System for ensuring the accuracy of geometric parameters in construction. Accuracy control

STATE STANDARD OF THE UNION OF THE SSR

PRECISION SYSTEM
GEOMETRIC PARAMETERS
IN CONSTRUCTION.

ACCURACY CONTROL

GOST 23616-79
(ST SEV 4234-83)

USSR STATE COMMITTEE
CONSTRUCTION

Moscow

DEVELOPED

State Committee for Civil Engineering and Architecture under Gosstroy of the USSR

USSR State Committee for Construction

PERFORMERS

A.V. Tsaregradsky; M.S. Kardakov (topic leaders); S.A. Reznik, cand. tech. sciences; G.A. Rastorova; L.N. Kovalis; S.N. Nersesov, Ph.D. sciences; IN AND. innovators; B.G. Borisenkov; V.D. Feldman; L.A. Vasserda, G.B. Shoikhet; D.M. Lakovsky; I.V. Kolechitskaya

INTRODUCED by the USSR State Committee for Construction

Member of the Board IN AND. Sychev

APPROVED AND INTRODUCED BY Decree State Committee USSR on construction matters dated April 12, 1979 No. 55

STATEUSSR COMMITTEE ON CONSTRUCTION

(Gosstroy of the USSR)

RESOLUTION

On the introduction of the standard of the Council for Mutual Economic Assistance “The accuracy of geometric parameters in construction. Accuracy control” and about changes state standard"Provision system geometric accuracy in construction. General rules accuracy control"

USSR State Committee for Construction DECIDES:

1. To put into effect from July 1, 1985, for application in the national economy of the USSR and in contractual and legal relations on cooperation with the CMEA member countries, approved at the 53rd meeting of the CMEA Standing Commission on Cooperation in the Field of Standardization, the standard of the Council for Mutual Economic Assistance "The accuracy of geometric parameters in construction. Accuracy control” (ST SEV 4234-83), by introducing it into the state standard “System for ensuring geometric accuracy in construction. General rules for accuracy control” (GOST 23616-79).

2. Fix the standard of the Council for Mutual Economic Assistance “The accuracy of geometric parameters in construction. Accuracy control” (ST SEV 4234-83) for LenZNIIEP Gosgrazhdanstroy.

3. Approve and put into effect from July 1, 1985 change No. 1 GOST 23616-79 “System for ensuring geometric accuracy in construction. General Rules for Controlling Accuracy”, approved by the Decree of the USSR Gosstroy of April 12, 1979 No. 55.

Chairman of the USSR State Construction Committee. Bashilov

STATE STANDARD OF THE UNION OF THE SSR

By the Decree of the State Committee of the USSR for Construction Affairs dated April 12, 1979 No. 55, the deadline for the introduction was established

from 01.01.80

This standard applies to the construction of buildings and structures, the manufacture of elements for them (structures, products, parts) and establishes the basic rules and methods for controlling the accuracy of geometric parameters.

The rules for controlling the accuracy of the geometric parameters of specific types of structures of buildings and structures and their elements, as well as the work performed, are prescribed on the basis of this standard in the relevant standards or in other regulatory and technical, as well as technological documents.

The terms used in the standard for statistical control correspond to those given in GOST 15895-77.

The standard complies with ST SEV 4234-83 (see reference appendix a).

(Revised edition, Rev. No. 1).

1. GENERAL PROVISIONS

determination with a given probability of compliance with the accuracy of geometric parameters with the requirements of regulatory, technical, technological and project documentation to the objects of control;

obtaining the necessary information for assessing and regulating the accuracy of technological processes.

geometric parameters of the elements and parameters that determine the position of the landmarks of the alignment axes and landmarks for the installation of elements, as well as the position of the elements in the structures (the range of tolerances for these parameters is given in GOST 21779-82 and GOST 21780-83);

geometric parameters of technological equipment, molds and tooling that affect the accuracy of manufacturing elements and their installation in structures and specified in the relevant technological documents.

controlled parameters;

applied method of control;

control plan and procedure for its implementation;

means of control, implementation rules and requirements for measurement accuracy;

method for evaluating the results of control.

1.3. - 1.6.(Revised edition, Rev. No. 1).

1.7. In enterprises and construction organizations it is necessary to develop enterprise standards, maps and checklists and other technological documents for control processes and operations that determine for specific control objects the location of control posts for the technological process, performers, the scope and content of control work, measurement methods and schemes, rules for collecting, processing and use of information on the results of control.

1.8. Normative-technical and technological documents that establish the rules for monitoring accuracy must undergo a metrological examination in accordance with the requirements of the standards State system ensuring the uniformity of measurements.

2. PURPOSE OF CONTROL METHODS

at small volumes of production, when selective control is not feasible;

with the unstable nature of production, including during the adjustment of technological processes;

with increased requirements for ensuring a given accuracy, associated with the need to use large-volume samples.

2.3. Sampling control should be appointed with an established stable production, when the statistical homogeneity of the technological process is ensured.

2.4. In the sampling method, attribute control should preferably be used.

Quantitative control is used for the most critical parameters, when their number is small and there is a need for further development of the process, and also if, according to production conditions, it is advisable to reduce the sample size compared to control on an alternative attribute. This method is applicable when the controlled parameters are independent of each other and have a normal distribution.

If necessary, some of the parameters can be controlled by a quantitative attribute, and some - by an alternative.

2.5. Inspection control should be carried out using the methods established in the relevant regulatory and technical documents for acceptance control.

4. SAMPLE CONTROL

The possibility of applying effective sampling is established on the basis of the results statistical analysis accuracy according to GOST 23615-79.

In justified cases, it is allowed to use other control plans in accordance with GOST 18242-72.

(Revised edition, Rev. No. 1).

4.4. When controlling by an alternative feature, the number of defective control objects (product units) in the sample is determined by its continuous control in accordance with Sec. .

4.5. The batch is accepted if the number of defective control objects in the sample is less than or equal to the acceptance number Ac 1, and is not accepted if this number is greater than or equal to the rejection number Re 1 .

With two-stage control, in cases where the number of defective control objects in the sample is greater than Ac 1 or less Re 1 the second sample is taken. If the total number of defective items in two samples is less than or equal to the acceptance number Ac 2 , the batch is accepted if it is greater than or equal to the rejection number Re 2 - not acceptable.

(Revised edition, Rev. No. 1).

