Strengthening the quality management of gas engineering construction is the basis to ensure the safe operation of the pipeline network. Through the operation of the quality system of Shenzhen Gas Engineering Co., Ltd., this paper summarizes the important role of implementing ISO9002 quality standard in standardizing the construction of gas engineering. Shenzhen Gas Engineering Co., Ltd. is the first enterprise in China to obtain the international quality certification of ISO9002 gas engineering industry, and occupies a dominant position in Shenzhen gas engineering market.
1 the purpose and significance of implementing ISO9002 quality standard in gas engineering enterprises
Gas engineering generally has the characteristics of many projects and wide distribution. The implementation of ISO9002 quality standard will encounter difficulties and problems that industrial enterprises do not have in both software and hardware. Therefore, it is difficult for gas engineering enterprises to implement ISO9002 quality standards. However, in the face of increasingly fierce market competition, enterprises must be prepared for danger in times of peace, and strive for survival, development and efficiency by quality. In order to improve the management level, economic benefits and engineering quality of enterprises, it is necessary to standardize engineering behavior and strictly implement ISO9002 quality standards, which is undoubtedly a golden key for enterprises to open up the market.
2. Establish quality system documents according to the requirements of quality standards.
In ISO9000 series quality standards, ISO9002 quality system-quality assurance mode of production, installation and service is a quality standard closely related to gas engineering. The quality system is established according to the requirements of quality standards and consists of three-level documents, namely, quality manual, program documents and work instructions (including various forms and quality records). The quality management of an enterprise is realized through the management of various processes within the enterprise. Therefore, it is necessary to clarify the requirements for process management, managers, managers' responsibilities, management methods and resources needed for the implementation of management, and express them in the form of documents, thus forming the quality system documents of the enterprise.
2.l Quality Manual is a programmatic document of quality system.
The quality manual is a first-level document that clarifies the company's quality objectives and policies and outlines the quality system. It is a programmatic document that must be followed for a long time in the operation of the quality system. It mainly includes quality policy, quality organization, quality responsibility and program outline. And the requirements of 19 quality elements specified in ISO9002 are basically described. The quality goal is an achievable and high-level concrete goal, and the quality policy is the overall pursuit of quality and the commitment to customers. Our quality objectives are: the first pass rate of the project100%; Quality policy is: every project, strive for perfection; Every customer is satisfied.
2.2 Establishing effective program files is the key to the normal operation of the quality system.
Program file is to program all activities and processes related to quality elements and save them in the form of files, which describes in detail the activities of various functional departments involved in implementing quality system requirements. Before implementing ISO9002 quality standard and establishing quality system, we have implemented some management systems, such as management regulations on document compatibility, quality and safety, materials and equipment, and project acceptance. In the above management projects, several management contents overlap with some quality elements of ISO9002 quality standard. How to treat the previous management regulations correctly and coordinate the inconsistency between ISO9002 quality standards and these management regulations is the difficulty in establishing a perfect and effective program document. According to the requirements of ISO9002 quality standard for quality system program files, 19 element should have corresponding program files. Considering the requirements of elements and the complexity of the company's corresponding activities, each element can be described by one program file or several program files. Program files must be practical and have clear goals. Don't write them well, which is difficult to do. A basic principle is' write what you do, do what you write'. For example, the management of engineering materials on the construction site does not apply to the management of material warehouses; The unqualified product identification on the construction site does not apply to the unqualified product identification of the factory; Documents that need work instruction specification should not rise to the level of program documents; The key points that must be described at the level of procedure documents cannot be listed in the work instruction. Here, only one element "process control" is taken as an example to illustrate the compilation of program documents. In order to describe this factor completely, seven control points that may directly affect the product quality in the production process are determined, which are the key points in the construction of Shenzhen gas project. According to these seven points, seven program files describing this element are formed, as shown in table 1.
2.3 Work instructions and forms standardize specific quality activities.
Work instructions and forms are the third-level documents of quality system, operational documents used to describe the technical details of specific processes and things, and the most detailed working documents in the process of quality system operation and product quality formation. Work instruction is also a program, but its object is specific work activities, and the object described in the program file is the quality activities of a certain system. When this form is used together with the report, a quality record is formed as evidence for the operation of the quality system. Table 2 extracts some job descriptions related to construction safety.
3 the implementation of ISO9002 quality standards plays an important role in standardization construction
The quality system we have established gives the "best and most practical" method to achieve the quality objectives, establishes responsibilities and authorities, and handles interfaces well, so that the quality system becomes an organic whole with clear responsibilities and coordination. After several years of operation, we summarized its important role in standardizing engineering construction and improving engineering quality.
3. 1 standardizes the structural behavior.
(1) Table 3 lists the relevant parameters of pipeline pressure test before and after the implementation of quality standards during the acceptance of Shenzhen gas project. In the past, the strength, water column, pressure parameters of air tightness test, holding time of strength test and pressure parameters of air tightness test of buried pipelines were inconsistent with the requirements of design specifications or construction specifications. Only through the implementation of the quality system can this irregular quality activity be corrected.
