1. PURPOSE
This method statement is to establish the work plan and inspection instruction for the assembly, fabrication, inspection and documentation to be performed in order to complete the construction of pipe hangers and supports which shall be in compliance with applicable drawings and specifications.
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2. SCOPE
This method statement covers all pipe hangers, spring, cold shoe, clamped, supports and embedded plate to be assembled, fabricated, installed and inspected Project.
3. REFERENCE
- Basis for Piping Engineering
- Piping Material Specification
- Piping Standard Drawing
- Piping Support Standard Drawing
- Specification for Piping Work
- Specification for Piping Fabrication by Each Service Class
- Specification for Painting
- Welder Qualification Procedure
- Material Control Procedure
- NDE Control Procedure
- Method Statement for Painting
- Method Statement for PWHT
- ASME B31.1 Power Piping
- ASME B31.3 Process Piping
- ASME Sec, IX Qualification Standard for Welding and Brazing
- ASME Sec. V Nondestructive Examination
- ASME Sec. II Welding Rods, Electrodes and Filler Metals
NOTE: In case of conflict between this method statement and reference documents, followed below.
As a standard practice, method statement will follow the specification and then, specification will follow the code.
In case the specification has conflict with method statement. It would be decided after discussions at the meeting.
4. ORGANIZATION AND RESPONSIBILITIES
The Construction Manager has the responsibility to:
- Plan the fabrication program and report it’s progress
- Manage all fabrication drawings.
- Preparation, revision and control of this document.
- Managing of raw materials.
- Managing of welding consumables.
- Inspect the fabrication and installation of support and changes of it’s design.
- Ensuring that design changes are incorporated into the work.
- Requesting NDE or PWHT, if any
- Requesting inspection to the QA/QC Team.
- Preparation of material requisition of material for support fabrication work.
- Control of welder and support welding data
- Requesting and preparation for welder and welding operator qualification.
The QA/QC Manager has the responsibility to :
- Review of all request including Daily Welding Inspection Report.
- Managing welder qualification.
- Managing welding control system.
- Managing of quality control.
- Managing inspection and test with regard to support fabrication and installation.
The Material Control Manager has the responsibility to:
- Receiving and maintaining of material
- Control of material stock status before release to construction team.
- Issuance of material to Support shop and other sections.
- Request the material receiving inspection to QA/QC team
5. GENERAL
Material to be installed will be withdrawn from the receiving area in accordance with material control procedure, the prefabricated sub assembly storage area, or the lay down area. Transferring the material from the storage area to work site will be performed in a manner which will not be deleterious to the material.
When storage requirements are not defined, the type of storage and protection shall be determined through arrangements with project owner.
5.1. General Work Sequence
- Make production plan considering material availability and area priority.
- Issuance of Isometric drawing or support style list to support fabrication shop.
- Request support material to material warehouse
- Receiving support material from warehouse and perform receiving inspection.
- Issue work order
- Cutting and end preparation
- Fit-up and tack welding
- Welding
- Inspection
- Blasting and primer painting work at paint shop
- QC documentation
- Release support and store on stock yard (13) Support issuance to Field support team.
5.2. Storage and handling material
- Material shall be stored separately by its type and specification and it shall be marked according to its designated color.
- Certificates verifying that materials or items used in the fabrication comply with Purchaser’s requirement. Certificates for each category of material shall be submitted.
- Materials shall be maintained to comply with any warranty conditions imposed by the manufacturer.
- Nylon slings shall be used for handling stainless steel material and straps.
5.3. Drawing and materials
- Pipe support shall be fabricated and installed in accordance with the approved drawing, pipes support style list.
- For pipes requiring post weld heat treatment, attachments required for supporting purposes shall be indicated on the piping isometric drawings.
- Pipe stanchions, pipe dummies and trunnions shall be made with same type of material as the connecting pipe. All other support material to be welded directly to the pipe shall be same type of material as the pipe itself.
5.4. Inspection and test
The inspection and test shall be notified to QA/QC team 24hours in advance prior to inspection and testing, and it shall be performed in accordance with the inspection and test plan.
6. WORK PROCEDURE
6.1. Control of pipe supports fabrication
6.1.1. Raw material
All material of pressure retaining parts shall be identified.
