gaskets are selected as original equipment by many of the leading global producers. Each design has been thoroughly tested in accordance with EN545:2010/ EN598:2007 and our Tyton-SIT® fully comply with the requirements of BS6920 as well as holding WRAS material approval at temperature of up to 60º.

What is Tyton-SIT®?

  • Designed to suit Tyton® socket (DIN28603)
  • Self-restrained gasket used to joint ductile iron pipes to EN545/ EN598
  • Used by all major pipe manufacturers globally since 1970’s
  • Around 45% of pipe joints in Europe are self-restrained

VIP have been manufacturing Tyton-SIT® since the 1970’s and to date, have supplied over five million units worldwide.

These are self-anchored joints which eliminate the need for thrust blocks at changes in direction, making them particularly suitable for difficult or unsuitable ground conditions such as soft ground or subsidence-prone areas; where space is limited; steep inclines or under rivers.


Benefits of Tyton-SIT® Vs Concrete Thrust Blocks:

  • Concrete thrust blocks are often impractical due to unstable ground (i.e. groundwater)
  • Contractors/ Engineers use far more concrete than the design stipulates “just in case”
  • Difficulty pouring in freezing conditions
  • Environmentally unfriendly; the cement industry is responsible for 5% of worldwide man made carbon dioxide (CO2)
  • Expensive to dispose of soil matter removed from trench
  • Impractical and can cause disruption in city centre excavations
  • In congested trenches, not always possible to pour thrust blocks without interfering with other utilities


thrust-block restraint-joint
Traditional concrete thrust block External Mechanical Restraint Joint

Benefits of Tyton-SIT® Vs External Mechanical Restraint System

  • External mechanical restraint systems cost considerably more
  • More difficult to install as access needed to reach bolts beneath the joint
  • Entire assembly needs to be protected from corrosion
  • Larger trench needed compared with Tyton-SIT®
  • Installation time of Tyton-SIT® typically 35% of the time taken to install External Mechanical Restraint
  • Quicker installation
  • Better for the environment
  • Less disruption
  • Lower installation costs
  • No large excavation required


Table of Tyton-SIT® Maximum Working Pressures:

Nominal Diameter (mm) Operating Pressure Maximum Working Pressure Maximum Test Pressure Maximum Deflection Degree
DN100 30 bar 35 bar
DN150 22 bar 27 bar
DN200 22 bar 27 bar
DN250 22 bar 27 bar
DN300 20 bar 25 bar
DN350 20 bar 25 bar
DN400 16 bar 21 bar


BS6920. Suitability of non-metallic products for use in contact with water intended for human consumption with regard to their effect on the quality of the water.

ISO 3302-1:2014. Specifies classes of dimensional tolerances and their values for moulded, extruded, and calendared solid rubber products.

BS EN 681-1. Elastomeric seals. Material requirements for pipe joint seals in water and drainage applications.

ISO 2230:2002. Rubber products. Guidelines for storage.

BS EN 598:2007+A1:2009. Ductile iron pipes, fittings, accessories and their joints for sewerage applications. Requirements and test methods.

BS EN 545:2010. Ductile iron pipes, fittings, accessories and their joints for water pipelines. Requirements and test methods.