Filoform FiloSeal+HD Re-enterable Cable Duct Seals & Sealing System

Filoform FiloSeal+HD Re-enterable Cable Duct Seals & Sealing System

Filoform FiloSeal+HD Re-enterable Cable Duct Seals & Sealing System

Duct Seals

Filoform FiloSeal +HD is a duct sealing system that is able to seal large heavy armoured power (multicore XLPE SWA) and high voltage cables in ducts, bore holes or transit frames – providing a strong support system using hexagonal tubes building a re-enterable seal with honeycomb structure.

FiloSeal+HD  cable duct seals are suitable for sealing any cable configuration or pipes contained in one duct and also allows easy re-entry of the seal to add or remove cables or pipes as required.

The cable duct seal kits have been extensively tested against pressure, pulling forces, chemicals, gases and hydrocarbons for adequate sealing of LV-HV cables against the danger of flood (water ingress) or gas migration.

UK DNO Approvals & Track Record

The Filoseal+HD system is in service and approved at electric utilities in the UK including: SPEN (Scottish Power Energy Networks), WPD (Western Power Distribution), NPG (Northern Power Grid), SSE (Scottish & Southern Energy) and various National Grid location substations up to 400kV.

WIMES Approved

WIMES Approved Water Industry Mechanical & Electrical Specifications

FiloSeal+HD cable duct sealing system is WIMES Compliant (3.02 Clause, and approved for use by UK Water Utilities including Thames Water, Anglian Water, Severn Trent Water, United Utilities and Welsh Water.

Operating Temperature

Filoseal+ products have an operating temperature of -40°C to +120°C.

Sealing Cable Ducts Against Gas & Water

The cable duct seal provides gas (including methane and chlorine) and water tightness for cable ducts up to 250mm outside diameter with fire resistant option available – the test report confirms a gas and watertight seal for 1 bar (48 hours – 10 metres of water) and 2 bar (20 metres of water).

Re-enterable cable sealing system is easy to apply regardless of the type of cable configuration in the cable ducts as it uses strong, but flexible hexagonal tubes to support the cable and provide a strong backing for the seal – typically used to seal medium and high voltage substation cable ducts providing 11kV-33kV power supply.

IP67 Sealing

Filoseal+ has been Tested to 1 bar over 48 hours (equivalent to 10 metres of water).

Filoseal+HD & Filoseal+HD FIRE has been Tested to 2 bar over 48 hours (equivalent to 20 metres of water).

IP67 = a unit/object can be dropped into a body of water up to one metre deep for half an hour. The IP Code, IEC Standard IEC60529, classifies and rates the degree of protection provided by mechanical casings and electrical enclosures against intrusion, dust, accidental contact and water. Formally cable duct seals and sealing systems are not categorised as objects per se as mentioned above. However, based on the description above, Filoform declares that their Filoseal+ and Filoseal+HD systems exceed IP67 waterproof ratings provided they have been installed correctly and according to their instructions.

Hydrogen Sulfide Gas

The duct sealing compound has been tested specifically for resistance and stability performance under exposure to hydrogen sulfide (H2S) gas to establish suitability for sealing cables installed in waste water treatment sites – following rigorous testing involving seal exposure to 200ppm concentration of H2S gas over a 120 hour (5 day period) the duct seal showed “No Change” to weight, dimensions, shore hardness or visual inspection.

The cable duct sealant withstands long term exposure to methane and chlorine gas concentrations without loss of cable sealing functionality. Additionally, the cable seals provide excellent resistance to aggressive chemicals and oils (including ASTM, mineral and silicon oil).

Bending Test For Cable Ducts

During the test the cable duct seal is subjected to a 1 bar pressure level and a single cable is bent at a distance of 10xd at an angle of 45°. After 1 minute, the cable is pushed back again into the original starting position – the test is then repeated in the opposite direction on the same cable. During and after this test, no leak should occur to the cable duct seal.

FiloSeal+HD - Honeycomb Structure

FiloSeal+HD – Honeycomb Structure

The FiloSeal+HD uses MD+ sealant applied simply via a skeleton gun The sealant is based on a silicone compound that cures with air (humidity).

After application and full curing the thixotropic MD+ forms a plastic elastomer mass with special qualities effectively sealing and bonding cable ducts while providing a high level of durability.

Cable separation is simplified due to the hexagonal tube design providing a strong backing for the Filoform MD+ to be applied on to.

Re-enterable Cable Duct Seals & Sealing System

Features & Benefits

  • Flexible, one component, adhesive and sealing compound in a cartridge – (310ml)
  • High levels of gas (chlorine and methane) and water tightness
  • Excellent adhesion, applicable to all common building materials
  • Shows fire resistance properties
  • Resistant against water, alkaline and chemicals
  • Resistant to termites (Mastotermes Darwiniensis) Northern Australian termites
  • Resistant to rats
  • Resistant to Hydrogen Sulphide / Methane and many other corrosive gases (NedLab)
  • Non corrosive
  • Solvent free
  • Shock absorbing
  • Non toxic, neutral and almost odourless
  • Also suitable for limiting the EX-zones during transitions (observe chemical resistance)
  • Suitable for any shaped cable duct / bore hole / opening
  • Quick and easy installation
  • A complete kit for sealing LV-HV cable ducts
  • Seals XLPE EPR PVC & PE sheathed cables, PILC, (HD) PE pipes – medium/high voltage cables
  • Suitable for renovations, can be installed retrospectively
  • Over 25 years of operational experience

Hydrocarbon Resistant Cable Seals

The duct seal system has been extensively tested against pressure, pulling forces, chemicals, gases, hydrocarbons, in conjunction with using FiloSeal+HD which uses the hexagonal backing system to support and separate the cables. The following table summarises the the Test Report conclusions.

