From compressor air receivers to steam boilers, every piece of equipment that works under pressure is a serious risk on site. In Türkiye, periodic inspection of pressure vessels is therefore not optional: it is a legal duty of the employer. This article explains when the inspection must be done, who may do it and what it covers, based on the Regulation on Health and Safety Conditions in the Use of Work Equipment (İş Ekipmanlarının Kullanımında Sağlık ve Güvenlik Şartları Yönetmeliği) as amended on 23 December 2025. It is especially useful for international companies operating plants in Türkiye, where the rules differ from those in many other countries.
What Is a Periodic Inspection?
The regulation defines periodic inspection as examinations and/or tests of work equipment carried out by authorised persons at the intervals and using the methods set out in the regulation. For pressure vessels this means document review, visual inspection, checks of safety devices, a hydrostatic test and, where needed, non-destructive testing. The result is a periodic inspection report stating whether the equipment can be used safely.
Which Equipment Must Be Inspected?
Table 1 of Annex III of the regulation lists pressure vessels and installations and their inspection periods. For the following equipment, the interval is at most 1 year, unless the relevant standard sets a different period:
- Steam and hot water boilers
- Heating (central heating, hot water and similar) boilers
- Thermal oil boilers
- Compressed air and gas tanks (including mobile or fixed compressor air receivers)
- Closed expansion tanks
- Calorifiers and accumulation tanks
- Dyeing machines (vessels)
- Steam cooking kettles
- Autoclaves
- Storage tanks for hazardous liquids (atmospheric, dished or prismatic)
Some equipment follows different rules:
- LPG and similar liquefied gas tanks are inspected (examination only) at the intervals given in a written plan prepared by the employer according to the relevant standards, with a reassessment at the end of 10 years.
- Cryogenic tanks follow the periods in TS EN ISO 21009-2 and TS EN 14197-3.
- API 650 type vertical cylindrical steel storage tanks have a maximum interval of 10 years.
These are maximum intervals. A risk assessment that considers the equipment’s age, frequency of use, environment and previous inspection results may require more frequent inspections.
When Is an Inspection Required?
In addition to the regular inspection, Article 7 of the regulation requires an inspection:
- After installation and before first use, where safety depends on installation and assembly conditions
- After major maintenance and repair
- For stationary equipment, every time it is relocated
- After events that may compromise safety, such as accidents, natural events, changes in operation or long periods out of use
The operator must also check the equipment visually and test its functions before each use. Equipment showing cracks, excessive wear or similar findings is taken out of service and immediately submitted for periodic inspection.
Who May Carry Out the Inspection?
The inspection must be done by an authorised person registered in EKİPNET, the Ministry of Labour’s register of periodic inspectors. For pressure vessels and installations, the regulation lists the eligible professions: mechanical, metallurgical and materials, mechatronics, chemical, manufacturing and aeronautical engineers, technical teachers with a mechanical or metal education background, and mechanical technicians. Inspections by unauthorised persons are invalid.
Other rules to be aware of:
- İSG-KATİP contract: the employer and the inspector must sign and mutually approve a contract in the İSG-KATİP system (the Ministry’s online OHS platform) at least 1 day before the inspection. Reports issued without a contract are invalid.
- NDT personnel: non-destructive tests carried out as part of the inspection must be performed by personnel certified to at least Level 2 under TS EN ISO 9712.
- Accreditation: periodic inspections of LPG tanks and installations may only be carried out by authorised persons working for an equipment inspection body. From 1 January 2027, the same requirement applies to steam boilers. Until the Ministry issues new rules, inspection bodies accredited by TÜRKAK to TS EN ISO/IEC 17020 for the relevant scope are accepted as equipment inspection bodies. Reports properly issued before that date remain valid for their term.
What Is Checked?
The inspection is carried out against the standard in force in the year the equipment was manufactured, together with the Simple Pressure Vessels Regulation (2014/29/EU) and the Pressure Equipment Regulation (2014/68/EU). A typical inspection includes:
- Document review: nameplate, manufacturing documents, maximum and operating pressure, maintenance records and previous reports.
- Visual inspection: shell, welded joints, nozzles, flanges and supports checked for corrosion, deformation, leaks and damage. See our visual inspection page.
- Safety devices: safety valves and similar devices must match the operating pressure where one has been set, or the maximum pressure on the nameplate where it has not. Pressure gauges and pressure switches are also checked.
