Name: Parthapratim Brahma
TWI India Ltd.
Mentor
Abstract
Boilers and pressure vessels are manufactured and inspected in accordance with codes and standards to comply with regulatory and contractual requirements. However, it is common knowledge that not all such pressure equipment performs uniformly to the desired quality level although certain stages are verified during construction according to the stipulated code of construction. Reliance on quality control and inspection alone will not help achieve the right quality which is the collective output of all processes involved during manufacturing. The focus must shift to ‘how we do’ from ‘what we check’. A well-established quality system will help interlink the key processes, measure the output of each process and continually improve the processes to make them more efficient. As a result, the products not only meet the regulatory needs but also achieve the desired quality level consistently and perform reliably.
Introduction
Boilers and pressure vessels are manufactured globally following certain codes and standards as normally stipulated by the national regulatory body at the location of installation. The requirements are typically established by way of a contract placed on the manufacturer by the buyer/user which details the scope, specification and selection of national/international codes of construction. Construction codes do specify minimum requirements to follow in respect of design, materials, fabrication process, inspection and testing, and certification to ensure safe operation. Often contracts stipulate the requirement of independent inspection either by a third-party inspection authority or by the buyer’s representative. The manufacturers do prepare a “quality control plan” or “inspection and test plan” to list out the stages of inspection and intervention by its own QC and external inspection authority. Such quality control plans undergo review by the inspection authority and often by the buyer’s representative before the start of fabrication.
Verification at planned stages by QC and external inspectors certainly would justify the reason for accepting those stages verified but may not necessarily confirm compliance with all aspects of code construction. Does the big question remain whether limited intervention through the QC approach can assure the integrity of manufacturing processes, and the right use of competency, materials, tools and techniques? Can we assure the integrity of the whole design by checking a few sampled calculations? Can we confirm that the materials used are from a known source? With demonstrable traceability to its source? Are we in a position to confirm that production welding was indeed made using the right weld procedure with the right parameters and consumables as established by qualification? What is the reliability of the test we witness? Mere quality control and the inspection-based system can’t assure all the above aspects to a satisfactory level. The inspection-based system can identify defects to the extent those are detectable and offer a reactive approach towards correcting defects (Fig 1) Such arrangements don’t offer credible opportunities to learn from mistakes, reach the root of a failure and take effective corrective action so that the mistakes aren’t repeated again.
Whereas a quality system or quality programme can help the manufacturer of boiler and pressure vessels to identify key processes, establish controls for desired output of each process and finally integrate those to assure products with consistent quality and reliability for the intended use.
What is a Quality System?
A “Quality System” is an organization’s blueprint: it identifies its business model and processes, provides details about how its people will work together to get things done, and establishes measurable norms (some call objectives) for performance so that weak links are identified and improvements are made.
A product is a collective output of a set of business processes. Some of the processes are considered key processes for the purpose of determining the level of quality, meeting customer and regulatory requirements and compliance with the construction codes. For example, in a boiler manufacturing company the processes of sales, design, material procurement, manufacturing, quality control, testing and even despatch could play an important role in achieving overall product quality. The question may be raised as to how a sales process might influence the quality of a boiler manufactured to the IBR Code. The simple explanation is that if the design specifications, site information, customer requirements, and regulatory needs are well clarified at the contracting stage, there is a greater opportunity to do it the right first time and less likelihood of alteration and rework at the manufacturing stage. Similarly, a design process is not all about calculating the thicknesses of the pressure part according to code but to take care of the whole boiler as a product to ensure safe operation, structural integrity and guaranteed performance, for the operational conditions received as design input.
All processes are interconnected and interdependent as the output of one can influence the succeeding process. For example, a good fabrication drawing with accurate construction details, the right manufacturing method, and tolerances based on shop capability as the output of the design process would certainly help ease manufacturing and improve productivity. It is therefore essential to focus on each key process and improve upon them so that collectively those would deliver an improved product. A well-established quality system would help integrate the business processes thereby assuring quality including compliance with code and standards at every stage without much dependence on a surveillance-based approach.
A quality system or quality programme is about defining the key processes and establishing suitable controls to manage those processes effectively. Some time output of a process can’t be assessed qualitatively as direct measurement of quality is not possible. Such processes are called “special processes” like welding, painting etc. Therefore process control is crucial for such processes to achieve consistent quality output. Let’s have a look at some of the elements in process control.
The process can be defined as a set of actions or steps or activities undertaken in order to achieve a particular outcome based on a given input. For example, let’s consider the fabrication process which has multiple actions or operations to convert a piece of metal plate to a pipe. The input here is the drawing /specification of the pipe giving size and shape and the raw material plate. Now the fabrication process will involve several activities like marking, cutting to shape, rolling/forming, welding, heat treatment etc. Each of these activities needs to be managed in such a manner that the end result would meet the requirement of specification and we shall get a good quality pipe. It is important to note here that the drawings and materials also should have come through controlled processes to ensure the right quality of the end product pipe.
