• Visual Test as per MSS SP-55
• Dimensional Test
  
  • Face-to-face dimensions as per ANSI/ISA-75.08.01, ANSI/ISA-75.08.06, and ASME B16.10.
  • Flange facings and dimensions as per ASME B 16.5
• Body Marking as per ASME B 16.5, ASME B 16.34, and MSS-SP 25.
• Chemical analysis and mechanical properties as per the applicable ASTM material code
• Non-destructive test as per ASME B 16.34
• Hydrostatic test as per ASME B 16.34 or MSS-SP61
• Seat leakage test as per ANSI/FCI 70-2.
• Functional and Performance test as per IEC 60534-4 and ISA 75.13.01

The following tests can be performed according to API 6D, API 6DSS, API 598, EN12266-1 or to customer specific requirements

• Hydrostatic testing
• Low pressure gas seat testing
• High pressure gas testing

In general, specification such as API598 or MSS SP-61 that govern leakage for soft seated valves call for ‘0’ bubbles of air or ‘0’ drops of water under the specified test conditions over the minimum test time period. These valves are therefore sometimes referred to as ‘zero leakage’ valves.
In reality, there really is no such thing as ‘zero leakage’, since microscopic amounts of material may indeed cross the seat or packing boundaries, especially if helium or hydrogen or other small molecule gases are used. Another common term for soft seated valves is ‘bubble tight’.

Less frequently, the leakage performance for soft seated valves is referred to as Class VI, which is the tightest leakage under FCI 70-2, and generally applies to resilient seated control valves (as opposed to metal seated control valves or soft seated shut off valves).
In fact, FCI 70-2Class VI (formerly ANSI B16.104) allows a small number of bubbles per minute, increasing with valve size, during the test, whereas API598and MSS SP-61 do not (for soft seat, but does for metal seat). FCI 70-2 Class VI is for soft seated control valves but is frequently used as a leakage acceptance test criteria for metal seated isolation valves such as ball and butterfly valves.
FCI 70-2 only requires a low-pressure test, consequently closure and seat tests should also be done per API 598 or MSS SP-61.

In actual fact even for metal seat valves the API 598 leak acceptance criteria for metal seated valves allows less leakage than FCI 70-2 Class VI above 150NB (6”) and 50NB (2”) and under. For zero leakage metal seated valves API 6D or API 598 soft seated zero leakage criteria can be specified (such as triple offset metal seated butterfly valves and some metal seated ball valves).
Special provisions for zero leakage gate valves can also be specified to BS 6755 and ISO 5208 under special zero leakage classes.
Metal seated valves, on the other hand, usually(not always, triple offset butterfly and ball valves for instance are available bubble tight) have some level of acceptable leakage when tested, defined first as some acceptable amount of liquid, under test conditions and over the time period of the test.

ISO 5208 (EN 12266-1) supersedes BS 6755-1 and specifies acceptable leakage rates such as ‘Rate A’ and ‘Rate B’. Rate A allows ‘no visible leakage’, similar to API 598 for resilient seated valves. Rate B is used for gate valves.

VT - Visual Testing

Visual Testing (VT) is an optical method to check objects for discrepancies. You can check with the naked eye as well as with tools like magnifying glasses or mirrors. Many imperfections, such as external cracks, can already be found with visual testing, which makes this type of inspection a simple but powerful procedure. It can be used to check some imperfections of welds, fractured surfaces, corrosion phenomena or grinding.

MT - Magnetic Particle Testing

Visual Testing (VT) is an optical method to check objects for discrepancies. You can check with the naked eye as well as with tools like magnifying glasses or mirrors. Many imperfections, such as external cracks, can already be found with visual testing, which makes this type of inspection a simple but powerful procedure. It can be used to check some imperfections of welds, fractured surfaces, corrosion phenomena or grinding.

