BS EN ISO 6284:1999 pdf free download.Construction drawings Indication of limit deviations.
1 Scope
BS EN ISO 6284Standard specifies methods for the indication of limit deviations on construction drawings.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of BS EN ISO 6284Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 286-1:1988, ISO system of limits and fits — Part 1: Bases of tolerances, deviations and fits. ISO 1803:—, Building construction — Expression of dimensional accuracy — Vocabulary.
ISO 4068:1978, Building and civil engineering drawings — Reference lines.
ISO 9431:1990, Construction drawings — Spaces for drawing and for text, and title blocks on drawings sheets.
3 Definitions
For the purposes of BS EN ISO 6284, the
definitions given in ISO 286-1 and ISO 1803 apply.
4 General
A limit deviation shall he indicated on a drawing only when there is a functional requirement to control dimension, orientation or form.
5 Indication of limit deviations
5.1 The following methods shall be used when requirements for accuracy are to be defined by limit deviations.
The indication of limit deviations shall be
a) a single reference in the space for text (see ISO 9431) in the case of repetitive deviations;
b) placed with, or adjacent to, the caption of the figure when limit deviation information applies only to sizes within that figure (for example, a cross-section detail);
c) placed with, or adjacent to, the size concerned when limit deviation information applies only to that size.
5.2 Limit deviations for size shall be indicated by the target size and the limit deviations. The target size and the values of limit deviations shall be given in millimetres (see Figure 1 and Figure 2). In the case of angles, the target size and the limit deviations should preferably be given in degrees, but may be given, if necessary, in gon.
Limit deviation information which is shown on drawings should be given in accordance with the example shown in Figure 1 a) for a symmetrical limit deviation and in accordance with Figure 1 b) or Figure 1 c) for an asymmetrical limit deviation.
5.3 Limit deviations for a position dimension are limit deviations for a dimension which locates one item in relation to another, for example, one reference line to another, a component to a reference line [see Figure 2 a) and iso 4068] or a finished
floor level to a datum level [see Figure 2 b)]. Levels relate to site zero datum and are given in metres with three digits to the right of the decimal sign.