BS EN ISO 11402 is an important international standard that specifies three methods for the determination of free formaldehyde content in phenolic, amino and condensed resins. Among them, the phenolic resin uses the Titrimetric method (muriatic acid hydroxylamine method) in aqueous or organic solutions, which is suitable for samples with free formaldehyde content not exceeding 15%; the amino resin uses the sulfite method; and the condensed Resin uses the potassium cyanide method. These methods provide a scientific basis for the accurate detection of free formaldehyde content in Resin, helping to evaluate the safety and environmental friendliness of the material and ensure its compliance with relevant regulatory requirements.