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Material Properties of Rubber Seals

Rubber Types

International designation EPDM NBR FPM
Rubber type Ethylene propene Nitrile Fluorine (Viton)
Nominal hardness IRHD 60 (+/-5) 60 (+/-5) 60(+/-5)
Color Black Black/yellow dot Green
Tensile strength MPa ≥ 10 N/mm² ≥ 10 N/mm² ≥ 8 N/mm²
Elongation after fracture % ≥ 300% ≥ 300% 260%
Max. temperature range -35/+100º C -30/+80º C -25/+200º C


Wearability B B B
Resistance to mineral oil D A A
Resistance to vegetable oil B A A
Resistance to benzene/petrol D A A
Resistance to aromatic compounds and hydrocarbons D B A
Resistance to ketones A D D
Resistance to ordinary diluted acids and alkalines A A A
Resistance to ordinary diluted acids and alkalines A C A
Resistance to air diffusion D C A

A = Very good service - B = Moderate service - C = Limited or variable service - D = Unsatisfactory

A lip sealing ring constitutes the seal between socket an spigot end. The lip sealing ring ensures quick and efficient jointing of the pipe system while providing a tight seal in case of both pressure and vacuum. BLÜCHER sealing rings are available in three different rubber qualities.


This sealing ring is black with a yellow spot and made from nitrile rubber and is the sealing ring to be used where there are petrol or oil residues on the waste water (e.g. in connection with oil and petrol separators at service stations, garages etc.).

The NBR lip seal should not be used where there is a risk of temperatures above 80ºC. NBR is not resistant to solvents.


This sealing ring is black and made of ethylene propene rubber. This is BLÜCHER’s standard sealing ring and it is suitable for all rainwater and waste water installations where there is no oil or no petrol residues in the waste water.

The EPDM lip seal is a good all-round rubber quality suitable for a wide range of applications.


For advice regarding the suitability of the different rubber qualities, consult BLÜCHER.


This sealing ring is Green and made from fluorine rubber (Viton®).

This is BLÜCHER’s sealing ring for special applications. The material is particularly heat-resistant and resistant to oil, solvents and strong acids. However, the FPM seal has only limited resistance to e.g. butyl acetate, acetone and methyl alcohol.

Load Ratings

Load ratings are based upon maximum anticipated traffic, in accordance with American National Standards ASME A112.21.1M.

Light Duty (LD) - Safe Live Load Under 2000 lbs.
Medium Duty (MD) - Safe Live Load 2000-4999 lbs.
Heavy Duty (HD) - Safe Live Load 5000-7499 lbs.
Extra Heavy Duty (XHD) - Safe Live Load Between 7500 and 10,000 lbs.
Special Duty (SD) - Safe Live Load Over 10,000 lbs.