BN-G-Y015 Piping Systems Inspection and Testing

Table of Contents

1. Piping Systems Inspection and Testing Scope
2. Check List
3. Field Inspection Procedure for Pipe Testing
4. Extent of Testing
5. Test Procedures
6. Line Completion, Flushing and Testing, Acceptance Procedure
7. References

1. Piping Systems Inspection and Testing

1.1 Scope

The purpose of this section is to provide guidelines to Company personnel, in particular to the Construction Specialists, for the inspection and testing of piping systems.

Primary responsibility for quality is that of the subcontractor who shall satisfy himself through his own quality system that specified requirements are met.

It is the responsibility of the Construction Specialists supported by the Welding Engineer to ensure that the subcontractor is in fact effectively applying his quality system and obtaining acceptable results.

The following specialist organizations are also implicated:

• For welding, non destructive and destructive testing firms.

• Possibly third party inspector to meet Authorities requirements.

Depending on the particular project, their services may be included in the piping subcontractor's scope or alternatively they may be directly controlled by Company.

Piping generally involves onsite or offsite prefabrication of spools. This activity may in some circumstances be part of a construction subcontract and controlled from site.

It is important that the quality systems put into place for piping works adequately cover the activities of these specialist organizations and of the prefabrication shops. Responsibility for their day-to-day supervision is that of the Piping Construction Specialist supported by auditing by the Quality Assurance Manager and by the Welding Engineer for specifically welding matters.

Subsequent sections 15.2 to 15.6 are in effect checklists of points requiring surveillance, inspection or testing. They are intended as a reminder and a help to the Construction Specialist. However, they are no substitute for reading and familiarizing oneself with the subcontract, requisitions, specifications, standards and drawings. In case of conflict it is these project specific documents which prevail.

The subcontractor creates his own quality system, which includes proposing the inspection and testing record forms to be used. Their suitability shall be judged by the Quality Assurance Manager in consultation with the Construction Specialist (see Reference 15.7.1).

The set of inspection and test record forms attached to this section:

• May be used as a basis to review the subcontractor's forms.

• May be imposed on the subcontractor as a self contained system, should the latter's forms be considered to be unsuitable.

2. Check List

• Institute system to ensure that pipespools shipped to site have been accepted and fully documented for visual/dimensional inspection, traceability, heat treatment and NDE before leaving the prefabrication shop.

• Check "Authorities" lines for proper installation and identification, matching material certificates and other authority job requirements.

• Check that all administrative back up is available on iso's.

• Verify that required vents at high points and drains at low points are correctly installed.

• Check that the proper size pipe, flange ratings, origins and destinations are in accordance with the drawings and specifications.

• Check that necessary swages, reducers and branch connections are correctly located.

• Verify that the proper type of material has been installed throughout the pipe system, especially in equipment, pumps, compressors etc.

• Check specifications for headroom in walk areas and overhead clearances in drive areas.

• Specifications may require relief-valves and pressure gauges to be checked in the subcontractor's shop. This should be checked as early as appropriate and tagged.

• Steam tracing requires inspection for length and size of tracer, branches (if allowed), trap, details, etc.

• Care should be taken when lines change specification at valves, etc. to make sure that required specifications are carried to the specified break point.

• Are jack screws required at orifice flanges or flanges with spectacle blinds?

• Check the specifications for the type of nipple required. Various nipples may be XH or alloy.

• Are blinds, spacers etc., installed at the locations called for?

• Relief valve stacks to the atmosphere, usually, require drain holes at low point. Some require weather hoods. Check project specification for the proper installation.

• Verify that both, piping- and instrument specifications and details have been utilized.

• Verify that proper tags are installed on equipment.

• Do mudlegs on steam lines require reinforcing pads, weepholes, nipples?

• Do mudlegs have clearance for expansion of the main header?

• Verify the requirements for sentinel drilling.

• Verify that the proper dope on screwed connections has been used.

