16.1.1 The responsibility for examination rests with the Vessel Manufacturer in accordance with the applicable Code and the requirements of this specification.
16.1.2 Additional examination of any weld joint at any stage of the fabrication may be requested by the Saudi Aramco Inspector, including repeating examination of previously examined joints. The Saudi Aramco Inspector also has the right to request or conduct independent
Nondestructive Examination of any joint. If such examination should disclose nonconformance to the requirements of the applicable Code or this specification, all repair and Nondestructive examination costs shall be done at the Vessel Manufacturer's expense.
16.1.3 All necessary safety precautions shall be taken for each examination method.
16.1.4 Surface irregularities, including weld reinforcement, inhibiting accurate interpretation of the specified method of nondestructive examination shall be ground smooth.
16.1.5 Examination of all welds shall include a band of base metal at least one inch wide on each side of the weld.
16.2 Inspection
16.2.1 The Saudi Aramco Inspector shall have free access to the work at all times.
16.2.2 Saudi Aramco shall have the right to inspect the fabrication at any stage and to reject material or workmanship, which does not conform to the specified requirements.
16.2.3 Saudi Aramco reserves the right to inspect, photograph, and/or
videotape all material, fabrication, coating, and workmanship and any materials, equipment, or tools used or to be used for any part of the work to be performed.
16.2.4 Saudi Aramco may reject the use of any materials, equipment, or tools that do not conform to the specification requirements, jeopardize safety of personnel, or impose hazard or damage to Saudi Aramco property.
16.2.5 All of the rights of Saudi Aramco and their designated representatives for access, documentation, inspection, and rejection shall include any work done by sub-contractors or sub-vendors.
16.2.6 The Vessel Manufacturer shall provide the Saudi Aramco Inspector all reasonable facilities to satisfy him that the work is being performed as specified.
16.2.7 The fabricator shall furnish, install, and maintain in a safe operating condition all necessary scaffolding, ladders, walkways, and lighting for a safe and thorough inspection.
16.2.8 Pressure vessels manufactured in accordance with this specification are subject to verification by the Saudi Aramco Inspector in accordance with Saudi Aramco Inspection Requirements Form 175-321900, Manufacture of Pressure Vessels.
16.2.9 Prior to final inspection and pressure testing, the inside and outside of the vessel shall be thoroughly cleaned of all slag, scale, dirt, grit, weld spatter, paint, oil, etc.
16.2.10 Inspection at the mill, shop, or fabrication yard shall not release the Vessel Manufacturer from responsibility for repairing or replacing any defective material or workmanship that may be subsequently
discovered in the field.
16.3 Pressure Testing
16.3.1 After completion of all external and internal welding, nondestructive examination, repairs and heat treatment, as applicable, and prior to painting, vessels shall be pressure tested using water as the testing media in accordance with the applicable Code, SAES-A-007 and this specification.
16.3.2 Pneumatic testing in lieu of hydrostatic testing requires the approval of the Manager of the Saudi Aramco Inspection Department.
16.3.3 Hydrostatic test pressure shall be held for a minimum of one hour per 25 mm of vessel thickness and in no case less than one hour.
16.3.4 Pressure testing for acceptance of the vessel shall not be made prior to the final postweld heat treatment.
16.3.5 All welded attachments provided with telltale holes shall be
pneumatically tested at minimum 70kPa (10 psi) prior to heat treatment and vessel pressure testing.
16.3.6 Telltale holes in external attachments must not be plugged during the vessel pressure test. Telltale holes in internal attachments must be seal welded prior to pressure testing of the vessel.
16.3.7 The use of shellacs, glues, lead, etc., on gaskets during testing is prohibited. No paint or primer shall be applied to a vessel prior to hydrostatic testing.
16.3.8 The Vessel Manufacturer shall furnish all test materials and facilities, including blinds, bolting, and gaskets.
16.3.9 Hydrostatic pressure testing shall be performed with gaskets and bolting identical to those required in service and as specified on the data sheet.
