- PURPOSE
- SCOPE
- SAFETY
- REFERENCE STANDARD & REGULATION
- DEFINITIONS
- RESPONSIBILITIES
- RESOURCES
- EXECUTION PROCEDURE
- CONSUMABLES & TESTING EQUIPMENTS
- TESTING PROCEDURE
- SAFETY ASPECT
1.0 Purpose
• The intent of this document is to define the method statement for installation of refrigerant copper pipes, pneumatic pressure testing and insulation work.
• To establish, document, implement and maintain a quality work instruction of HVAC refrigerant piping work, pneumatic pressure testing to ensure compliance with the procedure and applicable Saudi Aramco Standards for the project.
2.0 Scope
• The scope covers all HVAC refrigerant piping installation, pressure test, Vacuuming, insulation work. And to ensure that the work is performed in accordance with the Project Specifications and IFC drawings as defined in the scope of work and MTO.
3.0 Safety
• This policy covers all of the safety procedures of Zamil Projects (ZP). We are fully committed to our corporate goals: no accidents, no harm to people and no damage to the environment. In meeting with this policy, ZP will:
• Expect all personnel to demonstrate commitment and leadership in health, safety and environmental (HSE) protection. Managers at all levels will consider these issues as
the primary focus when making business decisions which may impact these critical areas.
• Meet or exceed compliance obligations of applicable HSE legislation and regulations and customer requirements.
• Provide employees with a safe place to work, clear expectations regarding HSE requirements and the necessary training to perform their jobs.
• Work closely with our customers to contribute effectively to their HSE programs and compliance efforts.
• Maintain a commitment to incident and pollution prevention and to continue improvement in HSE performance.
• House-keeping will be done on regular basis to keep the working area safe and clean.
Refrigerant gas cylinders shall be stored properly in accordance with Saudi Aramco general safety standards regulations requirements and fire code.
4.0 Reference Standard and Regulation
• The work under the all sections shall comply with the latest Edition of the applicable standards and codes of the following:
SCHEDULE Q” – Quality Assurance and Control, Inspection and Testing
SAEP-1154 – Guideline for Contractor’s Quality Plan
SAEP-122 – Project Records
ISO9000:2000 – Quality Management Systems — Fundamentals and Vocabulary
ISO9000:2008 – Quality Management Systems — Requirements
SAES-K-001 – Saudi Aramco Engineering Standard for Heating, Ventilating and Air Conditioning (HVAC)
SAES-K100 – Saudi Aramco Mechanical (HVAC) Codes
UPC -Uniform Mechanical Code
NFPA -National Fire Protection Association
ASTM -American Society for Testing & Materials
UMC -Uniform Mechanical Code
ASHRAE -American Society of Heating and Refrigeration Association of Engineers
5.0 Definition
• The Pneumatic pressure testing is a way to discover the premature failure of components in order to improve the reliability and safety of the tested system.
6.0 Responsibilities
6.1 Site Engineer:
Shall be responsible in the overall supervision of activities in connection with HVAC refrigerant piping work and pressure testing to ensure the correct follow of procedure. The project engineer shall define the parameter of the system that is being tested and make sure that all the components are ready and meet the safety regulations.
6.2 Site QC Inspector:
Performs inspections for copper pipes installation work prior to start pressure test. Performs inspection, monitors in-place pressure testing and assures that pressure testing is done according to approved procedure. QC inspector shall complete all required documentation in connection with pressure testing including calibration certification of all testing instruments and test readings according to approved method.
6.3 Site Supervisor:
Shall be responsible for preparation of pressure testing according to approved procedures and check all components against safety regulations.
6.4 HSE Officer:
Check the possible hazards of the activities to be done and co-ordinate to the site supervisors to rectify if there is any to ensure the safety of the workers at job site.
