Elastic compression seals (FERMADUR®)
Weather is a decisive factor in the application of many materials. Planning the deployment of workers and materials is often only conditionally possible, as reliable weather forecasts can only be given for a few days at a time. If there are longer periods of bad weather, it is possible that no work may take place at all. On the other hand, it is possible to seal joints in concrete construction elements and pipes almost independently of the weather if elastic profiles are used. Their sealing effect is the result of mechanical pressure and can be achieved even if the joint edges are damp or wet. The water pressure to be expected on the joint must be taken into account, as must the possible movement of parts of the construction. Other relevant criteria when choosing the sealing material to be used are resistance to corrosion and how it will react to chemicals. Pipes and joint fillings for sewers, for example, need to be resistant to the contaminated water.
Sealing of joints in concrete
Elastic seals have proved their value over many years. Rubber-based materials, in particular, are best suited for certain areas of application due to their excellent material qualities and their long life. The DIN 19 543 German industrial standard defines elastic seals as: "Elastomer seals that are introduced into the joints to be sealed by elastic deformation. Their sealing effect against fluids under pressure is dependent on the elastic reset force created by the deformation of the seal." The sealing effect is based on the pressure the installed profile exerts on the edges of the joints. No primer or other material to improve adhesion etc. is necessary, as there is no need for the profile to be bonded with the edges of the joint. The seals installed are elastomer profiles with a closed cell structure, smooth outer surface and circular cross-section. One of the advantages of this kind of sealing technology is that application is independent of weather conditions. The seals can be applied all the year round. In extreme cases, joints below the water level can be sealed against the pressure of water with immediate effect. Work can be carried out at temperatures of -5 °C to +50 °C. Under different conditions, it may be necessary to take special measures. Elastic profiles are used in new constructions and in renovation. Particularly in civil engineering, the additional sealing of construction and expansion joints using such seals is typical. These materials have also proved themselves over the years in constructions such as sewage works, swimming pools, sewage screening tanks, underground car parks and bridge cap joints. They are also often used in gravity sewers and rectangular flow channels, as well as in pipe driving. Some essential points must be considered to guarantee the seal of the joint. These include the instructions for pressing in the profiles and the information on the expected total movement in the joint, so that the necessary pre-stressing does not fall short and the maximum stress is not exceeded. The joint or pipe connection to be sealed must be exactly measured and the measurements recorded. These procedures also make drawing up the bills of quantities for charging purposes easier.
You can find out more about FERMADUR® here.
