To conduct a review, safe technical inspection according to the following steps:
- To prepare the testing: Item 3.1
- To check dossier: Item 3.2
- To check and handle preliminarily: Item 3.3
- To check outside, inside: Item 3.4
- To check the capability to bear pressure: Item 3.5
- To check the tightness (only apply to the cylinders containing toxic and flammable solvent-substance; other cylinders at request) Item 3.6
- Note: The following inspections are conducted only when the inspection results of the previous step has been satisfactory.
Before conducting the search: it must prepare fully human resource, tools, equipment, facility equipped to protect person necessarily, gas cylinder must be sanitized; the establishment must appoint a person to witness the search.
3.1 Preparation of testing
3.1.1 Based on the request of the establishment that has cylinders for testing, it must define the regime of testing:
+ Testing for the first time before putting the new cylinders into use: 5% of total cylinders.
+ Testing periodically or irregularly : 100% of total cylinders.
Note: Implementation of taking sample for testing at propability 5% of the cylinders must be ensured the representation for the groups of cylinder of the cylinder lot.
3.1.2 The cylinder testing may be implemented at the cylinder testing station or at the establishment requesting for testing:
+ When implementing testing at the station: to notify the establishment of the testing plans and requirements before implementing the testing, coordinate with the establishment for taking sample (the first testing).
+ When implementing testing on site: as implemented at the station and raising the requirements for the establishment to arrage the location for testing, the location for handling odd gas ... to ensure safety and environmental protection.
3.2 Inspection of dossier
Based on the regime of testing, dossier for reviewing includes:
- The first testing: profile of factory, list of cylinder lot.
- Periodical testing: The previous testing result, list of cylinders need to be tested.
- Irregular testing: The previous testing result, list of cylinders need to be tested, repair dossier.
3.3 Preliminary inspection and handling
3.3.1. To check the technical parameters stamped on the cylinder’s handle or neck; to compare with the technical data in the list of cylinders need to be tested; to remove the cylinders not belonging to the testing list and the cylinders with parameters missed orblurred.
3.3.2. To conduct visual inspection of the exterior status of each cylinder to remove the one which has abnormal phenomenom so that it is not enough qualification for normal work, such as bloated, sunken marks; broken handle, broken support; scratched by deepgrooves, pit, burning, peeled-off labels...
3.3.3.It must conduct the handling of odd gas in the cylinders for periodical or irregular testing:
3.3.4. The cylinders containing inert, inflammable, non-toxic gas may be directly discharged.
3.3.5. The cylinders containing flammable, toxic gas must be handled inner odd gas by the way of discharging, exshausting air by specially used equipment, later, air may be withdrawed for use or with safe handling measures, not directly discharged into the environment.
3.3.6. After the inner odd gas has been handled all, valve in the cylinder’s top shall be taken by specialized tools and equipment.
3.3.7.To check the tightness of valves and the safety parts (if any); to remove unsatisfactory valves.
3.3.8.To clean the inner part of cylinder; it needs to withdraw all dissolved solvent for the cylinders containing foam.
3.4 Inside and outside inspection
The inside and outside inspection is implemented according to the following orders:
3.4.1. To check the status of the surface, welds, threaded neck, support, handle.
3.4.2. To check the volum for molded, moulded cylinders and for cylinders in accordance with provisions of the manufacturers and compared to the volume of factory.
3.4.3. For welded steel cylinders (LPG ...) that the manufacturer specifies on inspection of volume, the provisions of the manufacturershall be applied.
3.4.3. To check the inside of cylinder by specialized flashing device to valuate status of the metal surface, the weld surface.
3.4.4. For cylinders having foam, the quality of foam shall be tested in accordance with guidance of the manufaturer.
3.4.5. To remove the cylinders that are unsatisfactory.
3.5 Inspection of the capability to bear pressure (hydraulic test)
3.5.1. For welded cylinders:
+ To refill fully reagents.
+ Testing pressure must be determined in accordance with provisions of the manufacturer countersunk at the appropriate position on the cylinder.
+ The time to maintain testing pressure is kept within a period of long enough time to determine the capability to bear pressure of the cylinder according to the provision of manufacturer.
+ The increase and decrease of pressure must be implemented slowly so that it shall not make sudden expansion affecting the sustainability of the cylinders.
+ For cylinders containing foam or testing by liquid not allowed, then testing by compressed gas, inert gas shall be implemented; when testing by gas, it must comply with the minimum safety conditions according to provisions in 3.15, 3.16 TCVN 6156:1996.
+ The volume expansion testing of cylinder: applied to the form of regular or irregular testing of each type of cylinder, the permanentexpansion of the cylinder is expressed by percentage of total expansion volume at the testing pressure and not exceeding 10%. Ifthis value is exceeded, the cylinder must be removed (provided in 11.2 TCVN 6294:1997).
3.5.2. For molded, moulded cylinders:
3.5.2.1.To implement as provided of the step 3.5.1. If the manufaturer provides for the standard of removing higher, it shall comply with the manaufacturer’s standard. Seperatly, it shall not be less than one minute for the time to maintain testing pressure in every case.
3.5.2.2. Based on the volume increase or the volume decrease of the cylinders to reduce its working pressure or remove them in accordance with provisions in 4.10 TCVN 6156:1996, if the manufacturer's specified standard is higher, such standard shall be applied.
3.5.3. To remove and clean reagents; to dry the cylinder’s inside.
3.5.4. To insert checked valves into the cylinders with the satisfactory testing results.
3.6 Inspection of tightness (tightness test)
3.6.1.To refill compressed gas or inert gas into the cylinder up to the pressure in accordance with provisions of the applicable standard or the manufaturer’s provisions.
3.6.2. To check tightness of connectors, valve joints ...of the cylinder with soap bubble or in the dedicated sealed testing tank. Thecyliders that are leaked must be handled and retested.
3.6.3. When the testing cylinders are satisfactory, the discharge of air, the drying of cylinders’ outside, degerating and aeration ofprotection shall be implemented (as required).