5. METHODS AND INSTRUMENTS OF MEASUREMENTS

2 dXmet£ 0,4 Dx, (3)

where dXmet- limit value of the absolute measurement error;

DX- tolerance of the controlled parameter.

APPENDIX 1a

Reference

Information data on compliance with GOST 23616-79 ST SEV 4234-83

ATTACHMENT 1

TYPES, METHODS AND OBJECTS OF CONTROL BY THE STAGES OF PRODUCTION

(Revised edition, Rev. No. 1).

APPENDIX 2

SAMPLING PLANS FOR ATTRACT

1. One step control

2. Two-stage control

(Revised edition, Rev. No. 1).

APPENDIX 4

Reference

Method for taking into account the additional risk of incorrect assessment of the results of control caused by measurement error

1. When assigning accuracy and choosing measuring instruments, it should be taken into account that measurement errors increase the risk of incorrect assessment of control results. At the same time, the probability of rejecting a suitable object of control or accepting a defective one as suitable increases.

2. If it is necessary to maintain the standard values ​​of the specified risk, adopted in the control plans in accordance with GOST 18242-72 and GOST 20736-75, when assigning sampling plans, the sample size can be increased.

The table shows the values ​​of the increased sample sizen¢ , calculated for the normal distribution law of the controlled parameter and the measurement errordx met = ± 2,5 sx met according to the formula

,

where n- sample size according to the control plan;

sx- standard deviation of the measured geometric parameter;

sx met- root-mean-square error of measurements.

Criteria for evaluating the results of control for an increased sample size are taken according to the control plan for the sample n

1,23n

1,15n

1,11n

1,065 n

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SYSTEM FOR PROVIDING THE ACCURACY OF GEOMETRIC
PARAMETERS IN CONSTRUCTION

(ST SEV 3740-82)

USSR STATE COMMITTEE
CONSTRUCTION

STATE STANDARD OF THE UNION OF THE SSR

Decree of the State Committee of the USSR for Construction of December 13, 1983 No. 320, the deadline for the introduction is set

from 31.01.84

This standard applies to the design of buildings, structures and their elements and establishes general provisions, methodological principles and the procedure for calculating the accuracy of geometric parameters in construction.

Based on this standard, methodological documents, establishing the features of calculating the accuracy of the geometric parameters of structures of various types.

The standard complies with ST SEV 3740-82 in the part specified in help application 1.

The terms used in this standard and explanations are given in the mandatory annex 2.

1. BASIC CONCEPTS

1.1. The calculation of the accuracy of geometric parameters should be carried out in the process of designing typical, experimental and individual structures of buildings and structures and their elements in order to ensure the assembly of structures with specified operational properties at the lowest cost.

1.2. Accuracy is calculated based on:

functional requirements for building structures of buildings and structures;

data on the accuracy of the applied technological processes and operations for the manufacture of elements, breakdown of axes and assembly of structures.

1.3. In the process of calculating the accuracy in accordance with the accepted design scheme, according to the accuracy characteristics of the constituent geometric parameters, the calculated limit values ​​​​of the resulting parameter are determined, which are then compared with the permissible limit values ​​\u200b\u200bof this parameter established on the basis of functional requirements (by calculating the strength and stability, in accordance with the test results or based on insulating, aesthetic and other requirements).

1.4. Compliance of the accuracy of the resulting parameter with the functional requirements is ensured if the following conditions are met:

where and are the calculated limit values ​​of the resulting parameter X;

and - allowable limit values ​​of the resulting parameter X. The difference is the functional tolerance.

1.5. The task of calculating the accuracy can be:

direct, when the calculated limit values ​​of the resulting parameter are determined by the known characteristics of the accuracy of the constituent parameters (test calculation);

inverse, when the established permissible limit values ​​of the resulting parameter determine necessary requirements to the accuracy of the constituent parameters.

1.6. According to the accuracy calculation results:

in the regulatory and technical documentation for the building structures of buildings, structures and their elements and in the working drawings, they specify, if necessary, the nominal values ​​\u200b\u200bof the resulting and constituent parameters, establish the requirements for the accuracy of these parameters and the rules for controlling accuracy;

in the technological documentation for the manufacture of elements, the breakdown of axes and the production of construction and installation works, they establish the methods and sequence of performing technological processes and operations, methods and means of ensuring their accuracy.

2. METHODOLOGICAL PRINCIPLES FOR CALCULATION OF ACCURACY

2.1. The decisions made as a result of calculating the accuracy should provide minimum labor and material costs in the construction of building structures of buildings and structures and the manufacture of their elements.

To this end, it is necessary to provide for the maximum possible tolerance values, as well as constructive and technological measures to reduce the influence of the accuracy of technological processes and operations on the accuracy of the resulting parameters.

2.2. The calculation of accuracy should be made, as a rule, from the condition of complete assembly of structures.

In some cases, with technical feasibility and economic feasibility incomplete collection may be envisaged. In this case, for cases where the actual values ​​of the resulting parameter will go beyond, additional operations should be provided for the selection of elements or the fitting of individual dimensions.

2.3. The initial equation for calculating the accuracy is equation (3), which expresses the relationship between the resulting and constituent parameters included in the calculation scheme:

where is the resulting parameter;

Component parameter;

The number of component parameters in the design scheme;

Coefficient characterizing the geometric dependence of the resulting parameter X from constituent parameter Xk.

As the resulting parameters in the preparation of design schemes, as a rule, the dimensions in the junction nodes of the elements and other dimensions are considered, which, with the accepted sequence of assembly of the structure, complete a certain cycle of technological operations that determine the accuracy of the component parameters, and in which the errors of these operations are compensated (recommended Appendix 3 ).

The dimensions of the elements, the dimensions that determine the distances between the axes, elevation marks and other landmarks, as well as other parameters obtained as a result of the specified technological operations, the accuracy of which affects the accuracy of the resulting parameter, are considered as constituent parameters.

If the constituent geometric parameters are statistically dependent, then this dependence must be taken into account when determining the calculated characteristics of the accuracy of the resulting parameter. Statistical dependence can be characterized by a correlation coefficient.

2.4. Accuracy is calculated based on statistical methods. In the general case, in a statistical calculation, the calculated limit values ​​of the resulting parameter and to check conditions (1) and (2) are determined by the following accuracy equations:

where is the nominal value of the resulting parameter X;

Systematic deviation of the resulting parameter X;

Standard deviation of the resulting parameter X;

and - values ​​of a standardized random variable, depending on the assumed probability of occurrence of values ​​of the resulting parameter below u.