Test DescriptionMeasurementResult Pass or Fail
Pressure2.0 Bar1.0 bar long term, 2 bar short termPASSED
Pulling Force100kg100kg – 1000 newtonsPASSED
Bend Test10xd at 45°10xd at 45, with 1 pressure barPASSED
Chlorine Gas100% for 7 daysSlight change on colour and texturePASSED
Methane Gas100% for 7 daysSlight change on colour and texturePASSED
Diesel100% for 2 yearsHardly any changePASSED
Petrol/Benzene100% for 2 yearsHardly any changePASSED
Ethanol100% for 42 daysHardly any changePASSED
AD Blue100% for 21 daysNo changePASSED
ASTM Oil100% for 2 yearsHardly any changePASSED
Hydrogen Sulphide (H2S)200ppm for 5 daysHardly any changePASSED


Installing & Preparing The Cable Duct Seal

The cable duct seal should be installed in accordance with the Filoform installation instruction.

1.Ensure cables and duct are cleaned and given a key using sandpaper

2. The hexagonal tubes are positioned onto the cables to be sealed and filled up all the voids and gaps using the small and large hexagonal backers to ensure the support system is adequately sealed

3. The hexagonal tubes must be installed leaving a 20mm gap at the front to apply the Filoform MD+ cable duct sealant

4. Once fully covered using the Filoform sponge to compress the duct sealant ensuring the sealant is compressed into the centres of the hexagonal tubes and around each of the cable to be sealed

5. The duct sealant can take 4-20 days to fully cure depending on air humidity – the more humidity the quicker the sealant cures.

Duct Sealing - Cleaning

Duct Sealing - Sanding

Duct Sealing - Installing Hexagons

Cable Duct Seal

Sealing Cable Ducts

Sealing Cable Ducts - Sponge

Duct Seal

Suitable To Seal HV Cable Ducts & Medium & High Voltage Cable Chambers

Filoform FiloSeal+HD – Technical Specification
Density1.2 gr/cm³
Pressureup to 2 bar
Pulling Force100kg (1000 newtons)
Bend Test10xd at 45º, with 1 bar pressure
Flow< 2mm
Skin over time (23C/55%RH)± 15 minutes
Curing3 mm / 24 hours
Hardness30 shore A
Tensile strength0.8 N/mm²
Operating temperature+5°C to +40°C
Temperature resistance-40°C to +120°C


FiloSeal+HD – Product Specification
Filoform Part RefCable Duct Seal DescriptionMaximum Duct Diameter (mm)Order Unit
280010FiloSeal+HD – 75mm > 110mmØ 110 max.per piece
280020FiloSeal+HD – 125mm > 160mmØ 160 max.per piece
280030FiloSeal+HD – 180mmØ 180 max.per piece
280040FiloSeal+HD – 200mmØ 200 max.per piece
280050FiloSeal+HD – 225mmØ 225 max.per piece
280060FiloSeal+HD – 250mmØ 250 max.per piece
Sealing Cables & The ATEX Directive

Cable duct seals are exempt from the requirement to certify for installation in hazardous area locations including Zone 1 & Zone 2 according to the ATEX Directive – the seals are classed as “non-sparking” and not capable of causing a source of ignition in potentially explosive atmospheres.

The following table summarises the results from the Test Report – please note the test results contained have been achieved in accordance with Filoform installation instructions and if not followed field results can vary. Size, material and cable volume of the duct all influence the duct seal performance.

Duct Seal Test DescriptionMeasurementResultPass Or Fail
Pressure2.0 Bar1.0 Bar Long Term, 2 Bar Short TermPassed
Pulling Force100kg100kg – 1000 NewtonsPassed
Bend Test10xd at 45º10xd At 45º, With 1 Bar PressurePassed
Chlorine Gas100% for 7 DaysSlight Change On Colour and TexturePassed
Methane Gas100% for 7 DaysSlight Change On Colour and TexturePassed
Diesel100% for 2 YearsHardly Any ChangePassed
Petrol / Benzene100% for 2 YearsHardly Any ChangePassed
Ethanol100% for 42 DaysHardly Any ChangePassed
AD Blue100% for 21 DaysNo ChangePassed
ASTM Oil100% for 2 YearsHardly Any ChangePassed
Hydrogen Sulphide (H2S)200ppm for 5 DaysHardly Any ChangePassed


FiloSeal+HD Duct Sealing System

FiloSeal+HD Duct Sealing System

Sealing Cables Ducts

Sealing Cable Ducts With Roxtec – cable sealing modules consist of two halves with removable layers and a centre core which is removed to permit cable or pipe installation in medium/high voltage substations, hazardous areas and electrical infrastructure

Roxtec Cable Transit Frames

Cable & Duct Sealing Transit Frames – T&D Approved Roxtec Distributor

Data Sheets