• ČÚBP (Czech Occupation Safety Office) Prague, now SÚIP (State Labour Inspection Office) Opava
• IBP (Occupational Safety Inspectorates), now OIP (Regional Occupational Safety Inspectorates)
• ITI (Institute of Technical Inspection) Prague

Implementation of inspections:

                                  Inspectors the competence of which is regularly examined by ITI Prague

In the Czech Republic the following specified pressure equipment has been defined for in-service inspections:

• steam boilers and liquid-containing boilers

  whose design pressure is greater than 0,07 MPa and the temperature of the working substance exceeds the boiling point at this pressure;

• stationary pressure vessels

  having maximum working pressure greater than 0,07 MPa and containing gases, vapours or caustic, toxic and explosive liquids at any temperatures or any liquids at a temperature exceeding their boiling point at the pressure of 0,07 MPa;

• pressure vessels for transport of gases

  whose critical temperature is lower than +50 °C or gases having absolute pressure (vapour tension) at the temperature of +50 °C greater than 0,3 MPa.

In-service inspections of steam and liquid-containing boilers and stationary pressure vessels (though having not the exact same definition range) are performed in compliance with PED (as well as SPVD). Similarly the in-service inspections of pressure vessels for transport of gases are performed in compliance with TPED.

Safety and pressure accessories are assessed as an integral part of the specified pressure equipment and inspected together with it.

Piping is not a specified pressure equipment, however, the operators are generally responsible for the care of its operating condition and consequently for performing periodic inspections and maintenance. Piping, e.g. water-steam piping in power industry, is subject every year to a visual inspection, and gas distribution piping, defined as one of gas equipment types, is subject to so-called checks once every year and to an inspection once every three years. Pressure tests of piping after its exposure to operation are normally not carried out and the performance of the piping can be verified by defectoscopic tests, according to circumstances.

The following are notdefined as specified pressure equipment:

• (a) boilers operating with radioactive substances or boilers located in neutron flux environment;
• (b) boilers with a volume not greater than 10 litres and a product of the maximum working pressure in MPa and volume in litres not greater than 10;
• (c) pressure vessels operating with radioactive substances or pressure vessels located in neutron flux environment;
• (d) pressure vessels with a volume not greater than 10 litres and a product of pressure and volume not greater than 10;
• (e) pressure vessels consisting of pipes, even of noncircular cross-section, whose inner dimension is not greater than 100 mm, without collectors, or, if applicable, with collectors, where the collector consisting of a pipe, even of noncircular cross-section, has inner dimension not greater than 150 mm;
• (f) radiators for steam or water (liquid) heating systems;
• (g) piping, its extended parts and incorporated pressure vessels (e.g. intended for pressure relief or as storage tanks), whose inside diameter (D) is not greater than three times the inside diameter (d) of the largest connected pipe (D is less than 3 d), as well as all the extended parts of piping and incorporated pressure vessels when they are used for transport of a working substance (e.g. manifolds, separators, collectors);
• (h) pressure-bearing parts of machinery and technical equipment which are not separate pressure vessels (e.g. cylinders of piston engines, steam turbine casings, air boxes of piston hydraulic pumps, compressor coolers, pressurized casings of encased power cabinets);
• (i) hot-blast stoves, dust extractors and gas scrubbers of blast furnaces;
• (j) inflatable non-metallic equipment where the internal pressure of a compressed gas provides for its shape and stiffness (e.g. tyres, pneumatic beams, floats);
• (k) gas receptacles where the volume of the pressure-bearing volume is not greater than 0,22 litres;
• (l) non-returnable pressure receptacles for aerosols and similar uses;
• (m) transportable pressure equipment covered by a separate regulation (Government Order No. 42/2003 implementing TPED).

I. Comments on the inspection of stationary pressure vessels

Vessels have to be subject to the following inspections and tests:

• (a) initial inspections,
• (b) inspections during ongoing operations,
• (c) internal inspections,
• (d) leak tests,
• (e) pressure tests.

