Application of quality costs to construction

This work has been carried out with the intention of establishing guidelines for the application of quality costs to construction. The reasons that have motivated its development is that the economic activity of construction has an important multiplier effect for the country; for this reason it is strategic to strengthen its business competitiveness.

application-of-quality-costs-to-construction

The work begins with the rapid review of the impact of the sector on the economic activity of the country, later the most important bases and / or concepts are developed, it should be noted that all the definitions have been extracted from the international standard ISO 8402, the definitions in addition to complementing its use with examples oriented for its implementation in the companies of the field. Likewise, an application is developed for which a part of a work is analyzed, the methodology proposes the development of four steps, the last being oriented to the achievement and / or strengthening of obtaining the margin of the works, that is, to help the search for business competitiveness.

It is clear that the objective of the work is very important for the business sector, but its application represents great efforts for the companies which will be rewarded with the economic benefits that will be achieved, in addition to the strengthening of the image, the trust of the clients, and improving positioning in its competitive market.

INTRODUCTION

The work has been developed in eight chapters, the first is the summary or presentation of the work, the second is the introduction that allows you to locate and guide your understanding. In the third chapter the impact of the construction sector on the economic activity of the country is supported, these three chapters are the general presentation of the subject.

The conceptual bases are developed in the fourth chapter, this is important since it allows to validate the methodological proposal, taking into account definitions of an international standard. The fifth chapter develops a practical application for which the case of a concrete structure work is taken, to facilitate the adoption of the proposed methodology, the use of four steps, properly developed, and with specific results, is proposed. It is necessary to mention that the approaches have been touched in the course: Quality in construction, this is an elective course of recent implementation in the UNI civil engineering curriculum.

The last chapters are oriented to the expected results, conclusions and recommendations, and annexes of the work.

As a final recommendation, it should be noted that the implementation of the methodological guidelines will bring collateral benefits in increasing productivity, another important issue that all companies are looking for with justified concern.

CONSTRUCTION SITUATION

The impact of the construction sector on the national economy is based on its contribution to the country's GDP. This information is supported by the data in Tables No. 01 and 02 (See Annex 8.1. And 8.2., Respectively). On the other hand, Table Nº 03 shows the variation of the GDP of the economic sectors within the years 1994 to 2000, note that the GDP of construction between the years 1994, 1995, and 1997 were the highest, with respect to the values ​​of the other sectors of the country's economic activity.

Graph Nº 01 shows the variations of the GDP of the Construction Sector in graphical form, it is clear that the conjunctural problems were registered from the year 1998, not only for this sector, but also for the other sectors of the country's economic activity.

It is known and disseminated by authorized specialists that the current recession is the strongest in recent years.

It is also clear that such macroeconomic figures cannot remain indefinitely under the current situation. Therefore, this topic is aimed at developing the application of the concept of quality-related costs (CRC) to construction, under the premise of supporting the achievement of the margin provided for in these. What is sought is for companies to prepare for those better times, since everyone expects it to arrive very soon.

THEORETICAL BASES

Main documents of the technical file

All engineering projects culminate in the preparation of the technical file, the following being considered as the most important documents:

Technical specifications

1. 1. Estimated work schedule Meter and budget Unit price analysis Red Pert / Cpm

Each of these documents contains information and data that directly and indirectly affect the quality of the product of the different construction processes.

Pareto chart application

In all works, the responsible manager has the metering and budget, the information contained in such document is: the unit price, the metering of the work, the subtotal (unit price product of each item by its corresponding metering), the total cost direct, the price of the work, the latter including the items of general expenses and profit.

This quality tool supports the application of the 20 - 80 rule, which can be applied to various topics, such as examples:

• 20% of the items represents 80% of the total amount of direct cost,

• • 20% of the problems represents 80% of the company's losses.

The cases in which this quality tool is applied are:

• Identify the most important or critical processes to improve quality.

• • Identify opportunities for improvement When it is necessary to draw attention to certain processes.

Basic definitions of quality

According to the Peruvian technical standard NTP ISO 8402, edition 1995 is understood by:

1. - The totality of the characteristics of an entity that give it the aptitude to satisfy the explicit and implicit needs.

1. 1. Quality requirements.- Expression of the needs or their translation into a set of requirements, established in quantitative or qualitative terms, for the characteristics of an entity, in order to allow its realization and examination. Quality control.- Techniques and activities of an operational nature, used to satisfy the requirements for quality. Records.- Documents that provide objective evidence of the activities carried out or the results obtained.

For the practical purposes of this topic, it is thought that it is more important to analyze, verify and implement, how such concepts should be implemented in the construction business, and verify the benefits of such actions.

