The Construction Technology Management Act, enacted on January 1, 1988, was revised 63 times in about 37 years this year and became the Construction Technology Promotion Act. The Construction Technology Promotion Act aims to promote the research and development of construction technology to improve the level of construction technology, promote related industries to properly implement construction work, enhance the quality of construction work, and secure safety to contribute to the promotion of public welfare and the development of the national economy.
In addition, in accordance with Articles 55 through 61 of the Construction Technology Promotion Act, the Construction Work Guidelines for Quality Management of Construction Work, which set the overall detailed standards for quality control of construction work, were also enacted in 2015 and implemented through revisions in 2017 and 2022. However, the quality control guidelines for construction work, which are the parent, were enacted in 2010, and ISO 9000 for quality control plans was introduced in 1997, which became the birthplace of the quality control plan used at the site construction site.
However, despite numerous revisions and on-site inspections to quality control so far, the reality is that fundamental changes in quality control and operations have not been well implemented. This can be attributed to institutional differences between the establishment of a quality management plan and the actual operation, insufficient implementation of practical quality management, institutional limitations in the area of quality management capabilities and quality activities, and unstandardized quality management.
Furthermore, human housing is directly related to the quality of life and is transforming into a consumer advantage market that requires greater high-quality services, making the requirements for all buildings from frameworks to finishes more demanding.
These changes in requirements can be seen only by changes in various laws, ordinances, and design standards. In line with the changing trend, quality control is also required to change.
It is also true that the number of quality managers assigned to the site is different from one to three (related to Article 50 (4) of the Enforcement Regulations of the Construction Technology Promotion Act), and that the actual number of employees working at the site is small and beginner.
In addition, due to the lack of experience of beginner quality managers, there is no clear data on what tasks to perform from the beginning of the field and how to perform them. Therefore, the reality is that despite each site performing the same task, the output data are different and there is no standard for the task to be performed.
In construction sites, quality management can be divided into three main categories: first test quality, second construction quality, and third system quality, which are also divided into three stages of quality management.
Quality management began in quality testing in early 1920 and continued to overall quality management (TQM) through quality management (QC) and quality assurance (QA), and quality management at construction sites has a difficult task to manage all three.
As a result, there are many required quality controls, but the actual implementation is limited to quality tests, and even this does not have standardized indicators for each site, resulting in differences in satisfaction and performance of quality management by site, and differences in quality management methods according to individual capabilities.
In order to reduce these differences in quality control according to individual capabilities and quality control by site, and respond to changing quality control, the system of quality management methods that must be required and implemented must also be changed and standardized. The construction order, construction method, and quality control method for each construction site may all be different, but the basic methodology in quality control is very similar.
Therefore, the purpose of this paper is to improve the work of quality managers in contact with the overall work by standardizing the quality management by quality management plan, test plan, test room operation, and apartment building type, and standardizing on documents for quality management (System Quality, Test Quality) from beginner to intermediate to advanced, and to improve on-site quality management by converting process-oriented work focused solely on documents and quality testing work to a project-oriented work through standardization of the process.
Accordingly, this paper systematically organizes, establishes, and operates the quality management plan, which is ISO 9001-based system quality, through the systematic construction of quality management so that anyone can establish a quality management plan. In addition, how to prepare and establish a quality test plan, how to reflect the design volume and test items, what procedures to go through to select test items, and what reports related to the test plan are described in detail so that beginner quality managers can prepare, establish, and operate quality test plans in the project.
In addition, as a result of managing the quality control of apartment houses by type of construction through book review, expected risk extraction and quality monitoring, and preemptive response to inspections and tests, it was found that a lot of improvement in construction quality, nonconformity reduction, and rework were reduced, but institutional problems that could further improve the occurrence of nonconformity were studied.
The results of the study on the impact of standardization and systematization of quality management tasks and the establishment of quality management plans for each type of construction on quality work and further improvement of nonconformities are as follows.
1. Analysis of work impact through the establishment of quality control and test planning
As a result of distribution and application to 20 to 26 sites after standardization of quality control plans and quality test plans, overall quality document management was improved by an increase of about 7 points (167 points → 176 points, 200 points standard) compared to the year before the quality review was applied by Checklist, and the reduced standard deviation between sites means that the overall execution performance of the process and the difference in work performance by site tend to enjoy.
As a result of the inspection before standardization, a total of 760 cases of nonconformity were found at 26 sites, and a total of 239 cases of nonconformity with the process evaluation accounted for 31.44% of the total nonconformity. The items in which nonconformities were found intensively were 1) construction information, 2) document management, 3) key quality management, 4) inspection, test, monitoring management, 5) nonconformity product management, and 6) self-quality inspection, and the most common documents related to quality tests.
