NOFIRNO Flood Defence - Cable Entry Sealing

GPT are one of CSD’s “Experienced Installers” for the NOFIRNO cable/pipe entry sealing products. CSD NOFIRNO is a mastic type product which bonds to the cable and the duct wall, and when properly installed, forms and impermeable seal, leaving the duct water and gas tight*. The high bonding strength and elasticity of the sealant provides a flexible seal which resists movement, shock and vibration, as well as high pressure. It is a well-established product which is used or specified by most UK utility companies.

The CSD system is fantastic at sealing ducts which have been poorly installed, or have been installed without any forethought of water ingress. Whereas mechanical systems require the ducts to be in a good condition and (almost) perfectly round the mastic type product can be installed in entries of any condition. See our sealing failed cable entries page for some of our more difficult installations.

The NOFIRNO system allows for easy adding or removal of cables. Simply core out a section of the seal and run the new cable/pipework through. The sealant is then applied around the new cable to re-seal. There is no need to disassemble the whole transit.

There is a fire rated system which can maintain integrity for up to 4 hours (tested in accordance with BS EN1366-3).

The CSD products come in a range of specifications to meet the requirements of the individual project.

Benefits of the CSD system can include.**

  • Ensures DSEAR compliance even in heavily filled cable ducts
  • WIMES & ATEX compliant
  • Tested to prove no deterioration in performance for more than 50 years
  • Suitable for trefoil cables
  • Resistant to Methane, Hydrogen Sulphide and Chlorine
  • No frame required
  • Easy re-entry for adding cables
  • Provides flood protection and protects against gas ingress
  • Resistant to submersion in petrol, diesel and synthetic transmission oils

*All work is quality checked and scored on the basis of the work. A perfect seal cannot always be guaranteed.

**List of manufacturer’s testing standards avaliable at

CSD Duct Sealing Case Studies

NOFIRNO cable duct sealing substation
flood defence duct sealing server room

Extracts from legislation and guidance

“In all cases, it should be noted that resilience to shallow flooding (up to 600mm) can often be secured by relatively simple protection for key assets, such as sealing entries to control rooms”

Energy Networks Association (ENA) Substation Resilience to Flooding report

"If possible design and construct ducts and chambers that prevent the ingress of water."

GPP 20 Dewatering underground ducts and chambers

Need advice for services and products? Call us now 01656 741 799

Geo Pollution Technologies (UK) LTD - company number - 04689357


GPT head office is based in South Wales and covers all areas of South Wales, West Wales and Mid Wales including Cardiff, Swansea, Bridgend, Newport, Port Talbot, Powys, Llanelli, Neath, Pembrokeshire and Aberystwyth.

We also cover the South West of England from our premesis in Exeter including Cornwall, Devon, Taunton, Redruth, Truro, St Austell, Falmouth, New quay, Torquay, Paignton, Bristol, Plymouth, Bath, Gloucester and Somerset, .

We also operate across the midlands, London, Birmingham, Leicester, Northampton, Derby, Stoke, Nottingham, Coventry, Liverpool, Worcester, Southampton, Swindon, Manchester, Sheffield, Slough, Heathrow, Leatherhead and Surrey.