MOS, Biện pháp thi công đường ống, Cách thi công đường ống, áp dụng cho các Tòa nhà cao tầng, văn phòng cao ốc, trung tâm thương mại, nhà máy. Tài liệu dùng ngôn ngữ tiếng anh, phù hợp cho các Kỹ sư, Ban quản lý làm việc trong môi trường nước ngoài
INTRODUCTION
PURPOSE
This Method of Statement (MOS) consolidates the technical specifications and drawings into a single, accessible document for reference by drafters, factory personnel, site installers, and QA/QC teams involved in the project It outlines the methodology to be adhered to for the installation of pipes and fittings at B3 and higher levels.
SCOPE
This Method Statement outlines the installation and preliminary testing procedures for the Air Conditioning System pipework at Basement B3 and elevated levels, in accordance with the specifications and approved shop drawings.
EXCLUSION
GENERAL
PROGRAM
To ensure a safe and efficient construction site, it is crucial that the shop drawings used are approved for construction Designated manpower must be adequately trained and oriented by the safety engineer All lifting equipment, tools, and mobile scaffolding should be inspected and approved by an authorized safety engineer Staff involved in the work must possess sufficient experience When workers ascend the working platform or ladder, they must keep their hands free Additionally, all materials on site must be properly secured and maintained in a clean condition The working period should align with the civil work and piping installation schedule, which will be provided upon receiving approval.
LOCATION – ADDRESS
Application for Basement 3 and all high floors.
APPROVALS
2.3.1Materials of submission (Waiting for submission & approval).
2.3.2Shop drawing (Waiting for submission & approval).
LABOUR RESOURCES
The pipnging team will coordinate and carry out as below organization chart:
COMMUNICATION
Office mobile phone or walkie-talkie will be used during working time.
SITE RESOURCES REQUIRED
2.6.2 Site electric panel should be needed as site condition.
TEMPORARY MATERIALS
Materials cover needs to be prepared on the floor and cover pipe when needed.
PROTECTION
Materials cover needs to be prepared on the floor and cover pipe when needed.
EQUIPMENT/TOOLS
Ensure the availability of equipment and tools provision for
AC Piping installation works as follows:
1 Tape measure or folding rule
5 Grinder 6 Clean rug and cloth
7 Protective Glasses 8 Electric Arc machine
25 Tool for pressure test (by water)
26 Pump for pressure test (by water)
HOT WORKS
Hot works involve welding activities that will be conducted following the hanger and support weld instruction manual These welding operations will take place in a clean workshop environment to minimize the risk of contamination from dirt.
Where such exothermic wielding works are in progress, fire extinguishers shall be provided at full times.
When such exothermic welding is carried out, the workers shall be provided with welding gloves.
CONFINED SPACE WORKS
EMERGENCY & SAFETY EQUIPMENT
MATERIALS REQUIRED FOR INSTALLATION
2.13.1 GI pipe & black steel pipe, fitting as elbow, tee, reducer, flange, threaded rod, bracket.
1 Black steel (BS) pipe 2 GI pipe
7 BS crew fiiting 8 GI crew fitting
13 Flange 14 Clamp for CD pipe
2.13.2 Hanger, support, anchor bolt, sealent.
SCHEDULE OF DRAWINGS
Refer to the shop drawing layouts for the floors listed below: ST106_MECH_MVAC_D_0003, ST106_MECH_MVAC_D_0004, ST106_MECH_MVAC_D_0005, ST106_MECH_MVAC_D_0006, ST106_MECH_MVAC_PC_B301, ST106_MECH_MVAC_PC_B302, ST106_MECH_MVAC_PC_B201, ST106_MECH_MVAC_PC_B202, ST106_MECH_MVAC_PC_B101, and ST106_MECH_MVAC_PC_B102.
SCHEDULE OF INSPECTION/T&C FORM
Refer to ITP form as the attached file in below.
ATTENDEES
a) Sub-contractor manager. b) Sub-contractor site manager. c) Main contractor MEP coordinator. d) Main contractor mechanical engineer. e) HKL M&E manager.
SAFETY BRIEFING
Safety is the top priority during construction, with safety personnel required to be on-site at all times to supervise and ensure compliance with safety regulations A stop work order will be issued if safety standards are not met All workers and staff must be oriented on safety requirements, and necessary safety equipment, including clothing, shoes, helmets, gloves, and safety belts, should be provided and regularly inspected Engineers are responsible for inspecting all subcontractor tools before use on-site, and a Safety Supervisor must be present for all safety inspections To protect workers, grounding wires for electric ARC processes must be installed, and wet cloths, protective glasses, and long-sleeve clothing must be mandated Additionally, fire extinguishers must be available in welding areas, and safety provisions should be implemented to ensure their functionality Special attention must also be given to safety when working with scaffolding.
