Denso Mastic 16A Duct Seals

Denso Mastic - Densoseal Duct Seal System British Telecom (BT) & British Gas Approved Duct Seals

Denso Mastic - Densoseal 16A Service Entry & Duct Seal System


Densoseal 16A duct seal systems is a firm fibrous mastic based on mineral fillers, organic fibres and water displacing materials. Densoseal 16A duct seal is packed into the ends of the duct by hand and moulded firmly around cables and against the duct to close any gaps or fissures.

Densoseal 16A is a non-setting self supporting mastic which may be applied to wet surfaces to seal ducts and conduits against ingress of gas and water. Densoseal 16A mastic conforms to British Telecom specification M212C for sealing cable ducts, conduits and service entry pipes or sleeves particularly below ground level to prevent entry of gas or water into buildings.

Densoseal 16A duct seal systems

Denso : Sealing of Service Entries & Ducts, Protection of Gas Escape and Water Ingress in Ducts & Service Entries

It is possible for gas to escape from buried gas pipes in the surrounding soil - this gas could diffuse to the surface and disperse harmlessly : alternatively, it could travel along the trench and enter via ducts or unsealed service entries into buildings posing an explosion risk. Where a utility service e.g. gas or water pipe or cable enters a building below ground, it must pass through a sleeve which is fixed into the wall. The space between the service and sleeve must be sealed such that it is permanently gas tight and capable of accomodating movement. This ability to permit movement is necessary to allow for soli compaction, settlement or subsidence - it is crucial the duct seal or service entry withstands water pressure and is not detroyed by vermin. Duct seals are similar - telephone and power cables (low and high voltage) are commonly ducted. Gas can accumulate in cable ducts and seep into exchanges, substations and switchrooms. Therefore it is necessary to achieve an effective seal in the space between the cable and the duct. Spareways without cables must also be sealed. Ducts below ground can also fill with water and this too would enter the exchange or substation - the duct seal must prevent this. 

Densyl Mastic
Densyl Mastic is a self-supporting non-setting mastic for waterproofing and for sealing service entries and ducts against entry of gas. Densyl mastic is approved by British Gas (Centrica) for sealing the annular space between carrier pipes and sleeves where services enter buildings below ground level.Description: Densyl mastic is a soft mouldable mastic based on saturated petroleum hydrocarbons, inert mineral fillers and organic fibres. Performed strip 330mm long with round or triangular profile or in 3 kilo blocks. Application: Densyl mastic strips can be rapidly applied to provide an effective gas and water tight seal capable of accomodating movement due to settling or vibration (where ducts are wet or a substantial head of water could form, Densoseal 16A should be used). 
Method: Densyl mastic is packed by hand into the annular space between the service or carrier pipe and the rigid sleeve which is fixed to the wall - mastic should be packed into the annulus to a depth at least equal to the diameter of the sleeve. Surface should be dry and free from loose rust, scale, dirt or previous entry sealants. Properties : Densyl mastic adheres to all metal surfaces, PVC, polythene and glazed earthenware - unaffected by natural gas and water. Withstands up to 5 kPa (0.5 metre head) water pressure for 30 minutes. 

Densoseal 16A
Densoseal 16A is a self-supporting non-setting mastic which has been developed for sealing cable ducts and conduits against gas or water penetration. Description: Densoseal 16A is a firm fibrous mastic based on polybutene, mineral fillers, organic fibres and water displacing materials. Application: gas and water can accumulate in underground ducts - where ducts terminate inside buildings, manholes or chambers they must be sealed against gas and water. Densoseal 16A is suitable for applications where ducts are wet or liable to fill with water. Method: Densoseal 16A is packed into the ends of the duct by hand and moulded firmly around cables and against the duct ensuring there are no gaps or fissures. The mastic duct seal should be packed to a depth at least equal to the diameter of the duct . Properties: Densoseal 16A adheres to conduit and duct materials such as steel, earthenware, lead and PVC.

Denso Duct Seal 16A Mastic - Rule of Thumb - to seal 1off 150mm cable duct requires 4.6kg Denso duct seal mastic

Adobe Denso Mastic Duct Seals - Densoseal 16A