7.0 RESOURCES
7.1 Tools required for installation work:
• Lifting Equipment
• Hand Tools
• Generator
7.2 Tools required for pressure & Vacuum test:
• Dry Nitrogen Gas
• Pressure relief Valve
• Regulator
• Pressure gauges
• Pressure test charging Hoses
• Drain Valve
• Gauge Manifold
• Soap solution
• Vacuum Pump
• Vacuumed gauge
7.3 Materials:
• Copper pipes (ASTMB28O – Refrigerant Pipes)
• Weather proof Sealant
• Angles and supports with Nut, Washers and Bolts
• Scaffolding
• Hardware
• Approved Insulation Materials
• Approved Aluminum Cladding with straps
• Accessories as per approved IFC drawings
7.4 Manpower:
• Site Engineers
• QC inspector
• Safety Officer
• Brazer
• Supervisors
• Technicians
• Labor
8.0 EXECUTION PROCEDURE
8.1 Material receiving procedure for Refrigerant Pipes:
• All materials and documentation relevant to a particular section of works will be checked by the Construction Department prior to the commencement of work ensuring that these are of the correct type as reviewed by the Client.
• Before commencement any construction works, pre-inspections will be carried out on all materials prior to them leaving the storage area. The Client will be invited to attend at these inspections at their discretion.
• Prior to the commencement of any construction works, areas and access will be inspected to confirm that they are in a suitable condition for construction works to commence.
• Piping materials, fittings, support and hangers insulation used for the installation shall be in Conformance to specifications or material approvals.
• Acquire hazardous permit prior to commencement of any gas filling or Purging work.
\contractor has to ensure that the procedure for handling, storage and preservation are Aramco Approved as per the requirement of Schedule Q, Quality requirements.
All copper tubing to be purchased shall be capped to avoid infiltration of dust and other foreign matters.
A Provide a piece of rubber sheet material to the contact point of dissimilar materials (copper tubing in contact with galvanized angular bar supports) to avoid chemical reaction and corrosion or otherwise wrap the portion of the contact point of copper tubing with at least 3 mm thick adhesive tape.
A Copper tubing to be used for refrigerant piping systems shall be ASTM B280, “ACR” type L, hard drawn, straights lengths, and shall be from approved source of manufacturer and vendor.
Traceability markings shall be indelibly marked and readable into the surface of the copper tubing specifying the name of manufacturer, ASTM B280, Type L, ACR, hard drawn.
A The designed pipe size diameter of copper tubing shall be confirmed and re-verified into the air conditioning equipment manufacturer ,if no any objection on it.
8.2 Refrigerant Pipes Installation procedure:
Take extreme care to keep refrigerant tubing/piping clean and dry prior to installation. Following procedures should be followed:
• Use only refrigeration grade copper tubing ASTMB280 properly sealed against contamination. Copper tubing often contains wax and other trouble-some contaminants. Ensure that this is checked.
• Refrigerant piping on split system should be designed and installed in accordance ·with approved IFC drawing.
• 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.
• Suitable P-type oil traps should be located at the base of each suction riser.
• The oil trap can be constructed with three elbows and is installed at the base of suction risers which carry gas on upward flow.
• 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.
• Sealed type liquid line filter driers are recommended in smaller capacity units and replaceable core type driers are recommended on higher capacity units. In both cases, do not leave the filter drier open to the atmosphere any longer than absolutely necessary.
• All Liquid and Suction lines shall be insulated with thermal insulation to prevent condensation.
• All Valves assembly (Solenoid & thermostatic expansion Valve with Side Glass & Filter dryer) shall be installed as per approved IFC/ISOMETRIC Drawings according to the Saudi Aramco Engineering standard and Project Technical Specification.
• Always consult with the concerned engineer for more detailed piping method according to site applications.
• 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.
• Lines should never be left loose or unsupported. Isolation or vibration-free hangers are to be used. Do not attach lines directly to a building to eliminate vibration and noise.
• All Refrigerant line shall be purged with 7 KPa gauge (1.0 psig) dry nitrogen while soldering, brazing or welding connections.
