- Quality Control may be defined as the set of operations including programming and coordinating intended to maintain or to improve the quality of the product confirming to the designed specifications at minimum cost.
- The aim of the Quality Control is to reduce the variations and to produce uniform material and workmanship having characteristics and performance desirable for the structure i.e., safety, serviceability and durability.
- The duty of a Quality Control Division shall be to test the materials and the finished product as per the specification and furnish the results with necessary advice to the construction staff within the frame work of specification.
OBJECTIVES OF THE QUALITY CONTROL ORGANISATION :
The main objectives of Quality Control division are Enumerated as under.
- To conduct the necessary tests on the materials of construction and finished products as per requirements of the tender specifications of works under construction
- To keep proper record of the results of testing of materials and finished products to enable to take corrective steps by the construction staff as and when found necessary.
- To conduct necessary tests on the materials and finished products with a view to assist the design wing to evolve suitable designs or to revise or to alter any design as necessitated by the availability of materials or changes in the characteristics of the materials.
The activities of Quality Control organization shall generally be confirmed to only such aspects of quality of the works and materials which are amenable to quantitative measurements by standard testing procedures. However, there is no bar for the quality control staff for checking the following activities which are directly attended to by the construction staff
- Suitability of foundation for structure.
- Treatment of foundation
- Mark outs and dam profiles
- Design aspects
- Water seals
However omissions in construction practices like cleaning, curing, mixing, laying and vibration of concrete, packing of masonry mode of moistening and compaction are pointed out by the Quality Control.
METHODS OF OPERATIONS OF QUALITY CONTROL :
- General: For testing and formation of specification the relevant ISI will be primarily followed. In the absence of ISI the IRC, BS, ASTM, USBR and US army corps of Engineers specifications, should be followed in the order of priority.
- Quality Control involves sampling, testing, analysis, computations and communication of test results. Sampling methods and testing procedures adopted must be as per the tender documents of the respective work.
- Before starting the work, the construction executive Engineer should send to the concerned Quality Control Sub-Division and Division the certified copies of the agreement to facilitate them to acquaint with the specifications, drawings, borrow areas etc., so that required testing and review can be done promptly.
PROCEEDURES OF QUALITY CONTROL :
INSPECTION OF WORKS :
Officers of the Quality Control Organization will regularly inspect the work in order to see that all the tests are carried out regularly and precisely as per the approved schedule of tests and procedures. During the inspections, they will review the frequency of testing, the arrangements for conducting tests, collection of samples and rectification of defective works, up-keep of the documents etc., They will also check periodically some percentage of computations of the various tests and record the check initials in the respective registers. The Inspecting Officers may also conduct visual inspection of construction practices and techniques which are not susceptible to regular testing and advise the construction staff for improvement of quality wherever felt necessary. The construction officers like Superintending Engineer/ Executive Engineer/ Assistant Executive Engineer should also inspect the work site and check the results by surprise visits in order to see that all the tests are carried out regularly and precisely.
COMMUNICATION OF TEST RESULTS :
The Quality Control Staff at site shall submit all the test results to their Quality Control Division every week in the prescribed proforma. The Executive Engineer, Quality Control Division will compile the results of all the works, review them and communicate the same to the Executive Engineer-in-charge of construction, Superintending Engineer, of the construction Circle and Chief Engineer (Construction) and the Chief Engineer, Design Organization, along with his observations for taking further action. The communication of the results shall be in the standard forms appended vide Appendix No.2
. The forms must contain the requirement as per the tender specifications so that the construction staff is able to know the implications of the results for taking further action.
ANALYSIS OF THE TEST RESULTS :
The Quality Control Organization shall obtain the month progress of various items of works from the construction division and analyze whether the quantities of materials tested as per day-to-day requisition of estimates at site are in commensuration with the quantities finished products to ensure that untested materials have not gone into the work. However the construction wings shall also review that the number of tests conducted commensurate with the total quantities executed. The final results of all the tests shall be statistically analyzed by the Quality Control office at the specified intervals and the analysis along with the diagrams and reports are communicated to the Executive Engineer (Construction), Superintending Engineer (Construction) and Chief Engineer (Designs) for review and verification of the design assumption with realized values.
The analysis of usage of materials may be submitted in Form No.Q.26
for monthly review, enclosed. Similarly Analysis of test conducted may be submitted in Form No.Q.25
for monthly review of test enclosed.
CO-ORDINATION BETWEEN THE CONSTRUCTION AND QUALITY CONTROL ORGANASATIONS :
- Mutual co-operation and proper co-ordination between the construction and quality control organization are very essential to maintain effective control on quality of work. The construction staff shall take full advantage of the quality control organization and provide all facilities for its effective functioning. This consists of i) keeping the Quality Control staff well informed about the construction schedule and day- to- day programme of work ii) sending indents for testing of materials well in advance and ensuring that un-tested materials do not go into the work and (iii) giving considerations to the test results and the advice given by the quality control Organization and taking corrective steps promptly. The Quality Control Organization is responsible for making effective arrangements at the site of work for conducting all necessary tests as per the specifications. The arrangements shall commensurate with the programme of work. The tests shall be performed promptly, immediately after the receipt of the requisitions. The test results supplied by the quality control organization shall be such as the enable the construction staff to take timely and corrective steps.
- With a view to discussing the local problem relating to co-ordinations of Quality Control Operations, monthly meetings of the construction and Quality Control Executive Engineers shall be held under the Chairmanship of the Superintending Engineer of the concerned Project.
- The disposal of various indents for testing the various corrective steps suggested by Quality Control Division and the action taken thereon by the construction division and any special circumstances having bearing on the quality of works encountered during the months shall be discussed during the meeting. The quantities of various materials for which indents for testing were received the number of tests conducted and the results of tests shall be reviewed in the monthly meeting with reference to the progress achieved during the month to verify whether indents for testing all the materials used were place, whether the indents for testing all the materials used were placed, whether the frequency of testing is adequate and whether the quantities of materials and finished products conform to the specifications. The subject relating to the co-ordination required for the instrumentation of dam and for conducting record tests and special tests shall also be discussed in these meetings. The copies of the proceedings, of these monthly meetings shall be submitted regularly to the Chief Engineers (construction) and Chief Engineer (Designs) for information and perusal.
- The Chief Engineer (Designs) will hold meeting with the project Chief Engineer and the Executive Engineers Quality Control Divisions and bring up to Chief Engineer, constructions notice promptly, all matters which need his attention and decisions.
QUALITY ASSURANCE :
O.K. cards are proposed to be issued by both construction and quality control authorities in respect of structures as well as canal and road works. the O.K cards to be issued at various stages of work depending upon the const of the works are specified for both construction and quality control authorities. the format of O.K. cards are at
||Canals and Roads
|Lay out and foundation
||Earth work i.e. Excavation and for embankment
||Lining or Metalling
The cost Limits as to issue of O.K. Cards :
||Estimated Cost of work
|Asst. Exe. Engineers
||Above Rs.1,00,000 upto Rs.5,00,00
||Above Rs.5,00,000 upto Rs.20,00,000
Note : In each package by different structures and items of works for which O.K. cards are to be issued, should be identified at commencement of works in the package.
If persistent bad work intentionally or unintentionally is continued by the contractor the construction authorities will be informed of the same by the quality control authorities, to stop the work forthwith and to rectify the defects.
The construction staff, quality control staff, inspection wing staff and contractor are all accountable for the assurance of the quality of the work.