(a) Initial inspections have to be performed for the following:

• new vessels,
• modified or repaired vessels,
• vessels after a change in the mode of their application or after relocation, with the exception of mobile, transportable and portable vessels.

Initial inspection of vessels has to be performed prior to their putting into service and comprise the following checks:

1. compliance with the requirements of clauses 26 to 34 of the Czech standard ČSN 69 0012 “Stationary pressure vessels. Operation requirements” (national standard), conditions necessary prior to putting the vessels into operation;
2. presence of information on the installed safety valves and other safety accessories and on the instruments for measuring, regulation, control and automation in the accompanying technical documentation (passport) in accordance with the Czech standard ČSN 69 0010-7-2 “Stationary pressure vessels. Technical guidelines. Testing. Part 7.2: Passport” (national standard);
3. in the case of modification, repair or installation: compliance with the requirements of decrees and standards with regard to the authorization of the contractor and the validity and completeness of the tests carried out by the contractor, and, where applicable, the validity of exceptions to the standards or decrees granted to the contractor;
4. completion of inspections of the specified technical equipment which is part of the vessel;.
5. verification that after a change in the mode of application the new way of vessel operation complies with its intended use and that the expected operating parameters comply with the basic characteristics of the vessel;
6. compliance of the vessel with the provisions of subclauses 92 (a), (d) and (e) of the Czech standard ČSN 690012 (essentially the scope of an inspection during operation).

The results of the initial inspection must be compiled in an inspection report which has to be attached to the passport. In the case of series-produced vessels usually delivered together with a source of pressure (e.g. mobile compressors, water stations with a vessel volume less than 400 litres and maximum pressure not greater than 0,5 MPa, fecal cars etc.), instead the initial inspection report a certificate of the product quality and completeness is issued, confirmed by an inspection engineer of the manufacturer.

(b) Inspections during ongoing operations

Inspections during ongoing operations have to be performed with respect to the vessel’s type, design, condition and age, working fluid and working conditions within the following time-limits:

1. the first inspection within two weeks after putting the vessel into service;
2. subsequent inspections at least once every year and for the vessels of cooling equipment at least once every two years.

Inspections during ongoing operations comprise in particular the following checks:

1. overall condition of the vessel and its safety accessories; regulation, isolation and interlocking equipment; measuring instruments and their signalling devices; heating units of heated vessels, etc.;
2. verification that the equipment and accessories referred to in (1) are properly maintained and checked and the prescribed documentation kept;
3. mode of operation, in particular verification that the permissible limits (pressure, temperatures, levels, output, etc.) are not exceeded;
4. cleanness and order in the surroundings of the vessel and safe and sufficient access to the vessels;
5. verification that the data plates remain legible and intact;
6. verification that the operators meet the requirements.

(c) Internal inspections

The purpose of internal inspection is to check and assess the internal and external condition of the vessel, including all nozzles and accessories. The internal inspection of the vessel has to be performed:

1. normally at intervals not longer than five years with respect to the vessel’s type, design, condition and age, working fluid and working conditions.

   In the case of vessels that are parts of mobile extinguishers which are not under pressure in their availability state, internal inspections are performed after every use of the extinguisher, but not later than in connection with the pressure test, i.e. at intervals not longer than nine years.

2. before and after any modification or following extensive repairs;
3. in cases where the vessel was out of service for a longer time than two years and has to be repeatedly put into operation;
4. following every relocation of the vessel (not applies to mobile, portable, transportable and newly delivered vessels);
5. in the case of seasonal (campaign) operation, prior to the beginning of every season (campaign), with the exception of heaters for central heating and hot water production;
6. prior to a change of the working fluid or in the case of chronic impairment of its quality;
7. in cases where the vessel has been put out of service for reasons referred to in clause 81 of the Czech standard ČSN 690012, if there is danger in delay;
8. following an gas explosion in the furnace of heated vessels resulting in damage to the brickwork or to pressure-bearing components of the vessel;
9. in cases where the heated vessel was operated with insufficient quantity of the heated working fluid, likely to be detrimental to the mechanical characteristics of the material of the pressure-bearing part;
10. following a serious degradation, change or freezing of the working fluid as well as in cases of similar abnormal conditions.