• Refrigerant piping placed underground shall be protected against corrosion.
• Supports for refrigeration piping shall be noncombustible.
• 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.
• Refrigerant piping and tubing shall be supported at points not more than 15 feet (4570 mm) apart.
• Refrigerant piping shall not be located within a required exit.
• The direction of flow and Type of line shall be indicated on refrigerant piping.
• Color code for both the lines liquid and gas lines as per the ARAMCO standard will be provided.
Copper brazing shall be done in accordance with ASME SEC IX and SAEP-323 Saudi aramco engineering procedure for contact welders and brazers performance qualifications testing and tracking requirements.
- The refrigerant gas manufacturer and or vendor shall furnish a declaration identifying the refrigerant by Standard — R designation and stating that it meets the ARI standard 700-93 in purity(UMC para. 1102.2).
- The Refrigerant piping system shall be identified in accordance with UMC standard 11-2 specifying the type of refrigerant, function and pressure shall be also indicated.
- The refrigerant field piping systems (suction line, liquid line and hot gas bypass line) shall be pressure tested in accordance with UMC requirements and ASHRAE standard requirements.
- Provide pipe sleeves (non- combustible type) to all refrigerant pipes passing through walls.
- Seal-off the gap and the hole openings with the approved fire stop sealant in all refrigerant pipe penetrations through the walls as per requirements of NFPA-90A.
9.0 Consumables and Testing Equipment
All testing equipment’s shall be calibrated by third party and calibration certificates should be submitted before start pressure test. Prior to start the pressure test and Vacuum testing to ensure the below requirements are already complied.
• Testing Manifold shall be checked for calibration with gauges to ensure correct reading.
• Relief valve shall be up to date of testing.
• Vacuum pump shall be calibrated.
• All valves are kept closed and ensure proper tightness i.e leak proof of gauge manifold and its fittings to minimize leaks during pressure test.
• Pressure relief valve shall be checked for calibration certificates as to ensure the safety of surroundings during the test.
• Pressure test shall not be performed with other medium but with dry nitrogen.
• Ensure that Relief valve setting will be as per UMC 1997 table 11-D at high side and 0.05% tolerance added 262.5 PSIG for R-134a.
• The required pressure test shall be maintained for 10 minutes.
9.1 Pressure Test Medium
The test shall be carried out using dry nitrogen.
9.2 Regulators
For all refrigerant systems, excluding CO2 systems, a 40 Bar (G) outlet single stage regulator will be typical as standard. This is to ensure that the outlet pressure of the regulator can never be significantly higher than the strength test pressure. Regulators have relief valves fitted. These must never be removed or tampered with.
9.3 Pressure Testing Charging Hoses
Some care is needed when selecting the pressure test charging hose. The preferred hose shall be 210ST Polyflex (2308N-04V00) thermoplastic hose assembly (with an allowable pressure of 700 Bar (G)) c/w ¼” BSP female swivel both ends and stainless steel swaged ends. This hose comes with a pressure test certificate and can be supplied in various lengths. Alternatively 6mm 0014mm ID stainless steel tubing (with an allowable pressure of 416 Bar (G)) with M6 stainless steel EO unions (with an allowable pressure of 315 Bar (G)) may be used. The refrigerant charging hose detailed in SS147 can be used for pressure testing but its allowable pressure limit prevents its use on CO2 systems.
9.4 Pressure Relief Valve
A pressure test relief valve shall always be mounted on the system being tested (or fit a CVP-HP or CVP-XP relief valve on a manifold). A pressure test relief valve (or manifold with CVP-HP or CVP-XP on small systems) is required for both strength and tightness testing. The pressure relief valve shall be mounted near to the point at which the charging line is connected with the minimum possible number of valves between it and the pressure test gas charging point. There must be no more than one stop valve between the charging valve and the relief valve. The relief valve shall be set between 1.15 and 1.30 times the system maximum allowable pressure for standard strength test at 1.1 times the maximum allowable pressure. If the strength test pressure is 1.43 times the maximum allowable pressure the relief valve shall be set at 1.5 times the system MAP.