• Check the insulation clearance between the adjacent pipe lines, equipment, structures, flooring, etc.

• Check the cleanliness of pipe, fittings, spools, etc. prior to installation.

• Check the use of specified graphite compounds or other lubricating mediums on bolts, studs, etc. (Note also where not to be employed).

• Check the location of valves for accessibility and operability.

• Check the location of valves to permit observation of instruments while operating the valve.

• Check that the material/equipment allowed to remain outside, is stored properly, if not immediately required for installation.

• Check that finger and/or foot traps are eliminated.

• Check that safety measures are observed and safe practices employed.

• Survey the steam tracing requirements early.

• Special attention must be paid to the slope of lines.

2.1 Valves

• Verify the flow direction of globe, check and control valves.

• Check the manufacturer's name tag description with the stock code number, description, trim, etc.

• Verify the operability of valve chain wheels.

• Verify that rising of the valve stem is free of obstructions. Are valve stem protectors required.

• If special packing is required institute and maintain a tagging system.

• Check the specifications for drains- and/or flushing connections to valve bodies.

• Check the specifications and the installation of a valve bypass.

• Verify valve lubrication requirements.

2.2 Bolts and Studbolts

• Verify bolts or studbolts requirements at each connection.

• Verify the dimensions of bolts or studbolts.

• When other than the standard studbolts are required, verify the stamp or color code on end of studbolts.

• Check the equipment specifications for the flange bolting requirements and verify installation.

• Make sure that all bolts or studbolts are installed and the nuts are tight at each connection. (Studbolts must have equal projection beyond nuts).

2.3 Gaskets

• Check the specification for type, size, material and color coding.

• Verify the alignment of the gasket.

• Check the equipment specification for gasket requirements and verify the installation thereof.

• For testing only, other than line specification gaskets may be installed. (Punch list should specify the right gasket.)

2.4 Small Bore Piping at Pumps and Other Equipment

• When the trim material is supplied by the vendor, verify that material used meets the specification.

• Check the pump piping trim installation against the pump vendor prints and the piping trim drawings (cooling water, lubricating oil, etc.).

• Verify the specification and material of pump plugs. All equipment openings must be checked.

• Check the specifications for pickling requirements.

• Check the specifications for stress relieving.

2.5 Pipe Supports

• Verify the type and proper installation of pipe supports, especially major supports. Small bore pipe supports are normally field designed, and verify that they are sufficient.

• Verify the requirement of anchors/guides on high temperature steam systems.

• Inspect the application, i.e. clamps, hangers, etc. and if same are in accordance with drawings and specifications.

• Check all pipe supports on insulated lines for sufficient (insulation) clearance, location, and the welding requirements.

• In all instances verify that any line designed to transport gaseous vapors is, when hydrotesting is required, sufficiently designed and supported for hydrotesting.

• Check all spring hanger installations for type required and the correct settings.

• Verify that all lines, flanged to equipment, are not placing undue stress on the equipment (nozzle).

• Check that all lines will allow for the required expansion for both test and service pressures (temperatures).

2.6 Seal Welding

• Check specifications for lines requiring seal welding and verify that total thread has been sufficiently welded.

• Check all equipment for seal weld requirements.

2.7 Insulated Lines

• Verify correct installation of support clips, shoes and guides on lines.

• Check clearances between other lines, conduit tubing, equipment, etc. for proper spacing.

• Verify that temporary or permanent flanges for screen/ filter removal are properly installed so as to allow removal if required.

• Verify that specified printing or other corrosion protective measures have been applied.

• Verify installation of reinforcing (nozzle) pad ventilation nipple.

• Maintain current hydrotest records so that up-to-date information of lines ready for insulation may be given to insulation/painting subcontractors.

2.8 Alloy Lines

• Verify that pre-heat/post-heat, stress relieving etc. has been properly completed. Maintain project records of same.

• Establish program to identify, tag, color code, etc., of all various types of alloy - from initial receipt until erection.

