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| METHOD STATEMENT for Installation of copper pipes for ac units of Work Purpose Abbreviations copper pipes installation copper tubes welding soldering |
PROCEDURE FOR REFRIGERANT COPPER PIPING
TABLE OF
CONTENTS
1. Purpose
…………………………………………………………………………………….…4
2. Scope ……………………………………………………………………………………...….4
3. ABBREIONS
4. REFERENCES
……………………………………………………………………………….4
5. Responsibilities
………………………………………………………………………………4
8. EVACUATION PROCEDURE
…………………………………………………………...…9
1.
PURPOSE
The purpose of this procedure is to
describe the quality control procedure to be followed
During installation of Refrigerant
Copper Pipes at Community project and to detail the instructions to be followed
and the documentation to be employed in order to ensure that safe installation
is executed in accordance with the project specifications and standards.
2.
SCOPE
The scope of this procedure is to
define all activities and requirements necessary for Refrigerant Copper Pipes,
Heating, Ventilation and Air Conditioning (HVAC) System at ‘and to ensure that
all works/activities, acceptance criteria, IFC drawings, specifications codes
community project in and to ensure that
all works/activities are in full compliance with project specifications,
drawings and HVACMEP standards related to installations standards, verifying Documents comply with HVACMEP Typical
Inspection Plan (HVACMEPTIP) related to installations.
3. ABBREVIATIONS:
HVACMEPIC
: HVACMEP Inspection Checklist
HVACMEPTR
: HVACMEP Test Report
SATIP
: HVACMEP Typical Inspection Plan
HVACMEPES
: HVACMEP Engineering Standards
ITP : Inspection & Test Plan
NCR
: Non Conformance Report
PPE
: Personal Protective Equipment
QA/QC
:
Quality Assurance/Quality Control
4.
REFERENCES
§ ANSI B31.5 – Refrigeration Piping.
§ ASHRAE Handbook – HVAC Applications,
Systems and Equipment, Fundamentals and
Refrigeration.
§ HVACMEPES -001 Heating,
Ventilating and Air-Conditioning
§ HVACMEPES-
100 HVACMEP Mechanical (HVAC) Code
5.
. RESPONSIBILITIES
5.1 Construction
Manager
1.To ensure that
all preparation and application works are carried out according to
That contact specifications, method
statement, and HVACMEP Engineering Specification and manufacturer data sheet.
2. To ensure that the progressing of work is
carried out according to the planned program and as per the approved Method
Statement
3. To ensure that all the manpower, equipment
and materials required to execute theWork are available.
4. To ensure that all related quality
procedures are practiced and implemented
5. To ensure that all safety matters related
to this procedure are being observed
5.2 QC Inspector
1.
To ensure full compliance of the work with the related
approved method statement
2.
Responsible to ensure that the correct, approved pipe
size, dimensions.
3.
Ensure that IFC drawings, Shop drawings displayed on
site during installation inspection.
4.
Ensure that the materials being delivered to site and
used are in accordance with The project specifications and approved material
submittal and material receiving RFI.
5.
Shall be responsible for the inspection, preparation
of RFI all documents and compiling them for the inclusion in the final
documentation packaged.
6.
To maintain comprehensive inspection and test records
for the purpose of Reference and documentation.
7.
Ensure arrangement and location of latest released for
construction drawings, and specifications.
8.
Ensure that tools/ equipment used for testing and
commissioning purpose is calibrated and certificates available. (Certificate of
calibration tool will be provided during inspection time separately).
5.3 Site Engineer
1.Coordinate all
the site activities accordance with approved IFC, Shop drawings, project
specification, approved method statement and HVACMEP Engineering Standards.
2.To provide all
necessary information and distribute responsibilities to his team
3.To monitor the
progress of work in relation with work program and to report to The PM.
4.To ensure that
the installer is well trained for this type of work.
5.To coordinate
with safety officer and to ensure that the works are carried out in safe
practicing method.