These gaskets may be used as service gaskets if the bolted joint is not disassembled after completion of hydrostatic pressure testing.
16.3.10 The manufacturer shall supply the following:
a) Minimum two sets of spare gaskets with a blind flange for each manway and blinded nozzle in the vessel.
b) Minimum one set of service gasket set and two sets of spare gaskets for each nozzle with companion flanges in the vessel.
c) All bolting with minimum 10% spare bolting (3 minimum for each size) per vessel.
16.3.11 Test pressure measured at the top of the vessel shall be:
16.3.11.1 For Division 1 vessels per UG-99(b):
PT=1.3 MAWP (S/ST)
16.3.11.2 For Division 2 vessels per 8.2.1:
Greater of:
i) PT = 1.43 MAWP
ii) PT = 1.25 MAWP (ST/ S) Where,
PT is the minimum test pressure
S is the allowable stress at design temperature ST is the allowable stress at test temperature ST/S is the lowest ratio for the pressure boundary
materials, excluding bolting materials, of which the vessel is constructed.
16.3.12 Water used for pressure testing shall be potable. For vessels manufactured from stainless steel, the water shall not contain more than 50 ppm chlorides with pH value not exceeding 7 at the time of filling the vessel.
16.3.13 Testing Conditions
a) Metal temperature throughout a pressure vessel shall be maintained at all times during pressure testing as follows:
1. At least 17ºC (30°F) above the warmest MDMT based on the temperature values on the impact test exemption curves of the applicable code, considering materials of
construction for all of the vessel’s components.
2. Not below 15°C (59°F).
3. Not above 50°C (122°F), unless there is information on the brittle characteristics of the equipment material indicating that a higher test temperature is needed.
b) The temperature of the test water shall be maintained at least 15ºC (59ºF) at all times during hydrostatic testing.
c) For pneumatic testing, medium test temperature shall be
maintained at least 11ºC (20ºF) above the dew point temperature of the testing medium at all times during pneumatic testing.
When compressed air is used, testing shall be performed when the dew point of air is between -20ºC to -70ºC (-4ºF to -94ºF).
d) The test pressure shall not be applied until the vessel and the test fluid are at about the same temperature.
16.3.14 Vertical vessels that are pressure tested in the horizontal position shall be adequately supported such that the primary stresses in any part of the vessel do not exceed 90% of the minimum specified yield strength of the vessel material.
16.3.15 Horizontal vessels shall be tested while resting on their permanent support saddles without additional supports or cribbing.
16.3.16 Vessels shall be protected from being over pressured, while being pressure tested, by use of pressure test relief valve(s) meeting the following:
a) Relief valves shall be of adequate capacity set to relieve at 10%
above the test pressure, provided requirements of paragraph 7.12.3 are met.
b) Sizing of relief valve(s) shall be according to API RP520, Part I.
c) The relief valve(s) shall be tested, dated, and tagged within one week prior to the pressure test.
d) The pressure test relief valve shall be accompanied with a calibration certificate that includes the cold differential test pressure (CDTP), test date and the spring range. The CDTP shall be within the spring range.
16.3.17 After completion of pressure testing, the vessel shall be completely drained and thoroughly dried including surfaces of internals.
For vessels made completely of stainless steels and vessels internally cladded or weld-overlaid with these materials, pickling and passivation shall be applied according to ASTM A380.
16.4 Manufacturing Repairs
16.4.1 The Saudi Aramco Engineer must review and approve crack repair procedures, required by the applicable Code, prior to commencement of repairs. It is the responsibility of the manufacturer to ensure that repairs done by the mill of any material defects, per the applicable Code, are documented.
16.4.2 After completion of repairs required by the applicable Code the following shall be repeated:
a) Heat treatment of the repaired section if it has been heat-treated prior to the repairs.
b) All nondestructive examinations (radiography, magnetic particle, dye-penetrant, etc.) performed on the repaired section prior to the repairs.
c) A weld map of all repairs shall be made a part of the final vessel documentation. The weld map shall include the nondestructive examination procedure and results, the welding procedure specifications and stress relief charts.