PT - Penetrant Testing

Liquid Penetrant testing (PT) is a flexible procedure that uses the capillary forces of cracks or pores. For this purpose, color or fluorescent penetrant (contrasted) is applied to a cleaned component, e.g. with a spray can, followed by a ‘developer’. The penetrant then ‘creeps’ into the smallest cracks and reveals the imperfections. Important for the handling of the substances are environmental aspects, storage, disposal and correct transport. For dye penetrant testing, the colors red and white (contrasted-developer) are usually used. Care should be taken with rough or brittle surfaces, as this can lead to so-called false readings, or with the color intensity, as these do not necessarily indicate the depth of a crack.

UT - Ultrasonic Testing

Ultrasonic testing (UT) allows a view into the inside of a component. To do this, a probe is moved over the surface of a component and the ultrasonic waves emitted by it or their reflections are tracked on a screen. A phased-array imaging test can also be performed, which allows easier interpretation. Both flat and voluminous imperfections can be inspected. In the case of surface imperfections, it is often superior to radiographic testing (RT). It is used, for example, for wall thickness measurement with vertical probes and for simple geometries with angle probes.

RT - Radiographic Testing

Industrial radiography involves exposing a test object to penetrating radiation so that the radiation passes through the object being inspected and a recording medium placed against the opposite side of that object. For thinner or less dense materials such as aluminium, electrically generated x- radiation (X-rays) are commonly used, and for thicker or denser materials, gamma radiation is generally used.

Gamma radiation is given off by decaying radioactive materials, with the two most commonly used sources of gamma radiation being Iridium-192 (Ir-192) and Cobalt-60 (Co-60). IR-192 is generally used for steel up to 2-1/2 - 3 inches, depending on the Curie strength of the source, and Co-60 is usually used for thicker materials due to its greater penetrating ability.

The recording media can be industrial x-ray film or one of several types of digital radiation detectors. With both, the radiation passing through the test object exposes the media, causing an end effect of having darker areas where more radiation has passed through the part and lighter areas where less radiation has penetrated. If there is a void or defect in the part, more radiation passes through, causing a darker image on the film or detector

Tensile Test

The tensile test is used to determine the strength (yield point, ultimate tensile strength) and toughness (elongation at break) of a material.

Tension test, also known as tensile test, is associated with the mechanical test of metal products subjected to a restrained load enough to bring to the rupture. The force applied is perpendicular to the cross-sectional area of the test item. Full section specimen will be tested in a 200 mm gage (8 in.) length. Four mechanical properties are determined from tension test, Yield Strength, Tensile Strength, Elongation & Reduction of Area

Bend Test

The qualitative ductility of material is determined by using bend test. In bend test, the specimen is bent over a specified diameter to a specified angle for a specific amount of time. After bending, the stressed side of bend test specimen is checked and verified. If no crack observed it indicates that the material had a good ductility, propagation a major crack on the bent side shows that the material lacked adequate ductility. The ASTM E290 provides the test procedure for bend test.

Impact Test

The material property changes from ductile to brittle in the certain temperature, as you decrease your services temperature, your ductility will be decreased, and your tensile strength will be increased. Reduction in ductility means your risk for brittle fracture will be higher.

If you drop a plain carbon steel 10 in. by 10 in. Plate from 6 feet height to concrete floor, you will only hear an impact noise and nothing more, but if you place this plate in laboratory freezer and cooled it down to the -100-degree F and then drop it, probably it will hit the floor and breaks to the several pieces.

Compression Test

In the compression test, a standardized specimen is loaded under compressive stress until it breaks or until a first crack appears.

Hardness Test

With the Brinell hardness test, a carbide ball is pressed into the material. The indentation surface serves as a measure of the hardness. (Brinell hardness test, Vickers hardness test & Rockwell hardness test)

Charpy impact Test

The Charpy impact test (Charpy V-notch test) is used to measure the toughness of materials under impact load at different temperatures

Fatigue Test

The fatigue test provides information about the strength of a material under continuously changing stress (dynamic load).

