**************** Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. Mazdoor Kisan Shakti Sangathan "The Right to Information, The Right to Live'' IS 10790-1 (1984) : Methods of sampling of steel for prestressed and reinforced concrete. Part 1: Prestressing steel [CED 54: Concrete Reinforcement] Jawaharlal Nehru 'Step Out From the Old to the New" aj^&vi iJii^s:y%K^ isb^^ni^seg :<>5&i| mT'5K^5?::5:^>^i»l K^^^iXSVCd^ Satyanarayan Gangaram Pitroda Invent a New India Using Knowledge Bhartrhari — Nitisatakam ''Knowledge is such a treasure which cannot be stolen" ^'^^^r k BLANK PAGE ^*-^^^ PROTECTED BY COPYRIGHT IS 110790 ( Parti J -1984 ( Reaffirmed 2005 ) Indian Standard METHODS OF SAMPLING OF STEEL FOR PRESTRESSED AND REINFORCED CONCRETE PARTI PReSTBESSINQ STEEL UDC 666 982*4 : fl69-l4'018'2?5'5 : 62fl 1 i3 ® Copjrighi 1984 INDIAN STANDAHI>S INSTITUTION MANAK RHAVAH, * BAHADUR SHAH 2 A FAR MARCj IS : 107iM) ( Part 1 ) - 1984 Indian Standard METHODS OF SAMPLING OF STEEL FOR PRESTRESSED AND REINFORCED CONCRETE PART 1 PRESTRESSING STEEL Building Materials and Components Sampling Sectional Committee, BDC 31 Chairman Representing Dr Mohan Rai Central Building Research Institute (CSIR), Roorkee Members Shri S. K. Goswami ( Alternate to Dr Mohan Rai ) Shri S. K. Banerjee National Test House, Calcutta Shri Bimlesh Kumar Export inspection Council of India, New Delhi Shri J. P. Maikhuri ( Alternate ) Shri Y. C. Gokhale Central Road Research Institute ( CSIR ), New Delhi Shri P. S. Gopinath Central Public Works Department, New Delhi Surveyor of Works ( NZ ) ( Alternate ) Shri S. C. Kumar Small Industries Service Institute, Trichur Shri K. V. K. Raju ( Alternate ) Shri M. V. Lakshmanaswamy Indian Statistical Institute, Bombay Dr a. G. Majdhava Rao Structural Engineering Research Centre ( CSIR ), Madras Shri D. S. Ramachandra Murthy ( Alternate ) Shri S. M. Mittal Railway Board ( Ministry of Railways ), New Delhi Deputy Director Research (B &S )-I {Alternate) Shri S. S. Rajput Forest Research Institute and Colleges, Dehra Dun Shri K. S. Srinivasan National Buildings Organization, New Delhi Shri T. R. Bhatia ( Alternate ) Dr V. V. SuBBA Rao Cement Research Institute of India, New Delhi Shri K. H. Babu ( Alternate ) Shri G. Venkatesulu Ministry of Shipping and Transport, New Delhi Shri Prafulla Kumar ( Alternate ) Shri D. S. Ahluwalia, Director General, ISI ( Ex-officio Member ) Director ( Statistics ) Secretary Shri A. K. Talwar Deputy Director ( Statistics ), ISI ( Continued on page 2 ) (§) Copyright 1984 INDIAN STANDARDS INSTITUTION This publication is protected under the Indian Copyright Act (XIV of 1957) and reproduction in whole or in part by any means except with written permission of the publisher shall be deemed to be an infringement of copyright under the said Act. IS: 10790 (Part 1)*19S4 ( Continued from page 1 ) Building Steels and Steel Products Sampling Subcommittee, BDC 31 : 1 Members Representing Shri M. G. Shade The Tata Iron and Steel Co Ltd, Jamshedpur Shri S. a. Haque ( Alternate ) Shri M. R. Doctor Special Steels Ltd, Bombay Shri S. G. Joshi ( Alternate ) Shri S. K. Goswami Central Building Research Institute ( CSIR ), Roorkee Shri G. K. Majumdar Hindustan Prefab Ltd, New Delhi Shri M. Kundu ( Alternate ) Shri P. R. Natarajan Structural Engineering Research Centre ( CSIR ), Madras Shri N. Jayaram ( Alternate ) Dr N. Raghvendra Cement Research Institute of India, New Delhi Shri H. K. Julka ( Alternate ) Shri H. N Subha Rao Hindustan Steel Works Construction Ltd, Calcutta ShRI J- Ghatak ( Alternate ) IS : 10790 ( Part 1 )- 1$84 Indian Standard METHODS OF SAMPLING OF STEEL FOR PRESTRESSED AND REINFORCED CONCRETE PARTI PRESTRESSIIMG STEEL 0. FOREWORD 0.1 This Indian Standard ( Part 1 ) was adopted by the Indian Standards Institution on 19 March 1984, after the draft finalized by the Building Materials and Components Sampling Sectional Committee had been approved by the Civil Engineermg Division Council. 0.2 This Indian Standard has been prepared with a view to unifying the quality control and sampling provisions applicable to all types of prestressing steel used in prestressed concrete. Some broad guidelines regarding the provisions for process control have also been indicated besides giving an objective sampling procedure helpful in large scale transactions. 