The determination of the calculated limit values ​​of the resulting parameter according to statistical characteristics using equations 4 and 5 is carried out in accordance with the mandatory Appendix 4.

2.5. In most practical cases, the calculation of accuracy should be carried out according to tolerances by a simplified statistical method, the use of which makes it possible to ensure the complete assembly of the structure when using the acceptance control plans for the accuracy of the component parameters established by the current standards with an acceptance level of defectiveness of 4% according to GOST 23616-79.

In this case, the accuracy equations for determining the calculated limit values ​​of the resulting parameter take the form:

where is the nominal value of the resulting parameter;

Estimated deviation of the middle of the tolerance field of the resulting parameter;

Design tolerance of the resulting parameter.

2.6. Rated values ​​and design characteristics the accuracy of the resulting parameter with statistically independent component parameters is determined on the basis of the initial equation (3) according to the following formulas:

where are the nominal values ​​of the constituent parameters;

Deviations of the midpoints of the fields of technological tolerances of the constituent parameters;

Technological tolerances of the constituent parameters.

2.7. With a small number of component parameters (up to three) and the absence of data on the statistical characteristics of their distribution, the accuracy calculation can be performed using the “minimum-maximum” method in accordance with the mandatory Appendix 5.

3. PROCEDURE FOR CALCULATION OF ACCURACY

3.1. To calculate the accuracy in accordance with clause 2.2, the resulting geometric parameters are identified, the accuracy of which determines the provision of the functional requirements for the building structures of the building and structure, and in accordance with clause 1.3, the permissible limit values ​​​​of these parameters are determined.

In this case, those of the same type of repeating parameters are selected for calculation, the calculated accuracy characteristics of which can receive the largest absolute value.

3.2. For each of the selected resulting parameters, in accordance with the designed technology and the sequence of marking and assembly works, a base is established that serves as the beginning of a certain cycle of technological operations and is the beginning of the accumulation of errors that must be compensated by this parameter, the constituent parameters are identified and a calculation scheme and an initial equation are made .

3.3. For each calculation scheme, a calculation method is selected and accuracy equations are compiled, as well as equations for determining the nominal size and accuracy characteristics of the resulting parameter.

The accuracy characteristics of the constituent parameters resulting from the performance of a certain technological process or operation are taken on the basis of the requirements of the relevant standards or assigned according to GOST 21779-82. In cases where a constituent parameter is the result of several technological processes or operations, its accuracy characteristics should be determined by calculation.

When compiling equations for determining the accuracy characteristics of the resulting parameter, one should also take into account the own deviations of the component parameters that occur during the installation and operation of structures as a result of temperature and other external influences.

3.4. Depending on the type of problem, the accuracy equations are solved by trial calculations based on the condition for fulfilling requirements (1) and (2).

In the direct problem, based on the accepted accuracy characteristics and the nominal values ​​of the constituent parameters, the calculated nominal and limit values ​​of the resulting parameter are determined and the accuracy conditions are checked.

In the inverse problem, based on the accuracy conditions, the nominal values ​​and accuracy characteristics of some component parameters are determined by the allowable limit and nominal values ​​of the resulting parameter.

3.5. If, as a result of the calculation, it is established that with the accepted constructive solution, production technology and other initial data, the conditions of accuracy are not met, then, depending on the technical feasibility and economic feasibility, one of the following decisions should be made:

improve the accuracy of the constituent parameters that have the greatest impact on the accuracy of the resulting parameter, by introducing more advanced technological processes;

reduce the influence of the constituent parameters on the accuracy of the resulting parameter by reducing the number of these parameters in the design scheme by changing the orientation method (base) and the sequence of technological processes and operations;

to revise the design solutions for building structures of buildings, structures and their elements in order to change the allowable limit and nominal values ​​of the resulting parameter;

provide for incomplete assembly of structures.

ATTACHMENT 1

Reference

INFORMATION DATA ON COMPLIANCE WITH GOST 21780-83 ST SEV 3740-82

Complete collection - collection, the level of which is equal to or exceeds 99.73%.

Incomplete collection - collection, the level of which is below 99.73%.

Base - a surface or axis, relative to which the position of other surfaces or axes is determined.

APPENDEDANDE 3

MAIN TYPES OF RESULTING PARAMETERS

Note. When considering the parameters characterizing the position of the elements, it should be taken into account that, a are equal in absolute value and determine the maximum deviation of the elements relative to each other. The min and max indices are taken conditionally to indicate the direction of the offset.

APPENDIX 4

Mandatory

DETERMINATION OF THE CALCULATED LIMIT VALUES OF THE RESULTING PARAMETER FROM STATISTICAL CHARACTERISTICS

(general case of statistical accuracy calculation)

1. In the general case of statistical calculation of the accuracy of the structure and elements of buildings and structures, the calculated limit values ​​of the resulting parameter for checking conditions (1) and (2) are determined by formulas (4) and (5) of this standard.

2. The calculated nominal value of the resulting parameter based on the initial equation (3) is determined by the formula (8) of this standard, and the calculated accuracy characteristics and - by the formulas:

where - systematic deviations of the component parameters;

Root mean square deviations of the component parameters.

3. Characteristics and, depending on the initial data available for calculation, should be determined by the results of a statistical analysis of the accuracy of the relevant technological processes and operations in accordance with GOST 23615-79 or by the accuracy characteristics and control plans established in the relevant standards or other regulatory and technical documents.

4. For the transition from the characteristics of accuracy and control plans established in the standards and other normative and technical documents, the following expressions are used to the statistical characteristics of accuracy:

where is the deviation of the middle of the technological tolerance field of the component parameter;

Technological tolerance of the component parameter;

The value of a standardized random variable characterizing the acceptance level of defectiveness of the accuracy control plan for the component parameter according to GOST 23616-79.

5. The values ​​of the quantities: and in equations (4) and (5) of this standard, as well as the values ​​for each component parameter are determined from Table. 1 depending, respectively, on the level of collection and the acceptance level of defectiveness of the established plan for monitoring the accuracy of the component parameter taken in the calculation.

Table 1

6. The proportion of assembly work that needs to be done additional operations for the selection of elements or the fitting of individual parameters, they are determined separately for cases where and according to the table. 2.

table 2

APPENDEDANDE 5

Mandatory

DETERMINATION OF THE CALCULATED LIMIT VALUES OF THE RESULTING PARAMETER BY THE “MINIMUM-MAXIMUM” METHOD

The calculated limit values ​​and the resulting parameter under conditions (1) and (2) are determined by the “minimum-maximum” method using the formulas of this standard

where is the calculated nominal value of the resulting parameter X determined by formula (8) of this standard;

Estimated deviation of the middle of the tolerance field of the resulting parameter X, determined by the formula (9) of this standard;

Estimated tolerance value of the resulting parameter X.

