Section Contents

EN 120 : 1992

Wood-based panels – Determination of formaldehyde content – Extraction method called the perforator method

EN 120 is used to determine the formaldehyde content of unlaminated and uncoated wood-based panels and is, therefore, applicable to OSB.  It is referenced in the harmonised European standard EN 13986: 2004 (relating to wood-based panels for use in construction – characteristics, evaluation of conformity and marking) as a means of determining the formaldehyde release classification E1 or E2.

This standard along with the three parts of EN 717 form a series which specifies methods for determining the formaldehyde in wood-based panels or its release from wood-based panels. Formaldehyde is extracted from test pieces by means of boiling toluene and then transferring to distilled or demineralised water. The formaldehyde content of the aqueous solution is determined photometrically by the acetylacetone method.

The table below lists formaldehyde emissions from OSB panels, as referenced in the harmonised European standard EN 13986


Formaldehyde Release Classification


Initial Type



Factory Production  Control



Content   ≤ 8 mg/100 g oven dry board1


Content > 8 to ≤ 30   mg/100 g oven dry board Content > 8 to ≤ 30   mg/100 g oven dry board
1  To ensure compliance with the limits for E1 OSB, the rolling average found from the internal factory production control over a period of 6 months should not exceed 6.5 mg HCHO/100g panel mass.

Review further information on any formaldehyde content in APA panels for plywood and OSB.