• Check alloy valves and gaskets against the specification, tag, color code, material (valve body ' trim), stock code number and description, etc.

2.9 Orifice Runs

• Check the specification for required straight length of pipe, without weld, upstream and downstream of orifice flanges.

• Check the specification for location of taps (horizontal, vertical or under an angle).

2.10 Testing

The testing operation will have been determined by the preparation of the testing systems. Pretest inspections are indicated in the check list.

Additionally:

Assure that test gauges are calibrated regularly. Permanent identification of test gauge traceable to calibration record shall be available.

Assure that control valves are excluded from test.

Assure that test gauges are set at high point.

Verify that check-valves are not being pressurized against the flapper (seat)

Assure the check valves do not block the flow of other lines included in the test system. (The check-valve flapper shall be removed or blocked in "open" position.)

Assure that vents are open when filling the test system.

Assure that flushing of the test system(s) can be accomplished.

Assure that blocking arrangements for spring supports are provided, when required (compensation for stress during testing).

Assure installation of a test blind before a closed valve. (Do not test, pressurize, against closed valves).

3. Field Inspection Procedure for Pipe Testing

3.1 General

This procedure describes the cleaning, testing and inspection of equipment and piping systems.

• Test media and pressures as indicated, in the Line Designation Tables and on the equipment drawings, shall be followed. No deviation from test media and/or pressures specified shall be permitted, without prior approval of Engineering.

• Normally all piping shall be tested hydrostatically, using (non saline) drinking water, plant water, fire water or any other approved test media.

• For austenitic stainless steel piping and equipment, the testing water shall be clean and free of silt and shall have a chloride content of less than 12 ppm, or demineralized water.

• Austenitic stainless steel piping and equipment shall be flushed after testing with demineralized water or passivated water.

• When hydrostatic testing is considered not practical it may be substituted by a pneumatic test, however, only with prior agreement between Company and client. Pneumatic testing, using air or other non-flammable gas, may be specified if the presence of any liquid in a system would cause operational difficulties e.g.:

Catalyst Lines

Equipment having internal insulation or other linings subject to damage by a test liquid.

Instrument air systems.

Lines for which a pneumatic test is approved shall be clearly marked on the test record sheet and Line Designation Table.

• All tests are normally to be witnessed by the client's representative and recorded on Company's test record sheets, which shall be signed by client's, Company's and subcontractor's representatives.

The test record shall include for each test:

• Identification of piping system

• Line number and size

• Termination points of system

• Test medium

• Test pressure

• Start time

• Finish time

• Duration

• Date of test

• Signature and names of representatives.

• Test gauge I.D. & calibration date

3.2 Preparation for Testing

Before testing, all equipment and piping shall be thoroughly cleaned of all dirt, welding slag and construction debris or other foreign matter.

• Tanks and drums shall be opened for inspection and the interiors thoroughly cleaned. The client's Start-up Engineer shall be present at final inspection to check internals against drawings. Cleaning of tanks shall be as per applicable Codes.
• Manhole covers are to be installed with permanent gaskets after final inspection.
• All temporary strainers must be installed before testing.
• Towers shall be inspected and checked to be sure that all internals are in place and that the trays are clean.
• Insulation or painting shall not be applied over welds, flanges and/or other mechanical joints prior to hydrotesting.
• Restrictions which interfere with filling, venting or draining, such as orifice plates, shall not be installed until testing and flushing is completed.
• Pressure gauges and the like which form a permanent part of the finished project are not to be installed until the system or unit has been tested and flushed.
• For hydrostatic testing, all piping and specifically those in other than liquid service, shall be adequately supported, using additional temporary supports where necessary. Spring or counterweight types of supports on these lines shall be provided with temporary supplementary supports designed to carry the full fluid test load.
• All expansion joints shall be inspected for correct installation and proper restraints prior to test.
• Control valves shall not be a part of the test system. Where bypasses are provided the test shall be performed through the bypass. Where necessary temporary spools shall be used in place of the control valves.
• Water should not be allowed to enter any of the following:
  - Compressor cylinders "
  - Pumps and turbines
  Instruments and instrument lines - (testing of process piping up to the first block valve of the instrument lines.)
• Vents shall be provided at high points of all vessels or connecting piping, to expel air. Drains shall be provided at all low points. Venting through high point flanges is acceptable where test systems do not warrant the installation of a vent. Filling the test system shall only be started after it has been verified that the high point vent is open.
• All floats in equipment shall be removed and the proper location of test blanks shall be checked before charging the system with the test medium.