0.3 Such process control and sampling procedures will help in the development of adequate quality assurance system in the manufacture and also in assuring adequate protection to the users against poor quality. Further, proper quality control during the process of manufacture would substantially reduce quality fluctuations of the various characteristics and thus, ensure supply of uniform quality of prestressing steels. For effective process control, the use of statistical quality control techniques is imperative, for which helpful guidance may be obtained from IS : 397 (Parti )-1972*, IS : 397 ( Part 2 )- 1975* and IS ; 397 ( Part 3 )-I980*. The purchasing organizations need guidance in economic and effective sampling inspection of the lots of materials being received by them to evaluate their quality before their actual use. The sampling procedures recommended in this standard, therefore, include provisions both for process control and lot inspection. 0.4 The reinforcing steel used in reinforced concrete is separately covered in Part 2 of this standard. 0.5 Itt reporting the results of test or analysis, if the final \alue, observed j:)t .caJoulated,. is to be rounded off, it*shdi-be done in accordance with 4a:>l960t^ ,\ 'y* '*Meth63 jpbf ^btisiical quality contp^ Pari 1 Coiitfbl charts fofvariafcles jJ^rj/V^v/^/o/i ). ' * • Part 2 Coiittdl charts for attlribUtes arid cotiiif c)f defeats (^/*j/ revision ); ■ Part 3 Special control chdftsr - ■- . - - titules for rounding off numerical Values ( revised ). IS: 10790 (Parti) -1984 1. SCOPE 1,1 This standard ( Part 1 ) prescribes the methods for sampling, sample sizes and the criteria for cx)nformity for prestressing steel used in prestres- sed concrete. Broad outlines with regard to the controls to be exercised during the manufacturing process have also been indicated. 2. TERMINOLOGY 2*0 For the purpose of this standard, the following definitions shall apply. 2.1 Acceptance Number — The maximum allowable number of defectives in the sample for acceptance of the lot. 2.2 Coll — One continuous length in the form of a coiL 2.3 Bar — A rolled rod or bar of steel of circular cross section. 2.4 Item — A coil or a bar on which inspection will be performed. 2.5 Lot — The quantity of material of the same grade and nominal size manufactured from steel fully tested in respect of physical, chemical and surface characteristics and processed under similar conditions shall constitute a lot. 2.6 Lot Size — The number of items in a lot. 2.7 Mean (J) — The sum of test results divided by the number of test results. 2.8 Ran^e (R) — The difference between the maximum and minimum values of test results in the sample. 2.9 Sample — Collection of coils or bars of prestressed steel selected for inspection and testing from a lot. 2.10 Sample Size — Number of items in the sample. 2.11 Acceptable Qualify Level ( AQL ) — The maximum percent defective that, for the purpose of sampling inspection, can be considered satisfactory as a process average. 3. PROCESS INSPECTION 3.1 The object of inspection by the purchaser is to ensure conformity of the tnaterial offered to him to the specification requirements, whereas the inspection done by the m^nufacttifdr during the t)f6dtiction is not only to ensiire the conformity to rfcleV^nt ^i^ecificatibiis, but also ' to maintain overall uniform quality. For pfdce^S control, the manufacturer sh^^uld test representative sample? of the matefial at regular intetvals, duriflg manufacture to control the quality VatiatiOn at .variotjs manufacturing stages. The impedioti le^^ls, gi^^eh in tablfe 1 ma}^ serve as a guid6 for routitte control ov^r the manufacturing process., ,.. IS : 10790 ( Part 1 ) - 1984 (1) (2) i) Raw material >i) After patenting iii) Before final pass in drawing iv) After final pass in drawing V) After stress relieving TABLE 1 PROCESS INSPECTION LEVELS ( Clause 3.1 ) Sl No. Stage Recommended Frequency of Inspection and Testing (3) One coil from every heat/cast received to be tested for chemical, physical and metallurgical characteristics Two coils to be tested for every patenting batch/lot Dimensional check every four hours Dimensional check and UTS for each coil Every fifth coil for dimensions, proof stress, UTS, elongation ductility and indentation. One coil every month for relaxation and susceptibility to stress corrosion 3.2 The manufacturer should maintain control of various characteristics of the prestressing stesl on the basis of the following considerations. 