Deviation of Material Dimensions

Forza Doors Ltd produce timber door leaves, frames and panels to agreed customer specific dimensions which are subject to tolerance guide lines as detailed in British and European Standards.

Door Leaves

BS5277:1976 Measurement of defects of general flatness of door leaves

The standard determines the method which has to be used to measure the defects of general flatness which is limited to that of the coincidence of the edges of a face of a door leaf with a reference plane. This measurement of the defects of general flatness consists in measuring on one face its twist as well as the longitudinal and transverse bending close to the edges.

The measurement of twist is carried out on one face of the leaf. Any three corners of this face determine a plane of reference. The deviation of the fourth corner is measured with respect to this plane. The measuring points shall not be more than 20mm from the edges.

Deviation from true plane (twist) shall not exceed: 6mm BS4787-1:1980.

The measurement of bending also carried out on one of the faces of the leaf with respect to straight lines parallel to each edge and located 20mm from each edge.

Deviation from face to straight lines (bow) in length: 4mm and (cup; horizontal bow) 2mm.

Twist and bending to be measured with a maximum uncertainty of +/- 0.50mm.

Deviation from squareness shall not exceed 1.5mm in 500mm BS5278.

Deviation from local surface flatness in any position or direction when measured with a 200mm bridge shall not exceed 0.50mm.

Deviation from customer specific dimension door leaf height +/-1.5mm BS4787.

Deviation from customer specific dimension door leaf width +/- 1.5mm BS4787.

Deviation from customer specific dimension door leaf thickness + 1.0/-2.0mm BS4787.

Operating Gaps:
between leaf and frame jamb 2mm either side +1.0/- 0.5mm BS4787
between leaf and frame head or transom 2mm + 1.0/- 0.5mm BS4787

All sizes specified are as at the time of handing over the door leaf to the customer and are at the moisture content agreed between Forza and the customer at the time of order as per Forza moisture specification 8% +/-2%.