As a result of distribution and application throughout the construction site in 2019, out of a total of 1144 nonconformities at 20 sites in 2019, 109 process inspections accounted for 9.53% of nonconformities, and 332 test-related nonconformities accounted for 29.02% of the total nonconformities. During quality inspections in 2019, the total number of cases increased due to the increase in proposals for risk hedging in terms of design and construction, but the actual nonconformity rate was 15.69%, which was improved from 18 years ago.
In addition, the discovery of nonconformities with documents decreased by 48% compared to the year before the application, repeated nonconformities occurred only in some items such as quality control items and document management, and significantly reduced nonconformities for other items.
2. An Analysis of the Impact of Construction Quality by Establishing Quality Management Plan for Construction Type in Apartment Houses
As a result of preparing/distributing quality management plans and educational data for each type of construction according to outsourcing contracts in apartment houses, strengthening screening for finished construction during quality review, and sharing and disseminating other PJT cases. Although the standard deviation by PJT decreased by about 10 points (445 points → 435 points) compared to the year before the quality review by Checklist was applied, the standard deviation by PJT showed a slight increase. This is due to the result of reflecting the finishing work other than earth and construction work and frame work during the internal review, and the number of nonconformities and corrective matters found during the review increased, and the quality deviation by PJT for the quality of the finish increased somewhat.
The number of product inspection results before standardization was 521, accounting for 69.46% of the total 750 cases, and the number of product inspection results in 2019 reflecting standardization was 901, accounting for 78.76% of the total 1,144 cases. 650 of 901 cases in 2019 were suggestions, and 251 cases were considered preventive activities for risk hedging in advance of quality, a 49.1% decrease from 2018.
However, in terms of visual products, the rating decreased compared to the year before the quality review was applied, and the standard deviation for each project showed a pattern of slightly increasing. This is the result of strengthening the quality inspection when applying the quality review, and it was found that the non-conformity rate significantly decreased except for design errors and construction suggestions for improvement that are not non-conformities. In addition, it was found that the number of non-conformity cases and findings of existing earthwork and reinforced concrete construction was significantly reduced.
In addition, nonconformities with finishing works account for 48% of all types of construction, and most of the findings of nonconformities have increased in PL Chang-ho Corporation, AL Chang-ho Corporation, Waterworks, Iron Chang-ho Corporation, Metal Corporation, Kitchen/General Furniture Corporation, and Glass Corporation. It disproves that the construction paper is vulnerable in terms of quality control at the time of construction and can be seen as a construction paper with the highest defect rate. Therefore, the quality control can be further supplemented by pre-Risk extraction and Hedge through review of additional quality management plans and design books for the construction work.
However, the reduction in nonconformity findings in earthworks and frame work can be seen as a result of quality control for each type of construction, and this improvement is expected in future finishing work.
3. Analysis of continuous causes of quality nonconformities
Despite the efficiency, systematization and standardization of quality documents, and quality enhancement for each type of construction, nonconformity cases continue to occur. Places with automation, such as manufacturing, can extremely lower the incidence of nonconformity and manage the nonconformity rate through sufficient improvement, but due to the nature of the construction site, there is little automation and most of it is done by humans, so human errors such as mistakes are inevitable.
However, the biggest reason for this continuous nonconformity is a lack of human resources and differences in individual capabilities.
In the case of safety and health at construction sites, it is possible to allocate manpower in proportion to the construction amount, but in the case of current quality, the minimum manpower standard is reflected at the site of 100 billion won or more, so it is not possible to arrange manpower in proportion to the construction amount. Therefore, it is necessary to change the legal standard for manpower allocation in proportion to the construction amount, as quality prevention activities to prevent quality risks such as design book review and construction feasibility review other than documents and test tasks are possible only when sufficient manpower is secured.
In addition, various efforts are required to develop individual capabilities in order to reduce the variation in field quality according to individual capabilities. There is a need for a plan to reduce the occurrence of quality nonconformities by circulating positions (quality ↔ construction), circulating arrangements for various project experiences, periodic quality inspections at the headquarters level and sharing inspection items.
Even if there is a good system, the lack of physical manpower and personal capabilities is bound to be an environment in which nonconformities inevitably occur.
Until now, quality control at construction sites has been recognized as a task that only quality managers do, and only the ready-mixed concrete test work has a lot of weight. In fact, it is also a reality that most quality managers also have this idea.
However, quality control cannot be done alone, nor can it be done alone. Quality control is not limited to reinforced concrete construction, and it is not limited to ready-mixed concrete testing. However, I think it is a customary matter that has occurred while performing such work until now.
Quality work can be regarded as quality work from design to construction. Design quality, construction quality, test quality, electrical quality, facility quality, etc. are all quality work. Therefore, all managers in the field must perform quality work, and quality managers must play a leading role so that all managers can perform quality work well.
This research project will serve as a guide for quality managers, especially beginner quality managers, who must play such a leading role.