The calculated tolerance value of the resulting parameter is determined taking into account the most unfavorable combination of deviations of the component parameters according to the formula compiled on the basis of the initial equation (3) of this standard

where is the tolerance of the component parameter;

Coefficient characterizing the geometric dependence of the resulting parameter on the constituent parameter.

SYSTEM FOR PROVIDING THE ACCURACY OF GEOMETRIC PARAMETERS IN CONSTRUCTION

(ST SEV 3740-82)

USSR STATE COMMITTEE FOR CONSTRUCTION

STATE STANDARD OF THE UNION OF THE SSR

Decree of the State Committee of the USSR for Construction of December 13, 1983 No. 320, the deadline for the introduction is set

This standard applies to the design of buildings, structures and their elements and establishes general provisions, methodological principles and the procedure for calculating the accuracy of geometric parameters in construction.

On the basis of this standard, methodological documents are developed that establish the features of calculating the accuracy of the geometric parameters of structures of various types.

The standard complies with ST SEV 3740-82 in the part specified in reference Appendix 1.

The terms used in this standard and explanations are given in the mandatory annex 2.

1. BASIC CONCEPTS

1.1. The calculation of the accuracy of geometric parameters should be carried out in the process of designing typical, experimental and individual structures of buildings and structures and their elements in order to ensure the assembly of structures with specified operational properties at the lowest cost.

1.2. Accuracy is calculated based on:

functional requirements for building structures of buildings and structures;

data on the accuracy of the applied technological processes and operations for the manufacture of elements, breakdown of axes and assembly of structures.

1.3. In the process of calculating the accuracy in accordance with the accepted design scheme, according to the accuracy characteristics of the constituent geometric parameters, the calculated limit values ​​​​of the resulting parameter are determined, which are then compared with the permissible limit values ​​\u200b\u200bof this parameter established on the basis of functional requirements (by calculating the strength and stability, in accordance with the test results or based on insulating, aesthetic and other requirements).

1.4. Compliance of the accuracy of the resulting parameter with the functional requirements is ensured if the following conditions are met:

where and are the calculated limit values ​​of the resulting parameter x;

and - allowable limit values ​​of the resulting parameter x. The difference is the functional tolerance.

1.5. The task of calculating the accuracy can be:

direct, when the calculated limit values ​​of the resulting parameter are determined by the known characteristics of the accuracy of the constituent parameters (test calculation);

the reverse, when the necessary requirements for the accuracy of the constituent parameters are determined from the established permissible limit values ​​of the resulting parameter.

1.6. According to the accuracy calculation results:

in the regulatory and technical documentation for the building structures of buildings, structures and their elements and in the working drawings, they specify, if necessary, the nominal values ​​\u200b\u200bof the resulting and constituent parameters, establish the requirements for the accuracy of these parameters and the rules for controlling accuracy;

in the technological documentation for the manufacture of elements, the breakdown of axes and the production of construction and installation works, they establish the methods and sequence of performing technological processes and operations, methods and means of ensuring their accuracy.

2. METHODOLOGICAL PRINCIPLES FOR CALCULATION OF ACCURACY

2.1. The solutions adopted as a result of calculating the accuracy should ensure minimal labor and material costs in the construction of building structures of buildings and structures and the manufacture of their elements.

To this end, it is necessary to provide for the maximum possible tolerance values, as well as constructive and technological measures to reduce the influence of the accuracy of technological processes and operations on the accuracy of the resulting parameters.

2.2. The calculation of accuracy should be made, as a rule, from the condition of complete assembly of structures.

In some cases, with technical feasibility and economic feasibility, incomplete collection may be provided. In this case, for cases where the actual values ​​of the resulting parameter will go beyond, additional operations should be provided for the selection of elements or the fitting of individual dimensions.

2.3. The initial equation for calculating the accuracy is equation (3), which expresses the relationship between the resulting and constituent parameters included in the calculation scheme:

where is the resulting parameter;

Component parameter;

The number of component parameters in the design scheme;

Coefficient characterizing the geometric dependence of the resulting parameter x on the component parameter xk.

As the resulting parameters in the preparation of design schemes, as a rule, the dimensions in the junction nodes of the elements and other dimensions are considered, which, with the accepted sequence of assembly of the structure, complete a certain cycle of technological operations that determine the accuracy of the component parameters, and in which the errors of these operations are compensated (recommended Appendix 3 ).

The dimensions of the elements, the dimensions that determine the distances between the axes, elevation marks and other landmarks, as well as other parameters obtained as a result of the specified technological operations, the accuracy of which affects the accuracy of the resulting parameter, are considered as constituent parameters.

If the constituent geometric parameters are statistically dependent, then this dependence must be taken into account when determining the calculated characteristics of the accuracy of the resulting parameter. Statistical dependence can be characterized by a correlation coefficient.

2.4. Accuracy is calculated based on statistical methods. In the general case, in the statistical calculation, the calculated limit values ​​of the resulting parameter and to check the conditions (1) and (2) are determined by the following accuracy equations

where is the nominal value of the resulting parameter x;

Systematic deviation of the resulting parameter x;

The standard deviation of the resulting parameter x;

and - values ​​of a standardized random variable, depending on the assumed probability of occurrence of values ​​of the resulting parameter below u.

The determination of the calculated limit values ​​of the resulting parameter according to statistical characteristics using equations 4 and 5 is carried out in accordance with the mandatory Appendix 4.

2.5. In most practical cases, the calculation of accuracy should be carried out according to tolerances by a simplified statistical method, the use of which makes it possible to ensure the complete assembly of the structure when using the acceptance control plans for the accuracy of the component parameters established by the current standards with an acceptance level of defectiveness of 4% according to GOST 23616-79.

In this case, the accuracy equations for determining the calculated limit values ​​of the resulting parameter take the form:

where is the nominal value of the resulting parameter;

Estimated deviation of the middle of the tolerance field of the resulting parameter;

Design tolerance of the resulting parameter.