Definitions a and b should be applied at the project conception stage, especially the definition of quality. The purpose is to determine those quality characteristics of the construction product, which will give it the ability to meet the explicit (expressed and defined in writing) and implicit (expectations) needs of the client.

Once conversations are exhausted, and project engineering begins, at this stage the professional responsible must define the quantitative or qualitative quality requirements to be met during the construction process. This must be done to run the construction process under systematically planned and controlled conditions. The responsible professional has this obligation since he is "the father of the child" (the product of construction).

This is where the question fits: How will the responsible professional ensure that his "son" (product of construction) will carry his characteristic features in his genes, the only sure way will be by planning the following:

• The mandatory execution of tests, controls, tests, verifications, etc., that must be applied during the construction process.

1. • Defining or citing acceptance criteria based on certain codes, product standards, and test method standards. Planning the use of records that demonstrate that what was planned was met and that the results meet the expected acceptance criteria.

the points indicated (1, 2 and 3) are part of the activities of an operational nature that must be carried out to verify the satisfaction of the quality requirements, remembering this is the definition of quality control. So, according to what has been expressed, this is where "The application of quality costs to construction" arises, since such activities are factors of quality costs.

It is a priority to establish that quality costs must be applied as a safe means to comply with the quality requirements established in the technical file. Failure to do this, is to generate voluntary or involuntary non-quality costs; and therefore, generate losses to the company.

Quality-related costs (CRC)

To apply the definition of CRC. it will have:

CRC = CDC + CNC

where:

CRC = Quality-related costs, CRC

CDC = Quality Costs, CDC

CNC = Non-quality costs, CNC

That is, the company responsible for construction must plan, and comply with controls, tests, tests, analyzes, previously planned, only in this way will satisfactory quality be achieved. It is necessary to comply with such premises, since otherwise the satisfactory quality will not be achieved, which means the following:

• Carry out reprocessing, redo the works corresponding to a complete game, in some cases, since the quality requirements would not have been met.

• • Replace purchased materials and supplies, since the analyzes carried out show that the quality requirements are not met.Complete processes in untimely stages (after having finished the processes), that is, generating higher direct and indirect costs, doing the work on more than one occasion The time taken to complete delayed work, due to non-compliance with quality requirements at the time of execution of the analyzed item.

All these activities: a, b, c, d, and other related activities are those that are part of the CNC, thus generating the start of losses on site.

Identification of control points

Having conceptually demonstrated the need to carry out activities of an operational nature (quality control), the question arises: At what point should they be carried out? How and what does it consist of? What should be controlled? What should be registered and who should do what?.

To answer all these questions it is necessary to foresee:

• The development of written instructions for the execution of quality control activities.

• • The identification of the control points, above all, it is necessary to define the opportune moment for their execution, the premise being: «comply with a control point, to avoid a CNC, which delays and increases construction costs».

A very simple example would be: the slump test is done once the mixer arrives on site (before the concrete is poured, and not after), it allows to control a quality characteristic of the requested concrete. If the acceptance criteria is not met, the concrete must be rejected. Testing after emptying has no practical purpose.

Another example would be: The test to check the degree of compaction of the preparation and compaction of the soil, must be done before the slab is emptied, since otherwise two situations could occur:

• By not knowing the value, one would be assuming that it has been met, therefore, the slab would be emptied. But in the absence of the record that records that the acceptance criterion has been met, there is a potential risk of failure.

• • After a certain time and if the failure of the slab occurs, it is easy to verify that the cause could be not having complied with the specified degree of compaction, and by not having carried out the test, the contractor must assume all responsibility. This means taking over the correction work: «Redo the slab, in addition to covering the production losses of the client, due to the inconvenience and stoppages of the production of the Client», this is a clear example of CNC.

In any case, the question would be: "What is better?", "Isn't it cheaper to comply with the planned tests?", "Wouldn't it be better to foresee the full application of quality costs, to avoid CNC?" "What is the benefit / cost ratio of quality costs versus non-quality costs?"

EXAMPLE OF APPLICATION

For practical purposes of the application, a part of a work has been chosen, this is referred to the specialty of "Concrete structure", for more details see annex 8.3.

The base data is:

• Specialty: Concrete structures

• Number of games: 24 games Total direct cost: S /. 265,349.51 General Expenses (6.43%): S /. 17,061.97 Profit (7.50%): S /. 19.901.21 Total budget: S /. 302,312.69

The recommended steps for applying quality costs are as follows:

STEP 1: Prioritize CDC application based on sub total.

This means that the entire team (construction organization) must know what the priorities are for construction planning, especially foreseeing the CDC according to the importance of the different construction processes.

From the revision of the meter and budget (Annex 8.3) it is observed that not all the items have the same impact on the final result of the work. To help this analysis, the Pareto Chart will be applied (see section 4.2). This will allow verifying the impact of the subtotal of each item of the meter in the planning of the work, and in the application of the CRCs.