All scaffolds should be assembled under the guidance of a qualified and experienced individual, typically the construction superintendent This supervision extends to relocating scaffolds as needed It is essential that each leg of the scaffold is placed on a stable and adequate footing, as loose boards, bricks, and other materials do not offer a safe foundation.
• Where the working platform in more than 10 feet off the ground, the scaffold shall have guardrails installed.
• If people are working under the scaffold, toe boards must be used to prevent tools and materials from falling on them.
Workers must avoid climbing the metal tubular frame of scaffolds and should use safer access methods, such as ladders or building access Mobile scaffolds have limited reach without guy wire support and are prone to overturning, necessitating a smooth, level surface for stability A complete guardrail system is required for heights above 10 feet and at all working levels Scaffolds should only be moved when unoccupied and should be pushed from the base, with wheel brakes engaged during use.
MITIGATION OF RISK
Monitoring impact damage during the pouring of concrete is essential for ensuring quality It is crucial to verify that the correct connections and materials are used, and that the final installation is thoroughly inspected This inspection should be documented with photographic records and signed off by the MEP coordinator, along with the M&E staff from the contractor, architect, and client.
ACTUAL WORKS METHOD STATEMENT
DELIVERY AND STORE
Upon arrival at the site, materials must be inspected and stored in accordance with the manufacturer's guidelines It is essential to keep materials in a covered and dry area When receiving pipe materials, manpower will be utilized to assemble the piping system Additionally, pipes and accessories should be safeguarded and covered with polythene sheets prior to installation.
HOW TO INSTALL PIPE
3.2.1 Material of Pipes and Fittings as table below:
When installing PVC Socket Type O piping systems, ensure all materials meet specifications and thoroughly flush the system before connecting to plant equipment Inspect each pipe and fitting for deformation and cracks, and cut pipes using approved methods such as power hacksaws or circular cutting machines, avoiding metallic wheel cutters Remove rough edges and burrs, reaming inside edges smooth During installation, cap pipe, fitting, and valve ends to prevent contamination, and reference grid lines for accurate placement of supports and hangers Use approved fasteners and install hangers at specified intervals, employing the correct jointing method for the main pipes Seal completed sections for pressure testing, ensuring adequate bracing and support throughout the process, and ensure that all welders are certified.
3.2.2 Pipe Hangers and Support: a) Vertical piping shall be supported as follows:
Risers: Steel angle and C-channel support. b) Horizontal piping shall be supported as follows:
Pipes shall be attached to or supported from structure using hangers and devices as approved detailed drawing
Each steel angle must be fixed by two (2) anchor bolts.
Steel angle sizes refer to appendix Pipe Support Standard.
All pipe must be fixed with slab support at each floor for pipe penetration Steel angle sizes refer to appendix Pipe Support Standard.
This drawing is submitted for approval, detailing various hanger support types: for concrete walls, pipes from beams, and condensate water pipes, along with provisions for additional support.
Additional support must be provided at changes of direction, both vertical and horizontal, and near the valve However, this support can be omitted if it aligns with the required standard spacing location.
- Galvanized Steel Pipe (GI pipe).
- All cutting must be done in warehouse or in designated areas at each floor All cutting must not be done at work area.
- Cutting angle must be right to pipe axis.
- Surface and inside of pipe (male screw) and inside of fitting (female screw) shall be free from dust, rust and oil
- For GI pipe, use wrench suited to pipe size
Valve size is Less than 100mm
Valve size is 100mm and above
Support near bend Support near bend Support near bend Support
300ｍｍ or below 300ｍｍ or below
- After inserting, scarring shall be repaired by Rust-resistant paint.
3.2.4.1 Scope of Application: PVC pipe
To ensure a successful adhesive bonding joint, verify that the pipes have the correct diameter and approved material before beginning work, paying special attention to the plain ends, which are most prone to damage Avoid rolling or skidding pipes against other materials, and ensure they are free from debris and foreign substances Use a permanent marker to mark the measured length on the pipe, and cut it squarely with a power handsaw or PVC cutter Chamfer the corners and remove any burrs using a reamer, file, or sandpaper, then clean the surface of dust, dirt, and oils with a clean rag before applying adhesive Finally, when jointing, insert the pipe into the joint socket and confirm that the length from the zero point to the end of the pipe is between 1/3 and 2/3 of the actual socket length.
