Flame retardants (FRs) are included into materials to protect them from fire. They can prevent fire starting (inhibit ignition), slow fire development, protect materials from heat damage and reduce smoke emission in fires.

PIN FRs are non-halogenated and are based on the elements phosphorus and nitrogen as well as inorganic materials. They can be chemically reacted, blended, pressure impregnated or used in paints or coatings. They are used to protect synthetic materials (plastics, composites), fibres, natural materials such as wood, and also to protect structural materials against heat (steel, concrete …). While some halogenated phosphorus compounds are used as flame retardants, these are not within the scope of pinfa.

The chemical structures, properties and applications of PIN FRs are summarised below. They are here grouped under Phosphorus, Nitrogen and Inorganic, but many PIN FRs combine two or three of these components. Combinations of PIN FRs are also often used to bring synergies between their different fire protective and smoke suppressant properties.