RFI Response RFP: HSCG88-16-R-PQQ015 Replace HVAC Bldg A & C San Diego, CA.

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1 1. There is verbiage in the hazardous material report referring to a state licensed abatement contractor. Within the recommendations part of the report (page 64 of 111 of the specification pdf) is the statement EAI recommends that any identified LBPs be removed by a state-licensed abatement contractor prior to any activities that may disturb the materials. Is this merely a recommendation by a consultant or is it a requirement of this contract that the abatement subcontractor have a California contractor s license? Will any other subcontractor be required to have a California contractor s license? R: All installation shall be performed as allowed by State licensed contractors. 2. Building A scope states to convert the existing constant air volume AH-2 to variable air volume. Confirm new supply fan and return fan VFDs and motors with grounding rings should be included in the scope of work? R: The conversion shall be from Constant Air Volume (CAV) to Variable Air Volume and Temperature (VVT), not Variable Air Volume (VAV). 3. Page 40, Section 7) VAV Terminal Units states use parallel type Fan-Powered VAV terminal units with temperature rise across electric reheat coils with ECM fan motors. The existing reheat coils are hot water. Please confirm a digital single duct VAV box with hot water reheat coils is acceptable? Fan-Powered VAV box with electric reheat will not be required. R: This is a design-build project. Contractor shall follow his engineer and manufacturer s recommendations. 4. Building C scope states to demolition of air handler unit. Confirm the air handler unit to be demo is AH-1 (located in the boiler mechanical room) serving the Recreation Area? 5. Confirm the base work Building C will have new VRF fan coils serving the Recreation Area? 6. Does the VRF outdoor heat pump unit Qty (5) require any enclosure around the concrete pads? R: No fence screening required.

2 7. Please confirm pre-tab air-balance readings should be included in the scope of work for Building A? R: Provide pre-tab air balance readings are not necessary. 8. Is a 3rd party commissioning agent involved? If so what level of commissioning will be done? a. Submittal review b. Construction document review c. Pre-functional testing d. Functional performance testing R: Third party commissioning agent is not required. TAB agent shall be a first subcontractor to the prime; and financially and corporately independent of the mechanical subcontractor. 9. Is a warranty coverage required for refurbished items such as existing pumps and air units? R:For refurbished items, provide one-year full warranty. 10. Where existing equipment is to be reused has it been verified for capacity, head or static pressure requirements for the addition of new equipment? 11. The specifications call for temporary heating and cooling. Where temporary heating and cooling is required what are the design conditions for temperature and humidity? R: Portable fans and heaters are acceptable for temporary cooling and heating needs during shutdown of HVAC system for construction. The acceptable temperature is 65 F in winter. Assume 24 hours 7 days operation. 12. What are the hours of operations for the temporary heating and cooling system? R: See response in # Are there any spaces that require special temperature and humidity conditions such as IT rooms or others? R: No. 14. Page 53, para 3.01.A The SOW indicates to To minimize interruption of building operation, contractor shall shut down one structure at a time, as well as

3 Provide temporary heating and cooling equipment during construction to allow continued operation of the building. This will be difficult and expensive to accommodate as written. If temporary heating and cooling equipment is construed as portable fans and electric floor heaters, no problems. From a shut-down perspective, Bldg A is no problem. However, the new condensing units for the (5) individual VRF systems in Bldg C will require removal of the existing chiller before any new work can commence. This means that all 5 sections of Building C will be without central heating and air one work commences and until work is finished. Can portable fans and portable floor heaters be used in these buildings for the duration of construction in those building? R: See response in # Page 3, para 1.03 indicates all site work shall be between the hours of 7:00 am and 5:00 pm, Monday through Friday. Page 53, para 3.01.A indicates Working on after working hours or weekend may be required to minimize interruption of building operation.. Can we assume we can work weekends or nights when required and coordinated in advance? 16. The SOW only calls for cleaning of ductwork in Bldg A, not Bldg C. Please confirm. 17. Existing ductwork in Bldg A and C is in fair to poor condition. Our concern is that this ductwork is appx 30 years old, and air leakage through existing failed duct joints may compromise functionality of the new system. Our recommendation to avoid this issue is to (minimally) remove existing duct insulation, inspect all ductwork, repair or replace with new any damaged ductwork discovered, reseal all duct joints, and re-insulate. Alternatively, for not much more cost new ductwork throughout could be provided. The age and apparent condition of the existing ductwork indicates it is at the end of its service life. Will the CG provide direction for this issue? R: See Schedule B for Revised Option Items. Inspection of ducts shall be part of the Base Item. Two (2) new Option Items are now included in the Schedule B: 1. Repair Duct Work, 2. Replace all Duct work with new. 18. Will the Construction Docs be required to be submitted and approved to/by the City of San Diego Plan Check Dept? R: No