2.6. The nominal values ​​and calculated characteristics of the accuracy of the resulting parameter with statistically independent component parameters are determined on the basis of the initial equation (3) according to the following formulas:

where are the nominal values ​​of the constituent parameters;

Deviations of the midpoints of the fields of technological tolerances of the constituent parameters;

Technological tolerances of the constituent parameters.

2.7. With a small number of component parameters (up to three) and the absence of data on the statistical characteristics of their distribution, the accuracy calculation can be performed using the “minimum-maximum” method in accordance with the mandatory Appendix 5.

3. PROCEDURE FOR CALCULATION OF ACCURACY

3.1. To calculate the accuracy in accordance with clause 2.2, the resulting geometric parameters are identified, the accuracy of which determines the provision of the functional requirements for the building structures of the building and structure, and in accordance with clause 1.3, the permissible limit values ​​​​of these parameters are determined.

In this case, those of the same type of repeating parameters are selected for calculation, the calculated accuracy characteristics of which can receive the largest absolute value.

3.2. For each of the selected resulting parameters, in accordance with the designed technology and the sequence of marking and assembly works, a base is established that serves as the beginning of a certain cycle of technological operations and is the beginning of the accumulation of errors that must be compensated by this parameter, the constituent parameters are identified and a calculation scheme and an initial equation are made .

3.3. For each calculation scheme, a calculation method is selected and accuracy equations are compiled, as well as equations for determining the nominal size and accuracy characteristics of the resulting parameter.

The accuracy characteristics of the constituent parameters resulting from the performance of a certain technological process or operation are taken on the basis of the requirements of the relevant standards or assigned according to. In cases where a constituent parameter is the result of several technological processes or operations, its accuracy characteristics should be determined by calculation.

When compiling equations for determining the accuracy characteristics of the resulting parameter, one should also take into account the own deviations of the component parameters that occur during the installation and operation of structures as a result of temperature and other external influences.

3.4. Depending on the type of problem, the accuracy equations are solved by trial calculations based on the condition for fulfilling requirements (1) and (2).

In the direct problem, based on the accepted accuracy characteristics and the nominal values ​​of the constituent parameters, the calculated nominal and limit values ​​of the resulting parameter are determined and the accuracy conditions are checked.

In the inverse problem, based on the accuracy conditions, the nominal values ​​and accuracy characteristics of some component parameters are determined by the allowable limit and nominal values ​​of the resulting parameter.

3.5. If, as a result of the calculation, it is established that with the adopted design solution, production technology and other initial data, the accuracy conditions are not met, then, depending on the technical feasibility and economic feasibility, one of the following decisions should be made:

improve the accuracy of the constituent parameters that have the greatest impact on the accuracy of the resulting parameter, by introducing more advanced technological processes;

reduce the influence of the constituent parameters on the accuracy of the resulting parameter by reducing the number of these parameters in the design scheme by changing the orientation method (base) and the sequence of technological processes and operations;

STATE STANDARD OF THE UNION OF THE SSR

SYSTEM FOR PROVIDING THE ACCURACY OF GEOMETRIC
PARAMETERS IN CONSTRUCTION

Key points

GOST 21778-81

(ST SEV 2045-79)

USSR STATE COMMITTEE
CONSTRUCTION

Moscow

DEVELOPED

Central Order of the Red Banner of Labor Research and Design Institute for Standard and Experimental Design of Dwellings (TsNIIEPzhilishcha) of Gosgrazhdanstroy under Gosstroy of the USSR

Central Research Institute for Standard and Experimental Design of Schools, Preschools, Secondary and Higher Schools educational institutions(TsNIIEP of educational buildings) Gosgrazhdanstroy under Gosstroy of the USSR.

Central Research and Design and Experimental Institute for Organization, Mechanization and Technical Assistance to Construction (TsNIIOMTP) of the State Construction Committee of the USSR

Zonal Research and Design Institute for Standard and Experimental Design of Residential and Public Buildings (LenZNIIEP) of Gosgrazhdanstroy under Gosstroy of the USSR

PERFORMERS

S.A. Reznik, cand. tech. sciences (topic leader); A.V. Tsaregradsky; L.A. Wasserdam; L.S. Exler; D.M. Lakovsky; I.V. Kolechitskaya; V.N. Sverdlov, cand. tech. sciences; R.A. Kagramanov, Ph.D. sciences; M.S. Kardakov; L.N. Kovalis

INTRODUCED by the Central Order of the Red Banner of Labor by the Research and Design Institute for Standard and Experimental Design of Dwellings (TsNIIEPzhilishcha) of Gosgrazhdanstroy under Gosstroy of the USSR

Director B.R. Rubanenko

APPROVED AND INTRODUCED BY Decree of the State Committee of the USSR for Construction of December 2, 1980 No. 184

STATE STANDARD OF THE UNION OF THE SSR

Decree of the State Committee of the USSR for Construction of December 2, 1980 No. 184, the deadline for the introduction is set

from 01.07.1981

This standard applies to the design and construction of buildings and structures, as well as to the design and manufacture of building structures, parts and products for them and establishes the main characteristics of accuracy and the main provisions for the purpose, technological support, control and assessment of the accuracy of geometric parameters that ensure compliance with functional requirements to buildings, structures and their individual elements at all stages of building design and production.

The main provisions established by this standard are developed by a set of standards for the System for ensuring the accuracy of geometric parameters in construction.

In accordance with the requirements of the System standards, newly developed and revised standards and other regulatory and technical documents for specific elements and structures of buildings and structures, working drawings and technological documentation establish requirements for the accuracy of structures, their elements and performance of work, as well as methods and means of technological support and accuracy control.

The terms used in the standard and their definitions are given in Appendix 1.

The standard complies with ST SEV 2045-79 in the part specified in Appendix 2.

1 . ACCURACY CHARACTERISTICS

Estimated systematic deviation d mx with a normal distribution of the geometric parameter is the sample mean deviation d mx, i.e. the average value of deviations in the sample, determined by the formula

If the mean value mx parameter practically does not differ from its nominal value x nom, then the relationship between the accuracy characteristics is characterized by the formulas:

Characteristics of the accuracy of a geometric parameter with a normal distribution

2 . PURPOSE OF ACCURACY

2.1 . The accuracy of geometric parameters at all stages of building design and production should be established depending on the functional, structural, technological and economic requirements for buildings, structures and their individual elements.

2.2 . Compliance of the assigned accuracy with functional, structural, technological and economic requirements is established by calculating the accuracy in accordance with GOST 21780-83 or other methods.

