Pipe penetration seals are used to achieve a seal for pipes penetrating through walls, floors, pipeline casings etc. Pipe Penetration Seals are used to stop the spread of fire and smoke to adjacent areas. A variety of seals are used in the industry.
Pipe penetration seals are available in two types :
- Fixed penetration seals
- Flexible penetrations seals
Fixed penetration seals
The pipe is guided at the penetration location. Where flexibility is required at the penetration location, this type of seal must not be used. It is important to bear in mind that the sleeve opening size should be as per the selected manufacturers recommendation.
Material for manufacture of penetration seals is EPDM elastomer for general service, which is suitable for temperatures between -40°F to 250°F. Where the penetration seal may come in contact with hydrocarbons, the material used is Nitrile which is suitable for temperatures up to 210°F. The pressure plates which hold the seal elements are generally made of glass reinforced plastic.
Penetration seals are available to provide a waterseal for pressures up to 20 psig. Where walls or floors have pipe penetrations that could be subject to spillage, water tight seals are recommended.
Where fire protection is required, penetration seals fire rated as per UL are available. The material for fire rated seals is graphite impregnated EPDM and the pressure plates are made of steel. For high temperature applications upto 400°F, Silicone elastomer is used for penetration seals.
Installation of Fixed penetration seals
The following link penetration sleeve installation shows a typical installation of fixed type penetration seal.
Flexible penetration seals
Flexible penetration seals are designed to close the pipe sleeve opening while allowing movement of pipe during operation. Flexible seals are capable of handling large displacements, can absorb misalignments, angular deviations and eliminate stress concentration.
They are quick and easy to install and require negligible maintenance. They can be tailor made to fit any size of pipe and pipe sleeve. Flexible seals can be fire and blast rated.
The following link flexible penetration sleeve installation shows a typical installation of flexible type penetration seal.
Link Seals
Image courtesy: PROJEX
Link-Seal® is a flexible belt of interconnected rubber links used to seal the void area in between pipes and wall openings. Link-Seals are considered to be the premier method for permanently sealing the annular space between the pipes & penetrations of any size and the walls, floors or ceilings they pass through.
Specially formulated to withstand attack from ozone, UV radiation, water, hydrocarbons and a wide range of chemicals, Link-Seals are available in liquid, gas, oil, temperature & fire resistant models.
Link-Seals are available for a wide variety of special applications including:
- temperature extremes.
- exotic chemical combinations.
- slightly “out of round” or non-centered installations.
Advantage of using Link Seals
Following are the advantages of using Link Seals:
- Can maintain positive hdyrostatic seal up to 5 bar.
- Can withstand temperatures up to 230°C.
- Provide maximum protection against corrosion.
- Have long seal life.
- Facilitate quick installation without use of chemicals or any special tools.
- Can be installed when the system is in operation.
- If a leak occurs at any time in the future due to excessive pipe movement, the Link-Seals can be tightened to stop the leak.
- Installation times are significantly less than other methods.
- Allows small pipe movements without breaking the seal.
- They are easy to dismantle.
Image Courtesy:FLEXICRAFT
Material of Link Seals
For most standard applications, EPDM rubber (black) is the right material.
Nitrile rubber (green) is used if the seal is likely to be exposed to hydrocarbons.
For high temperature applications, Silicone rubber (grey) is used as seal material.
For fragile pipes, EPDM rubber (blue) with shore hardness of 40+5 is used.