액화수소 긴급차단장치 제조의 시설 기술 검사 재검사 추가안전기준(안)

1. 적용범위

이 기준은 「산업융합촉진법」 제10조의3 제8항에 따라 산업통상자원부장관이 규제특례를 부여(공고 제2021-ㅇㅇㅇ호 중 확인서-ㅇㅇ호의 ㅇㅇㅇㅇㅇㅇㅇ, `21.ㅇㅇ.ㅇㅇ일)한 또는 중소벤처기업부고시 제2020-54호(2020년 7월 28일) 중 “ㅇㅇ ㅇㅇㅇㅇㅇ 규제자유특구 지정” 제6호의 표(규제샌드박스) 제ㅇ호(ㅇㅇㅇㅇㅇㅇㅇ)의 ㅇ에 따른 “액화수소 긴급차단장치 제조의 시설·기술·검사·재검사 추가 안전기준”에 대하여 규정한다.

2. 기준의 적용

2.1 액화수소 긴급차단장치는 KGS AA 317 “고압가스용 긴급차단장치 제조의 시설·기술·검사·재검사 기준”을 적용하여 적합해야 한다.

2.2 기본 안전기준과의 관계

긴급차단장치 제조의 시설·기술·검사·재검사등에 관하여 추가안전기준에서 정한 사항은 기본 안전기준을 적용하지 않는다. 다만, 추가 안전기준의 요구수준이 기본 안전기준 보다 낮다고 판단되는 경우에는 기본 안전기준을 적용한다.

2.3 2.2에도 불구하고, 액화수소 긴급차단장치는 이 기준 3.1에 따른 극저온 성능 시험을 실시하여 적합해야 한다.

3. 극저온 성능

3.1 긴급차단장치의 극저온 성능시험의 유체는 액화수소로 한다. 다만, 다음 중 어느 하나에 해당하는 경우에는 액화수소 이외의 액화가스를 극저온 성능시험의 유체로 사용할 수 있다.

(1) ISO 21014 “Cryogenic vessels – Cryogenic insulation performance”(초저온 압력용기의 초저온 단열성능 기준)를 준용하여 액체헬륨 또는 액체네온을 사용하는 경우

(2) 긴급차단장치의 극저온성능 시험을 액화수소 또는 액체헬륨으로 실시하여 3.2에 따른 작동 성능시험에 적합할 경우에는 해당 시험 이후에 제조되는 안전밸브{동일 제조사가 제조한 것으로서 동일 형식(구조·재료·용량 및 성능 등에서 구별되는 제품의 단위를 말한다)의 긴급차단장치를 말한다}의 극저온 성능시험의 시험유체는 액화질소를 사용하여 작동 성능시험을 실시할 수 있다.

3.2 긴급차단장치 극저온 성능시험에 대한 시험방법 및 합격기준은 ISO 28921-1“Industrial valves — Isolating valves for low-temperature applications

Part 1: Design, manufacturing and production testing” 5.1에 따른다.

부  칙

이 기준은 2021년 00월 00일부터 시행한다.

<ISO 28921-1:2013“Industrial valves — Isolating valves for low-temperature applications - Part 1: Design, manufacturing and production testing”

5.1 저온 시험

5.1.1 저온 시험 전에 시험 밸브는 부속서 A(Annex A)에 명시된 대로 대기압 시험을 거쳐야한다. 시험 후 밸브는 세척 된 밸브와 건조 가스로 쉘 및 시트 시험을 수행하지 않는 한 내부적으로 건조 및 탈지되어야한다.

5.1.2 시험 가스는 헬륨이어야 한다. 그러나 –110°C 이상의 온도에서 시트 테스트를 하는 경우 10% 헬륨과 혼합된 질소를 사용할 수 있다.

5.1.3 냉매의 유형은 –196°C의 온도에서 테스트하기 위해 액체 질소를 사용한다. -196 °C보다 높은 온도의 경우, 제조업체와 구매자 간에 달리 합의하지 않는 한 열전달 유체와 혼합된 질소 가스 또는 드라이아이스를 사용한다.

5.1.4 시험 온도는 최소 밸브 설계 온도 또는 구매자가 지정한 온도에 따른다. ± 5% 범위 내에서 ± 5°C를 초과하지 않는 일시적인 온도 변화는 허용된다.

5.1.5 –196°C 또는 –50°C에서의 저온 시험의 경우 부속서 A의 시험 절차를 따른다. 다른 시험 온도의 경우 그에 따라 절차를 수정한다.

5.1.6 시험 후 밸브를 육안으로 검사하고 만족스러운 상태가 발견되면 철저히 세척, 탈지 및 건조한다. 밸브를 분해할 필요는 없다.

5.1.7 모든 시험 데이터는 기록되어야 한다. 시험 및 최종 시험 완료 후, 시험 결과는 시험 보고서에 문서화한다. 테스트 보고서에는 테스트 조직, 책임자, 테스트 중에 참석한 구매자 또는 공급 업체 증인의 이름이 포함되어야 한다.

