All pressurized gas containers must be used by undergoing regular retesting at the interval of 3~5 years by specialized testing institution in order to prevent danger of pressurized gas and to ensure safety of the public.
Test specifications

KGS
(Article 35 of the law on pressurized gas safety management)
AC 218 Less than 3,000L of container without joints (including cartilage container) (including toxic gas)
AC 217 Less than 200L welding (acetylene, cryogenic) container (excluding toxic gas)
AC 414 Less than 200L general composite container
AA 316 Container component parts for pressurized gas
DOT
(DOT 49CFR 173.34 & CGA Pamphlet)
DOT-3AA Seamless Cylinder - Max. Water Capacity 453L
Min. Service Pressure 150 psig
DOT-3AAX Seamless Cylinder - Min. Water Capacity 454L
Min. Service Pressure 500 psig
DOT-3T Seamless Cylinder - Min. Water Capacity 454L
Min. Service Pressure 1,800 psig

Name of designated tests

Types of container Types of gases Content volume
Seamless cylinder Oxygen, nitrogen, argon, hydrogen and carbon gas, etc.
General pressurized gas and special gas container
1 ~ 125 L
Large sized container
(ø750 x 3500 mm)
Cartilage container
(ø789 x 11541 mm)
more than 125 L
Composite materials container
(exclusion of composite materials container without
liner and composite materials container with plastic liner)
Less than 450 L
Welded cylinder Cryogenic container
(Oxygen, nitrogen, argon, Freon and helium)
Less than 500 L
Acetylene container Less than 80 L
Container component parts Valve for container and other component parts for the containers
for compressed natural gas for automobile with size exceeding 125L
-
Container component parts with built-in diaphragm -
Container component parts for general industrial pressurized gas,
and inhalation of air and oxygen
-

Pressurized gas safety management act
Article 17 (testing of container, etc.)

Those who manufactured, repaired or imported container, etc. (including the foreign manufacturer of containers, etc.) must undergo testing by the Minister of Trade, Industry and Energy, mayor of the municipality or city prior to the sales or use of such container, etc. However, some or all of the tests for the containers, etc. stipulated by the Presidential Order can be omitted <amendment on 2008.2.29., 2013.3.23.>.

② If the container or particular facility corresponds to any one of the following after having been tested in accordance with the Clause ① above, the holder of the said container or the particular facility must have such container or particular facility to undergo retesting by the mayor of the municipality or city. However, if the particular facility of those who comply the standard stipulated by the Presidential Order with outstanding performances in the in-house testing among those who received approval according to the Clause 1 of the Article 4 corresponds to the item No. 1, some or all of the retesting for such facility may be exempted in accordance with the stipulation made by the Presidential Order <amendment on 2008.2.29, 2009.5.21., 2013.3.23.>.

     1. Lapsing of the period stipulated by the Order of Minister of Trade, Industry and Energy
     2. Occurrence of damages
     3. Damaging the mark for passing
     4. Change in the type of pressurized gas to be charged

③ The mayor of the municipality or city must destroy the container or particular facility that failed to pass the testing or retesting according to with the Clause 1 or 2 above in accordance with the regulations stipulated in the Order of the Minister of Trade, Industry and Energy. However, the particular facility may be repaired and undergo test according to the Clause 1 or 2 above in accordance with the regulations stipulated in the Order of the Minister of Trade, Industry and Energy <amendment on 2008.2.29., 2013.3.23.>.

④ The mayor of the municipality or city must mark the container that passed the test according to the Clause 1 or 2 with the engraved seal stamping with necessary details in accordance with the regulations stipulated by the Order of the Minister of Trade, Industry and Energy <amendment on 2008.2.29., 2013.3.23.>.

⑤ In the event of not having undergone the testing or retesting of the container in accordance with the Clause 1 or 2, it must not be displayed for the purposes of assigning, renting, using or selling to others

⑥ The mayor of the municipality or city must issue certificate of pass if the container stipulated by the Order of the Minister of Trade, Industry and Energy passes the testing or retesting according to the Clause 1 or 2 <amendment on 2008.2.29., 2013.3.23.>.

⑦ Those who manufacture or import containers for which the entire testing of the container is omitted in accordance with the regulations of the Clause 1 must notify such to the mayor of the municipality or city in accordance with the regulations stipulated by the Order of the Minister of Trade, Industry and Energy <amendment on 2008.2.29., 2013.3.23.>.
⑧ Standards and duration of the testing and retesting according to the Clauses 1 and 2, and other necessary issues shall be determined by the Order of the Minister of Trade, Industry and Energy <amendment on 2008.2.29., 2013.3.23.>.

[Full amendment on 2007.12.21.]

Period of retesting

Types of containers Period of retesting
No. of years after the new testing
Less than 15 years 15 ~ 20 years More than 20 years
Welded cylinder
(with the exclusion of container
for liquid petroleum gas welding)
More than 500 L 5-year interval 2-year interval 1-year interval
More than 500 L 3-year interval 2-year interval 1-year interval
Seamless cylinder and
composite material container
More than 500 L 5-year interval
Less than 500 L 5-year interval for those with less than 10 years since the new testing, 3-year interval for those with more than 10 years
Container component parts Those not attached
to the container
Prior to the attachment to the container (corresponds only to those that have been more than 2 years since the last testing)
Those attached to the container After 2 years of the testing, whenever the container to which the component part is attached is being retested
※ References
1) Composite materials container and container for the compressed natural gas automobile will be discarded after 15 years from the date
      of the manufacturing testing.
2) Component parts excluded from the application of useful lifespan
      A) Valve for medical gases stipulated under KS B 6214(pressurized gas container valve)
      B) Container component parts for inhalation of air and oxygen



FLOW - CHART
Current status of facilities owned
Information on product testing
NKTECH Co., Ltd., an institution specializing in gas testing, executes not only retesting of the industrial pressurized container but also retesting of ultra-large container and air respirator container as well as retesting of valve for special gas container with built-in diaphragm. Having established ourselves as an institution specializing in testing of pressurized container and container valves, we shall ardently strive to remunerate the passionate support our clients have given us by assertively fulfilling the requirement of our clients.