Deformations Region Boundary of Joint
To properly install a PVC socket, first, mark the pipe surface with a permanent marker at the actual socket length from the pipe's end Next, apply a thin, even layer of adhesive to both the outside of the pipe and the inside of the socket Insert the pipe firmly without twisting, ensuring it is pressed down securely The standard control time for this process is 30 seconds for pipes with a diameter of 50mm or less, and 60 seconds for those exceeding 50mm.
Tightening torque shall be adjusted to the torque of Gaskets
Check the torque of Gaskets.
Tightening bolts must be tightened up evenly The order for tightening up shall in accordance with figure 10.
Marking shall be applied on Tightening bolts and nuts by permanent marker pen when tightening finish Then additional tightening shall be done and checked by visual.
Figure The Order For Tightening Up
3.2.5 Installation of chilled water pipe in Riser:
3.2.5.1 Pipe is hoisted from ground level to the designated temporary holding floor by lift:
Hoisting point at ground level of site shall free from obstruction.
Prepare and install the pipe support channel according to the shop drawing details at the designated levels, ensuring readiness for the hoisting and installation of the pipe riser to facilitate a smooth and efficient process.
Erect scaffolding with working platform (if necessary) to provide proper and safe working access.
Chilled water pipes are hoisted to the designated temporary holding floor by the material lift
Ensure an adequate number of workers equipped with safety gear are deployed to the floors prepared for pipe riser hoisting and installation Their role is to carefully guide the pipe down to the designated temporary holding area before it is moved to storage.
3.2.5.2 Pipe is transferred from the temporary storage area to respective final position in riser shaft by using manual lifting device as chain block or electric winch:
Upon pipe riser hoists to the temporary holding floor, erect that pipe by using chain block and lift down the pipe to the right position of riser shaft.
Deploy sufficient workers with safety gear to the floors that ready for pipe riser installation, to guide the pipe slowly down to respective final position.
Once the pipe riser rises above slab, slowly tilt the pipe riser back to riser shaft and follow by lowering the pipe riser till the final position.
Proceed to install the permanent bracket first and then install the pipe support once the pipe riser positioned.
Upon completion of operation, cap the pipe and proceed to the next stage of installation.
JOINTING OF PIPING
Black steel pipe & GI pipe will be jointed in accordance with manufacture’s recommendation and technical specification.
WELDING
The main welding process used to install the pipelines is manual welding with coated electrode.
Cleaning the surface of pipe Surface shall be free from oils, dirt and dry well
Welding procedures must adhere to specific guidelines to ensure quality and safety First, check the bevel according to the pipe thickness, and if incorrect, revise it using a grinder Align the pipe's center on a line, and utilize the electric arc process for all welding, with electrode selection approved by the Mechanical Engineer Spot welding requirements vary by pipe size: three points for sizes up to 300A, six points for 350A-500A, and eight points for 550A and above For flange welding, perform a single spot weld with the flange surface perpendicular to the pipe axis, followed by three to four additional spot welds before the official weld Roll the pipe for continuous welding from top to bottom, and for fixed pipes, weld from bottom to top After welding, clean all welded areas with a wire brush and grinder, ensuring the welding point is free from rust A visual inspection of all welded pipes is mandatory, with the completed weld width not exceeding 3.2mm beyond the original groove Any defects must be reported to the Engineer, and no repairs are permitted; instead, cut the pipe 250mm on either side of the defective weld and repeat the welding process for rejoining.
TESTING
The chilled water pipe and condenser water pipe will be hydraulic tested to 1.5 times of working pressure.
T&C REGISTER
APPENDIX
CERTIFICATE OF CALIBRATION
Waiting for pressure gauge calibration The meantime, we may use brand new pressure gauge.
INSTRUMENT CATALOGUE AND MANUAL BOOK
BX1-180B Input Voltage (V): 230/400 Non-load Voltage (V): 48 Current range (A): 60-180 Rated Duty Cycle (%): 180A@10%, 75A@60%
Input Capacity (KW): 7 Class of insulation: H Applied Welding Rod (mm): 2.5-4.0 Fuse (A): 20
BX1-200B Input Voltage (V): 230/400 Non-load Voltage (V): 48 Current range (A): 60-200 Rated Duty Cycle (%): 200A@10%, 82A@60%
Input Capacity (KW): 7.5 Class of insulation: H Applied Welding Rod (mm): 2.5-4.0 Fuse (A): 20