3.2.1 Following an unsatisfactory test result, the manufacturer should take all necessary steps to rectify the deficiencies and shortcomings in the process. Products which do not satisfy the requirements are to be segregated. 3.2.2 Results of the inspection and testing should be recorded and evaluated statistically. The records may be preserved for adequate period of time say 2 to 3 years so that they can be referred to in case of difficulties and complaints. 3.2.2.1 The scrutiny of the test results may be carried out with the aid of statistical methods adopting the variables or attributes approach as appropriate. The variables approach shall normally be applied for proof stress, tensile strength, elongation, weight, dimensions, rolling and cutting tolerances and chemical requirements. The attributes approach might be applied in respect of bending test and visual characteristics. For this purpose, reference may be made to IS : 7200 ( Part 1 )-1974*, IS : 7200 ( Part 2 )-1975t, IS : 6200 ( Part 1 )-1977t IS : 6200 ( Part 2 M977§, IS : 7300-197411 and IS : 7600-197511. 3.3 On the basis o^ \h.Q process inspection data, the manufacturer may issue relevant test certificate to proVe the conformity of a lot ^ to the reqtiirefndnts of any specification, ;, "■'/' ''** *PreS!esit2itioti of. statistical data: Part 1 Tabulation and .summarization. tPi^entfttion of statistical d&ta: Part 2 iJiagratnmatic representation of data, ist^tistical tests of sign'ificaiice: Part i /-. Normal and i^-tests {first te^isiott). iSf^tisticai tests of Significaride: Part 2 A:^-test {first revision ). yMethods of regtesSioft atid correlation, If Analysis of variance. IS:10790(Partl)-1984 3-3.1 When such test certificate cannot be made available to the purchaser or when the purchaser so desires, the procedure laid down in 4 shall be followed for judging the conformity or otherwise of a lot to the requirements of relevant specifications. 4. LOT INSPECTION 4.1 Lot — The quantity of material of the same grade and nominal size manufactured from steel fully tested in respect of physical, chemical and surface characteristics and processed under similar conditions shall constitute a lot. 4.2 The samples shall be selected and examined for each lot separately for ascertaining their conformity to the requirements of the relevant specifications. 4.3 Scale of Sampling and Criteria for Conformity 4.3.1 VisuaU Dimensional and Weight Characteristics 4.3.1.1 The number of items to be selected for visual, dimensional and weight characteristics as mentioned in the respective Indian standard specification depend upon the size of the lot and shall be in accordance with Table 2. These items shall be selected from the lot at random. In order to ensure the randomness of selection, procedures given in IS : 4905-1968* may be followed. TABLE 2 SCALE OF SAMPING AND ACCEPTANCE NUMBER FOR VISUAL, DIMENSIONAL AND WEIGHT CHARACTERISTICS {Clauses 4^A.lA•^^•2 and 4,^.\3 ) Lot Size For Visual Characteristics For Dimensional and Weight Chraracteristxcs Sample Acceptance r- Size Number Sample Acceptance' Size Number (1) (2) (3) (4) (5) Up to 25 8 5 26 to 50 13 18 51 to 100 20 1 13 1 101 to 150 32 2 20 1 151 t6300^ 50 > . ^T 32 2 361 to .500 to 5 ... JO ,:. , .. . ^^ 501 and above 125 7 80 5 '* value Note — The above sampling plan hSs an assbchtisd AQL'of 2*5' i^efeent; This iieof AQLwill hold good getiefaily in ca§eof ^arge^l^^^ ' -^^ - ^Methods for random sampling. is : 10790 (Parti). 