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NSF 61 certified gasket material for water systems

Specially formulated compressed gasket material based on NBR and aramid fiber, WaterSIL is a universal high-pressure gasket material that is certified to NSF 61 and meets strict chemical leaching requirements.

Applications: NSF/ANSI 61 certified gasket material for use in potable drinking water systems and fixtures for public drinking water, food and beverage, hospitality, and plumbing supplies.


Potable water systems have miles of piping and other devices such as pumps, meters, and valves. All of these components require gaskets. Gaskets materials certified to NSF/ANSI 61 ensure the safe passing of water on its journey to the consumer's tap.

NSF/ANSI 61 established minimum health effects requirements for the chemical contaminants and impurities that are directly imparted to drinking water systems. It also determines what contaminants may migrate or leach into drinking water and confirms that they are below the maximum levels allowed to be considered safe. Market leaders strive to attain NSF certification as a mark of distinction that assures their product does not leach harmful contaminants or impurities into drinking water.

Certification to NSF/ANSI 61 ensures that the products meet the Safe Drinking Water Act requirements that protect public drinking water supplies in the US. NSF/ANSI 61 certification an often meet or fulfill the testing requirements for many other countries as well.

WaterSIL is specifically formulated to meet the NSF/ANSI 61 standard for sealing materials. It also has excellent dielectric strength properties. The dielectric strength is the maximum working voltage a material can withstand without breaking down, thus limiting corrosion in pipeline systems.

Look for the WaterSIL logo and NSF mark on the packaging to ensure your gasket material complies with NSF/ANSI 1 - Drinking Water System Components - Health Effects.

KLINGER Thermoseal WaterSIL

Typical values refer to 1/16" material unless otherwise specified

Compressibility ASTM F36J 10 %
Recovery ASTM F36J 50 % minimum
Dielectric Strength ASTM D149-95a 18 kV/mm
KLINGER cold/hot compression
  Thickness Decrease 73°F (23 °C)
  Thickness Decrease 572 °F (300 °C)

10 % initial
25 % additional
Density ASTM F1315 100 lb/ft3
Creep Relaxation ASTM F38 B (1/32") 25 %
Sealability ASTM F37 A (1/32") < 0.25 ml/hr
Thickness Increase in H2O ASTM F146 0 - 5 %
Weight Increase in H2ASTM F146 0 - 5 %
Line Call Out ASTM F104 F712111B4E12K6M4
NSF/ANSI 61 Certification
  Pipe Gasket Size 1" to 144"
  or 1.3 sq. inch per liter in other

Potable Water at Commercial Hot
180°F (82°C) Max

Color and Markings White Unbranded


The pressure/temperature graphs shown are the most current method of determining the suitability of a gasket material in a known environment. However, chemical compatibility must also be considered.

pT diagram for thickness 2.0 mm:


       LIQUIDS                                                               GASES & STEAM


In area 1 the gasket material is suitable using common installment practices subject to chemical compatibility

In area 2 appropriate measures are necessary for installation of the gasket to ensure maximum performance. Please call or refer to KLINGERexpert for assistance.

In area 3 do not install gaskets in these applications without first referring to KLINGERexpert or contacting KLINGER Thermoseal's technical support service.
The ability of a gasket to make and maintain a seal depends not only on the style and quality of the gasket material, but also on medium being sealed, the flange design, the amount of pressure applied to the gasket by the bolts and how the gasket is assembled onto the flanges and tightened. These factors are beyond the manufacturer's control. Please take note of our installation manual in TECHNICAL RESOURCES.