There are four major controls available to manage a process for desirable output (see Fig 3):
- Process, procedures, techniques
- Technology
- People
- Organisation culture
Processes, procedures, and techniques are tools to control a particular activity or group of activities. Typically, these are documented instructions describing how to perform an activity. Technology contributes to process improvement, accuracy, and repeatability in operations by way of automation or the use of advanced technology. People are the key to managing any process. The skill and competency of people would possibly have a larger impact on the level of quality output. Lastly, the organisation culture encourages people to work in a team and complement each other for a significant output.
An Organisation must find a balance between these four mechanisms for optimal control of a process. Control mechanisms described above are interdependent and therefore the degree of application of a particular mechanism would depend on others. For example, a process managed by highly qualified and competent people may not need many documented work instructions to perform their tasks compared to a situation where available skill is of average nature.
Now once the controls are in place, measurable objectives may be set to monitor the performance of the process and its effectiveness to achieve the desired output. This is a crucial part of process control as it offers the opportunity to identify the root cause of a problem and fine-tune it by taking corrective steps to eliminate the root cause. This is a much different approach from just correcting a defective item as is usual in an inspection-based system. A quality system with a process-based approach would facilitate the elimination of a root cause thereby improving the process with less defective output.
Role of people in Quality system
Often, we hear that a well-established quality system doesn’t depend on people. It is not entirely true as the effectiveness of a quality system would depend on the people who operate within the system. The role, responsibility and authority of people at all levels must be well clarified commensurate with their competency for a quality system to function efficiently. There are three categories of people in a quality system:
- a) “Performer” like a designer, recruiter, shop production supervisor, material procurement personnel, welder, radiographer etc.
- b) “Verifier” like QC personnel, internal auditor etc.
- c) “Knower” like managers, senior management, finance
In a quality control-based programme, more emphasis is usually given to the “verifier” who is given the task of verifying each and every piece of work done by others. It is not only time-consuming but also has certain limitations in verifying all aspects of construction, particularly those involving special processes. Moreover, it adds to the cost of quality as time and effort are spent on detecting defective items, and reworking and repair of those items.
Quality can be built by the “performer” of an activity and therefore a strong quality system will have equal focus on those who perform work, be it a drawing preparation, purchase order issue, storage of materials, manufacturing a dished head or conducting non-destructive testing. A quality system would capture these activities and identify corresponding controls including responsibility and authority. Good record-keeping is an essential part of an efficient quality system.
The “knowers” are the people who take decisions based on available data. A good quality system would promote measurement of performance and supply of credible data to management for efficient resource planning and investments in technology etc.
Quality System requirements by International Boiler Codes
Recognised International codes for boiler construction such as ASME Sec I, EN 12952, EN 12953, AD 2000, and TRD (Technical Regulations for Boilers in Germany) all have requirements for manufacturers to operate the documented quality systems. European Code for water tube boiler EN 12952 Part 5, Annexure F has described the quality management system for the manufacturers to address various elements like a quality manual, document control, organisation, design, purchasing, manufacturing, examination, and field assembly. This section further referenced ISO9001 and ISO3834 – 2 &3 as the quality management system standards to comply with by the manufacturers. ISO9001 is the quality management system standard providing a generic structure to manage the key business processes seeking continual improvement. There is a great focus on leadership and management accountability towards quality and meeting regulatory requirements. ISO 3834 series is a set of quality system standards specific to manufacturing organisations using fusion welding of metallic materials.
ASME Boiler code has very specific requirements for boiler manufacturers to implement a quality control system and its evaluation by ASME designee during assessments. Let us look at how a quality system is defined by ASME Sec I, rules for the construction of power boilers.
“PG-105.4 Quality Control System. Any manufacturer or assembler holding or applying for a certificate of authorization shall demonstrate a quality program that meets the requirements of ASME CA-1 and establishes that all code requirements including material, design, fabrication, examination (by the manufacturer), and inspection for boilers and boiler parts (by the authorized Inspector) will be met.”
CA-1 is the standard for conformity assessment by ASME International. It is noteworthy that the emphasis is on demonstrating the quality system to ensure that all code requirements are met.
ASME Sec I, A 301 has described the requirement of a written quality system which shall be made available to the ASME designee during his audit. A written documented quality system consists of a quality manual supported by quality procedures and instructions. The boiler manufacturer or assembler has the freedom to prepare the quality manual and procedures to suit its organization, operations, products and complexities. The outline of the written quality system is provided in A 302 of Sec I. Let us discuss these elements in brief.