Part number, material specification and heat number shall be marked on the piece to be cut, and it shall be recorded on the material identification record, and it shall be inspected by QC inspector before cutting.
6.1.2. Cutting
Support materials may be cut to shape and size by flame or thermal cutting.
Stainless steel materials shall be cut by mechanical means or plasma arc cutting, but flame cutting shall not be allowed. Surface to be welded shall be free from slag and excessive notch foreign matter.
Pipe support assemblies may be acceptable if items having greater strength are substituted for those indicated on the drawings.
6.1.3. Welding
Welding shall be performed in accordance with the approved WPS and drawing by qualified welder.
These fabricated support shall be inspected and recorded using the ‘Daily Fabrication Inspection Report’ (Attachment 1).
Field welding to pipes for the purpose of pipe support shall be limited as far as practical. Field welding for pipe support purposes shall not be performed on the following pipe materials.
- Materials requiring post weld heat treatment (PWHT)
- Non-ferrous materials
All welding shall be done before post weld heat treatment
Stainless material shall be segregated from normal carbon steel during fabrication and erection in order to avoid the contamination.
6.1.4. Marking and Tagging
When welding has been completed, designate person will tag on each support body with stamped tags.
The characters on such tags shall be a minimum of 3/16 inch and tags shall be securely attached to the assembly.
6.1.5. Painting and Stock
When fabrication of pipe support is done, prepare the painting request form and transport to painting area. (Attachment 5)
Painting subcontractor shall paint and submit painting inspection report to contractor. Painted pipe support should be marked and properly identified and shall be stored in the designated area and preserved from dust and rust until issue to field erection. (Attachment 4)
6.2. Control of Pipe supports installation
6.2.1. General
As a general practice, appropriate adjustment / modification / addition of support shall be made by construction contractor according to the actual field conditions, especially for small bore piping.
All pipe support must be installed as per specification and drawing.
- Isometric drawing
- Piping arrangement drawing
- Pipe support standard drawing
- Special pipe support drawing
- Pipe support index
Piping shall be properly anchored and guided before pressure testing.
Support should be fabricated and installed prior to the piping installation, and use of temporary supports is to be minimized.
In case the temporary supports are required, the supports arrangement shall be made sure so that they have sufficient bearing strength and stable supporting for the piping system.
All temporary supports shall be removed before hydro test.
Field welded supports shall be set correctly in place and adjusted to the final position before welding.
For sliding supports, bearing surfaces shall be sufficiently clean to ensure unrestricted movement.
Clamp bolts on clamped shoe type support should be checked as per standard pipe support drawing.
Support shall not be welded to the equipment unless otherwise specified.
In case that stainless steel piping without insulation is resting on the steel structure, pipe rack or piping support directory, stainless steel plate shall be installed between piping and structure to avoid direct contact, even if this information is not shown in support drawing.
6.2.2. Concrete expansion anchor bolts
Installation of concrete expansion anchor bolt shall be performed in accordance with vendor information.
6.2.3. Locking devices (Bolts / Nuts)
The support height shall be adjusted by construction team to the actual field condition. All threaded connections, except high strength bolts, shall be secured by locking devices to prevent loosening during service.
Wherever possible bolts/stud shall be locked in place with double nut. (Jam nut) A nut tack welded to the bolt/stud shaft may also serve as a locking device and may be used except where welding is prohibited on the bolt material.
6.2.4. Installation of Spring hangers
Installation of constant and variable spring hangers shall be in accordance with the manufacturer’s instruction, the design drawing and the procedure.
Spring hangers shall be easily accessible after installation within the limits of possible, and the scales shall be unobstructed and visible.
Field engineer should be ensured that the travel stops are engaged and maintained thus on all spring hangers until the piping system are placed in service, except during such time of checking and marking adjustments on the spring hangers.
Spring supports shall be installed with the spring locks in place and the travel shall be cold set position.
These spring locking plates or pins shall not be removed until hydro static testing and insulation of the piping system has been completed, but before the line is put into service, as directed by commissioning group.
If the spring force on empty line will cause possible damage to connected strain sensitive equipment, the spring locks shall remain in position until the line is filled with the actual service fluid.
The relevant support and support drawing shall bear the warning “block against empty position” and the locks shall be attached with the spring support during operation. The travel stops on spring hangers shall be engaged during filling, testing and draining of pipe systems for hydro test.
