Inspection and quality control
Inspection and checking occurs at each stage in the fabrication process and after final assembly.
These checks are usually carried out by independent staff who examine for:
- Straightness
- Flatness
- Inherent defects
- Dimensions
- Connections
- Alignment of holes
- Welding
- Finishes/cleanliness
Welding will be subject to non destructive testing, often in the form of ultrasonic, magnetic particle or radiographic testing.
The nature of welding is that it is likely to include "imperfections". The skill is to ensure that these imperfections are sufficiently minor as not to become "defects", whereby they would impair the performance of the welded joint. The procedures that are used in this regard include prior approval of welder competence and the welding specifications to be used.
Where in-depth weld examination is required, this will be conducted at the appropriate stage determined by the nature of the work and to the level specified by the engineer. In the interests of economy however, it should be noted that radiographic and allied techniques are not only expensive operations but attract additional cost penalties due to the disruptive influence upon production; selective judgment should therefore be exercised to confine the programme to those areas critical to performance.
Reputable fabricators have a Quality Assurance (QA) system which complies with published standards.
Quality Assurance is achieved through a management system to ensure a firm is able to achieve and maintain the quality of services or product. This Quality Assurance may be a critical factor when architects and engineers are required to recommend a fabricator – particularly without prior personal, direct experience of working with the company.
The British Constructional Steelworks Association launched its own Quality Assurance Certification Scheme for both member and non-member companies. The principal objective is the assessment and progressive review of companies engaged in the steelwork fabricating industry and this extends to erection and work on site.
Surface treatment is normally carried out after fabrication and before delivery to site.
The treatment, such as cleaning and painting with primer, is usually carried out at the fabricator's works. For special treatments, or unusual specifications, it may be necessary to ship the fabricated components to a specialised facility. It may also be necessary to make good any small areas damaged during delivery or erection. This is particularly so when site welding is used. Further details are included in the unit on 'Corrosion Protection'.
