DuctSeal HG Cable Duct Sealing System

Patent-Pending Trefoil/Triplex Cable Separation
Our unique tubular rubber backing system can be configured as continuous strips, rings, or cross-shapes, delivering reliable support and separation for large single-core or trefoil cables. This one-of-a-kind design simplifies installation, ensures stability, and provides DSEAR-compliant trefoil cable sealing.

Advanced MEKO-Free, Non-Hazardous Sealant
DuctSeal HG incorporates GreyStuff and RedStuff – FyBrid flexible intumescent sealing compounds. These formulations are zero-halogen, MEKO-free, and non-hazardous, ensuring maximum installer safety and environmental compliance.

Water & Gas Tight
Provides a robust gas-tight and water-tight barrier against ingress, safeguarding ducts in critical infrastructure applications.

Resistant to Toxic Gases
Specifically designed for the water industry, DuctSeal HG is resistant to methane, chlorine, and hydrogen sulphide, protecting cables from chemical attack.

Hydrocarbon Resistance
Built for petrol forecourts and fuel distribution sites, DuctSeal HG withstands long-term exposure to hydrocarbons and other aggressive chemical agents.

Flame Retardant Performance
Independently tested to UL94:2013 / ANSI UL94:2018, ensuring flame retardancy for high-risk environments.

Industry Compliance
Fully compliant with DSEAR, WIMES, DCG, APEA Blue Book, and ATEX standards, making it suitable for water utilities, petrochemical plants, energy networks, and civil infrastructure.

Microbial Defence
Resistant to fungal and bacterial growth, providing durable protection in damp and contaminated environments.

Prevents Water Treeing
Creates a watertight seal that blocks moisture ingress and protects cable insulation from water treeing degradation.

Minimal Cable De-Rating
At a 20mm seal thickness, thermal resistance is just 5.1 K/W, allowing cables to maintain their maximum current-carrying capacity.

British Manufactured
All DuctSeal HG components are proudly designed and manufactured in the UK, ensuring consistent quality, performance, and reliable supply.

Indoor Air Comfort GOLD and Zero MEKO Protection

GreyStuff has been independently tested for ultra-low VOC emissions and has achieved Indoor Air Comfort GOLD. This means it has been assessed against some of the strictest European indoor air quality requirements for construction products, including BREEAM Exemplary Level, EMICODE EC1 Plus, French A+ and EU Taxonomy criteria.

For DuctSeal HG installations, this is important because heavy-duty duct sealing work is often carried out in enclosed or restricted areas such as plant rooms, chambers, substations, service risers, utility spaces and ducted cable networks. A low-emission duct sealant helps support cleaner air during and after installation, making it a strong choice for engineers, installers and contractors working in demanding environments.

What Indoor Air Comfort GOLD Means

Indoor Air Comfort GOLD is a recognised certification for low product emissions. It brings together a wide range of European VOC emission requirements into one certification, helping show that a product supports better indoor air quality and sustainable building standards.

For specifiers and contractors, this helps make GreyStuff suitable for projects where air quality, low VOC emissions, sustainability and environmental performance are important.

Why Zero MEKO Matters

GreyStuff is formulated with zero MEKO. MEKO, also known as 2-butanone oxime, is used in some traditional sealants and can be released during the curing process. In comparison, GreyStuff avoids MEKO-based curing chemistry, helping reduce unnecessary exposure to MEKO-related emissions during installation.

This is especially beneficial for engineers who regularly work close to sealants, often by hand and in confined or poorly ventilated areas. Choosing a zero MEKO duct sealant helps support safer working conditions by reducing exposure to a substance associated with occupational health concerns.

Compared with MEKO-Containing Sealants

Some conventional sealants still use MEKO-based curing chemistry. When these products cure, they may release MEKO into the surrounding air. For engineers working directly over duct openings, or applying sealant in restricted spaces, this can create avoidable inhalation exposure.

GreyStuff provides a cleaner alternative by removing MEKO from the formulation. This helps reduce exposure during application and curing while still delivering the flexible, re-enterable, water and gas tight performance required from a professional duct sealing system.

Benefits for Engineers and Installers

Indoor Air Comfort GOLD: Independently tested for ultra-low VOC emissions and compliance with strict indoor air quality standards.

Zero MEKO formulation: Does not use MEKO-based curing chemistry, helping reduce unnecessary chemical exposure during installation.

Cleaner air during installation: Supports improved air quality in chambers, risers, plant rooms, substations and other enclosed work areas.

Better for heavy-duty applications: A responsible choice for engineers and contractors working with larger cables and more demanding duct sealing projects.

Supports sustainable projects: Suitable for specifications where BREEAM, EMICODE, French A+, EU Taxonomy and low VOC requirements are important.

No compromise on performance: GreyStuff remains flexible, re-enterable, water and gas tight, while supporting a cleaner working environment.

A Cleaner Choice for DuctSeal HG

DuctSeal HG uses GreyStuff as part of a heavy-duty, re-enterable duct sealing system designed to protect cable ducts from water, gas, smoke, vermin and harsh industrial environments. With Indoor Air Comfort GOLD and zero MEKO technology, it supports both reliable duct protection and a cleaner installation environment for the people applying it.

Electrostatic Properties

GreyStuff has been independently tested to assess its electrostatic behaviour in accordance with recognised industry standards for electrical insulation and static charge performance.