4. Extent of Testing

4.1 Piping

• Piping which connects to lines installed by others shall be isolated from these lines by valves or test blanks. When it is necessary to include portions of such lines in the test, the client shall be consulted during test loop preparation stage to determine the test requirements.

• To facilitate the testing of piping systems, vessels and equipment may be included in the system only when the test pressure specified is equal to or less than that for the vessels and equipment and a suitable testing medium is used.

• Pumps, compressors and turbines shall not be subjected to the field test pressure.

• Lines and systems which are open to the atmosphere, such as drains, vents, open safety valve discharges do not require pressure testing. These lines shall be examined, by any suitable means, to determine that all joints are properly made. Snuffing steam lines and similar shall be service tested.

• Safety valves, rupture discs and other pressure relieving devices shall not be subjected to the piping test pressure.

• Instrument piping from orifice flanges to the first block valves shall be tested with the piping test system. Unions on the downstream side of the block valves shall be broken to avoid introducing foreign matter in the instrument lines. Connections to instruments shall be made only after testing has been completed. Do not subject the pneumatic transmitters, pneumatic receivers, controllers, valve positioners, control valve diaphragms, etc. to test pressure.

• The testing of pneumatic instrument transmission lines should be under the direction of Company's Instrument Engineer who will specify the testing procedure, using vendor's recommendations where applicable. The testing procedure shall be submitted to the client for obtaining approval, prior to testing.

• Underground pressure lines, such as pressure sewers, drains, etc. shall be hydrostatically tested The test pressure shall be as indicated in the Line Designation Tables or as shown on the underground piping drawings.

• Each section of gravity sewer system shall be hydrostatically tested.

• Lines containing check valves shall have the pressure source upstream of valve.

4.2 Branch Reinforcements

• Each reinforcement pad (or section thereof) shall be tested with air at max. 6 bar gauge. A bubble test solution such as Sherlock, Snoop or equivalent, shall be applied to inspect all welds.

• The pipe weld of the branch connection (pipe to pipe), while bubble testing the reinforcing pad, will have been tested when the pressure gage reading remains constant.

• When testing a testsystem verify that the nipple or nipple holes of the reinforcing pad are open, so that the pipe weld of the branch connection (pipe to pipe) will be tested.

• In case of air tests, flange bolting shall not be tightened during testing of the system.

4.3 Equipment

• As far as practicable, the piping test pressure shall be carried through all equipment, to assure tightness at nozzle connections.

• All new field fabricated vessels shall be hydrostatically tested in place.

• The test pressure and test medium shall be in accordance with the equipment drawings and or specifications.

• Equipment and piping shall, in general, be tested in groups or systems comprising vessels, heat exchangers and piping for which the maximum allowable test pressure (test pressure at least the minimum of every component) DOES NOT EXCEED THE MAXIMUM TEST PRESSURE OF ANY COMPONENT IN THE SYSTEM.

• When vessels are to be tested separately, verify that all nozzles and other connections for piping are blanked or disconnected. When testing piping, connecting to equipment and vessel, pipe connections are to be blanked and vents and drains of vessels are to be left open.

• At completion of testing/flushing, air cooler bundles are to be blown out with air.