As a result, the metered and ordered budget is obtained as shown in Annex 8.4., From this it can be seen that seven (07) items represent 80.98% of the total direct cost. That is, the work of the team, of the work organization, should be oriented more towards the seven (07) prioritized items. Graph Nº 02 (see annex 8.5.) Shows the ABC curve, which identifies regions A, B, and C, which represent the priorities involved.

As a final summary of Step 1, the items that require the most attention and / or that have the greatest impact on the planning and control of the execution of the work will be identified.

STEP 2: Identify CDC cost factors.

By definition the CDC are:

CDC = CDP + CDE

where:

CDC = Quality Costs

CDP = Quality prevention costs

CDE = Evaluation quality costs

For practical purposes, the point of application of CDP and CDE should be defined. CDPs will be applied up to the starting point of the construction process. The CDE will be applied from the point or date of the start of the construction process, and represents compliance with quality control during construction.

Another criterion for conceptualizing the amount of CDPs is that they should be defined more properly during the development of the project engineering, and to a lesser extent during the execution of the construction.

The factors of the CDP that would remain as part of the work would be:

• Visit suppliers and subcontractors to check their aptitude for the execution of works for the work.

• • Calibration of equipment, such as topography, pressure gauges for the test piece breaking, etc. Qualifications of the personnel who will participate in the execution of the work Contracting of courses or talks necessary to improve the results of the work, etc.

The CDE are obviously the cost factors of quality control (see section 4.3.), For further clarification we will have:

• Granulometric analysis of aggregates.

• • CBR tests, bearing capacity, settlement tests, rupture tests of concrete specimens, etc.

Which obviously are the cost factors of CDE. Consequently, if you ask what the results of Step 2 would be, you would have to answer: "It is to identify all the cost factors of CDP and CDE in order to determine the magnitude of CDC", it is clear that the company must incurring the CDC under the objective of avoiding the CNC, this demonstrates the excellent benefit / cost ratio.

STEP 3: Identification of control points and records

In step 2, the control points for the reinforced concrete processes should have been detailed, which will be expanded:

• Granulometric analysis of aggregates, initial and periodic.

• • Tests to check the mix design. Verification of aggregates, etc. Settlement tests. Life time control of concrete. Control of vibrations of concrete. Control of obtaining concrete specimens. Control of curing of concrete. Verification of concrete finishing surfaces, etc.

According to the quality requirements of the project, the applicable control points must be identified, it is also necessary to define the quality records to have the control data, and due verification of compliance with the established acceptance criteria.

It is necessary to point out that the contractor would have to be the main interested party in complying with the CDC to avoid the execution and / or cover the CNC. This is independent of the very fact of the existence and requirement of supervision, it must be carried out as a normal way of working for the company, and by the application of a clear quality policy of the contracting company.

The result of step 3 is to determine the activities that will be part of the quality control that must be fulfilled during the execution of the construction processes.

STEP 4: Strengthening the margin of the work

It is convenient to analyze that each unit price analysis foresees the execution of a construction process under certain conditions but only in a single opportunity; that is, the work must be done right the first time. If total or partial reprocessing must be carried out for the works, the inherent costs must be deducted from the utility; therefore, the expectation of the margin foreseen in the work will not be met. This is the challenge for each person responsible for the execution of the work.

In summary, complying with the CDC is a matter of extreme importance as it has to do with the need to be competitive.

EXPECTED RESULTS

1. By strengthening the application of the philosophy of quality to the construction business, it will be possible to make companies in the construction business more competitive, meaning that their inefficiencies are not charged to their prices, on the contrary they may improve their prices without affecting their profits in a large way. Quality costs represent a results-based management system, whose philosophy will obviously give excellent results in increasing the productivity of companies. It is clear that the implementation of this model would also guarantee the increase in company productivity.

CONCLUSIONS AND RECOMMENDATIONS

1. The application of the costs related to quality to construction is synonymous with moving safely towards competitiveness, it is evident that monitoring of results will be required. The application of such costs should be the own initiative of the contracting companies, not You must expect that the supervision requires such compliance, since it is not the obligation of the supervision to seek the competitiveness of the contractor. It is necessary that the executives of the construction companies take due note of the proposals developed in this topic, since forms are established clear to economically support the implementation of quality management in their companies. Remembering this is a sure way to business competitiveness.

ANNEXES

1. Table Nº 01: GDP for major activities: 1991 - 99, physical volume index. Table Nº 02: GDP for major activities: 1991 - 99. Values ​​at current prices. Meters and works budget for: Reinforced concrete structures. Meters and Budgets prioritized by the Pareto graph. ABC curve for the subtotal criterion.

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