2.3 . The accuracy of geometrical parameters should be established by means of the accuracy characteristics given in clause 1.3 . Preferred characteristics are limit deviations relative to the nominal value of the parameter X, accepted as a rule (atd x c= 0), equal in absolute value to half the value of the corresponding functional or technological tolerance, taken in the accuracy calculation.

Note . In justified cases, if it is necessary to partially compensate for the systematic errors of technological processes and operations that increase with time, the limit deviations should be set as asymmetric (d x s¹ 0).

2.4 . Functional tolerances regulate the accuracy of geometric parameters in mates and the accuracy of the position of elements in structures.

The range of functional tolerances is established by GOST 21780-83, and their specific values ​​​​are determined by the formula (4), in which xmin And xmax or d x inf And d x sup are taken on the basis of functional (strength, insulation or aesthetic) requirements for structures.

2.5 . Technological tolerances regulate the accuracy of technological processes and operations for the manufacture and installation of elements, as well as the performance of marking work.

Tolerance values ​​in millimeters or angular values ​​must correspond to the numerical series:

1 ; 1.6; 2.4; 4; 6; 10 or

1 ; 1,2; 1,6; 2; 2,4; 3; 4; 5; 6; 8; 10.

Each number in the series can be increased or decreased by multiplying it by ten with an exponent equal to an integer.

The nomenclature and specific values ​​​​of technological tolerances for accuracy classes of processes and operations should be taken in accordance with GOST 21779-82.

Accuracy classes are selected when performing accuracy calculations depending on the means of technological support and accuracy control and production capabilities adopted (see clause 4.5).

3 . TECHNOLOGICAL SUPPORT OF PRECISION

3.1 . When designing buildings, structures and their individual elements, developing technology for manufacturing elements and erecting buildings and structures, it is necessary to provide, and in production - to apply the necessary tools and rules for technological accuracy assurance.

3.2 . The technology for manufacturing elements and erecting buildings and structures must comply with the conditions adopted when assigning accuracy.

3.3 . Technological processes and operations must contain as an integral part the control of the established accuracy (input, operational and acceptance).

3.4 . Depending on the results of the operational control of accuracy, in order to prevent marriage, it is necessary to regulate technological processes and operations according to the tolerances for setting up equipment established in the technological documentation.

3.5 . The accuracy of the geometric parameters of buildings, structures and their individual elements is considered to be ensured if it is established that the actual values ​​of these parameters comply with the regulatory and design requirements.

4 . CONTROL AND EVALUATION OF ACCURACY

4.1 . The accuracy of geometric parameters is controlled by determining their actual values, as well as accuracy characteristics and comparing them with the requirements established in the regulatory and technical documentation.

4.2 . Depending on the tasks of control, the type of controlled products or operations, as well as the volume of production, accuracy control is set to be continuous or selective.

4.3 . Control rules, including the geometric parameters selected for control, means, methods, conditions and number of measurements, as well as the rules for processing their results, should ensure the necessary accuracy and comparability of the results of determining the actual values ​​of the parameters and be established in standards and other normative and technical documentation along with the values ​​of the accuracy characteristics.

4.4 . Geometric accuracy should be controlled in accordance with GOST 23616-79.

4.5 . The assessment of the accuracy of a geometric parameter in the aggregate of its actual values, which can be provided by a certain technological process or operation, in order to classify the process or operation to the appropriate accuracy class, is performed based on the results of control and statistical analysis of accuracy according to GOST 23615-79.

ATTACHMENT 1

Mandatory

TERMS AND DEFINITIONS

Assembly of structures is a property of independently manufactured elements to ensure the possibility of assembling structures of buildings and structures from them with the accuracy of their geometric parameters corresponding to the operational requirements for structures. The quantitative characteristic of the collection is the level of collection, which is estimated by the proportion of assembly work performed without additional operations for the selection, fitting or regulation of the parameters of the elements

Interchangeability of elements - in the system for ensuring the accuracy of geometric parameters in construction - the property of independently manufactured identical elements to provide the possibility of using one of them instead of the other without additional processing at a given level of assembly of structures. The interchangeability of elements is achieved by observing uniform requirements for the accuracy of their geometric parameters.

Accuracy of a geometric parameter - the degree of approximation of the actual value of a geometric parameter to its nominal value

Geometric parameter - linear or angular value

Size - the numerical value of a linear quantity in the selected units of measurement

Nominal value of a geometric parameter (nominal size for a linear value) - the value of a geometric parameter specified in the project and which is the starting point for deviations

The actual value of the geometric parameter (actual size) - the value of the geometric parameter, set as a result of measurement with a certain accuracy

Limit values ​​of a geometric parameter (limit dimensions) - values ​​of a geometric parameter, between which its real values ​​\u200b\u200bshould be located with a certain probability

Tolerance - the absolute value of the difference between the limit values ​​of a geometric parameter

Tolerance field - a set of values ​​of a geometric parameter, limited by its limit values

Actual deviation of a geometric parameter (actual size deviation) - algebraic difference between the actual and nominal values ​​of a geometric parameter

Systematic deviation of a geometric parameter (systematic deviation of size) - the difference between the average and nominal values ​​of a geometric parameter

Limit deviation of a geometric parameter (limit deviation of size) - algebraic difference between the limit and nominal values ​​of a geometric parameter

Upper limit deviation of a geometric parameter (upper limit deviation of size) - algebraic difference between the maximum limit and nominal values ​​of a geometric parameter

Lower limit deviation of a geometric parameter (lower limit deviation of size) - algebraic difference between the smallest limit and nominal values ​​of a geometric parameter

Deviation of the middle of the tolerance field - the algebraic difference between the middle of the tolerance field and the nominal value of the geometric parameter

Functional tolerance - the tolerance of a geometric parameter that establishes the accuracy of the assembled structure from the condition of ensuring the functional requirements imposed on it

Technological tolerance - the tolerance of a geometric parameter that establishes the accuracy of the execution of the corresponding technological process or operation

Accuracy class - a set of values ​​of technological tolerances, depending on the nominal values ​​of geometric parameters.

Each accuracy class contains a number of tolerances corresponding to the same degree of accuracy for all nominal values ​​of a given geometric parameter.

Note . In the standards of some CMEA member countries, instead of the term "Nominal value of a geometric parameter", the term "Basic value of a geometric parameter" is used.

APPENDIX 2

Reference

INFORMATION DATA ON COMPLIANCE WITH GOST 21778-81 and ST SEV 2045-79

The fourth paragraph of the introductory part of GOST 21778-81 corresponds to the introductory part of ST SEV 2045-79.