• The pressure at the equipment low point will be checked when hydro-testing. The test pressure as indicated on the equipment drawing shall be increased by the static head to arrive, at the equipment's low point, test pressure.

4.4 Instrument Items

• Gauge glasses and liquid level chambers etc., should be tested, as an integral part of the pipe line or equipment to which they are connected, using very clean water.

• Prior to pressure testing verify that the test pressure of the test system is not higher than the design test pressure of each component. Any instrument not meeting this requirement shall be removed from the piping and/or equipment, and the line shall be plugged, capped or blanked.

• Consult the Instrument Engineer about the specific testing requirements of the instrument hook-up lines.

5. Test Procedures

5.1 Hydrostatic Test

• Pressure is to be applied by means of a pump.

• Verify whether installation of a so called "sun relief valve" is required. This in relation to outside temperature and the test procedure (duration).

• The filling hose from the pressure generator shall be connected to the lowest drain point of the system. The pressure generator shall not be connected to a test-system until ready to test, and shall be disconnected immediately after the test is completed. The pressure generator shall be disconnected when not attended.

• The pressure generator and equipment to be tested are to be provided with separate indicating test pressure gauges. These gauges are to have a test certificate and will be checked calibrated periodically. Cross checking of pressure gauges can be achieved by installing a three-way-valve.

• The final test pressure shall be maintained to permit complete inspection of all joints for leakage or signs of failure. Any connection leaking during a pressure test shall be repaired and retested to the specified test pressure. When all joints are checked for signs of failure and do not leak the pressure generator shall be shut off and the pressure held for a duration as specified in the test procedures.

• Any lines changed in configuration, after having been tested, shall be retested unless waived by the client in writing.

5.2 Pneumatic Test (Only if jointly approved by client and Company)

• Equipment to be pneumatically tested shall be thoroughly cleaned and free of oil/grease deposits.

• The required air pressure will be supplied by a compressor. The air compressor shall be of a portable type and equipped or provided with a receiver, aftercooler, oil separator and relief valve.

• The compressor shall not be left unattended during the test. When, the air compressor must be left unattended, the test system must be blocked-off first and the pressure in the system relieved.

• All pneumatic tests shall include a preliminary check of not more than 1.5 bar. The pressure shall be gradually step by step increased, providing sufficient time between steps to allow conditions to stabilize and check for leaks. All joints shall be checked with soap suds.

• The pneumatic test pressure shall not exceed 110% of the design pressure, however, with a maximum of 7 bar gauge.

• Test pressure shall be maintained for a period of time to permit a thorough inspection of all joints for leakage or signs of failure. Any joint found leaking during a pressure test shall be repaired and retested to the specified pressure. Any lines changed in configuration, after having been tested, shall be retested unless waived by the client in writing.

• Flanged joints shall be prepared for pneumatic testing, by taping with masking tape and punching a 1/8" (3mm) dia. hole through the tape for soaping (bubble testing).

5.3 Test Pressure Gauges

• All gauges used for field testing, shall be in a good working condition with a minimum of 4½ inch in diameter and the pressure gauge range shall be such that the test pressure is within 40% and 90% of the full range.

• Calibration

Test pressure gauges shall be calibrated, prior to- and regularly during the course of the test program, using a standard Dead Weight Gauge Tester. Any gauge which does not permit a correct adjustment of the zero reading, or has an error of more than ±2½% of the full scale range, shall be discarded. New gauges shall be calibrated too, prior to use.

5.4 Miscellaneous

• Prior to hydro-testing piping systems, air at approximately 1.5 bar gauge may be used as a preliminary test to locate major leaks, etc. thereby avoiding the necessity of draining the system to make repairs.

• Equipment, holding for any length of time a testing medium, must be checked and vented regularly to relieve any pressure- or vacuum build up by temperature changes or "gas" forming.

• For prohibitors agents in the test media (corrosion protection, etc.) additional safety valves and other safety requirements consult with the client.

