TCVN 9260:2012 ISO 6284:1996 Construction drawings – Indication of limit deviation

Foreword

TCVN 9260 : 2012 is completely equivalent to ISO 6284 : 1996.

TCVN 9260 : 2012 was converted from TCXD 251 : 2001 (ISO 6284 : 1996) in accordance with Clause 1, Article 69 of the Law on Standards and Technical Regulations and Point a), Clause 1, Article 7 of the Government’s Decree No. 127/2007/ND-CP dated August 1, 2007 detailing the implementation of some articles of the Law on Standards and Technical Regulations.

TCVN 9260 : 2012 was compiled by the Institute of Architecture, Urban and Rural Planning, proposed by the Ministry of Construction, appraised by the Directorate for Standards, Metrology and Quality, and promulgated by the Ministry of Science and Technology.

1. Scope

This standard specifies methods for indicating limit deviations in construction drawings.

2. References

The following referenced documents are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

TCVN 5896 : 2012¹⁾, Construction drawings – Location of views, text and title block on drawings.

TCVN 9261 : 2012¹⁾, Construction works – Tolerances – Expression of dimensional accuracy – Principles and terminology.

ISO 286 – 1 : 1988 ²⁾, ISO code system for tolerances on linear sizes – Part 1: Basis of tolerances, deviations and fits.

3. Terms and definitions

For the purposes of this standard, the terms and definitions given in ISO 286 – 1 and TCVN 9261 : 2012 apply.

4. General requirements

Limit deviations shall only be indicated on drawings when checking of dimensions, orientation or shape is required.

5. Indication of limit deviations

5.1. When accuracy requirements are specified by limit deviations, the following methods shall be used to indicate limit deviations:

a) In the case of repeated deviations, textual notes shall be provided (see TCVN 5896 : 2012);

b) Placed together with or adjacent to the notes of views when the limit deviations only apply to dimensions within the view (e.g. as in a detailed cross-section);

c) Placed together with or adjacent to the relevant dimension when the limit deviations only apply to that dimension.

5.2. Dimensional limit deviations shall be indicated by the basic size and limit deviations. The basic size and values of limit deviations shall be expressed in millimeters (see Figure 1 and Figure 2). In the case of angles, the basic size and limit deviations shall be expressed in degrees, or gon if necessary.

Information on limit deviations indicated on drawings shall conform to the example in Figure 1a) for symmetrical limit deviations, and Figure 1b) or Figure 1c) for asymmetrical limit deviations.

Dimensions in millimeters

Figure 1 – Examples of indicating dimensional limit deviations

5.3. Positional limit deviations are dimensional limit deviations used to position one element in relation to another, for example a reference line in relation to another line, an element in relation to a reference line (see Figure 2a) or the elevation of a finished floor level in relation to a chosen datum (see Figure 2b).

Elevations are given in relation to the “0” level of the construction site and are expressed in meters with three digits after the decimal point.

Dimensions in meters

Figure 2 – Examples of positional limit deviations

ANNEX A (Informative) BIBLIOGRAPHY

ISO 129 – 1 : 2004¹⁾, Technical drawings – Indication of dimensions and tolerances – Part 1: General principles;

ISO 406 : 1987²⁾, Technical drawings. Tolerancing of linear and angular dimensions;

ISO 1101 : 1983³⁾, Technical drawings – Geometrical tolerancing – Tolerancing of form, orientation, location and run-out- Generalities, definitions, symbols, indications on drawings.

1) ISO 286- 1 : 1988 has now been replaced by ISO 286 – 1 : 2010.

1) ISO 129-1: 2004 replaces ISO 129: 1985

2) ISO 406 has been withdrawn and replaced by ISO 14405

3) ISO 1101 has now been revised