Inflatable sealing technology: "Innovative and economical solutions for cable entries"

Sealing against periodically accumulating water (3 m water column DIN 18195-x) and gas diffusion.
In addition: solutions against propagation of fire and smoke penetration.


Sealing cushions for

cable and duct entries, distribution cabinets, cable conduits,
ore boreholes, wall feed-throughs, service entries in buildings,
annular spaces and more.

For inner diameters up to 500 mm.


Reasons for using sealing technology for

feedthroughs to protect against water entry or gas diffusion e.g. carbon monoxide

  • Prevention of personal injury caused by gas diffusion
  • Prevention of damage to property in buildings and technical rooms
  • Prevention of short-circuits caused by water entry
  • Prevention of network failure caused by optical fibre breakage
    (optical fibres are particularly sensitive to water entry or immersion in water)
  • Cable manhole facilities do not have to be pumped out
  • Prevention of costly repair and renovation measures


  • Penetration of water and mud in cable manholes,
    substations, technical rooms etc.

  • Damage and breakage of technical components,
    fibre breakage in joint boxes
  • Soil particles and water may be washed into  the conduit and swept along it. High costs may be incurred for removing the contamination and cleaning up. See §4 BBodSchV (German Federal Soil Protection Act and Ordinance).
  • Conduits blocked by contaminants can cause damage to cables during installation. Damage may also be caused by solutions with pH2-pH12 entering conduits.

The requirements of international telecommunication network providers

Regulations governing the closure of cabled ducts against the entry and further passage of water,
and the requirements for the sealing elements used for this purpose, are to be found in the following:

  • Deutsche Telekom TS 0307/96
  • British Telecom pls LN584
  • France Telecom (RAD) ST/FTR/7644
  • Bell Canada 2017-05-23 (Rev.)
  • DOI Japan
  • Fibre Optics CT GmbH - Prüfgrundsätze E-PG-DMPK-1 und E-PG-DMPK-2

Requirements of international telecommunication network providers for sealing elements

(also to be found in Fibre Optics CT GmbH – Test principles E-PG-DMPK-1 and E-PG-DMPK-2)


Examples of requirements are:

  • •Tightness against 3 m water column and gas diffusion
    (* after removal and re-installation without damage to conduit or cables)

  • Service life (defined by the total leak rate)
  • Tightness after temperature cycling from -15°C to +30°C (ageing)
  • Tightness despite vibration
  • Resistance to chemicals, petrol, diesel or kerosene mixtures, paraffin oil, cable lubrication agents

* A more stringent demand from France Telecom, Fibre Optics CT GmbH


Wolf GmbH: Inflatable sealing cushions – APPLICATIONS

Wolf GmbH: Inflatable sealing cushions – Advantages

  • Reliable sealing against water entry and gas diffusion for round or
    boreholes, or concrete, plastic, cast iron or stoneware cable conduits
  • Universal application, independent of cable and duct diameters  or
    cable configuration, i.e. the diameter and number of cables in a duct)
  • Reusable sealing cushions
  • Additional sealing  solutions are available against smoke penetration or fire propagation
  • Installation, removal and retrofitting are quick and easy
  • CO2-free inflation with compressed air

Inflatable sealing cushions from Wolf GmbH …

fulfil and even exceed international requirements

These include:
T-Com TS 0307/96, France Telecom RSD CSE C75-11H, British Telecom LN584,
Testing for power cables VDE 0278-629-1/A1 and DIN EN 61442, as well as the DVGW*
provisions in VP601 for service entries for gas and water in houses, etc.

*standardization body for the gas and water industry

  • Sealing effectiveness against pressing water up to 5 m water column
  • Tightness against gas diffusion < 0.1 bar, in acc. with DVGW-VP601
  • Fulfilment of the demands of temperature cycling tests
  • Resistance to various chemicals with pH2 to pH12, petrol, diesel, kerosene…
  • Reusability, with a removal time of < 1.5 min, in acc. with FO PB 179/2011

Advantage: A comparison of service lifetimes

We measured and compared the total leak rates of inflatable sealing elements in an independent laboratory.
Zhe result: Wolf sealing elements outperformed those of competitor products and exceeded the
Deutsche Telekom requirement, i.e. they have a longerservicelife

Tightness 3 m water column and gas diffusion 0.1 bar

Extract from Test Report FO 127/2013


Practice-oriented test setup


Temperature cycling test (ageing)

Extract from Test Report FO 076/2010 und FO 176/2011. Short-circuit requirement and tightness tests after ageing (temperature cycling) 



Simulation of cable sheath temperature 70°C (in alternating cycles)



Ambient temperature cycling with tightness check



Requirements fulfilled!


