MD5 Duct sealing system

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Duct sealing systems MD5 are designed to provide an effective and straightforward solution for gas and watertight sealing of one or multiple cables/conduits in ducts or boreholes. MD5 protects against damage caused by gas and water leaks.

This duct sealing system is highly flexible in use and can be installed in vertical and horizontal duct or boreholes, and is suitable for boreholes drilled at any angle.

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The MD5 duct sealing system uses a specially formulated two-component expanding polyurethane resin. The polyurethane sealant is supplied in a two-component cartridge. The two liquid parts are formulated to be mixed at a 1:1 ratio, using the 2K cartridge and mixing nozzle provided.

After injecting the resin into the duct, the resin starts expanding by forming CO². During the expansion, the polyurethane resin penetrates all areas between the two foam flanges inside the duct. MD5 is suitable for all openings regardless of the shape of the duct or borehole and cable configuration.

After full curing, the Filoform two-component resin provides a 100% gas and watertight seal and offers excellent mechanical strength & rodent resistance. MD5 duct sealant is compatible with common cable jacket /sheath materials and PE drinking water conduits. The cured duct sealant is an inert solid mass that does not affect any of the materials inside of the duct.

The MD5 system has been designed to support and separate multiple cables in a duct / conduit using our uniquely designed duplex foam, whilst reducing excess expansion of resin out the front of the duct; This ensures a neater, less messy professional finish.  The opening of the duct does not need to be completely round.



  • One box solution
    Everything needed to seal one duct end (except a caulking gun).
  • Cable Separation
    It is vital, to make sure the duplex foam is wrapped around each cable, to create separation from each other and the inside of the duct.
  • Running water
    The duct & cables must be as dry as possible with no running water and free from any dirt, oil, greese & debris. MD5’s resin can cope with small amounts of moisture in the duct or on the cables, but larger amounts of water will reduce the effectiveness. Please contact our technical department if you have any questions.

Cure time

MD5’s resin can be installed in temperatures from 5°C (41°F). In colder temperatures, expansion can be slower but will expand and cure over a more extended time. Expansion time between 8-10 minutes at temperature ranging between 15-20°C.


Should any un-mixed material spill onto a surface, a solvent wipe can be used to help clean the area.

Reentering & removal

Properties of Cured resin: Fairley dense structure however can be dug out with a blunt tool & Hammer with some degree of difficulty.(Please note there is between 10-15 cm (4-6”) of the expanding resin in each seal depending on the size of duct)

  • Remove all of the front foam that is separating the cables with a pair of pliers or cutting tool
  • Using a hammer & chisel or similar tool to break the seal around the cable and the inside of the duct
  • If there is room and the cables are de-energized, a power tool to speed the process up could be used. Once the seal is broken from the cable, there may be a crust of resin still present on the cable; this is due to the excellent adhesion our resin has. The hardest part of removing this seal is the crust that forms when the resin soaks into the foam flange.


MD5’s specially formulated two-component resin is part of the same chemical/product family of similar electrical and construction industry products. These products have been widely used for decades. As with all two-component resins safety precautions must be understood to handle and install these types of materials. MD5’s resin is contained in a state of the art 2K cartridge, which reduces contact with the raw materials. When the two components are mixed, the resin expands and forms a high density, closed-cell polyurethane foam and is inert and non-toxic when fully cured.

Storage conditions

The cartridges should be kept in a cool, dry environment and away from direct sunlight. Product shelf life is 18 months, and providing the cap is correctly inserted after use, then remaining product in the cartridge can be used within two months of opening.

Specifications & Standards

  • Gas and watertight up to 1.5 bar / 21 PSI (30 days)
  • Gas and watertight up to 2.5 bar (7 days)
  • After injecting, the polyurethane sealant will expand and cures/hardens with a high density and a closed cell structure
  • Easy and quick installation
  • One complete kit - Everything you need except for a standard caulking gun
  • Suitable for single & multiple cables
  • Compatible with a wide range of cable and conduit materials: PVC & PEsheathed cables, PILC cables, (HD)PE ducts, & PE drinking water conduits • High mechanical strength, resists ground movement, shocks and vibrations
  • Complies with DIN 18322 underground cable laying works - gas & watertight cable and conduit entries into buildings • Complies with 2011 NEC Articles 225.27, 230.8, 300.5(G), 300.7 (A) on Raceway Seals, and 501.15

Click here to download the TDS with more technical test data(TDS)


Curing properties Unit Value
Start time expansion Seconds 50-70
End time expansion Minutes 8-10
Curing time (Tack-Free time) Minutes >12
Compressive strength N / cm² >60
Density kg / m³ 90-110
Thermal resistance long term °C 100
Closed cell percentage % >90
Thermal stability    
Thermal aging, 28d 90°C no visual damage V
Form stability, size and visual % <1
Compression strength after aging N / cm² >40
Weight loss after aging % <0,5
Hydrolysis test    
Water absorption, at 40 years, fully immerged % <10
Water absorption 28 days at 90 °C % <5
Weight loss max. % 0,5
Compression strength after Hydrolysis test N / cm² >40
Form stability after Hydrolysis test Visual PASS
Chemical resistance    
0,1N Na₂SO₄ 30 days PASS
0,1N NaCl 30 days PASS
0,1N H₂SO₄ 30 days PASS
0,1N NaOH 30 days PASS
Diesel 30 days PASS
Gasoline 30 days PASS
H2S, 200 ppm 5 days, 40°C, 95% air humidity PASS
Mold   Good
Rodents   Good
Shelf life    
Storage time before use, under restricted conditions Months 18



More Information
More information

Download: Technical Data Sheet (TDS)

Download: Material Safety Data Sheet (MSDS) (on request)

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Sku Product Name Duct diameter min.-max. (mm)

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80347 MD5-160mm Ø 160 max. Order unit per piece
80345 MD5-110mm Ø 110 max. (set for 2 seals) Order unit per piece