Intumescence

Intumescence (Latin: intumescencia, from tumor - swelling) denotes an expansion or swelling, i.e. an increase in volume of a solid body without chemical conversion.

Fire protection

In the photomontage, the small orange became the large blackish piece of intumescent material. This intumescent layer forms a light carbon foam , a light ash of low conductivity. This effect is often used to protect cables and structural steel. During intumescence, water is released, which dilutes acids and has an endothermic / cooling effect.

Intumescent mastic as Ab partitioning in a concrete ceiling having a 2-hour fire resistance rating .

S90 fire seals made of fire protection bricks. The intumescence creates an ash shield that increases the distance to the fire and prevents spontaneous combustion on the side facing away from the fire.

In fire protection, the term describes the appropriate "swelling" or foaming of materials. Intumescent building materials increase in volume and correspondingly decrease in density when exposed to heat . As a rule, intumescent materials are used in preventive structural fire protection, where they can perform the following tasks:

• Foam to form a light insulation layer as a heat brake. Expandable graphite ( expandable graphite ), for example, releases gases when exposed to heat. For example, if it is added to the insulating jacket of an electrical line, it forms a "foamed" layer of ash with the incinerating insulating material , which hinders the supply of oxygen - and thus the spread of the flame.
• Endothermic cooling through evaporating crystal water (hydrates); z. B. in building materials made of gypsum
• Formation of a fire protection bulkhead through expansion pressure, e.g. B. when filling the cavity, the a-melting plastic - pipe leaves in a wall or ceiling opening.

Intumescent building materials are also called "intumescent layers". In Germany , intumescent building materials, the building products they contain and the types of construction made with them are subject to approval.

→ see main article fire protection coating

Further meaning

In medicine , intumescence means an increase in the size of an organ or tissue (it can also be used to describe corresponding pathological changes - tumor ).

Web links

Commons : Intumescence  - collection of images, videos and audio files

• New coatings based on cellulose with intumescent properties (accessed on March 20, 2020)
• "Fire protection - an interesting, diverse field of application for construction chemistry" (accessed on March 20, 2020)
• Method establishment and investigations of the pyrolysis processes of intumescent fire protection coatings by means of coupled thermogravimetric and mechanical analysis (TGA-FTIR-MS and TMA) as well as DSC microscopy (accessed on March 20, 2020)
• Innovative fire protection products for rail vehicle construction (accessed on March 20, 2020)
• Flame protection of polymer building materials: Evaluation of concepts on the basis of small-scale cone calorimeter studies (accessed on March 20, 2020)