Testing was conducted to:

• BS EN 60079-32-2 / IEC 60079-32-1 (Surface Resistivity – electrostatic hazards guidance)
• BS EN 61340-2-3 (Volume Resistivity – resistance through material)

Test Results

• Surface Resistivity: > 2.0 × 10¹³ Ω/sq (at 25% RH)
• Volume Resistivity: > 1.7 × 10¹² Ω·m

One Kit Per Duct
Each kit includes all components required to seal one duct, based on the kit size selected.

Note: A standard caulking gun is required (not included but available separately). Depending on the cable fill percentage, one kit may seal more than one duct. For advice, contact our technical team on +44 (0)161 874 1480.

Cable Separation & Support
Correct separation is essential for performance. The patent-pending tubular rubber backing system can be configured in continuous strips, rings, or cross-shapes to provide support and separation for large single-core, trefoil, or triplex cables. This ensures safe spacing, prevents movement, and guarantees DSEAR-compliant trefoil sealing.

Running Water Conditions
For best results, ducts and cables must be dry and free from running water. Clean surfaces of all dirt, oil, and grease before applying GreyStuff or RedStuff. If running water is present, please call +44 (0)161 874 1480 for technical advice. In most cases, we recommend using a Kraso Mechanical Seal.

Cure Time
GreyStuff and RedStuff cure at approximately 3–4mm per day, depending on humidity and temperature. Higher humidity and warmer conditions accelerate curing.

Minimum seal depth: 20mm for effective performance.

Cleaning
Uncured material can be removed using solvent-based wipes. Once cured, the compound must be removed mechanically.

Health & Safety
Both GreyStuff and RedStuff are based on a neutral curing, MEKO-free system, making them non-hazardous and installer-safe during application.

Compliance      
DuctSeal HG is fully compliant with:

• WIMES (Water Industry Mechanical & Electrical Specifications)
• APEA Blue Book (petrol forecourts)
• ATEX & DSEAR (explosive atmospheres)
• DCG (Ducted Cable Guidance)
• Sewers for Adoption
• Network Rail PADS

Re-Entry & Removal
Once cured, the compound has a hardness similar to a rubber eraser. This allows ducts to be re-entered or resealed when required.

Always use sharp tools on de-energised cables. AC Cable Solutions accepts no responsibility for damage caused during re-entry.

Cable Suitability
GreyStuff and RedStuff are solvent-free, single-component systems that do not damage cable sheaths or stain duct surfaces.

Storage & Shelf Life
Store in a cool, dry location away from direct sunlight.

Shelf Life: 12 months unopened
After opening: reseal tightly and use within 1 month.

Why choose DuctSeal HG for duct sealing?
DuctSeal HG isn’t just another duct seal—it’s a patent-pending system that delivers trefoil/triplex cable separation, gas- and watertight performance, and long-term protection. Its modular backing system supports heavy cables and simplifies installation, while our advanced FyBrid intumescent sealants provide non-hazardous, halogen-free sealing. The result is a versatile, re enterable solution that meets the highest safety and compliance standards.

What makes DuctSeal HG different from other duct sealing kits?
Unlike standard sealing systems, DuctSeal HG features a patent-pending tubular rubber backing system that can be configured for rings, continuous strips, or trefoil cable separation. Combined with GreyStuff and RedStuff sealing compounds, this design offers DSEAR compliance, hydrocarbon resistance, and flame-retardant performance, setting it apart from conventional solutions.

Is DuctSeal HG suitable for harsh environments?
Yes. DuctSeal HG is engineered for demanding sectors, including:

• Water industry (resists methane, chlorine, and hydrogen sulphide)
• Petrol forecourts and fuel sites (hydrocarbon resistant, APEA Blue Book compliant)
• Energy and utilities (WIMES and ATEX compliant)
• Industrial and civil infrastructure (resistant to moisture, chemicals, bacteria, and fungi)

Can DuctSeal HG be used for retrofits?
Absolutely. As a re-enterable sealing system, DuctSeal HG is ideal for both new builds and retrofitting existing ducts, allowing easy access for future cable upgrades or maintenance.

Is DuctSeal HG WIMES compliant?
Yes. DuctSeal HG complies with WIMES 3.02 (2019), clause 6.4.3.2(b) and is approved for use by water authorities across the UK and Ireland.

How does DuctSeal HG perform under pressure?
When installed to specification, DuctSeal HG delivers gas- and watertight performance up to 2.0 bar, suitable for most utility and industrial duct applications.

Does DuctSeal HG resist hydrocarbons and chemicals?
Yes. DuctSeal HG is specifically designed to withstand hydrocarbons, oils, and aggressive chemicals, making it suitable for petrol forecourts, refineries, wastewater plants, and chemical facilities.

Is DuctSeal HG flame retardant?
Yes. DuctSeal HG has been independently tested to UL94:2013 / ANSI UL94:2018 standards, providing proven flame-retardant performance for high-risk installations.

Does DuctSeal HG protect cables against water treeing?

Yes. By creating a watertight barrier, DuctSeal HG prevents moisture ingress, protecting insulation and preventing water treeing damage to power cables.

Will DuctSeal HG reduce cable performance?
No. At a 20mm seal thickness, the system has a thermal resistance of just 5.1 K/W, ensuring minimal cable de rating and preserving maximum current capacity.

Can DuctSeal HG be re-entered or removed?
Yes. Once cured, GreyStuff and RedStuff achieve a rubber-like consistency, allowing ducts to be re-entered and resealed when required. For safety, use sharp tools only on de-energised cables.

Why buy from AC Cable Solutions?
AC Cable Solutions is the UK’s trusted supplier of duct sealing systems, providing British-made, industry compliant solutions backed by expert technical support and next-day delivery. Our focus on quality, safety, and compliance ensures reliable results across all projects.