6.2.5. Floor of base mounted supports
Grouting is required between concrete surface and structural pipe support attachment plates.
All grout work shall be performed in accordance with relevant work procedure.
Non shrink grout shall be mixed and placed in according with the manufacturer’s written instruction.
6.2.6. Wall or ceiling mounted supports
Pipe support base plates shall be mounted flat against the wall or ceiling.
Irregularities on the wall or ceiling surface that prevent flush mounting on the base plate, such as fins, protrusions, and excessive roughness, shall be removed by grinding. Grouting is not required except when depression, grooves, holes or other cavities under the base plate that are not amenable to removal by grinding.
These shall be filled with grout before mounting the base plate.
6.2.7. Hanger rod and turn buckle installation
Threading of hanger rods shall be performed in accordance with ASME B31.3 para 321.1.5, thread designation UNC and, shall have a minimum of three full thread exposed when the nut is tightened on the hanger rod threads.
Lubricant for threaded portion of rod is not required.
For galvanized threads cut in the fields, the threaded portion of the rod shall have a touch-up coating.
To compensate for pipe elevation discrepancies, hangers are usually provided with means to permit vertical adjustment during and after installation
Threaded devices such as turnbuckles, clevises, etc. are acceptable, provided that after the adjustment the result is no less than full thread engagement.
6.2.8. Shoe or pads installation
For shoes shall be welded to the piping with careful way avoiding any welding defects.
Special care must be taken to the anchor points, as they are to be heavily loaded.
Shoes pads for low alloy steel piping shall be of the same material as the pipes. In case of lines having shoe or saddle support, site measurement between distances of supports may be given and marked on the assembly.
The supports are then welded on the spool assembly on the ground.
In case of lines having guide or anchor the supports are to be welded in position. All supports / saddle welded to main pipe shall undergo the same testing requirement as that of main pipe.
For the installation of Embedded plate shall be followed in accordance to Concrete Works Procedure.
6.3. Welding and welding attachment
- All welding shall be in accordance with approved welding procedure specification.
- The material of the attachment which is directly welded to the pipe shall be as shown on the pipe support detailed drawings.
- Welding must be carried out by qualified welder in accordance with approved welding procedure specification.
- Material traceability report shall be recorded the heat-number of attachment and verified by QA/QC inspector and Contractor’s inspector for stainless steel and alloy steel. (Attachment 2)
- Daily welding inspection report shall be signed off by QC inspector after visual inspection.
- All weld attachment on pipe shall be identified by marking the weld and welder number.
- All welds will be identified on the isometric drawing and shall be inspected by welding inspector and recorded in daily welding inspection report. (Attachment 3)
6.4. Post Weld Heat Treatment (PWHT)
- Performance of PWHT shall be in accordance with post weld heat treatment procedure.
- The QA/QC shall review PWHT record and submit to owner for review.
6.5. Non Destructive Examination (NDE)
- The management and request of NDE shall be in accordance with NDE control procedure.
- The QA/QC shall review NDE record and submit to owner for review.
6.6. Paint and Touch up painting
- At completion of fabrication and installation, painting subcontractor shall paint or touch up paint the pipe support according to painting specification and procedure.
- Pipe construction manager is responsible for keeping and maintaining all related documents.
6.7. Progress check
- Progress of fabrication and installation in pipe support shall be measured together with piping progress using progress measuring program.
- Every support item shall be tracked by this system.
7. HEALTH SAFETY ENVIRONMENT AND SECURITY
All workers shall wear PPE required as below.
- Safety helmet
- Safety glasses
- Safety shoes
- Gloves
- Mask, if required to prevent inhalation of dust and welding gas
- Ear plug, if required by conditions.
Safety shall be requested and carried out in accordance with safety procedure.
8. ATTACHMENTS
- Attachment 1: Daily Fabrication Inspection Report (DFIR)
- Attachment 2: Material Traceability Record (MTR)
- Attachment 3: Daily Welding Inspection Report (DWIR)
- Attachment 4: Inspection Report for Embedded Plate Fabrication (IREPF)
- Attachment 5: Release Note for Field Installation (RNF)
- Attachment 6: Release Note for Painting (RNP)
- Attachment 7: Job Safety Analysis (JSA)
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