• When equipment or piping system will be tested in the field for strength, testing will be executed in accordance with the project specification and procedures and local rules and regulations. However, if the local rules and regulations are less stringent than the project specifications and procedures, the project's shall prevail.

5.5 Flushing

• Before hydrostatic testing, all lines shall be thoroughly flushed with clean test fluid.

• All steam headers and branches will be steam blown, with sufficient pressure, until steam discharge is clean and leaves no deposits on a test target-plate.

• After flushing, all strainers and filters shall be cleaned.

For more details see Reference 15.7.2.

5.6 Draining

• All equipment shall be completely drained after hydrostatic testing. DRAINING SHALL ONLY BE STARTED AFTER IT HAS BEEN VERIFIED THAT THE VENTS ARE OPEN.

• The rate of drainage from the equipment shall be controlled in respect to the inflow of air to the equipment to prevent formation of a vacuum or partial vacuum.

• Piping systems shall be drained of the test liquid. Check valves shall be opened to ensure that test liquid and/or other entrapped deposits are drained/removed.

5.7 Chemical Cleaning

• Subsequent to flushing and testing, certain lines may require chemical cleaning (e.g. compressor suction lines, intercoolers, interstage and bypass lines, lubricating and seal systems, etc.). Such lines will be defined on the Line Designation Table and the chemical cleaning procedure is specified in a separate specification.

6. Line Completion, Flushing and Testing, Acceptance Procedure

6.1 Defining and Managing Test Systems

In the first place test systems must be defined such that every element of piping to be tested throughout the project is included in one test system or another. Thus all pipework is tested.

A test system, which does not necessarily coincide with the piping of a whole functional system, is an ensemble of piping which is tested on the same occasion. Its limits are set by blind flanges and within the system there may be temporary jumpers and pup pieces. In addition there shall be the necessary drains, vents, pressure gauges and connections to make the test.

For flushing and blowing other temporary connections may have to be made and temporary filters installed.

Test systems are defined by marking limits on P&ID’s. Then connections are detailed on isometric drawings. Depending on the size and nature of the project, test systems may be defined by the Company Home Office Engineering Department or by Company on site with the cooperation of the piping subcontractor.

6.2 Completion of Construction and Preparation for Testing

Whatever the arrangements made to define the test systems, it is the task of the Construction Superintendent assisted by the Piping Construction Specialists to organize the series of tests to cover all the pipework. This necessitates the establishment and updating of P&ID’s and isometric drawings, with the test systems numbered. From these master documents, “test packs” are issued to those executing the tests generally the piping subcontractors and to those supervising, namely Company.

In the meantime, prefabrication and site erection of piping and supports with its associated non-destructive testing, visual and dimensional checks shall have been proceeding. Records of these operations are made in the isometric dossiers and on welding and NDE records.

When the piping subcontractor considers that a section of pipework, (a set of isometrics, ideally corresponding to a test system) is complete he shall declare so officially, inviting Company to punchlist. (See reference 15.7.3 for further details).

Once the punchlist items have been completed in construction, the piping shall be adapted and connected to give the configuration shown on the test pack defining the test system.

The above described successive steps are recorded on form RB26C02, refer to forms section. The issue of this form, duly signed off is confirmation that the test system is ready for the start of flushing, testing and blowing. The completed form is added to the test pack.

6.3 Flushing, Testing and Blowing

Completing form RB26C02 for a test system, leads to opening of a form RB26C03. This form for a given test system enables successive stages of:

• Flushing

• Pressure testing

• Blowing

• Reinstatement

• Release for heat tracing/painting/insulation (where applicable)

to be recorded.

The pressure test is recorded in more detail on form RB26C05, refer to forms section.

The case of underground piping is covered by a single form covering all operations to completion, testing and backfilling. This is form RB26C04.

6.4 Tracking

Successive steps of these operations for the whole project are tracked by marking-up the “Master” P&ID’s and isometrics. In addition tracking is done using form 26C01, copy attached.

7. References