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Quality Management Systems

in the Road Construction Industry

Summary

This paper provides background information and an introduction to Quality Management and provide an outline of what steps to follow to initiate the development of such systems.

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1                  Definitions

To assist in clarification when reading these guidelines, the following definitions will be helpful. They are based upon the definitions put forward in ISO 8402-1986 and apply to products and services.

Service: The activity of a consulting engineering firm as it interfaces with a client and the results of all this firm's activities to meet the needs of the client.

Quality:The totality of features and characteristics of a product or service that bear on its ability to satisfy stated or implied needs.

Quality Loop; Quality Spiral: Conceptual model of interacting activities that influence the quality of a product or service in the various stages ranging from the identification of needs to the assessment of whether these needs have been satisfied.

Quality Policy:The overall quality intentions and direction of an organization as regards quality, as formally expressed by top management.

Quality Management: That aspect of the overall management function that determines and implements the quality policy.

Quality Assurance: All those planned and systematic actions necessary to provide adequate confidence that a product or service will satisfy given requirements for quality.

Quality Control:The operational techniques and activities that are used to fulfil requirements for quality.

Quality System: The organizational structure, responsibilities, procedures, processes and resources for implementing Quality Management.

Quality Plan: A document setting out the specific quality practices, resources and sequence of activities relevant to a particular service, contract or project.

Quality Audit: A systematic and independent examination to determine whether quality activities and related results comply with planned arrangements and whether planned arrangements are implemented effectively and are suitable to achieve objectives.

Quality Surveillance: The continuing monitoring and verification of the status of procedures, methods, conditions, processes, products and services, and analysis of records in relation to stated references to ensure that specified requirements for quality are being met.

Quality System Review: A formal evaluation by top management of the status and adequacy of the quality system in relation to quality policy and new objectives resulting from changing circumstances.

Design Review: A formal, documented, comprehensive and systematic examination of a design to evaluate the design requirements and the capability of the design to meet those requirements and to identify problems and propose solutions.

Inspection:Activities such as measuring, examining, testing, gauging one or more characteristics of a product or service and comparing these with specified requirements to determine conformity.

Reliability:The ability of an item to perform a required function under stated conditions for a stated period of time.

Nonconformity:The non-fulfilment of specified requirements.

Defect:The non-fulfilment of intended usage requirements.

Specification:The document that prescribes the requirements with which the product or service has to conform.

2                   Introduction

This guideline provides an outline of the quality management systems (QMS) used in the construction industry. The use of QMS is essential to ensure cost effective and efficient management of the road network can be implemented. An assured quality of product enables accurate maintenance strategies, both periodic and routine, to be development and implemented.

When dealing with the construction of road and bridge works, especially by contract, the need for a QMS system is essential. The three parties to the contract, the Client, the Engineer and the Contractor, must all play their part towards effective QMS.

This guideline has two main purposes.

a)      Provide background information and an introduction to Quality Management and convincing evidence that firms must, as a matter of survival, adopt Quality Management practices, and

b)     Provide an outline of what steps to follow to initiate the development of a Quality Management system.

3                   Overview

3.1             General

Quality is defined as the “degree or grade of excellence”. Quality management system (QMS) is a term used to cover all aspects of producing and accepting a finished product. In this case the finished product is a road or a bridge.

A popular definition of QMS is the management of those activities, which concern making sure the quality of a product, is what it should be within an organisation. This definition has two parts.  “Making sure the quality of a product is”, is the first part and deals with the decisions necessary to determine conformity to the specifications.   The second part - “what it should be” - deals with the basic engineering properties of the material or construction process. QMS also embodies, in the appropriate organisation, specification development, process control, product acceptance, training, communications, and laboratory and technician certification.

Proper design, adherence to specifications, use of quality materials, and the use of qualified personnel are all necessary to provide adequate assurances of quality achievement. Involvement of Government Agencies, academia, and industry are also seen as vital to the effectiveness of implementing effective Quality Management Systems.

QMS systems used in road construction project will generally include the three functions; process control, acceptance control, and independent assurance.

3.2             Process Control

Quality cannot be tested or inspected after completion of many construction components.  Therefore quality must be present in the product from the beginning. The contractor or manufacturer best performs process control because they have control over the product during the construction process.

In many contracts the contractor must submit a process control plan to the client for review or approval prior to the beginning of work.  The plan must provide details of the number and frequency of tests to be carried out. It should also give criteria for when action will be taken to undertake corrective measures.  Other details that might be included in a process control plan are the verification of calibration certificates, and the frequency of plant inspections. An example of a contractors quality control plan is provided in Appendix A and an example of a supervising consultants quality control plan is provided in Appendix B.

Control charts are used extensively in the process control for civil engineering works. Control charts provide a visual warning, which enables identification of when a contractor or material supplier should investigate possible problems. Some of the benefits that have been attributed to control charts include;

1                    early detection of trouble;

2                    establish process capability (output rates);

3                    optimise performance and hence reduce costs;

4                    set appropriate inspection frequency;

5                    basis for altering specification limits;

6                    permanent record of quality and hence a basis for acceptance;

7                    quality awareness.

It is in all parties interest to ensure problems are solved at an early stage and hence, the Engineer may become deeply involved in the contractors process control.

3.3             Acceptance Control

Acceptance control, sometimes referred to as quality control, is provided by the client and may consist of compliance testing, and/or process control monitoring. However, the type of technical specification used in a contract has important implications in the way that acceptance control is administered. Therefore it is necessary to discuss the different types of technical specification which may be used.