Clause 1.1 of GOST 21778-81 includes the requirements of clause 1.1 of ST SEV 2045-79.

Heck. 1 GOST 21778-81 corresponds to hell. 1 ST SEV 2045-79.

Clause 1.2 of GOST 21778-81 includes the requirements of clause 1.2 of ST SEV 2045-79.

Clause 1.3 of GOST 21778-81 includes the requirements of clause 1.3 of ST SEV 2045-79

Clause 1.4 of GOST 21778-81 includes the requirements of clause 1.4 of ST SEV 2045-79.

Clause 1.5 of GOST 21778-81 corresponds to clause 1.5 of ST SEV 2045-79.

Clause 1.6 of GOST 21778-81 includes the requirements of clause 1.6 of ST SEV 2045-79.

Clause 1.7 of GOST 21778-81 includes the requirements of clause 1.7 of ST SEV 2045-79.

Heck. 2 GOST 21778-81 corresponds to hell. 2 ST SEV 2045-79.

Clause 2.1 of GOST 21778-81 corresponds to clause 2.1 of ST SEV 2045-79.

Clause 2.2 of GOST 21778-81 includes the requirements of clause 2.2 of ST SEV 2045-79.

Clause 2.3 of GOST 21778-81 includes the requirements of clause 2.3 of ST SEV 2045-79.

Clause 2.5 of GOST 21778-81 includes the requirements of clause 2.4 of ST SEV 2045-79.

Chapter 3 GOST 21778-81 corresponds to section 3 of ST SEV 2045-79.

Clause 4.1 of GOST 21778-81 corresponds to clause 4.1 of ST SEV 2045-79.

Clause 4.2 of GOST 21778-81 corresponds to clause 4.2 of ST SEV 2045-79.

Clause 4.3 of GOST 21778-81 includes the requirements of clauses. 4.3 and 4.4 ST SEV 2045-79.

Mandatory Appendix 1 GOST 21778-81 includes information Appendix 1 ST SEV 2045-79.

The note to the mandatory Appendix 1 of GOST 21778-81 includes these notes to clause 1.2 of ST SEV 2045-79.

Standardization. GOST 23616-79: System for ensuring the accuracy of geometric parameters in construction. Accuracy control. OKS: General provisions. Terminology. Standardization. Documentation, Technical drawings. GOSTs. The system for ensuring the accuracy of geometric.... class=text>

GOST 23616-79

System for ensuring the accuracy of geometric parameters in construction. Accuracy control

GOST 23616-79
Group G02

INTERSTATE STANDARD

System for ensuring the accuracy of geometric parameters in construction
ACCURACY CONTROL
System for ensuring the accuracy of geometrical parameters in construction. Control of accuracy

ISS 01.100.30
91.010.30

Introduction date 1980-01-01

Decree of the State Committee of the USSR for Construction Affairs dated April 12, 1979 N 55, the date of introduction was set to 01.01.80
EDITION (April 2003) with Amendment No. 1 approved in May 1984 (IUS 9-84).

This standard applies to the construction of buildings and structures, the manufacture of elements for them (structures, products, parts) and establishes the basic rules and methods for controlling the accuracy of geometric parameters.
The rules for controlling the accuracy of the geometric parameters of specific types of structures of buildings and structures and their elements, as well as the work performed, are prescribed on the basis of this standard in the relevant standards or in other regulatory and technical, as well as technological documents.
The terms used in the standard for statistical control correspond to those given in GOST 15895-77*.
________________
* On the territory of the Russian Federation, GOST R 50779.10-2000, GOST R 50779.11-2000 apply.

The standard complies with ST SEV 4234-83 (see Appendix 1a).

1. GENERAL PROVISIONS

1. GENERAL PROVISIONS

1.1. Control of the accuracy of geometric parameters is mandatory integral part quality control and is carried out by comparing the actual values ​​of the parameters or characteristics of accuracy with the established ones.

1.2. In the production process at enterprises and construction organizations, input, operational and acceptance control of accuracy should be carried out.

1.3. Accuracy control should provide:
determination with a given probability of compliance of the accuracy of geometric parameters with the requirements of normative-technical, technological and project documentation for the objects of control;
obtaining the necessary information for assessing and regulating the accuracy of technological processes.
(Changed edition, Rev. N 1).

1.4. The following are subject to accuracy control:
geometric parameters of the elements and parameters that determine the position of the landmarks of the alignment axes and landmarks for the installation of elements, as well as the position of the elements in the structures (the range of tolerances for these parameters is given in GOST 21779-82 and GOST 21780-83);
geometric parameters of technological equipment, molds and tooling that affect the accuracy of manufacturing elements and their installation in structures and specified in the relevant technological documents.

1.5. Accuracy control rules are established depending on the nature of the control object and controlled parameters, production volumes and the stability of technological processes, taking into account the cost and required control reliability.

1.6. Standards and other regulatory and technical documents that establish control rules should define:
controlled parameters;
applied method of control;
control plan and procedure for its implementation;
means of control, implementation rules and requirements for measurement accuracy;
method for evaluating the results of control.

1.4-1.6. (Changed edition, Rev. N 1).

1.7. Enterprises and construction organizations should develop enterprise standards, control charts and checklists and other technological documents for control processes and operations that determine for specific control objects the placement of control posts for the technological process, performers, the scope and content of control work, methods and measurement schemes , rules for the collection, processing and use of information on the results of control.

1.8. Normative-technical and technological documents that establish the rules for monitoring accuracy must undergo a metrological examination in accordance with the requirements of the standards of the State System for Ensuring the Uniformity of Measurements.

2. PURPOSE OF CONTROL METHODS

2.1. Accuracy control is assigned mainly selective by alternative or quantitative criteria, and, if necessary, continuous.

2.2. Continuous control should be assigned:
at small volumes of production, when selective control is not feasible;
with the unstable nature of production, including during the adjustment of technological processes;
with increased requirements for ensuring a given accuracy, associated with the need to use large-volume samples.

2.3. Sampling control should be appointed with an established stable production, when the statistical homogeneity of the technological process is ensured.

2.4. In the sampling method, attribute control should preferably be used.
Quantitative control is used for the most critical parameters, when their number is small and there is a need for further development of the process, and also if, according to production conditions, it is advisable to reduce the sample size compared to control on an alternative attribute. This method is applicable when the controlled parameters are independent of each other and have a normal distribution.
If necessary, some of the parameters can be controlled by a quantitative attribute, and some - by an alternative.