9.5 Calibrated Gauge
A calibrated gauge with current calibration certificate shall be used. The pressure gauge used during the pressure tests should be within 20% to 80% of its range at the test pressure
so the pressure is in the central part of the gauge, i.e. it shall have the dial graduated over a range of about double the intended maximum pressure.
9.6 Pressure Test Manifold
When pressure testing site pipework a pressure test manifold may be used. The manifold is introduced to:
• Enable two parts of a system to be tested simultaneously
• Vent a part of the system
• Allow connection of a pressure gauge
• Allow connection of a pressure test relief valve (if required)
10.0 Testing Procedure
10.1 General
1) All test packages shall be prepared by Zamil for Copper pipes pressure test. And also should be submitted to Client for their review and approval.
2) Equipment that is not to be subjected to the pressure test shall be either disconnected from the system or isolated by a blank or similar means.
3) Pressurization shall be carried out in a controlled fashion at all times and the pressure shall be applied gradually.
4) When open to the system, the pressure source shall not be left unattended.
5) During initial pressurization of the system up to strength test pressure and until the pressure is reduced to tightness test pressure, at least two people shall be in attendance.
6) The system shall never be approached if the pressure is greater than 10% of the allowable pressure unless the pressure has been reduced by at least 10% from the previous highest pressure.
7) Never attempt to tighten anything (e.g. screwed fittings) with the system under pressure. Always isolate and blow down.
8) A strength test shall be held for a minimum of five minutes. Never approach the system during this time.
9) OFN shall not be vented into a closed space where it could become an asphyxiation hazard.
10) The values of test pressures to be used shall be marked on the relevant drawings/certificates.
- A.. The pressure test shall exclude the evaporator coil and condensing coil because these copper pipes will be factory tested or pressure tested.
- Completely flush all the refrigerant piping line systems (suction line, liquid line and hot gas bypass line) with dry nitrogen gas prior to conduct pressure testing and refrigerant charging into the systems.
- Charge the refrigerant line systems with recommended type of refrigerant as per air conditioning equipments manufacturer’s requirements, instructions and recommendations.
- Avoid direct quenching of the brazed copper tubing joints to water to protect the pipe joints from any unnecessary crack.
- Location for oil trap requirement for the refrigerant suction pipe line system shall be confirmed and re-verified to air conditioning equipment manufacturer as per their recommendations and instructions.
- Filler rod specifications for copper brazing shall be AWS A5.8.
- Brazing procedure , BPS and BPQR for copper brazing shall be submitted to Aramco PID (SAPID) brazing inspector for approval.
- Copper brazers shall be tested, qualified and approved by Aramco PID Welding/brazing inspectoror approved by third party contractor authorized by Aramco.
- All copper brazers shall be Aramco approved and shall have a valid job clearance card issued from Aramco Welding/Brazing PID inspector.
10.2 Pipework Test Pressure
• The pneumatic test pressure shall be not less than 1.2 nor more than 1.5 times the design pressure of the piping system. The test pressure shall not exceed the maximum allowable test pressure of any non-isolated component, such as vessels, pumps, or valves, in the system. The tightness test pressure shall be 1.0 x the allowable pressure.
10.3 Strength Test
• The strength test shall be carried out prior to the tightness pressure test. The pressure test shall be carried out using OFN applied through an approved pressure reducing valve.
• Pressure shall be raised gradually. An initial examination may be made at low pressure, provided the gas pressure does not exceed 10% of the allowable pressure. Thereafter pressure shall again be raised gradually.
• The strength test procedure may be interrupted if leaks need attention. In general, and at any stage in the procedure, repairs to leaks shall not be carried out unless the pipework system has been subjected to a pressure at least 10% higher than the pressure proposed for the checking for leaks. Repairs must only be carried out with that section vented to atmosphere.
