AC_Chillers_Renewal_DEK,_Updated_SOW.doc

51400_JAH_0118_420

WORK ITEM 1: Air Conditioning Systems, Evaporator Renewal

1. SCOPE

1.1 Intent. This work item describes the requirements for the Contractor to install new evaporator in two (2) of the ship’s three (3) air conditioning plants. The new evaporators will be provided as GFM.

1.2 Government-furnished property.

($/UNIT)

2. REFERENCES

Coast Guard Drawings

Coast Guard Drawing 420-WAGB 514-2, Rev D, Diagram of Hot & Chilled Water System

Coast Guard Drawing 420-WAGB 505-1, Rev E, Piping General Notes & Installation Details

Coast Guard Drawing 420-WAGB 508-1, Rev D, Pp & Mchry Insulation Sched

Coast Guard Drawing 420-WAGB 801-1, Rev J, Booklet of General Drawings

Coast Guard Publications

Surface Forces Logistics Center Standard Specification 0000 (SFLC Std Spec 0000), 2014, General Requirements

Surface Forces Logistics Center Standard Specification 0740 (SFLC Std Spec 0740), 2014, Welding and Allied Processes

Surface Forces Logistics Center Standard Specification 6310 (SFLC Std Spec 6310), 2014, Requirements for Preservation of Ship Structures

Coast Guard Technical Publication (TP) 5158, 01-NOV-03, S9514-Fa-MMC-010 - Air Conditioning System (75-Ton)

Other References

The Society for Protective Coatings (SSPC) Surface Preparation Specification No.1 (SSPC-SP 1), 2016, Solvent Cleaning

The Society for Protective Coatings (SSPC) Surface Preparation Specification No.3 (SSPC-SP 3), 2004, Power Tool Cleaning

3. REQUIREMENTS

3.1 General.

3.1.1 CIR. Not applicable

3.1.2 Tech Rep. The Contractor shall provide the services of qualified Tech Rep, who is familiar with the air conditioning equipment, to accomplish the following tasks – on site:

· Provide manufacturer's proprietary information, software, and tools pertinent to the equipment/system.

· Assist with proper repair methods, and ensure compliance with manufacturer's procedures and standards during disassembly, inspection, repair, modification, calibration, and reassembly of the equipment/system.

3.1.2.1 The Contractor shall ensure that the Tech Rep has experience with the York Marinepak Air Conditioning Systems on the HEALY.

3.1.2.2 The Contractor shall submit the name of the Tech Rep to the COR at the Arrival Conference.

3.1.3 Protective measures. The Contractor shall furnish and install suitable covering to seal off and protect all non-affected surfaces/equipment and spaces in the vicinity of the work area against contamination during the performance of work. Upon completion of work, remove protective material and inspect for the presence of contamination. Clean all equipment and spaces, contaminated due to improper protection, to original condition of cleanliness.

3.1.4 Interferences. The Contractor shall handle all interferences in accordance with SFLC Std Spec 0000, paragraph 3.3.5 (Interferences).

3.1.5 Personnel qualification. The Contractor shall ensure that all personnel servicing Air Conditioning and Refrigeration (AC&R) equipment that uses CFC or HCFC refrigerant hold a current Environmental Protection Agency (EPA) Technician Certification, Type IV (Universal Certification), and meet all State and local regulations and licensing requirements.

3.1.6 Refrigerant draining and recovery. The contractor is required to pump down and drain the refrigerant charge from the affected systems to perform the work in this specification item, the Contractor shall recover the refrigerant for reuse upon completion of work.

3.2 Background information. The Coast Guard has determined that the evaporators on two (2) of the three (3) air conditioning units can no longer be repaired. It is the Coast Guard’s intent to install new evaporators for each of the two (2) affected air conditioning units. The existing evaporators serve as foundations for each of the two (2) air conditioning compressors associated with each of the air conditioning plants.

The Contractor shall disassemble the air conditioning plants to remove the existing evaporators. The Contractor shall design, fabricate and install new foundations for the compressors and for the evaporators and shall provide and install new piping connections as required. The new evaporators shall be mounted in place of the existing units. The Contractor shall install new chilled water piping and new refrigerant supply and discharge piping and new relief piping to the new evaporators.

3.3 Initial survey. The Contractor shall perform the following work:

3.3.1 Accompanied by the Coast Guard Inspector, the Contractor shall conduct a visual survey of each of three (3) air conditioning plants.