Internal inspection of vessels of cooling equipment has to be performed only in cases referred to in (2) and (7).

In the case of vessels whose design precludes the internal inspection from being performed in specified time-limits or to the specified extent, the internal inspection or its substitute has to be performed in the following way:

1. in the case of inaccessible vessels (vessels without access openings, inspection covers, manholes or removable internals), the following has to be carried out every five years:
   • pressure test, unless the vessel is subject to any of the exemptions, or
   • leak test and ultrasonic check of suspected sections.

   For the ultrasonic wall thickness check, the method and instrumentation must be so chosen and used, as to ensure a sufficient measuring accuracy. The check has to be performed primarily in sections where an extensive thinning of the wall thickness could be expected;

2. in the case of internally insulated vessels, i.e. lined, rubber-coated, lead-coated or with other wall protection, only the condition of the insulation, lining and other protection has to be checked;
3. in the case of vessels with divided filling (e.g. catalysts, reactors, etc.), a partial internal inspection has to be performed so that at least once every five years each part of the vessel is examined.

(d) Leak tests

The purpose of the leak test is to demonstrate that the pressure-bearing part of the vessel including the accessories is leak-proof at the working pressure.

The leak test has to be carried out:

1. after every internal inspection;
2. in the case of need to determine more precisely the location and extent of a leak;
3. after replacement of expanded heat-exchanging tubes or pressure-bearing parts which were subjected to functional and pressure tests already during the manufacture (e.g. replaceable cooling or heating bundles) and after subsequent welding of nozzles or welded-on pieces whose outer diameter is smaller than the largest unreinforced opening, under compliance with the specified conditions.

(e) Pressure tests

The purpose of the pressure test is to demonstrate the strength and tightness of the vessel at the test pressure. As a rule it is carried out using water or, where appropriate, other non-corrosive, non-poisonous and inexplosive liquid at a temperature not higher than 50 °C. The pressure test has to be carried out:

1. not later than nine years after the previous pressure test, unless a shorter interval is stated in instructions for putting the vessels into service;
2. following every repair, adaptation or modification;
3. following an interruption of operation longer than two years, if necessary according to the internal inspection;
4. following a relocation of the vessel (not applies to mobile, portable, transportable and newly delivered vessels), if necessary according to the internal inspection;
5. after exceeding the maximum working pressure or the maximum working temperature which could impair the quality of the vessel wall material.

In the case of vessels which on serious technical grounds cannot be subject to a pressure test under specified conditions, and provided that the health or safety of persons is not endangered, the pressure test or its substitute has to be performed in the following way,:

