SAES-L-150 PDF – Pressure Testing of Plant Pipelines

This article is about SAES-L-150 which is about Pressure Testing of Plant Piping and Pipelines and download SAES-L-150 PDF for piping and mechanical engineers, supervisors and project managers. This is saudi aramco standard based on international codes and standards and useful for piping and mechanical engineering knowledge to get job as engineers, QC Supervisors and QC managers, Engineering managers and technicians.

SAES-L-150 PDF Download

SAES-L-150

SAES-L-150 Pressure Testing of Plant Piping and Pipelines

This standard provides essential guidelines for conducting pressure tests on newly constructed plant piping and pipelines. These pipelines and piping systems are designed and built in accordance with relevant codes such as ASME B31.1, ASME B31.3, ASME B31.4, or ASME B31.8, as applicable. The purpose of this standard is to supplement the requirements outlined in ASME B31 and other applicable codes.

Furthermore, this standard also covers the mandatory requirements for pressure testing existing plant piping and pipelines. These tests are conducted for the purpose of revalidation or after any necessary repairs have been carried out.

It’s important to note that there are specific exclusions listed in SAES-A-004 that are not covered by this standard. These exclusions define certain cases or scenarios where this standard may not apply. Therefore, it is crucial to refer to SAES-A-004 to identify any exceptions or exclusions to the pressure testing requirements outlined in this standard.

General Requirements for SAES-L-150 PDF Download

According to SAES-A-004, the following general test requirements apply:

1. Hydrostatic Test for Newly Constructed Pipelines:
   • All pipelines, before initial operation, must undergo a hydrostatic test.
   • The test pressure should comply with Section 8 of the standard but not be lower than the minimum requirements of ASME B31.4 or ASME B31.8, as applicable.
2. Hydrostatic Strength Test for Newly Constructed Plant Piping:
   • All newly constructed plant piping, before initial operation (unless exempted), must undergo a hydrostatic strength test.
   • The test should follow the requirements of SAES-A-004 and ASME B31.3 or ASME B31.1, as applicable.
3. Hydrostatic Test for Existing Plant Piping and Pipelines:
   • After any repairs or alterations that affect the integrity of the pressure-containing parts of existing plant piping and pipelines, a hydrostatic test is required.
   • The test pressure should comply with the applicable code requirements.
4. Exclusion for Skid Mounted Piping Systems:
   • Skid mounted piping systems that have been successfully shop tested according to 01-SAMSS-010 and witnessed by a Saudi Aramco Inspector or designated representative are exempt from in-situ field strength testing.
   • However, if the packaged piping system undergoes subsequent repair, modification, or damage, the shop test becomes invalid.
5. Pressure Testing of Sampling Piping Systems:
   • Sampling piping systems should be pressure tested as an integral part with the connected piping or equipment.
6. Tie-in Butt Welds:
   • Provision should be made for conducting a strength test on tie-in butt welds when new piping connects to either new or existing piping systems.
   • The test pressure should be based on the minimum requirement of the code for tie-ins to existing systems.
   • If a strength test is deemed impractical, it may be substituted with 100% radiography, subject to approval.
7. Exceptions for Second Pressure Testing:
   • For piping systems that have already passed successful pressure testing, a second pressure test is required only if new welding activities and post weld heat treatment (PWHT) are mandated.
   • For cases where PWHT is not required, a second pressure test is not necessary for seal welds of threaded connections and attachment welds of non-pressure containing parts.
8. Exclusion for Certain Piping:
   • Piping such as drains, vents, and piping downstream of pressure relieving devices that discharge directly to the atmosphere with a maximum internal pressure not exceeding 69 kPa (ga) (10 psig) can be excluded from in-situ pressure testing.
9. Block Valves and Valve Testing:
   • When block valves are used for blocking or isolating hydrotest sections, the differential pressure across the valve seat must not exceed the seat test pressure during the strength test or the rated seat pressure during the tightness test.
   • Field hydrotesting requirements for valves should follow SAES-L-108.

These requirements ensure that proper pressure testing is conducted for newly constructed and existing piping and pipelines, promoting the integrity and safety of the systems.

Pressure Testing of Plant Piping

The specific requirements for pressure testing of plant piping are outlined in section 7 of the standard. Here are the key points:

1. Test Pressure Calculation:
   • The hydrostatic strength test pressure for each section of newly constructed piping should produce a hoop stress of 90% of the specified minimum yield strength (SMYS) at the test temperature.
   • The test pressure is calculated based on the pipe’s nominal wall thickness minus the mill tolerance.
   • The test pressure should not be less than the minimum test pressure specified in ASME B31.3.
2. Test Duration and Leak Detection:
   • The test pressure should be maintained for a sufficient time, but not less than 30 minutes, to ensure there are no leaks.
   • All joints, including welded joints, should be left exposed during the strength test for visual leak detection.
   • External coating and priming of joints are not allowed, except with approval from the Manager of Inspection Department and the proponent Organization representative. The pipe itself can be externally primed and coated.
3. Jacketed Piping:
   • For jacketed piping, the internal line should be hydrotested as per the requirements of paragraph 7.1.
   • All field welds should be visible for leak detection during the hydrotest.
   • The jacket should be hydrotested according to ASME B31.3, ensuring that the maximum allowable external pressure for the internal line is not exceeded.
4. Exemptions:
   • Specific exemptions to the requirements in sections 7.1 and 7.2 are listed in section 7.5 of the standard.
   • Examples of exemptions include lube and seal oil piping, underground process piping, flare lines, piping in vacuum service, and certain service tests.
5. Revalidation of Existing Plant Piping:
   • For revalidation purposes of existing plant piping, the test pressure should meet the minimum requirements of ASME B31.3.
   • The actual wall thickness of the piping and the flange rating should be considered when calculating the test pressure.

These requirements ensure that plant piping is pressure tested adequately to verify its strength and integrity before operation, promoting safety and reliability.

Pressure Testing of Pipelines

The specific requirements for pressure testing of pipelines are outlined in this section. Here are the key points:

1. Test Pressure Calculation:
   • The hydrostatic strength test pressure for each section of newly constructed pipelines should be calculated to produce a hoop stress of 90% of the specified minimum yield strength (SMYS) of the pipe material based on the nominal wall thickness.
   • The test pressure at the lowest point of the pipeline, considering the hydrostatic head, should not result in a hoop stress greater than the SMYS.
   • The strength test pressure should be maintained for a duration of two hours.
2. Test Temperature and Combined Stress:
   • The strength test temperature should not result in a combined longitudinal stress exceeding the SMYS.
   • The combined longitudinal stress is calculated based on 0.7 times the hoop stress at the test pressure, plus temperature stress, plus bending stress.
3. Tightness Test:
   • A tightness test should be conducted immediately after the completion of the strength test.
   • The tightness test pressure should be set at 95% of the strength test pressure.
   • The tightness test pressure should be maintained long enough for the inspector to examine all exposed joints.
4. Extended Tightness Test:
   • If the pipeline is buried or insulated, or partially buried or insulated for more than 300 meters (1000 feet) or 10% of its total length (whichever is less), a 24-hour recorded tightness test should be conducted.
5. Revalidation of Existing Pipelines:
   • The test pressure shall be a minimum of 1.25 times the Maximum Allowable Operating Pressure (MAOP) for pipelines with design factors of 0.6 and 0.72.
   • For pipelines with design factors of 0.4 and 0.5, the test pressure shall be a minimum of 1.4 times the MAOP.
   • When calculating the test pressure, the flange rating should be taken into consideration.