Technical specifications are prepared in such a way that both compliance testing and process control monitoring can be undertaken. There are generally two types of technical specification; the "method" specification and "end" specification.

The "method" specification" dictates the method, which a contractor must use to produce the end product. Compliance testing will consist of checking the methods that are being used by the contractor to ensure he complies with the contract.

The "end" specification does not dictate any method that the contractor must use. It specifies the end product and details a series of compliance tests which must be undertaken to determine its acceptance or otherwise. This provides the greatest flexibility and control for the contractor in his methodology. Table 1 shows advantages and disadvantages to the two different methods. However, in practise, emphasis is usually placed on the "end" specification with limited "method" specifications where deemed essential.

Compaction of material illustrates the difference between the two types of technical specification.

If a "method" specification is used for compaction it will be necessary to specify the type of equipment to be used, how much water to be applied and the number of passes required to obtain the desired compaction. Compliance testing will consist of inspection of the equipment, measuring the amount of water and counting the number of times the equipment passes over the area. It will be the client's risk in the event of failure, assuming the contractor adherence to the specification.

If an "end" specification is used for compaction it is necessary to specify the required compaction and means by which this compaction will be measured. In this case the compliance test would be carried out in accordance with the AASHTO T180 test, which determines the in-situ density of the soil in a prescribed scientific manner. The contractor will be free to use any method to achieve this end result. 

Table 1 - Advantages and Disadvantages of “Method” and “End” Specifications

Compliance testing is therefore, an important function and is performed to provide the client with information that relates the end product to the limits set within the specification.  The client generally performs the compliance testing function for construction for its own projects.  However, it generally appoints a supervising consultant to fulfil this function on its behalf. Competent independent materials testing laboratory may also be appointed directly by the client or by the supervising consultant to carry out the testing of materials.

Compliance testing involves considerable number of personnel on each project together with extensive relevant testing equipment. This is not an area for saving money and sufficient resources must be allocated to ensure effective compliance testing is undertaken.

Monitoring of the contractor's process control also provides valuable information. It confirms the contractor's intentions towards quality and provides an early warning for potential problems. It is essential that the technical specifications are prepared in such away that supervisory staff may carry out appropriate process control monitoring.

For example, it may be necessary to specify a flow gauge on a bituminous distributor to allow continuous monitoring of bitumen spray rates. This is clearly not part of the compliance testing yet provides valuable information prior to carrying out the compliance tests.

3.4             Independent Assurance

Independent assurance (IA) is a management tool that requires a third party (e.g. an external laboratory), not directly responsible for process control or acceptance control, to provide an independent assessment of the product. Independent assurance may also form a part of Acceptance Control.

The purpose of an IA program is to make independent checks on the reliability of the results obtained in acceptance sampling and testing and not for directly determining the quality and acceptability of the materials and workmanship. Personnel not normally responsible for process control or quality control perform the tests.

Independent assurance only monitors the accuracy of the tests being carried out on the materials on a very small scale.  If the difference between the initial testing and the duplicate testing is unacceptable, this must be further investigated immediately, as any inaccurate testing could result in sub-standard materials being accepted.

As far as this independent assurance factor is concerned, it must be determined at the outset of the project that duplicates of all samples will be kept.  These duplicates are for regular control as well as for selection and subsequent testing by the client on a regular basis (monthly) of a portion of all the material samples.

As an example, steel reinforcement is used extensively in reinforced concrete, a primary ingredient for structures. This is generally supplied by the Ethiopian Steel Industry and a test certificate for strength accompanies each delivery. It is not practical to have steel strength testing equipment on each site and hence, testing will be carried by independent testing facilities within Addis Ababa.

3.5             Testing Methods

Requirements and limit values are laid down in the specifications in regard to the properties of materials and workmanship to be supplied. Tests are conducted and measurements taken for controlling the relevant properties of the workmanship and materials supplied, and the results of such tests and measurements are assessed on the basis of the prescribed criteria for compliance with the specified requirements.

A judgement of the quality of a product, especially in civil engineering, is generally based on observations taken at random. Since it is impractical to test 100% of construction materials, an appropriate sampling methodology has been developed.  If the sampling is not done in a random fashion, it is likely that bias will enter into the procedure. 

Variation within construction materials is very common. Multiple testing will not be identical (i.e. repeatable) and tests have inherent variability that cannot be eliminated.  Due to this variability, individual results cannot be accurately predicted.  However, groups of test results from a systematic procedure tend to be predictable.

A statistical approach provides the means to determine the actual properties of the material. Normal distribution methods are used extensively and they provide mean values, standard deviations, variance etc.

Where the process monitoring and acceptance control are determined from tests which are relatively time consuming, other tests may be considered for rapid evaluation during construction. For example, moisture content determination may be obtained using quicker drying methods than are required by the specification.

Testing procedures are usually prescribed by a variety of international Standards organisations. ERAs preferred methods are prescribed by "American Association of State Highway and Transportation Officials Inc" (AASHTO). However, test procedures from other countries may also be used if not available within AASHTO. This includes the UK, South Africa, Tanzania, etc.

3.6             Conclusion

Considerable amounts of money are being used in maintaining and expanding the Ethiopian road network. It is essential that value for money is obtained and that this is demonstrated by formal monitoring of construction procedures (process control) and end results (acceptance control).

However, it must be emphasised that, when considering the contract construction process, clear and appropriate technical specifications are required to ensure a satisfactory end product.

It should also be noted that the quality of the end product is never guaranteed. However, if a suitable QMS system is operational, there is a higher level of confidence that the quality of the construction will be acceptable.

Appendix A

An Example of Compliance Tests for a Component of a Road Project

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