Annex A

(normative)

Test procedure for production testing of valves at low temperature

A.1 General

The following procedure covers the testing for sealing and operability of valves at one of the following temperatures:

a) valve tests at –196 °C;

b) valve tests at –50 °C;

c) an alternative temperature of between –50 °C and –196°C may be specified based on an agreement between the purchaser and manufacturer. The test temperature shall be equal to or lower than the minimum design temperature of the valve, provided the materials are suitable.

A.2 Test procedures

A.2.1 Testing flow chart

See Figure A.1.

A.2.2 Ambient temperature test

A.2.2.1 Valve tests

Shell and seat testing shall be in accordance with ISO 5208. The shell test pressure shall be 1,1 x CWP if tested with gas and 1,5 x CWP if tested with alcohol or water. The seat closure test pressure shall be at (6 ± 1) bar.1) After each test is complete, the valve shall be thoroughly dried.

A.2.2.2 System proving test

A.2.2.2.1 Test pressure

A system proving test shall be performed at the maximum valve cold working pressure or maximum seat test pressure, whichever is the lower.

A.2.2.2.2 Test procedure

For external leakage detection, a soap solution or helium leak detector shall be used. Any detected leakage shall be eliminated. For the seat test, the test procedure shall be in accordance with ISO 5208 except the test pressure shall be limited to CWP. However, for soft seated ball valves of free floating design, the test pressure shall be limited to (6 ± 1) bar.

A.2.3 Low-temperature test

A.2.3.1 Valve cavity purging

A purge of test gas at a supply pressure of (2 ± 0,5) bar shall continuously flow through during cool down. Metal seated valves shall be in a half-open position, while for soft seated ball valves, the closure member shall be in the fully open position and shall only be operated for cavity purging.

A.2.3.2 Cooling of the valve

If the cooling media is liquid, the test valve shall be slowly submerged in the coolant to a depth such that the level of the coolant covers at least the top of the valve body to bonnet joint. If the cooling media is cold gas, the valve shall be installed in the cooling tank so that the valve body and the body to bonnet joint is exposed to the cold gas. During the valve cooling, the purge of test gas shall be maintained.

A.2.3.3 Low-pressure seat test

When the test valve is at the designated test temperature, the purge of the test gas shall be turned off. The test valve shall be operated to the full open position, and pressurized to (2 ± 0,5) bar with the test fluid. With the downstream isolation valve open (see Figure A.2) and test gas flowing through the valve, the

valve shall be then closed and the (2 ± 0,5) bar pressure shall be re-established. The valve shall be then fully opened and closed five times. The closing and opening torque shall be measured and recorded during the first and the fifth operation cycle. After completion of the last open-close cycle and after the pressure and leakage stabilization has occurred, the seat leakage shall be measured and recorded.

A.2.3.4 High-pressure seat testing

The high-pressure seat test shall be performed and recorded in four equal pressure increments, beginning with the first increment at a quarter of the valve allowable cold working pressure or maximum operating pressure when specified. The last increment shall be equal to the allowable CWP. Except for actuated valves where the actuator size is specified and selected for operation at a differential pressure less than CWP, the high-pressure seat test may be reduced based on the specified differential pressure. During each pressure increment, enough time shall be allowed to stabilize the pressure and the test temperature (see A.5). The valve seating and unseating torque shall be measured and recorded during each pressure increment.

A.2.3.5 Final external test at low temperature

After completion of the high-pressure tests, the valve shall be operated five times by opening and closing through its full stroke. The operating force shall not exceed 360 N, except for manual valves, the maximum initial force required for valves seating or unseating shall not exceed 1,000N. The test valve shall be partially opened, pressurized to the allowable CWP or specified differential pressure and the designated test temperature shall be re-established. The test valve shall be pressurized for at least 15 min prior to lifting it from the cooling tank.

After the temperature and pressure has stabilized, the valve shall be closed, removed from the cooling tank and checked for external leakage. The valve external leakage for the valve stem and the outside perimeter of the bonnet shall not exceed 50ppmv or 1,78x10–6mbar·l·s–1 per millimetre stem diameter for the stem, and 1,78 x 10–7 mbar·l·s–1 per millimetre seal diameter for the bonnet or body joint. For the measurement of the external leakage, the leakage shall at no time throughout the duration of the test be higher than the above specified limits for more than 10s.

A.2.4 Warm-up procedure and post-test examination

A.2.4.1 After the external leakage test, the test valve shall be de-pressurized and shall be allowed to warm up to ambient temperature. A forced warming-up is not permitted. Except for soft seated ball valves, for which the closing member shall be in fully open position, the closure member shall be in the half open position.

A.2.4.2 After successful testing, the assembled valve shall be thoroughly cleaned, dried and inspected for ease of operation or any signs of internal binding or galling and packaged in accordance with Clause 7.

