Its inspectors, as referred to in this section, must be persons employed by inspection organizations recognized as a valid inspection authority (see 1-3-7) in the country of manufacture or installation.
The inspector, to inspect or certify boilers under the provisions of this standard, must be independent of the manufacturer and the buyer and not hire any of them, except in cases where the boiler is purchased by government agencies or under the auspices. In these cases, the recognized inspection units of these organizations can carry out the inspections specified in this standard.
Inspection during boiler construction:
Each boiler must be inspected by an official inspector or certified by a reputable inspection authority during construction. Adequate inspections must be carried out to ensure that materials, construction, and testing are in all respects in accordance with this standard.
A reputable inspection authority has the right to request evidence that the design complies with this standard.
A reputable inspection authority should have access to the boiler builder’s work while the work is in progress and should be free to inspect the construction process and to reject any parts that do not comply with this standard.
Prior to the construction of the boiler, the reputable inspection authority must inform the manufacturer of the stages of construction in which special material tests will be performed, and the manufacturer must inform the inspection authority when these steps will take place, but This should not preclude valid inspection reference tests from being performed at any of the other stages or from rejecting materials and procedures whenever they are found to be defective.
A reputable inspection authority should perform the tests in the following steps:
A: When the sheets reach the boiler factory:
Inspect the characteristic marks on the sheets with those registered in the sheet manufacturer’s certificate.
The reported results of mechanical and chemical properties in the sheet manufacturer’s certificate should be checked with the specifications provided in the standard.
Monitoring for marking test plates for identification before the mother sheets are cut.
B: When a shell sheet and end plates are formed and the edges of the sheets are ready for welding, and when the test plates are joined.
C: During the various stages of welding below, if appropriate to the welding method and as agreed between the manufacturer and the inspection authority.
1: When the first layer of welding is placed along the main joints and test plates.
2: When these weld seams are completed on one side and are ready for welding on the other side of the boiler.
3: When the pimples are completed.
D: Inspection of radiographic films or non-destructive test reports.
E) When the welding test specimens are prepared from the pre-selected test plate to certify the required tests.
F: When the valves are ready, when the base pipes or similar fittings are welded in place, and subsequently when the boiler is completed.
G: When the construction of the boiler is completed, during the hydraulic test and again after the end of the test for internal and external inspection.
Boiler pressure tests:
When all welds have been completed and after heat treatment, if required by the regulations, each boiler must be hydraulically operated at a pressure equal to 1.5 times the design pressure, without any sign of weakness or defect. To be tested. A reputable inspection authority must witness the test.
The pressure test should be continued for at least 30 minutes.
From a safety point of view, it is important that the boiler is properly vented to prevent air bubbles from forming before the pressure test.
Note 1: It is recommended that the water temperature not be less than 7 ° C during the hydraulic test.
Note 2: After 30 minutes, it is recommended that the pressure be reduced to a minimum of 1/1 design pressure and a maximum of 0.9 hydraulic test pressure before approaching the boiler for close inspection.
NOTE 3: At the end of the hydraulic test, the discharge should be gradual.
After completing the boiler inspection process, if it is found that repairs are needed during or after the hydraulic test, the repairs and any heat treatment, the boiler should be re-tested under pressure according to the method described above. Dad.
Providing boiler documentation:
– Maps, documents and information sheets of the boiler:
Drawings, documents or information sheets, complete information about the dimensions and design pressure of each boiler along with details of the materials used in its construction must be provided by the manufacturer to the buyer and a valid inspection authority. If the installation of the boiler on site is not accepted by the manufacturer, he must provide complete information about the proper installation of the boiler.
After completing the boiler, if necessary, appropriate drawings, documents and information sheets for the knowledge of a valid legal authority should be accompanied.
Radiographic films, ultrasonic test reports, heat treatment diagrams, and records of in-house inspections must be retained by the boiler manufacturer for at least 5 years after the boiler inspection process.
In the boiler inspection process, the manufacturer must issue a certificate stating that each boiler has been designed, constructed and tested in all respects in accordance with related standard. This certificate must be certified by a reputable inspection authority as evidence that the boiler has been constructed and tested in this way. If the installation has been inspected by another reputable inspection authority, each reputable inspection authority must certify the certificate in relation to the work they have supervised.
If the design and construction operations have been carried out by separate organizations, each organization must issue a certificate for the work. Alternatively, a joint certificate can be issued signed by each organization in connection with the work done. Each certificate as mentioned above must be certified by a reputable inspection authority.
The certificate must include the maximum allowable working pressure (design pressure) and boiler number of the boiler.
Inspection process of boilers during construction in accordance with the laws of the National Standard Organization of Iran has mandatory standards No. 4231 and 7911. Adequate and thorough inspections must be carried out to ensure that consumables, construction and testing are carried out in all respects in accordance with these national standards. Therefore, according to mandatory standards No. 4231 and 7911, each boiler must be inspected during the construction process by official inspectors or certified by the National Accreditation Organization of Iran.