- Operating pressure marking: vessels used below their maximum pressure must have the operating pressure clearly marked.
- Hydrostatic test: see the rules below.
- Non-destructive testing: where needed, wall thickness is measured by ultrasonic testing, and welds are examined for surface defects by liquid penetrant or magnetic particle testing.
Hydrostatic Test: What Pressure and How Often?
Unless the standard states otherwise, an examination is carried out at every periodic inspection, and the hydrostatic test is applied at two levels:
- At every periodic inspection (at most once a year): at the operating pressure, or at the maximum pressure if no operating pressure has been set.
- At least every three years and after every major maintenance and repair: at the test pressure given in the equipment’s manufacturing standard, or at 1.5 times the maximum pressure if the standard gives no value.
The test may be done with water or with another liquid permitted by the standard or the manufacturer.
What if a hydrostatic test is not possible? If the nature of the equipment or compelling process conditions make the test impossible, the NDT methods given as an alternative in the equipment’s standard (or, without a standard, in the manufacturer’s instructions) may be used. The reason must be stated in the report, and the NDT reports are kept as annexes to it. Importantly, under the regulation, being unable to stop the equipment or the process is not a valid reason. Maximum intervals still apply when inspection is done by NDT.
What Must the Report Contain?
The regulation defines the content of the report in detail. A valid report includes:
- Company details, social security (SGK) registration number and the İSG-KATİP contract number
- Start and end date and time of the inspection, and the start date of the next inspection
- The inspection method (standard number and title)
- Nameplate data of the equipment and the values measured
- Test values, the measuring instruments used and their calibration details
- The defects found
- The conclusion: a clear statement that the equipment may be used, or may not be used until the defects are corrected
- The inspector’s name, profession, EKİPNET registration number and signature (unsigned reports are invalid)
The employer must keep the reports, with a wet or secure electronic signature, for as long as the equipment is in use.
What If the Report Says “Not Suitable”?
If the report states that the equipment must not be used until defects are corrected, it may not be used until they are. The employer must place a clearly visible warning on the equipment. After the defects are corrected, a second inspection is carried out and a new report is issued stating that the equipment may be used.
For equipment whose report format and criteria have been published by the Ministry, defects are graded as minor or major. Minor defects must be corrected before the next periodic inspection, or they count as major. Equipment with major defects may not be operated until they are corrected.
Employer Checklist
- List your pressure equipment and the date of each one’s last inspection.
- Approve the İSG-KATİP contract at least 1 day before the inspection.
- Carry out the preparations the inspector asks for (draining, access, isolation and so on).
- Record operators’ daily visual checks and all maintenance and repairs.
- Keep reports for the life of the equipment and follow up any “not suitable” results.
- If you operate steam boilers, plan inspections from 1 January 2027 with an accredited equipment inspection body.
Frequently Asked Questions
How often must a compressor air receiver be inspected?
Compressed air and gas tanks, including compressor air receivers, must be inspected at least once a year unless the relevant standard sets a different period.
Can our OHS specialist carry out the inspection?
No. Only authorised persons from the professions listed in the regulation and registered in EKİPNET may do it. Joint health and safety units (OSGBs) and their staff may not provide periodic inspection services, and a person who maintains a piece of equipment may not carry out its periodic inspection.
At what pressure is the yearly hydrostatic test done?
At every periodic inspection the test is done at the operating pressure, or at the maximum pressure if no operating pressure has been set. The higher-pressure test is done at least every three years and after major repairs, at the test pressure of the manufacturing standard or 1.5 times the maximum pressure.
Where must the report be kept?
At the workplace, available for inspection by the authorities, for as long as the equipment is in use. Mobile equipment used away from the site must carry its latest report with it.
Conclusion
A periodic inspection only fulfils its purpose with the right interval, an authorised inspector, a valid contract and a complete report. FKT NDT carries out periodic inspections of pressure vessels and boilers, and the related non-destructive tests, on site. Contact us to plan the inspection schedule for your equipment.
This article is based on Türkiye’s Regulation on Health and Safety Conditions in the Use of Work Equipment (Official Gazette 25.04.2013/28628) as amended in Official Gazette 33116 of 23.12.2025. Legislation may change; the current Turkish text is available at mevzuat.gov.tr.