2.5. Inspection control should be carried out using the methods established in the relevant regulatory and technical documents for acceptance control.

2.6. Types, methods and objects of control by production stages are given in Appendix 1.

3. TOTAL CONTROL

3.1. With continuous control, the accuracy of this geometric parameter is checked in each control object (unit of production).

3.2. Control is carried out as the relevant technological operations are completed or the finished product is released, or after the formation of batches of products or the completion of a certain amount of construction and installation work.

3.3. The control standards for continuous control are the upper and lower limit deviations from the nominal dimensions or from the nominal position of a reference point, a point on a straight line or a plane, which determine the requirements for the accuracy of the controlled parameter.
In some cases, the control standards may be the largest or smallest limit sizes.

3.4. To determine the correspondence of geometric parameters to control standards, according to established measurement rules, actual deviations or actual dimensions are found.

3.5. The object of control is considered suitable for this controlled parameter, if one of the following conditions:

; (1)
. (2)

3.6. In order to reduce the complexity of control, verification of compliance with conditions (1) and (2) can be carried out without determining quantitative values ​​and using limit gauges or templates.

3.3-3.6. (Changed edition, Rev. N 1).

4. SAMPLE CONTROL

4.1. During selective control, the accuracy of this geometric parameter is checked by established plan control in a sample consisting of a certain number of control objects (product units) in the total volume of a batch (in a stream) of products or in the volume of work performed.
The possibility of using effective selective control is established on the basis of the results of a statistical analysis of accuracy in accordance with GOST 23615-79.

4.2. For control, random samples are formed in accordance with the requirements of GOST 18321-73.
When controlling the accuracy of layout work and installation of elements, a sample is made up of a certain number of landmarks fixed in nature or installed elements from their total number, which is included in the volume of construction and installation work taken as a batch.

4.3. In the control by an alternative attribute, the control standards are the maximum deviations and (or and ) and acceptance and rejection numbers and , characterizing the maximum number of defective units in the sample.
A single-stage or two-stage control method can be adopted, which are equivalent in the resulting assessment.
At the same time, control plans are set in accordance with Appendix 2, depending on the production conditions and the acceptance level of defectiveness adopted for this controlled parameter, taking into account Appendix 3.
In justified cases, it is allowed to use other control plans in accordance with GOST 18242-72*.
________________
* Within the territory of Russian Federation GOST R 50779.71-99 applies (hereinafter).

(Changed edition, Rev. N 1).

4.4. When controlling by an alternative attribute, the number of defective control objects (product units) in the sample is determined by its continuous control in accordance with Section 3.

4.5. The batch is accepted if the number of defective test items in the sample is less than or equal to the acceptance number , and is not accepted if this number is greater than or equal to the rejection number .
With two-stage control, in cases where the number of defective control objects in the sample is greater and less, the second sample is taken. If the total number of defective units in two samples is less than or equal to the acceptance number, the lot is accepted; if it is greater than or equal to the rejection number, it is not accepted.
(Changed edition, Rev. N 1).

4.6. When monitoring by quantitative characteristics, the control standards are , and tabular coefficients that characterize the ratio between the actual and standard accuracy characteristics that is acceptable for a given control plan.
The rules for control by quantitative sign are assigned in accordance with GOST 20736-75*.
________________
* On the territory of the Russian Federation, GOST R 50779.74-99 applies (hereinafter).

4.7. Deviation during random inspection of a lot can be presented for complete inspection.

5. METHODS AND INSTRUMENTS OF MEASUREMENTS

5.1. The methods and measuring instruments used for accuracy control should provide the necessary accuracy and reliability of these measurements and be assigned in accordance with the characteristics of the object of control and the controlled parameter, taking into account their labor intensity and cost.

5.2. The accuracy of control measurements must comply with the condition

Limit value of absolute measurement error;
- tolerance of the controlled parameter.
(Changed edition, Rev. N 1).

5.3. When calculating the limiting values ​​of errors, random and unavoidable systematic errors of the method and measuring instruments are taken into account.

5.4. The method for taking into account the additional risk of incorrect assessment of the results of control caused by measurement errors is given in Appendix 4.
(Changed edition, Rev. N 1).

5.5, 5.6. (Excluded, Rev. N 1).

5.7. The means used, as well as measurement methods, must be certified by the state or departmental metrological service in accordance with the requirements of the standards of the State System for Ensuring the Uniformity of Measurements.

APPENDIX 1 (recommended). TYPES, METHODS AND OBJECTS OF CONTROL BY THE STAGES OF PRODUCTION

APPENDIX 1. (Changed edition, Rev. N 1).

APPENDIX 1a (informative). Information data on compliance with GOST 23616-79 ST SEV 4234-83

APPENDIX 1a
Reference

APPENDIX 2 (recommended). SAMPLING PLANS FOR ATTRACT

1 One step control

Notes:

That part of the plan, including the sample size, which is located under the arrow, is applied.

The part of the plan, including the sample size, above the arrow is applied.

3. The acceptance number is on the left, the rejection number is on the right.

2 Two-stage control

Notes:

1. - applies that part of the plan, including the sample size, which is located under the arrow.

2. - applies that part of the plan, including the sample size, which is located above the arrow.

3. Acceptance numbers , are on the left, and rejection numbers and are on the right.

APPENDICES 2, 3. (Changed edition, Rev. N 1).

APPENDIX 4 (informative). METHOD FOR ACCOUNTING FOR THE ADDITIONAL RISK OF INCORRECT EVALUATION OF THE INSPECTION RESULTS CAUSED BY MEASUREMENT ERROR

APPENDIX 4
Reference

1. When assigning accuracy and choosing measuring instruments, it should be taken into account that measurement errors increase the risk of incorrect assessment of control results. At the same time, the probability of rejecting a suitable object of control or accepting a defective one as suitable increases.

2. If it is necessary to maintain the standard values ​​of the specified risk, adopted in the control plans in accordance with GOST 18242-72 and GOST 20736-75, when assigning sampling plans, the sample size can be increased.
The table shows the values ​​of the increased sample size calculated for the normal distribution law of the controlled parameter and the measurement error by the formula

where is the sample size according to the control plan;
- standard deviation of the measured geometric parameter;
- root-mean-square error of measurements.

Criteria for evaluating the results of control for an increased sample size are adopted according to the control plan for the sample.