1984 4.3.1.2 Each item selected according to col 1 and 2 of Table 2 shall be inspected for visual characteristics and freedom from defects. Any item failing to meet any of the requirements shall be considered as defective. If the number of defectives fourtd in the sample is less than or equal to the corresponding acceptance number given in col 3 of Table 2, the lot shall be considered as conforming to the requirements of visual characteristics. Note — In case of those lots which have been found unsatisfactory, all the items in the iot may be inspected for visual characteristics and the defectives may be removed, if agreed to between the purchaser and the supplier, 4.3.1.3 The lot which has been found satisfactory with respect to visual characteristics shall be further inspected for dimensional and weight requirements. The number of items required for this purpose shall be taken at random in accordance with col I and 4 of Table 2. These may be taken from those items which have been found conforming to visual characteristics. If the number of defectives found in the sample for weight or dimensional requirements is less than or equal to corresponding acceptance number ( see col 5 of Table 2 ), the lot shall be considered as conforming to the requirements of the relevant specifications; otherwise not. 4.3.1.4 The lot which has been found satisfactory in visual, dimensional and weight characteristics shall be further tested for physical and chemical characteristics according to 4.3.2 and 4.3.3. 4.3.2 Physical Characteristics 4.3.2.1 The specimens for physical characteristics like tensile strength, proof-stress, ductility, elongation, relaxation and susceptibility to stress corrosion as given in the respective Indian Standard specification, shall be taken in such a manner that it represents the material and shall be so prepared that it conforms to the relevant specification to ensure uniformity of test procedure. 4.3.2.2 The number of items required for tensile strength, proof-stress ductility, and elongation shall be in accoxdance with col 1 and 2 of Table 3. These may be taken from those items which have been found satisfactory in visual, dimensional and weight requirements. From each of the items so selected, the required number of test specimens shall be prepared for conducting the tests specified. 4.3.2.3 When tests for relaxation and susceptibility to stress corrosion are required to be carried, six specimens obtained from the items selected in 4.3.2.2 shall be tested. In case the number of items is less than six, additional items may be selected from the lot at random. Is : 10790 ( Part 1 ) - 19^4 TABLE 3 SCALE OF SAMPLING FOR PHYSICAL AND CHEMICAL TESTS ( Clauses 4.3.2.2 and 4.3.3.1 ) Number of Items in a Lot Number of Items to be Selected (1) (2) Up to 50 2 51 to J50 3 151 to 500 5 501 and above 8 4.3.2-4 For ascertaining the conformity of the lot in respect of tensile strength, proof stress and elongation, the following procedure shall be adopted: a) When two items are selected from a lot and tested, the lot shall be considered as conforming to the requirements of tensile strength, proof stress and elongation if both the samples pass in each of the tests. b) When the numbe_r of items selected from a lot is three or more, the mean { x) and range {R) are calculated from the test results for each characteristic. The lot shall be considered as conforming to the specification if the value of (^—0*4 i? ) is greater than or equal to the corresponding minimum specifica- tion limit of the characteristic in the relevant specification. 4.3.2.5 The lot shall be considered as conforming to the requirements of ductility test, relaxation test and susceptibility to stress corrosion test if each of the test results is found to be satisfactory. 4.3.3 Chemical Characteristics 4.3.3.1 The number of items required for chemical analysis shall be taken at random in accordance with col 1 and 2 of Table 3. These may be taken from those items which have been found conforming to visual, dimensional and weight requirements. 4.3.3.2 From each of the items so selected, drilling shall be taken and a composite sampie of these drillings shall be made. The lot shall be considered as complymg with the requirements of various chemical constituents, if the analysis made on the composite sample conforms to the requirements of the relevant specifications.