3.3.2 With the aid of ship’s force, operate each of the three (3) air conditioning plants and, using a halide gas detector, inspect each of the air conditioning plants for refrigerant leaks. Document each of the existing refrigerant leaks.

3.3.3 Submit a condition found report (CFR) noting any unusual conditions and recommending any repairs.

3.3.4 Any repairs of existing refrigerant leaks shall be the subject of a contract modification.

3.4 Receive new air conditioning evaporators. The Contractor shall perform the work:

3.4.1 Receive each of the two (2) new air conditioning evaporators. Inspect each of the evaporators for any indications of damage in shipping.

3.4.2 Hydrostatically test the shell and tube sides of each of the new evaporators. Ensure that there are no leaks in the new evaporators. Follow test pressure guidance provided by manufacturer.

3.4.2.1 Drain the test fluid from each of the evaporators and blow out both sides of the new evaporators with clean, dry air to remove any remaining moisture from the evaporators.

3.4.3 Submit a CFR noting any shipping damage and any leakage in any of the evaporators.

3.5 Evaporator work sequencing. The Contractor shall coordinate all work with the Coast Guard Inspector to ensure that at least one (1) air conditioning plant remains operational at all times. The Contractor shall not disable all of the air conditioning plants simultaneously but shall maintain air conditioning for the cutter.

3.6 Refrigerant draining and recovery/Chilled water system draining. The Contractor shall pump down, drain, and store the refrigerant charge from the affected circuit on each air conditioning plant as repairs are made to the unit. Each refrigerant circuit contains 140 lbs. of refrigerant R-22, for a total of 280 lbs. of refrigerant per air conditioning unit. Upon completion of other work, return and restore the refrigerant charge to the affected air conditioning plant. The No. 2 Air Conditioning Plant shall not be modified. Repairs are being conducted on the No. 1 and No. 3 Air conditioning plants only.

3.6.1 Pump down and drain both refrigerant circuits on each of the two (2) affected air conditioning plant.

3.6.2 After pumping down the refrigerating circuits, place a charge of dry nitrogen on the system to prevent entry of moisture or contaminants.

3.6.3 Oil Removal. Drain the oil from the oil separator/reservoir on each refrigerant circuit.

3.6.4 Isolate each of the two (2) affected air conditioning plants as required to perform work. Drain the affected portions of the chilled water system.

3.6.5 Collect all the chilled water drained and dispose of the water in accordance with all federal, state, and local regulations. Chilled water has been treated with ethelene-glycol anti-freeze to prevent the system from freezing up during northern deployments.

3.7 Air conditioning plant modifications. The Contractor shall perform the following work:

3.7.1 Disassemble each of the two (2) affected air conditioning plants. This work will require removal of each of the compressors associated with each the two (2) affected air conditioning plant.

3.7.1.1 Electrically and mechanically disconnect each of the two (2) compressor/motor assemblies associated with each of the two (2) affected air conditioning plant. Remove and store each of the compressor/motor assemblies in the compartment. Cover all open ends to prevent contamination from entering the compressors or the open refrigerant piping.

3.7.2 Remove each of the two (2) affected evaporator assemblies from the existing air conditioning plants.

3.7.3 Transport each of the two (2) affected evaporator assembly to the Main Deck and turn it over to the Coast Guard Inspector for disposition.

3.7.4 After completion of hydrostatic testing and inspection, transport each of the of the two (2) new GFM evaporators to the Refrigeration Machinery Room (3-33-1-E).

3.7.5 Fabricate and install new foundations to support each of the two (2) compressor and motor assemblies and the new evaporators for each of the two (2) affected air conditioning plant.

3.7.6 Modify the mounting for the evaporators in each of the two (2) affected existing air conditioning plants. The new evaporators must be securely mounted to the air conditioning plant to prevent vibration. Provide rubber padding wherever the new evaporator assemblies contact the existing mountings.

3.7.6.1 The existing evaporator assemblies are larger than the new evaporator assemblies (existing evaporator assemblies are 11-5/8 inch dia. x 8 ft. lng.; new evaporator assemblies are 8-5/8 inch dia. x 93-3/4 inch lng.). See attached sheets for data on DX75-2 evaporator.

3.7.6.2 Using Figure FO-1 75 Ton Air Conditioning System Piping Diagram in CG Tech Pub 5158, identify locations to break the refrigerant piping to allow existing evaporator to be removed and new evaporator to be installed. This piping includes two (2) refrigerant supply lines, two (2) refrigerant discharge lines and two (2) relief lines for each of the two (2) affected evaporators.