4 19. Bldg A the SOW (para 1.01.a.1.a) indicates (in essence) to demo existing reheat coils and replace with new VAV Terminal Units (TU s) with reheat coils. These TU s would be provided with air from an older, to-be-re-furbished constant volume cooling only AHU, with a new bypass damper being provided for air volume control. The SOW (para 1.01.a.1.d) also indicates Implement all mandatory control strategies per California Title 24 as allowed by the modification. It would appear this project would not be allowed per T24 requirements, due to the simultaneous heating and cooling, as well as the lack of airflow reduction before heating is implemented. Please advise. R: Contractor shall calculate max. cooling (primary) airflow; min. cooling (ventilation setting) airflow, min. heating (max. of ventilation and 30% of primary) airflow (during cooling mode) settings. All hot water reheat coils shall be sized to satisfy space heating requirement at min heating airflow setting. New DDC control shall incorporate, include but not limit to, zone temperature control, night setback, morning warm up, economizer control, hot water temperature reset and all applicable control strategies that are not restricted by the existing equipment. In addition, cut off hot water boiler and pump when outside air temperature reaches 65 F and above. 20. Bldg C - Page 39, para 1.04.E indicates an economizer shall be provided. This is on the VRF system. There is no manufacturer that sells a VRF system with an economizer cycle for the refrigerant. Can we assume this requirement is void? R: Delete Page 39, par 1.04E. 21. Bldg A Page 56, para 3.03 calls for cleaning, flushing, and pressure testing of all existing piping systems that are to be reused. These piping systems are over 30 years old, and have been through several earthquakes. We plan on performing an air test first, followed by a hydro test at 1.5X minimum working pressure, or 100 psi, whichever is greater. Should the piping/joints fail the hydro test who will be responsible for the cost of piping repairs? More importantly, a failure may result in water damage; who will be responsible for cleanup? With the unknowns of this system, would the USCG want to consider replacing all existing heating water piping in building A? R: Visual inspect the entire hot water heating piping system for leaks prior to replacing hot water reheat coils, report all leaks to KO. Assure no leaks on all new work and repair as necessary before insulate the pipes. No pressure test is required. 22. Bldg A and C: New HVAC equipment to be provided will be furnished to replace existing equipment. No new HVAC zones will be provided, except if requested in the future by the USCG. Please confirm.

5 R: Provide HVAC system and zones in accordance with functions of the buildings and engineer s recommendation and applicable codes. 23. Page 48, para 1.06.K: A two year unlimited warranty is specified. However, on page 9, para 1.13 a one year warranty is indicated. Is the requested warranty one or two years? R: Two Years 24. Bldg C Can we assume that routing of new VRF refrigerant piping can follow the same routing as the existing chilled water piping? On this same topic, some new piping may be required to cross from building to building at the ceiling of the covered walkway. Can this piping be exposed? R: For Building C, each structure shall have its own independent heat pump or heat recovery system and control. If some new piping is required to cross from building to building, this piping shall be properly protected in accordance with manufacturer s recommendations and applicable structural codes. 25. Bldg A and C Should we plan on adding attic insulation? R: Only Building A as instructed by the spec. 26. Bldg A page 31, para 1.01.a.d: SOW indicates to provide major maintenance and rehab work on the existing HVAC equipment. Para 1.04, fifth para calls out all coils, and fins shall be of copper or factory corrosion resistant coatings. This section also indicates 250hr salt test finish for indoor and 1000hr salt test for outdoor equipment. Can we assume these requirements (for coils and cabinets) do not apply to the existing ahu/condensing unit? Note that if these requirements are applicable, it would probably be cheaper to provide new equipment than to dis-member existing equipment and rebuild using new components. R: Paragraph 1.04 applies to new equipment. 27. The specification Part 3 Execution 3.01 Special Requirement F.2 states all refrigerant pipe joints shall be brazed. Due to the building wood structure and potential fire risk we would like to use a mechanical joint connection method that is approved by the VRF manufacture. VRF Manufactures have approved mechanical fitting methods for refrigerant piping installations for applications such as this. Will a mechanical fitting connection vs. a brazed joint method be allowed for refrigerant piping?

6 R: No mechanical joint connection is allowed.