• Thereafter the pressure will be increased in stages until the strength test pressure is reached. After the strength test pressure is reached, the pipework shall be isolated from the pressure source and held for a minimum of 10 minutes.
• There should be no appreciable drop in pressure during this time.
10.4 Tightness Test
• Following the strength test, the pressure in the system shall be reduced to the tightness test pressure and held there for a minimum of 30 minutes. There should be no appreciable drop in pressure during this time. A tightness inspection test shall be carried out with a “soapy bubble” trace solution.
• The complete system (including components which have been previously strength tested) shall be tested for tightness. Components previously tested in the factory shall be re-tested on site to ensure leaks have not developed at mechanical joints during transportation and positioning.
• The pressure will then be reduced by venting the OFN to atmosphere.
10.5 Leak detection
• The modern electronic leak detector is the most sensitive type. Because of its extreme sensitivity, this electronic detector cannot be used in a contaminated atmosphere/ windy environment/ insulated pipe joints, etc. where misleading signals are very much likely.
• The other effective method of leak detection is with Halide torch. A small amount of refrigerant burning in the presence of copper has a bright green color. A larger amount will burn with a violet colored flame. This method is also prone to the influence of contaminated atmosphere/ wind / insulated pipe joints.
• Since the leak detection by the above methods are not so dependable at site condition, the simplest and oldest method of leak detection by means of soap bubbles is most recommended. Use a commercial solution such as liquid soap or equivalent.
• Prepare a solution of liquid detergent or liquid soap with water in the proportion of one (1.0) pint (0.5 liter) of detergent or soap and four (4) quarters (3.8 liters) of water. Prepare the solution in advance to allow the bubbles and foam to disperse before using.
• Apply the soap solution to all fittings and brazing joints in a continuous film relatively free of bubbles and observe closely for any minor soap bubbles generating from the
brazed joints.
• A qualified technician can identify the difference between the bubbles caused by leak and bubbles naturally present in the soap application.
• If any doubt of leak is detected, it should be confirmed with other instruments such as electronic instrument or Halide torch.
• After rectification of leaks, if any, all the above leak detection formalities have to be repeated.
10.6 EVACUATION PROCEDURE:
• Connect the vacuum pump to both the high and low sides of the Field Pipe line with flexible hose of ¼ “.
• Turn on the vacuum, and continue to operate it until the manifold gauge on the vacuum pump reaches the manufacturer’s suggested low pressure of -30 psig.
• Perform vacuum pressure test of the refrigerant piping line systems for a holding time of 24 hrs test duration prior to refrigerant charging.
• The vacuumed pressure in the field piping shall be hold for 24 hours for observation.
• Do not operate the ACCU equipment compressor while vacuum is attached and operating.
• SAPID QA/QC inspector to witness the hold Vacuumed pressure before & after 24 Hrs.
10.7 PIPE INSULATION AND CLADDING:
• Refrigerant suction lines shall be insulated from the evaporator to the compressor.
• Pipe work insulation shall have a flame spread/smoke developed rating not in accordance with project specification of factory pre molded fiber glass noncombustible to ASTM C518 with a thermal transmittance not greater than 0.032 W/m2K at 24°C.
• Piping insulation shall be applied only where the Pressure test and other inspections required are completed.
• Before insulation, all surfaces shall be thoroughly cleaned to remove slag, rust, grease, etc. Insulation shall be applied only on dry surface.
• Insulation installed outdoors shall be protected from moisture and sunlight degradation by 0.5mm (26 gauge) aluminum jacket or an approved and acceptable method..
• Outdoor insulated piping shall be finished with aluminum sheet 0.5 mm (26 gauge) thicknesses, and all seams and joints shall be caulked.
• The suction line, liquid (discharge) line system and hot- gas by pass line systems shall be insulated with approved thermal insulation as per HVAC design specifications due to condensation at suction line and hazards of discharge line and hot gas bypass line.