Chemical testing and analysis are vital for regulatory compliance and to understand the quality and composition of chemical substances and materials that are used in products, industrial processes and manufacturing.

Element’s intergranular corrosion testing helps reveal errors of batches that are incorrectly processed, and highlight any areas where updates are needed. We utilize different chemicals and test conditions to evaluate a range of metallic materials for intergranular corrosion, including stainless steel (austenitic, duplex and ferritic grades), nickel alloys, and aluminium alloys. Using a variety of methods, including ASTM A262, ASTM G28 and ASTM A763, we can provide critical data about the metals corrosion resistance to prevent failures in the field.

We have our own Thermal shock apparatus to test the glasses for gauges as per BS-3463-1975. ASVIN has the facility to conduct this test in their premises.

The Valve Shell test or body test is conducted based on the valve manufacturer approved test procedure. The most valve manufacturers standard procedures are driven by the requirements of API 598 (Valve Inspection and Testing) and ASME B16.34 (Valves — Flanged, Threaded, and Welding End)

The valve is mounted on the test bench and shall be partially open. The valve body is subjected to the hydrostatic pressure. The result of the test will be satisfactory if no leak observed from the valve body, packing gland, etc. No leakage is acceptable. The pressure also shall not be dropped during the test. 

For example, if you have a valve with cast steel material (A 216 Gr. WCB) and rating of 2500, you should refer to the table 2.1.1 in ASME B16.34. The table says your working pressure is 425.5 bar at 38°C (100°F). It equals to the 6524.85 psi. Now multiply this value by 1.5 and your test pressure will be 9382.3 psi. You have to round it to the next 25 psi, and it will be 9400 PSI.

Valve Body Test Duration

On both API STD 598 and ASME B16.34 shell test duration depends on the valve size. The valve size less or equal 2 inch the test duration will be 15 seconds, between 2 1/2 and 6 inch 60 seconds, between 8 and 12 inch 120 seconds and above 14 inch will be 300 seconds. 

The test water temperature shall be between 41°F (5°C) to 122°F (50°C). If the valve material is the stainless steel, then chloride ion content shall be less than 100 ppm.

The applied pressure gages for shell test shall be calibrated and pressure gage shall not be less than 1.5 times of test pressure and not be more than 4 times of test pressure. In above example, a 15000 psi pressure gage will be appropriate, but a 12000 psi pressure gage will not be accepted since the range is less than 1.5 times of test pressure. 

Common industry guidelines for pressure testing valves can be found in ASME B16.34, API 598, MSS- SP-61, API 527, and ISO 5208. Many tests are recorded on paper wheel charts or manually, although digital options are becoming more prevalent.

The API STD 598 requires the valve being tested at 110% of the maximum allowable pressure at 38 °C (100 °F). The ASME B16.34 requires the test be performed not less than 110% of the 38°C (100°F) pressure rating which almost is the same. 

If you have a valve with 2500 pressure rating and with cast steel material such as A216 Gr. WCB, then your maximum working pressure as per ASME B16.34 table 2-1.1 will be 425.5 bar (6254.85 psi). The 110% of this value will be 6880.3 psi. So you have to perform seat leak test with 6880.30 psi.

Valve Seat Leak Test Duration

ASME b16.34 require the seal leak test be performed 15 seconds for valves with size less than 2 inch and 30 seconds for valves between 2 1/2 to 8 inch, 60 seconds for valves between 10 and 18 inch and 120 seconds for valves greater than 20 inch. The API 598 timing requirement is similar

During seat leak test valve shall not leak from the stem and packing, and the leak will not be permissible. The certain amount of leakage from sealing surface of disc and seat is permissible.

The API Std 598 provides the allowable amount of leakage in Table 6, and it is measured based on drops per minutes. The amount of leakage also depends on the valve size. 