A.3 Test temperatures

A.3.1 Ambient temperature

The test is performed at between 5℃ and 40℃

A.3.2 Low temperature

A.3.2.1 Test is performed at –196℃ ± 5℃

A.3.2.2 Test is performed at –50℃ ± 5℃

A.3.2.3 When an alternative test temperature of between –50 °C and –196 °C is specified, all the remaining requirements of this part of ISO 28921 shall be met.

A.4 Test pressures

A.4.1 Low-pressure seat test

The test is performed at (6 ± 1) bar during the seat test according to ISO 5208 and (2 ± 0,5) bar during the low-temperature seat test (see A.2.3.3).

A.4.2 Incremental high-pressure seat test

The actual gas pressure during the seat test shall stabilize within ±1 bar for valves up PN 40 (Class 300) and ±3 bar for higher pressure valves.

A.5 Duration of seat test

The duration of each seat test shall be at least:

— 3 min for valves DN 10 to DN 400; NPS 3/8 to NPS 16;

— 5 min for valves DN 450 or NPS 18 and larger.

Each time the test valve is pressurized and after the pressure and temperature have stabilized, there shall be a waiting period prior to the start of seat testing of equal to or longer than the minimum required duration of the seat test. The same minimum duration applies to the actual seat test.

A.6 Direction of seat test

For globe, gate, ball and butterfly valves, the seat test is conducted in the normal or preferred flow direction for the valve. For check valves, the seat test is conducted in the reverse flow direction of the valve. For valves with bidirectional sealing, each sealing direction shall be tested separately unless otherwise agreed to by purchaser.

A.7 Allowable seat leakage rates

The maximum allowable seat leakage shall be in accordance with Table A.1.

A.8 Test set-up for low-temperature tests

A.8.1 Test equipment

The cooling medium shall be contained in an insulated stainless steel tank that is open on the top. Each test valve shall be blinded with blind flanges that are equipped with support brackets as necessary and small bore tubing connected to the pressurizing media. After insertion into the tank, the valve shall be oriented such that the stem position is vertical. Check valves may be oriented in either the vertical or horizontal disc position. Thermocouples shall be attached to the valve body, bonnet and end flange, except that the number of thermocouples may be reduced where the size of the test valve makes the use of multiple thermocouples impracticable. However, in all cases, a minimum of one thermocouple, located in the valve bonnet area and one inside the valve are required. A minimum of one thermocouple shall be provided to monitor the temperature of the cooling medium. A simplified schematic arrangement for immersion cold testing is shown in Figure A.2. Its purpose is to facilitate understanding of the standard test. It is not a required arrangement.

A.8.2 Cooling of the valve

Cooling begins as the valve is lowered into the test tank and submerged into the cooling medium. The valve temperature, as well as the cooling medium temperature and level shall be continuously monitored and recorded. The test shall begin when the valve temperature is stabilized within the specified test temperature tolerances. See Table A.2.

A.8.3 Test gas

Test gas, see Table A.3, from a charged bottle is used to provide test pressure on the inlet side of the valve.

A.8.4 Instruments

All instruments (flowmeter, pressure gauges, torque wrench, etc.) shall be calibrated. Calibration shall remain valid for a maximum duration of six months after the date of test.

A.9 Flowmeters, flowmeter calibration, seat leak and correction factors

A.9.1 Flowmeter

Test valve seat leakage shall be measured at the flowmeter, and shall be at standard atmospheric conditions. Any type of flowmeter may be used, provided it can be calibrated, for example measuring cylinder, gas flowmeter soap film type or flow rotameter. Some flowmeters (e.g. electronic mass flowmeters) are not affected by pressure or temperature changes.

When such a flowmeter is used, test gas pressure and temperature measurements (as well as correction) at the flowmeter is not required.

A.9.2 Flowmeter calibration

The flowmeter shall be calibrated for the test gas. Alternatively, the flowmeter manufacturer correction factor may be used to relate the calibration gas (typically nitrogen) to the test gas.

A.9.3 Temperature correction

The temperature of exiting test gas shall be measured (before the flowmeter). Use the perfect gas relationship assuming constant pressure to determine the temperature correction for the flow rate.

where

V1 is the test gas volume exiting the flowmeter, in cubic millimetres (mm3);

V2 is the test gas volume expressed (corrected) at ambient temperature, in cubic millimetres(mm3);

T1 is the test gas temperature exiting the flowmeter, in Kelvin (K);

T2 is the standard ambient temperature (298 °K), in Kelvin (K);

Q1 is the test gas flow exiting the flowmeter, in cubic millimetres per second (mm3/s);

Q2 is the test gas flow exiting the flowmeter and expressed (corrected) at ambient temperature, in cubic millimetres per second (mm3/s).

A.9.4 Pressure correction

Measurement of exiting gas pressure (as well as correction) is not required.