Foreword

TCVN 9259-8:2012 is fully equivalent to ISO 3443-8:1989.

TCVN 9259-8:2012 was converted from TCXD 211:1998 (ISO 3443-8:1989) in accordance with Clause 1, Article 69 of the Law on Standards and Point a), Clause 1, Article 7 of the Government’s Decree No. 127/2007/ND-CP dated August 01, 2007, detailing the implementation of some articles of the Law on Standards and Technical Regulations.

The TCVN 9259 series under the general title “Tolerances for building” includes the following parts:

• TCVN 9259-1:2012, Part 1: Basic principles for evaluation and specification.
• TCVN 9259-8:2012, Part 8: Dimensional inspection and verification of construction work.

The ISO 3443 series “Tolerances for building” also includes the following parts:

• ISO 3443-2:1979 – Part 2: Statistical basis for predicting fit between components having a normal distribution of sizes
• ISO 3443-3:1987 – Part 3: Procedures for selecting target size and predicting fit
• ISO 3443-4:1986 – Part 4: Method for predicting deviations of assemblies and for allocation of tolerances
• ISO 3443-5:1982 – Part 5: Series of value to be used for specification of tolerances
• ISO 3443-6:1986 – General principles for approval criteria, control of conformity with dimensional tolerance specifications and statistical control – Method 1
• ISO 3443-7:1988 – Part 7: General principles for approval criteria, control of conformity with dimensional tolerance specifications and statistical control – Method 2 (Statistical control method)

TCVN 9259-8:2012 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 published by the Ministry of Science and Technology.

1. Scope

This standard specifies procedures and lists of items to be agreed upon by the parties involved in a construction project. These provisions are applied in the dimensional quality inspection process as well as the requirements used in construction work.

NOTE: Annex A includes a list of recommendations to be used where applicable.

2. Requirements

Prior to commencing installation work, the following points shall be agreed upon and monitored by the concerned parties:

a) The objects and important characteristics that need to be checked and must refer to the tolerance requirements;

b) The construction stages that must be inspected;

c) The parties responsible for inspection;

d) The sampling plan and reference to measurement methods;

e) Procedures and methods for resolving non-conformities;

f) Determination of the start and end time of the inspection work;

g) Documentation of the inspection work.

ANNEX A (Normative) RECOMMENDATIONS

This annex specifies the list of recommendations stated in Article 2.

A.1. Objects and important characteristics that require inspection

In some cases, the following important objects with their characteristics need to be inspected:

a) Primary points, auxiliary points and positioning points, protective and conversion points, if any, both vertically and horizontally, must be checked according to ISO 4463;

b) Dimensions and elevations of foundations;

c) Dimensions of prefabricated components transported to the construction site;

d) Concentricity or position of the base of a component;

e) Verticality, especially of stairwells and elevator shafts;

f) Joint gaps between components;

g) Bearing surface dimensions of components;

h) Levelness of component surfaces and building floor slabs;

i) Alignment of surfaces;

j) Surface shape and inclined sections.

A.2. Construction stages requiring inspection

In addition to checking the above points, the inspection of construction work should focus on:

a) Upon receipt of components at the construction site and before installation;

b) At important stages, such as the final installation time for each storey;

c) Upon acceptance of a batch at the factory.

A.3. Responsible parties

The responsible parties are usually the main contractor or subcontractor, or their designees. During construction, the following types of inspection work may be carried out ⁽¹⁾.

a) Supervision upon receipt ⁽²⁾;

b) On-site inspection;

c) Acceptance inspection ⁽²⁾;

d) The responsibility for carrying out these types of inspections depends on the agreement. Separate types of inspections may be combined if necessary.

A.4. Sampling plans and reference to measurement methods

Characteristics of significant importance to the function of the structure (safety, installation, economy, etc.) are all inspected by sampling or 100% inspection must be used (See ISO 3443-6 and ISO 3443-7). Inspection work is carried out according to the methods specified in ISO 4463-1.

The dimensions and shape of the structure or components need to be inspected using the methods in TCVN 9262-1:2012. If the positions of the measurement points are not specified, these positions need to be selected in accordance with TCVN 9262-2:2012. The accuracy of the measurement needs to be agreed upon by the involved parties.

The designer indicates the characteristics that are important to the function of the structure and proposes special inspection plans for these characteristics.

A.5. Procedures and methods for resolving non-conformities

Deviations from accuracy requirements need to be reported to the designated responsible person as agreed, to determine the steps to be taken when this deviation exceeds the accuracy requirements.

Cost issues need to be taken into account in the agreement.

A.6. Determination of start and end time of inspection work

The inspection time needs to be announced in the agreement. This time may include both construction time and/or warranty period.

A.7. Documentation of inspection work

Appropriate records at the site need to be maintained, using a number of construction logs and data files according to easily readable forms.

This record includes the following information:

a) Object;

b) Measured values and calculation methods, with analysis;

c) Date and time of inspection;

d) Inspection location;

e) Name of the inspector;

f) Equipment used, serial number, calibration certificates, measurement accuracy;

g) Checking of tools used;

h) Positions of measurement points (new positions);

i) Reference benchmark points used;

j) Temperature and other atmospheric components;

k) Other factors that may have an influence, such as the age of the components.

ANNEX B (Informative) BIBLIOGRAPHY

ISO 3534¹⁾, Statistics – Vocabulary and symbols.

ISO 4463-1:1989, Measurement methods for building – Setting-out and measurement – Part 1: Planning and organization, measuring procedures, acceptance criteria;

TCVN 9262-1:2012, Tolerances for building – Methods for measuring construction works and prefabricated components – Part 1: Measuring methods and instruments;

TCVN 9262-2:2012, Tolerances for building – Methods for measuring construction works and prefabricated components – Part 2: Position of measurement points.

(1) In addition to on-site inspections listed, components can be inspected at other locations.

(2) The terms are consistent with ISO 3534.

1) ISO 3534 currently has new versions: ISO 3534-1:2006; ISO 3534-2:2006; ISO 3534-3:1999.