6.Site engineer
shall inform mechanical Quality Control Inspector for internal inspection to
check work has been done accordance to IFC & Shop Drawings, HVACMEP standards
prior to preparing internal RFI for inspection and the time schedule.
5.4
The safty Engineer
1.Ensure that
the work is performed under the safety measures of the approved HSE plan Prior
to the commencement of any activities, work force will receive Tool Box on the
project safety requirement. This tool box talk will include both activity
issues as well as general safety requirements.
2. To
maintain continuous inspections of the site activities, advise and train the
Involved personnel on daily basis to prevent accidents, personal injury or Property
damage
5.5
Site Supervisor/Foreman
1. Shall have the
knowledge of installation of copper Piping system in order to explain the
method statement to his subordinates.
2. To ensure that
work is carried out properly and according to manufacturer recommendations and
instructions received from the site engineer
3. To ensure that
tools, labor and materials are available
6. SAFETY
1. Prior to the
commencement of any activities the work force will receive Tool box Talk on the
project safety requirements. This tools box talk will include both activity
issues as well as genral
safety requirements
2. Direct supervisor
will ensure that Protection Equipment’s, PPE, are used by site Personnel at all
times during this activity
3. Coordinate
fully with the safety officer in order to maintain safe working Condition and
proper housekeeping of the site.
4. All equipment
and accessories have been certified for their capacity and integrity.
5. Safety and
risk assessment shall be performed for every job or task, which has the
potential for harm.
6. All
personal are issued with personal protection equipment.
7. Provide hand
gloves and educate workers for safe operation.
8. Always keep
the gas cylinder in vertical position.
9. Always keep
fire extinguisher during brazing.
7. PROCEDURES:
1. Take extreme care to keep refrigerant
tubing/piping clean and dry prior to installation. The following procedures should be followed:
2. Check approval
of working drawings.
3. Check size and
route of piping for laying refrigerant pipe as per approved IFC drawing.
4. Install the
supports for pipe and check the levels.
5. Clean
thoroughly the outer face of pipe and inner face of pipes and fittings by
blowing air or brushing. Prior to copper joint brazing all cuts pipe ends and
particularly those immediately upstream of devices should be completely
de-burred and any distortion in bore diameter shall be rectified.
6. Install the
refrigerant pipe care should be taken to ensure that the flow and regulating
devices (filter/drier, sight glass, solenoid valves, isolation valves (only for
large capacity units)) are installed correctly with respect to flow direction.
7. Flush the
entire pipe system with nitrogen gas at 150 – 200 psig to remove all debris
inside the pipe.
8. Carry out the
pressure test by using Nitrogen gas at 250psi and for 24 Hrs. for check the
leakage and soap solution will be applied in case of leak.
9.Record the reading in
the pressure test report.
10. Provide pipe
insulation and cladding for external refrigeration pipe with the specified
insulation material.
11. Vacuum the
system to 29 in. HG for 24 Hrs.
12. Break the
vacuum using Refrigerant up to its standing pressure to Zero (Operation
Pressure).
13. Charge the
system with refrigerant up to its standing pressure (operating pressure).
14. System is
ready for start-up, commissioning and record the data.
15. Use only
refrigeration grade copper tubing, properly sealed against contamination.
16. The horizontal
sections of the suction line should always slope towards the condensing
unit. There should be 1/2-inch drop for
each 10 feet of line, which is sufficient to return oil.
17. Suitable
P-type oil traps should be located at the base of each suction riser.
18. The oil trap
can be constructed with three elbows and is installed at the base.
19. No trap should
be placed directly ahead of the compressor.
This is to prevent slugging of the compressor with oil or liquid
refrigerant trapped there.
20. Suction lines
must be insulated with closed cell (min. 3/4" thick) elastomeric thermal
insulation to prevent condensation.
Liquid lines require no insulation unless they run through high
temperature areas.
21. Always consult
with the concerned engineer for more detailed piping method according to site
applications.
