Skip to content
Submit a quotation form and a member of our team will be in touch to assist you with your order
Submit a quotation form and a member of our team will be in touch to assist you with your order

Duct Seal HG Cable Duct Sealing System (large heavy cables) - ≤2 Bar Pressure Resistance


Duct Seal HG (Water & Gas) is a NEW re-enterable duct sealing system that is extremely flexible in its ability to seal large, heavy cables & pipes in ducted networks to protect and stop the ingress of harmful or flammable gases, liquids, smoke, and vermin.

Duct Seal HG comes complete with our PATENT PENDING unique tubular rubber backing system that can be joined together in a long continuous strip, joined to make a ring/collar, but best of all, joined in a cross shape to create a perfect shape for separating trefoil/triplex cables. This unique design ensures DSEAR compliance but also aids the installer as it’s simple & quick to create the support & separation on large cables or pipes. The PATENT PENDING ULTIMATE backing system, which is one of a kind, is combined with our NEW Fybrid flexible intumescent, zero halogen, & zero Meko adhesive and sealing compound, GreyStuff. All are designed and manufactured in the UK.

Duct Seal HG, along with Grey Stuff, is a non-hazardous, FyBrid superior single-component, neutral curing sealant that has been specifically developed to cope with the harsh environments around duct openings to ensure ducted networks and penetrations are protected.

Key Features:

  • One-of-a-kind patented trefoil/triplex cable separation - The best in the market
  • Network Rail Compliant
  • MEKO-free, Fybrid, Non-Hazardous Intumescent sealant 
  • Water & Gas Tight
  • Resists Toxic Gases - Ideal for the Water Industry (methane,  chlorine, & hydrogen sulfide)
  • Resists Hydrocarbons - Perfect for the Petrol Forecourt industry
  • Flame Retardent - tested to UL94: 2013 ANSI / UL 94: 2018
  • Microbial Defence - boosted to resist fungi & bacteria
  • MADE IN UK - All components are designed and manufactured locally

Areas of Application:

  • Data Centres 
  • Sub Stations
  • Pumping Stations
  • Waste to Energy Plants
  • Wind Farms / Turbines
  • Electrical Utilities
  • Rail - Network Rail Compliant - Catalogue Numbers Available, CLICK HERE
  • All Construction sectors 
Product No. Product Duct Opening Max Unit Sold
Using 1 x DuctSeal HG Kit – up to 100mm
DSHG100 Duct Seal HG 100mm x1 Kit
Using 2 x DuctSeal HG Kits – up to 150mm
DSHG150 Duct Seal HG 150mm x2 Kits
Using 3 x DuctSeal HG Kits – up to 200mm
DSHG200 Duct Seal HG 200mm x3 Kits
Using 4 x DuctSeal HG Kits – up to 225mm
DSHG225 Duct Seal HG 225mm x4 Kits
Using 5 x DuctSeal HG Kits – up to 250mm
DSHG250 Duct Seal HG 250mm x5 Kits

One Kit per Box
All components included to seal 1 x duct as per the kit size mentioned (Caulking gun not included, but can be sold separately). ** One kit may fill more than one duct, depending on cable % fill. Call 0161 806 1666 for advice**

Cable Separation
It’s imperative to ensure separation between each cable and from the inside of the duct. Our unique daisy-chained circular tubes easily separates and supports single or multiple cables.

Using our patent pending tubular rubber tubes, various shapes can be made to help with cable separation, for example, trefoil/triplex cables.

Running Water
The duct & cables should be dry for best results with no running water. All dirt, oil or grease must be cleaned before applying GreyStuff. If you have running water, please contact AC Cable Solutions for advice on 0161 806 1666. Most of the time, we recommend using a Kraso Mechanical seal - Click here for further information. 

Cure Time
Grey Stuff will cure 3-4mm daily, depending on the Humidity and temperature. The higher the humidity %, and temperature, the quicker GreyStuff will cure. A minimum requirement of 20mm GreyStuff is required for an effective seal.

Uncured material spillages can be cleaned with a solvent-based wipe.

Health & Safety
Grey Stuff is based on a neutral curing system that is hazardous-free to protect users when carrying out tasks like sealing cable ducts. Non-hazardous Zero MEKO.


Re-entry & Removal
Grey Stuff will cure to a similar hardness of a rubber eraser, so re-entry and removal are achievable. The ease of this depends on the type of tools used. For example, a sharper tool will be easier than a blunt-ended tool. Only use sharp tools when cables are de-energized. AC Cable Solutions accepts no responsibility for damaged cables.

Cable Suitability
Grey Stuff is a single-component neutral curing system containing no solvents. Our formulation does not damage the properties of a cable sheath or stain surfaces.

Grey Stuff should be kept in a cool, dry environment and away from sunlight. Product shelf life is 12 months. Once opened, any remaining product can still be used for 1 month afterwards, provided the screwcap is securely fitted.

Features & Standards
Water & Gas tight to 2.0 bar Feature Measurement
Non-slumping Density 1.27
High bonding strength Colour Anthracite Grey
Odourless when curing Skin Over Time 10 mins
Flexible Curing 3-4mm per day
Intumescent Tack free time 22 mins
Very strong porous sticky char is formed when exposed to fire, which has excellent thermal insulation properties. Hardness 35 to 38 Shore A
Microbial resistance – coverage against Fungi, E-Coli, Escherichia coli, Staphylococcus aureus, & A. brasiliensis Elongation 250%
UV & Ozone resistant Flow
3.33 million cPs at 380°C
Non-hazardous Tensile strength
0.72 N/mm^2
Zero halogens used Operating Temperature +5 to 40°C
Emits 0% MEKO Temperature Resistance -35 to +120°C
Resistant to Hydrocarbons (Petrol, Diesel, ASTM oil, & LPG Gas) Intumescence Activation Temperature 210°C
Resistant to Methane, Hydrogen Sulphide, & Chlorine gas – Independently tested. Pressure Resistance 2.0 Bar
Resistant to many other gases & liquids, for example, ADBLUE, & Antifreeze. Shelf Life 12 months
Complies with DSEAR duct sealing regulations
WIMES compliant, as described in the WIMES Specification in section, 3.02 2019 clause
Complies with 2011 NEC Articles 225.27, 230.8, 300.5(G), 300.7 (A) on Raceway Seals, and 501.15 (B)(2)
Petrol station forecourt accepted, as per the technology described in the APEA Blue book - 4th Edition, 4.6.8
ATEX Compliant – Contains no moving parts or any form of material that can create a spark
Age tested to 50 years – Independently tested