Chemical resistance

In order to verify chemical resistance pH2 to pH12, various substances were tested in the presence of TÜV-Süd* (Test protocol FO 175/2011)



Requirements fulfilled !



4x times fillable with air totally



2x times fillable with air totally


Sealing cushion

16.1 QAK/V-L and
16.2 QAK/V-L
with swelling material

16.3 ZKAK/V-L and
16.4 ZKAK/V-L
with cellular rubber

Wolf GmbH inflatable sealing cushions - Products

sealing tape


Self-sealing, heat-fixed nonwoven material made of PP fibres and special super-waterabsorbent fibres, UV-stabilised. Geotextile robustness class TL Geok EStB05-3


Self-sealing cellular EPDM rubber tape. Closed-cell, soft-elastic cellular rubber, cell size approx. 0.1 - 0.5 mm



Cannot be fitted if in direct contact
with standing or flowing water!


Can be fitted in
standing or
flowing water!




No unwanted adhesion


No unwanted adhesion




Directly on contact with water


Directly on contact with water




Reusable (can be refitted) after the swelling material has completely dried out


Reusable (can be refitted) after the rubber has regained its original shape


Wolf GmbH inflatable sealing cushions - Products

Now including: Heat protection F60 or F90

Fire-resistant sealing elements (Product Group 17), supplied ready-equipped with fire-resistant tapes (in brush form), available in two categories, F60 and F90.


Although the sealing element itself will lose tightness in the event of fire, the foaming exfoliated graphite forms a stable, flameproof mass at a temperature of 145 °C,
reliably shutting off the cable duct from heat, smoke penetrationandfirepropagation.
The cable duct remains uncontaminated!


Wolf GmbH: Fire-resistant sealing cushions

  • Include all the familiar benefits of the sealing cushion (valve), for example: no penetration by water or gas
  • Make the process of retro-fitting of cables or ducts quick and easy (reusability)
  • Help to prevent mice and rats from entering
  • Heat protection F60 and F90 are resistant to ageing, water, thawing and UV
  • Start to react at a temperature of approx. +145°C

Wolf GmbH: Fire-resistant sealing cushions

  • Funktion test with flame exposure lasting 110 minutes at temperatures up to +680°C
  • The fire-resistance tape fulfils the conditions for approval, DIBt* No. Z 19.11-1713
    * German building supervisory authority

Easy assembly – few accessories - simple

for multi-configured cable ducts or cable feedthroughs
Swelling sealing tape or sealing inserts


Standard compressor with
pressure gauge (display max. 4 bar)
Filling capacity max. 20 l/min


Wolf GmbH Sealing technology - Easy removal!

No adhesion to surrounding structures
Non-destructive removal


Competitor product:
Difficult removal
Disposable product


Videos of installation and removal on YouTube

Sealing element (valve) (4 x reusable)

Sealing Bag (Reusable once)

Wolf GmbH sealing technology - Innovative and reliable!

  • It is important to protect cable ducts and infrastructure systems if follow-on costs and breakdowns are
    to be avoided and problems such as water entry, gas diffusion or fire are to be effectively prevented
  • As a rule, renovation and repair are more expensive than precautionary protective measures
  • Wolf GmbH has products for fibre-optic security technology, such as water detectors,  unauthorised access and hazard
    alarms (EMA and GMA), which complete the full product range and serve the purpose of timely danger detection.
  • All products are the result of expertise gained in long years of practical
    experience and can be tailored to the needs of your particular application

Wolf GmbH

Zazenhäuser Straße 52
D - 70437 Stuttgart

Tel.:  +49 (0)711 87 39 41
Fax.: +49 (0)711 87 12 30

Email: Service(at)