22. All piping
should be kept short and with as few fittings as possible. This is to prevent excessive pressure drop in
the lines. Do not clamp the lines
together without insulation, unless it is necessary to use them to provide a
heat exchanger.
23. Lines should
never be left loose or unsupported.
24. All
Refrigerant line shall be purged with 7 Kpa gauge (1.0 psig) dry nitrogen while
soldering, brazing or welding connections.
25. Refrigerant
piping and tubing shall be securely fastened to a permanent support within 6
feet (1.8m) following the first bend in such tubing from the compressor and
within 2 feet (610mm) of each subsequent bend or angle.
26. Refrigerant
piping shall not be located within a required exit.
27. The direction
of flow and Type of line shall be indicated on refrigerant piping.
28. Before joining
2 metals together, be sure the surface is free from grease, rust and oxides.
29. Location of
stand casing / holder for gas cylinder shall secured.
30.
Personnel to perform brazing/welding shall be
certified prior to commence of any brazing / welding activities.
9.
EVACUATION
PROCEDURE
· After the piping pressure test is completed, dehydrate
the system by placing a vacuum of 1.7 kpa (0.5in Hg) absolute pressure.
· Remove cores from the service valve.
· Connect the low side of manifold gauge set with Y. HVACMEPE
in-line tee to vapor line service valve.
· Connect the high side of the manifold gauge set to
liquid line service valve.
· Connect micron gauge available connector on the Y. HVACMEPE
in-line tee.
· Connect the vacuum pump to the center port of the
manifold gauge set.
· Open both manifold valves and start the vacuum pump.
· Evacuate the system to at least 500 microns.
· When the system has reached 500 microns, perform the
following:
-
Close
manifold gauge valves
-
Close valve
on vacuum pump
-
Tum off
vacuum pump
-
Disconnect
manifold gauge center port hose from vacuum pump
-
Attach
manifold center port hose to a dry nitrogen cylinder with a pressure set to
165psig and purge the hose.
-
Open the
manifold gauge valves to break the vacuum in the line set.
-
Close the
manifold gauge valves.
· Shut off the dry nitrogen cylinder and remove the
manifold gauge hose from the cylinder. Open the manifold gauges to release the
dry nitrogen from the line set.
· Repeat the evacuation process two more times. On the
third time, allow the vacuum pump to run an additional of 30min after the
system reached 500 microns.
· After 30min:
-
Close the
manifold gauge valves
-
Close valve
on the vacuum pump
-
Close the
manifold gauge valves
-
Tum off
vacuum pump
-
Let the
system stand for 15min
-
Close the
manifold gauge valves
· The micron reading should not increase more than 500
microns in 15 minutes.
If
it does, then there is either a leak or there is moisture in the system. In
case of leak, repair the source of leak and then repeat the triple evacuation
process.
· Hold vacuum for 24 hours or cycle vacuum and dry
nitrogen purge according to manufacturer recommendations.
· When the pressure requirement is met, disconnect the
manifold hose from the cylinder. Perform the following:
-
Close the manifold gauge valves
- Reinstall
service valve cores by removing the manifold hose from the service valve.
Quickly install cores with core tool while maintaining a positive system
pressure.
-
Charge system with quantity and type of
refrigerant as per manufacturer requirements.
10.
Handling
and Storage
on receipt of the
refrigerant copper pipes and accessories at site necessary precautions shall be
taken for unloading, shifting and storage as follows:
1.all refrigerant
pipe and its accessories shall be inspected, handled and stored properly upon
receipt at site.
2.it shall be stored
in aplace free of water, dust and adequately covered to avoid and kind of
damages.
3.all insulation
material shoall be inspected for the thickness and densities.
4.while unloading,
shifting and storage, it should be ensured that there are no transit damage.
5.any discrepancies,
damage, and etc. found to the material will be notified and reported to qa/qc
engineer and project enginner for further action.
6.material found not
suitable for site use should be removed from site immediately.
7.all material to be
used shall be as per approved.
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