(2) How the quality system regulates the construction behavior, and the acceptance of low-pressure pipelines is also very convincing. During the 5KPa water column test of low-pressure pipeline, the national code and design instructions did not specify the sampling ratio, and the customary practice of sampling according to the total number of households 10% for many years lacked theoretical basis. But summing up our practical experience proves that this habit is feasible. Therefore, we have standardized this quality activity in the quality system document. Here, I also hope that the design unit can make it clear in the design documents.
3.2 Ensure the stable improvement of welding quality.
Welding is one of the key points of gas engineering quality control. Before the implementation of the quality system, welders rely on personal experience and technical level in the welding process, and some key parameters affecting welding quality lack standardized and unified descriptions. After the implementation of the quality system, we made a welding process card (see Table 4) to guide the operation of welders and plumbers, to clarify the uncertain parameters, to make the previous operation affected by human factors procedural and standardized, and to improve the welding quality steadily. Figure 1 shows the change of weld quality grade evaluated by X-ray nondestructive testing from 1995 to 2000.
3.3 The anti-corrosion and thermal insulation quality of buried pipelines is obviously improved.
The anticorrosion and thermal insulation quality of buried pipelines is related to the service life of pipelines. Shenzhen is located in the coastal area, so the anticorrosion of pipelines is particularly important. After the implementation of the quality system, we designed work instructions and related quality records such as pipe groove, derusting of internal and external surfaces of the pipe, painting primer, winding insulation tape until installation and backfilling. At the same time, the indirect factors affecting the quality of anti-corrosion and thermal insulation are standardized, and standards are formulated from the aspects of residual soil removal and ditch fence. Figure 2 shows that before and after the implementation of the quality system, we used electric spark to detect the damaged points of pipeline insulation and corrosion protection.
3.4 Improve the construction capacity of difficult projects.
The implementation of the quality system ensures the quality of some difficult projects, and there are perfect quality assurance operating procedures. Table 5 shows two representative projects of gas pipeline projects in super high-rise commercial buildings that we have completed in recent two years. Through the analysis of relevant technical parameters, the rigorous and scientific quality system provides a strong and effective organizational guarantee for the smooth implementation of these projects.
3.5 Popularize and apply new processes, technologies and materials. Combined with the quality difficulties that are easy to produce unqualified products put forward in the Report on Corrective and Preventive Measures of Quality System and the Report on Quality Audit, corrective measures are implemented to meet the requirements of quality system. Table 6 summarizes the application of some new processes, technologies and materials.
3.6 Broaden the record range of quality activities and improve the quality records.
Quality records are operable, inspectable, traceable, witness and systematic. Before the establishment and implementation of the quality system, all quality records are limited to the completion data of gas project specified by Shenzhen Archives. After the implementation of the quality system, according to the basic requirements of the quality system, all quality activities should have corresponding quality records, even if the records are not required to be filed in the completion data. For example, there is no effective method to detect the welding quality of PE pipes in China at present. The welding quality of lattice steel pipe can be detected by X-ray nondestructive testing, and X can only be judged by visual inspection and pressure test. Therefore, the quality records of completion data do not need to be filed. However, according to the requirements of the quality system, we made and used the welding records of Jiang E-tube, recording the relevant welding parameters (such as time, temperature and current), welding position, operators and so on. , thus making our quality records more scientific, true and comprehensive. Table 7 extracts some quality records established after the implementation of the quality system.
3.7 The quality of personnel has been steadily improved.
The 19 element of the quality system clearly requires training, and specifies the training requirements and training objectives. In quality activities, we made training plans and kept training records, and incorporated training education and quality improvement into quality activities. Table 8 shows the certificates of 1996 and 2000. Among them, all plumbers have obtained professional qualification certificates through examination by the administrative department of the Municipal Labor Bureau, which is the first batch in the national gas construction industry.
4 Some important factors affecting the implementation of the quality system
The quality system ensures the rationality of construction technology and procedures, the standardization of construction operation, and the rationality of procurement, storage, inspection and testing of engineering equipment and materials. We believe that several factors to ensure the standardization, institutionalization and proceduralization of all quality activities are "people, machines, things and laws".
4. 1 People are the key to all quality activities.
The quality system stipulates the post responsibilities and authority of personnel, and only when employees perform their duties can the implementation of the quality system be guaranteed. At the same time, all personnel related to quality activities must be trained and qualified before they can take up their posts, and special types of work (such as welders and electricians) must hold relevant certificates.
4.2 The management of construction machinery and equipment is a necessary condition for quality activities.
The purchase, inspection, use, maintenance and maintenance of mechanical equipment run through the whole process of quality activities, and corresponding and feasible quality records must be established.
4.3 Engineering material management is the basis of quality activities.
Engineering materials shall be purchased, accepted, kept, collected and distributed according to the design documents, technical specifications and process requirements, so as to ensure that the materials put into use meet the specified requirements.
4.4 Perfect quality system documents are an important means to ensure project quality.
In the process of implementing the quality system, local procedural documents should be revised according to actual needs to ensure the scientific and normative quality system.
Concluding remarks
Through the implementation of ISO9002 quality standard in recent years, the construction safety has been more effectively guaranteed, the construction quality has been steadily improved, and it has won the Luban Award, the highest national architectural quality award. SGS, a British certification body, supervised and audited our quality system twice last year, and none of the audit reports was slightly unqualified, which shows that we have achieved fruitful results in implementing ISO9002 quality standards.