In above example, the valve shall be tested at 6880.3 psi and the pressure shall be held for 120 seconds (we assume the valve is 24 inch). During these 120 seconds, the amount of leakage shall not be more than 48 drops /min. (as per table 6 in API 598)

A graduated lab test tube is used for measurement of the leakage. The other side of the valve connected to this tube and amount of leakage is measured.

You do not need to count the drops; you just need to keep the time (120 seconds in above example). 1 millilitre is equal to 16 drops. you can convert millilitre to drops after completion of the test and determine the test result. 

The ASME B16.34 does not provide the permissible leakage values and refers that to the agreement

The test pressure shall not be less than 110% maximum allowable pressure at 38 °C (100 °F). For example, if you have a 900 Ib, 20 inch valve with A216 Gr. WCB material, your MAP will be 2252 psi (as per Table 2-1.1 ASME B16.34). The 110 % of this value will be 2477 psi. So your backseat test pressure will be 2477 psi. 

Backseat Test Duration

The valve test duration depends on the valve size as per API Std 598. The test duration is 15 seconds for valve less than 2 inch, 60 seconds for valves greater than 2 inch  The valve packing gland shall be closely inspected while it is under backseat test pressure. Similar to valve shell test, no leak is acceptable for backseat test.

We specialise in Helium leak testing of valves, which, among all, represent the ideal solution for leak testing in valves. This method is characterised by a very high level of sensitivity, quantifiable and reliable results, and the possibility to partly or fully automate the process, integrating it directly into the manufacturing line too if required. In order to seal to less than 10 -7 , the valve loading tension is increased, which somewhat lowers the maximum operating temperature and the valve lifetime. Currently, only select material can seal to 10 -8  in most valve styles. Valcon M rotor material can seal to 10 -10 , but has a temperature limit of 50°C.

Not all valves can achieve these leak rates. As a general rule, the larger the valve seal and port size, the higher the leak rate. ASVIN Valve can perform type testing on valves of all sizes, materials and types.

To make Nuclear Power Plants (NPP) more acceptable by the public, there is a need to conform to the stringent safety criteria evolved continuously. Among the several safety aspects, the seismically induced effects call more attention at the present scenario. But the adequate full scale testing of the critical components can render a more realistic simulation. Extensively shake table testing is used for the seismic qualification and research purposes. It provides the means to excite structures in such a way that they are subjected to conditions representative of true earthquake ground motions.

The seismic qualification tests were conducted as per the test procedure given in IEEE STD 344-1987 standards. IEEE recommended practice for seismic qualification of class 1E equipment for Nuclear Power Generating Station. Valves are one of the active components in the SFR system. The seismic operability of active components can be established only by shake table testing. Shake table testing includes fixing of the equipment into the shake table, exiting the table with a seismic excitation equal to or larger than the design earthquake, resonance search test in all the three directions for 1 to 50 Hz to identify the system frequencies and assessment of the functionality and structural integrity of the valve during and at the end of the test.

The valve that has been experimentally qualified completed type test for OBE & SSE cycles, the same will not be utilized in the reactor application. The methodology involved in the seismic qualification of the unconventional valve presented in this paper. Among the various shake table experiments carried out for the seismic qualification unconventional valves, the experiment carried out for the Inclined Fuel Transfer Machine (IFTM) Gate valve is referred in this paper for the above purpose. It is one of the unconventional type large in size and heavy gate valve available in the SFR system. ASVIN Valve can perform type testing on valves of all sizes, materials and types.

For valves with fire safe requirement, offered valves should have type fire test certificate as per BS EN ISO10497 / API 6FA / API 607. ASVIN Valve can perform type testing on valves of all sizes, materials and types.

Valve “type testing” is a new protocol where valves are tested at the operating pressure and temperature ranges specified by the manufacturer. This requires that some valves are tested at temperatures down to the cryogenic range and/or over 1000 degrees F.

In addition to the temperature and pressure testing extremes, the valves are also often required to be tested for fugitive emissions leakage during the test program. ASVIN Valve can perform type testing on valves of all sizes, materials and types.