- Authority & Responsibility: The role responsibility and authority of people involved in the quality system shall be clearly documented. Persons involved directly with quality control functions shall have well-defined authority and organizational freedom to identify the quality problem and initiate action to avoid those.
- Organization: An organization chart to show the relationship between the management and other functionaries like engineering, purchase, manufacturing, and QC to reflect the actual organizational structure. The purpose is to identify the organizational groups and associate them with relevant functions for which they are responsible. This helps create a synergy between the functions and achieve compliance with the code at all appropriate stages.
- Drawings, Design calculations and Specification control: The manufacturer shall have a documented procedure to ensure that current approved documents are used for ordering materials, manufacturing, inspection etc. Also, the purpose of a system is to ensure that design documentations are prepared by authorized and competent personnel.
- Materials Control: The quality system shall describe how materials are ordered, received, and stored with accurate traceability. The controls shall be established to ensure receipt of correct materials with identification marking and test reports as required by code. The correct issue of materials to shop also needs to be addressed.
- Examination and Inspection programme: The quality system shall address adequately how the fabrication process is carried out, and QC inspection is carried out with documented evidence of stages being complied with code and standards. The Authorized Inspector (AI) who provides the designated oversight, shall have the right to identify stages for his “Hold” and “Witness” inspection.
- Non-Conformities control: The manufacturer shall have documented process to identify non-conformities at any stage of construction and a systematic method to correct those non-conformities with the agreement of AI. The item can only be considered for code-required stamping and certification only after closing out all non-conformities satisfactorily.
- Welding Control: The quality system must address a process to qualify welding procedure and welder performance qualification as per Sec IX and another part of the code. The qualification and responsibility of those involved with qualification shall be adequately addressed. The process shall also describe how production welding will be controlled to ensure code compliance.
- Non Destructive examination (NDE): The quality system shall describe the NDE methods and procedures which are to be used during boiler construction as per Sec I. The system shall address how NDE personnel and procedures are qualified and certified before use.
- Heat Treatment: The quality system must address the methods, controls and verification process to ensure that code-required heat treatments are completed.
- Calibration: Measuring instruments and test gauges used for Sec I boiler construction must be calibrated with required accuracy according to recognised national standards and ASME code.
- Record Retention: The manufacturer’s quality system shall describe the type of records to retain as objective evidence and duration to demonstrate how compliance with the code was made. Such records are subject to review by the ASME designee and authorised inspection agency.
- Sample Forms: The documented system shall have identified controlled formats which are to be used for recording various activities in code construction
- Inspection of boilers and boiler parts: this section shall describe the inspection by the authorized Inspector, and how the manufacturer’s representatives will coordinate and arrange for his inspection as per code. The AI and his supervisor shall have full access to all documents and sites of fabrication during code construction. The AI must be provided with a copy of the current quality manual for his review and acceptance before the start of a coding job.
- Pressure relief device: this section is meant for boiler safety valves manufacturer to describe how code compliance would be ensured with required oversight by a certified individual.
- Certification: This section shall describe how documents are reviewed and authorized/approved for release within the organisation. If any different method other than written signatures is used, the quality system must describe the procedure to ensure the integrity of the approval and authorisation process.
Indian Boiler Regulation
Indian Boiler Regulations-1950 has a set of administrative and technical regulations which are to comply during the construction and installation of a boiler in India. According to Boiler Act 1923, the manufacturer of the boiler must make such facilities available at its premises which are essential for meeting the regulations specified in IBR and for the verification competent person. Regulation 4(c) stated that boiler manufacturers must carry out manufacturing activities under the supervision of a competent person. Places like Reg 248 mentioned certain capabilities of manufacturers in respect of welding machines, non-destructive and other testing, heat treatment etc. Also described the scope of inspection witness for the competent person including drawing approval. However, there is no specific mention of a quality system and its implementation by allocating responsibility and authority for various functions within a manufacturing organisation. It is therefore important for the inspecting authority and competent persons to encourage the manufacturer to implement a quality system in similar line with international codes to ensure the integrity of the functions with adequate process control. Such a quality system would not only help the manufacturer perform its activities efficiently but also support the inspection by competent persons in a more robust manner to ensure compliance with regulations. The inspecting authority may perform initial and periodic assessments to ensure continuity in the system with improvements.
Conclusion
A well-established quality system will allow for good control over key processes and improve efficiency by optimizing resources. It will help the manufacturer by bringing more transparency in working processes and thereby accountability of people responsible for the process. The process of quality control and statutory inspection will be more effective and reliable when backed up by a documented system and records generated during operations. It is the time for Indian boiler industry to recognise the “Quality” of a product that depends on how it is ‘built’ and not how it is ‘inspected’.
