Although the ultimate ambition is easy to define, i.e. building airtight and continuous barriers, the selection of materials should to take account of the specific project application.

The manufacturer's responsibility is defined by Civil law (article L 111-11, L 111-20 of the Construction and Building Code). Article 1792 gives a definition of who is considered to be a "builder". A "builder" is responsible for any damage that would jeopardise the sturdiness of a building or affect one of its components or items of equipment that is inseparable from the rest of the building, foundations, framework, enclosures and roofing. Article 2270 sets a time limit for the guarantee.

A certificate is issued as a result of tests carried out by an approved laboratory, at the manufacturer's request. It certifies the compliance of a material with regard to specific requirements (fire-resistance, foodstuff compatibility, etc.).

• Reaction to fire
There are two major categories for material:
1/ Classified as incombustible: M0
2/ Classified as combustible: M1 Non inflammable
  M2 Hardly inflammable
  M3 Medium inflammable
  M4 Easily inflammable
Panel classification is certified by the NF markings or by certification (no more than 5 years old) issued by an approved laboratory. Non flame-retardant panels are classified M3 for thickness’ greater 18mm and M4 for thickness less than 18 mm.

• Fire resistance
Fire resistance is the time during that construction elements are able to fulfil their role despite the effects of the fire. This resistance is determined using the calculation rules defined in the French" DTU Règles Bois Feu 88", or in accordance with tests conducted by an approved laboratory. Legislation on fire resistance concerns the following building elements: doors, walls and partitions, posts, beams, floors and ceilings. The following classifications are used:
- Stability: the time that the element resists fire during the test.
- Integrity: the length of time that the element also complies with the criteria for flame protection and the absence of inflammable gasses.
- Insulation: the time for which the element gives heat insulation during the test.
A construction element can be classified as: 1/4 hour, 1/2 hour, 1 hour, 1 hour and half depending on the time it complies with the test criteria.

• "E" Classification defines the behaviour of a panel regarding emission of formaldehyde.

• "F" classification defines the behaviour of the panel regarding the production of smoke.