1. air boxes located in the area of a distribution system or air boxes which are part of a distribution system are subject to a pneumatic tightness test using the working fluid and to an ultrasonic check of suspected sections once every nine years;
2. vessels with internal lining, rubber-coated vessels or vessels with other wall protection are subject to a pressure test after complete relining and prior to a repair of the wall protection;
3. drying drums using steam or air as working fluid and installed on supporting structure which is not able to withstand the water load are subject to a pressure test only during major overhauls;
4. vessels of cooling equipment are subject to a pressure test only during major overhauls;
5. insulated vessels with deep-cooled liquefied gases as working fluid are subject to a pressure test once every nine years; during a major overhaul, instead the pressure test, a pneumatic tightness test has to be carried out (by means of inert gas or air, where appropriate) using detection penetrants on accessible welded joints;
6. vessels which cannot be reliably drained after the pressure test, and belonging to a technological installation the process of which requires a reliably dry equipment, are subject, instead the pressure test, to a pneumatic tightness test by means of inert gas or air, where appropriate, using detection penetrants on welded joints;
7. high vessels (e.g. columns in chemical industry) with a relatively high hydrostatic pressure are subject to a pneumatic tightness test using the working fluid and to an ultrasonic check of suspected sections;
8. all-welded systems (i.e. vessels interconnected by piping with welded joints) are subject only to a pneumatic tightness test (by means of inert gas or air, where appropriate) and to an ultrasonic check of suspected sections;
9. insulated vessels with intermediate jackets are subject to a pressure test at least once every nine years; during a major overhaul a pneumatic tightness test has to be carried out (by means of inert gas or air, where appropriate) at the working pressure which must not drop after equalization of the temperature for a period of one hour;
10. inaccessible and visually incontrollable expansion vessels with a membrane or bag are subject once every five years to a leak test at pressure of the fluid increased to the value of maximum working pressure. Demountable vessels with a membrane or bag with a non-corrosive working fluid are subject to a pressure test in connection with replacement of the membrane or bag;
11. vessels of austenitic steels with an evacuated powder insulation and having liquid gases stored at cryogenic temperatures as working fluid, are subject once every nine years only to a pneumatic tightness test carried out after shutdown of the vessel and using the remaining working fluid at the maximum working pressure for a period of at least 24 hours. During this time a test of leaking into the insulation space and an examination of welded joints in accessible parts of the external and internal interconnecting piping of the vessel by a detection method are carried out;
12. vessels of oxygen plants constituting an all-welded system and located in an insulating cover of a low-temperature unit are during a major overhaul subject only to a pneumatic tightness test (using inert gas or air) for a period of at least 24 hours at the maximum working pressure maintaining constant temperatures;
13. methods of carrying out the pressure test other than those mentioned in (1) to (12) may be permitted by the supervisory body.

II. Comments on the inspection of steam and liquid-containing boilers

Boilers have to be subject to the following inspections and tests:

• (a) inspections during ongoing operations,
• (b) internal inspections,
• (c) leak tests,
• (d) pressure tests.

(a) Inspections during ongoing operations have to be performed:

1. after three months of operation,
2. following an interruption of operation longer than two months at the start-up of the boiler.

(b) Internal inspections have to be performed:

1. before and after every cleaning of the steam boiler in the space of the working substance, not later than after one year of operation. In the case of boilers with a perfect water treatment and output above 50 t/h of steam, the inspector may extend the term by a year;
2. prior to putting into operation, if the boiler was out of service for a longer time than one year;
3. before and after every major overhaul or modification and/or reconstruction;
4. before and after every relocation of a stationary boiler;
5. in the case of boilers in seasonal operation, prior to the beginning of every season;
6. following an impairment of the prescribed quality of the feedwater or boiler-water which could result in a dangerous pollution or damage to the steam boiler walls;
7. after exceeding the design pressure or the maximum pressure or the maximum temperature which could adversely affect the properties of the material of the boiler walls;
8. in all cases where the boiler has been put out of service because of safety hazards;
9. when ordered by the supervisory body.

(c) Leak tests

The purpose of the leak test is to demonstrate that the pressure-bearing part of the boiler including the accessories is leak-proof at the working pressure.

The leak test has to be carried out:

1. after every internal inspection;
2. following every opening and re-closing of the pressure-bearing part of the boiler;
3. following minor repairs, e.g. replacement of seals at removable joints;
4. when ordered by the supervisory body.

(d) Pressure tests have to be performed:

1. not later than nine years after the precedent pressure test was carried out;
2. following every relocation of a stationary boiler to a new workplace prior to its restarting;
3. following an interruption of operation longer than two years;
4. when ordered by the supervisory body.

Související

Související témata Autorizované osoby, ČÚBP, ITI, ČOI, ÚNMZ Právní a technické předpisy