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Belzona® Seals Transformer Bunding



Power (POWR)



Gaskets, Seals and Shims (GSS)


Customer Location:

Electrical power company, Sweden


Application Date:

August 2010


Application Situation:

Bund for oil-filled transformer at electrical sub-station in central Sweden.



The bunding for oil-filled transformers was made up of many interconnected small concrete bunds. Connection to each bund was through polyethylene pipes. These pipe penetrations were sealed with rubber sleeves. The outer walls had polyurethane foam inserts. The glands and end-plugs were leaking since the concrete bunds were moving independently of each other. There were 32 penetrations in total with 62 sealing points on either side of the penetrations. The power company decided to seal all the pipe penetrations. The 18 end plugs in the outer wall were also replaced with Belzona. 



Belzona® 4111 (Magma Quartz)

Belzona® 2141 (ACR-Fluid Elastomer)



Concrete and polyethylene


Application Method:

Application was carried out in accordance with modified versions of Belzona Know-How System Leaflets GSS-4 and TCC-15. Belzona® 2141 was used to seal each side of the pipe penetrations and Belzona® 4111 was used to replace the end caps in the perimeter wall. 


Belzona Facts:

The customer was very satisfied with the application. Following an inspection in 2012  which showed no leakage of thawed ice which had accumulated in the bunds over two winters, a similar bund was sealed using the same procedure.


Photographs Description

  1. Transformer sub-station in central Sweden 
  2. Diagram of the secondary containment under the transformer. Note the glands and end plugs 
  3. Leaking gland 
  4. All penetrations were sealed with Belzona® 2141
Case study pic one


 Case study pic two


 Case study pic three


 Case study pic four


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