3.7.7 Fabricate and install new refrigerant piping for each of the new refrigerant evaporators. The new piping shall include two (2) refrigerant supply lines, two (2) refrigerant discharge lines, and if needed, two (2) refrigerant exhaust lines. New piping shall follow the same routing as the existing piping shown in Figure FO-1 Piping Diagram D 66935 076-84422-002B, in CG Tech Pub 5158.

3.7.7.1 The Contractor shall flush all new piping prior to installation.

3.7.7.2 The Contractor shall hydrostatically test all new refrigerant piping in the shop before final installation.

3.7.8 Provide new chilled water piping to each of the new evaporators. New chilled water piping shall be as shown in CG Dwg 420 WAGB 514-2. The Contractor shall provide new flexible connections to the supply and discharge of each of the new evaporator assemblies. For bidding purposes, assume ten (10) lin. ft. of each of the mentioned piping shall be needed for each new evaporator. A total of 30 lin. ft. of new chilled water piping shall be required.

3.7.8.1 New piping shall be cleaned and flushed prior to installation. Follow standard guidance for piping installation in CG Dwg 420 WAGB 505-1.

3.7.8.2 Provide and install new piping hangars for all new piping.

3.7.9 Reinstall each of the compressor/motor assemblies on the new foundations.

3.7.10 Electrically and mechanically reconnect each of the compressor/motor assemblies.

3.7.11 Verify the alignment of each of the compressor/motor assemblies to the existing refrigerant piping. Ensure that there is no excessive strain on the piping.

3.8 Restoring the System to Operating Condition Following Repairs. Perform the following work on each refrigerant circuit which had the refrigerant pumped down and drained.

3.8.1 Conduct a pressure test on the unit using dry nitrogen. Soap test all joints. Follow guidance in Section 6.2.1 of the Technical Manual. Mark any leaks for repairs.

3.8.2 After completion of the dry nitrogen test and repair of any leaks, conduct a leak test of the condensing unit using refrigerant and nitrogen.

3.8.3 After completion of testing of the system, evacuate the system using a vacuum pump. When the system is evacuated, secure the vacuum pump and hold the vacuum for twenty-four (24) hours to demonstrate that there are no air leaks and that there is no moisture in the system. Re-check vacuum levels at completion of this period to demonstrate that there is no system leakage.

3.8.4 Charging Oil. The Contractor shall charge oil into each of the oil separators. A total of 1.75 gallons of oil will be charged into each separator. New charge oil shall be furnished by the contractor. Follow guidance in the technical manual.

3.8.5 Charging Refrigerant. The Contractor shall charge the refrigerant, which was previously removed from the system back into the affected evaporator. Follow guidance in the Technical Manual.

3.8.6 Refill the water drained from the chilled water system with fresh water treated with ethelene-glycol, 50/50 mixture.

3.9 Test Operation. With the aid of ship’s force the Contractor shall test, operate the air conditioning plant for a period of at least four (4) hours.

3.9.1 After the air conditioning plant has stabilized in operation, take and record a copy of the operating parameters. Operating parameters are shown on Sheet 2-16 of the Technical Manaul.

3.9.2 Provide a written report of all nondestructive test findings to the Coast Guard Inspector.

3.10 Insulation renewal. The Contractor shall install new insulation and repair any insulation which was damaged during the course of this work item. Follow guidance in CG Dwg 420 AGB 508-1. Paint all new insulation as described in SFLC Std Spec 6310. Restore flow labels where they were removed.

3.11 Touch-up preservation. The Contractor shall prepare and coat all new and disturbed exterior and interior surfaces to match existing adjacent surfaces, in accordance with SFLC Std Spec 6310, Appendix A (Cutter and Boat Exterior Painting Systems) and Appendix B (Cutter and Boat Interior Painting Systems), respectively, and as applicable. Abide by all touch-up requirements outlined in SFLC Std Spec 0000, Appendix A (Requirements for Preservation of Ship Structures).

4. NOTES

4.1 Equipment description. The cutter is equipped with three (3) York Marinepak air conditioning plants. Each air conditioning plant is rated for 75 tons cooling capacity and each plant operates on R-22 refrigerant. Modifications to the evaporators shall only be conducted on the No. 1 and No. 3 Air Conditioning plants.

4.1.1 Each air conditioning plant has two (2) separate cooling circuits which consists of two (2) compressors, two (2) condensers, one (1) evaporator, two (2) dehydrators, two (2) oil separators, two (2) motor controllers, two (2) separate circuit controllers and various temperature and pressure switches as required to make the units operate.