ADDENDUM #4. Lanier Filter Plant Ozone System Safety Improvements BL079-14

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1 September 24, 2014 ADDENDUM #4 Lanier Filter Plant Ozone System Safety Improvements BL Q1. Please clarify how many submarine doors the perimeter gaskets and gasket hardware must be replaced on. A1. The number of submarine doors opened shall be at the Contractor s discretion based on their means and methods for demolishing the existing dissolved ozone sample piping inside the Ozone Contactors, installing new piping, and providing for a safe work environment per state and Federal guidelines while working inside the ozone contactors. Any and all submarine doors which are opened by the Contractor shall have their gaskets replaced. Existing hardware may be reused unless it is worn or otherwise degraded such that a gastight seal cannot be achieved with the existing hardware and/or the hardware will not allow for future disassembly and access. Hardware replacements shall match existing. The submarine doors referred to are located in the lower level pipe galleries of the Ozone Building. There are three (3) submarine doors installed per ozone contactor and four (4) contactors. Twelve (12) total submarine doors are available for the Contractor to perform the work and may be accessed at the Contractor s discretion. Q2. Also, please confirm there are only 4 checkered plates that must be resealed. If not, how many checkered plates are present? A2. To clarify, the checker plates are located in the Ozone Generator Room, upper level of the Ozone Building. Each ozone contactor has one (1) approximately 65-inch square checker plate (a total of four (4)). Below, each of the checker plates is a secondary gastight hatch. There are four (4) of these and they have their own hardware and gasketing separate from the checker plates above them. Thus, if the Contractor desires to access the ozone contactor from above in the Generator Room, for each contactor accessed, the Contractor shall be responsible for replacing the gaskets for the checker plate AND it s underlying gastight hatch. Existing hardware may be reused unless it is worn or otherwise degraded such that a gastight seal cannot be achieved with the existing hardware and/or the hardware will not allow for future disassembly and access. Hardware replacements shall match existing. The number of checker plates and gastight hatches opened shall be at the Contractor s discretion based on their means and methods for demolishing the existing dissolved ozone sample piping inside the Ozone Contactors, installing new piping, and providing for a safe work environment per state and Federal guidelines while working inside the ozone contactors.

2 Additional Clarifications: 1. In Addendum #1 (dated September 12, 2014), delete clarification 2 in its entirety. The Bid form shall not include the Part 3 - Additive Alternate section as previously directed. Deleted requirements are shown below. Part 3 Additive Alternate The Bidder shall include within their lump Total Bid (lump sum) an allowance for the following items: Demolition of the four (4) stainless steel sample sinks located in the basement of the Ozone Building. Core drilling twelve (12) new holes into the existing 1-6 reinforced concrete vertical walls of the Ozone Contactors to accommodate the new ¾ dissolved ozone sample piping as described in the Bid Documents. The utilization of this task would be in lieu of enlarging the existing penetrations, if based on Engineer s evaluation of the of existing piping, it is found to be advantageous or required to do so. All such Work shall be at the direction of the Engineer. This Work shall only be performed only if directed by the Engineer. The Contractor submits the following deduct for all Work, labor, materials, and disposal costs associated with this Additive Alternate should the activity not be required. The deduct shall be utilized to adjust the final project cost upon completion and acceptance of the Work. Additive Alternate Demolition and disposal of the four (4) stainless steel sample sinks located in the basement of the Ozone Building. Core drilling twelve (12) new holes into the existing 1-6 reinforced concrete vertical walls of the Ozone Contactors. Deduct from Total Bid (Lump Sum) $ $ 2. Figures of Section are revised and reissued in the attachment to this addendum.

3 3. The bid opening date has been extended as follows: Sealed bids will be received by the Gwinnett County Department of Financial Services Purchasing Division-2 nd Floor, 75 Langley Drive, Lawrenceville, Georgia until 2:50 P.M. local time on October 1, 2014 and then publicly opened and read aloud at 3:00 P.M. Any bid received after 2:50 P.M. will not be accepted. Bid envelope must be marked on the outside with Bid Number, name of Bidder, date and time of opening. Contractor providing the utility work must have a current valid Utility Contractors License. This addendum should be signed in the space provided below and returned with your bid. Failure to do so may result in your bid being deemed non-responsive. Company Name Authorized Representative Thank you. Holly Cafferata, CPPB Purchasing Associate III

4 ADDENDUM #4 Lanier Filter Plant Ozone System Safety Improvements BL Attachments The following attachments are provided on the pages that follow. Specification Section Figure 24-26

5 There are three (3) submarine doors installed for each ozone contactor, on the vertical walls in lower level pipe galleries of the Ozone Building. There are twelve (12) total. For all submarine doors opened by the Contractor during the course of the Work, Contractor shall replace gasket materials, replace hardware as required, and perform and provide all other requirements as noted or specified. DETAIL BELOW PROVIDED FOR INFORMATIONAL PURPOSES ONLY, CONTRACTOR SHALL FIELD VERIFY ACTUAL DIMENSIONS. NOTES: 1. Contractor shall provide replacement gaskets for submarine doors opened during the Work. 2. The number of submarine doors opened shall be at the Contractor s discretion based on their means and methods for demolishing the existing dissolved ozone sample piping inside the Ozone Contactors, installing new piping, and providing for a safe work environment per state and federal requirements while working inside the ozone contactors. 3. Gasket materials shall be ozone compatible. 4. If submarine doors in the Generator Pipe Galleries are to be opened by the Contractor, the following submittals shall be provided for Engineer review and approval prior to gasket fabrication: a. Summary of submarine doors, including: make, model, dimensions, and hardware summary (hardware quantity, type, size, spacing, and material). b. Photographs of the existing installation before and after opening. c. Photographs and summary of existing gaskets, including dimensions, bolt patterns, materials, and thickness. d. Documentation from the submarine door manufacturer including recommendations for gasket materials and thickness. e. Submit gasket fabrication drawings and quantities for gaskets to be replaced. Include material types and replacement hardware to be provided. 5. Existing hardware may be reused unless it is worn or otherwise degraded such that a gastight/watertight seal cannot be achieved with the existing hardware and/or the hardware will not allow for future disassembly and access. Hardware replacements shall match existing. 6. Replacement gaskets shall be of the following materials: a. Each gasket shall be one piece and fully molded solely of 1/4 thick PTFE (GARLOK GYLON Style 3505, or equal). Figure 24. Gastight/Watertight Door Resealing Requirments GWINNETT COUNTY DWR LFP Ozone System Safety Improvements -25- BV September 2014

6 Existing checker plate access hatches on the Generator Room floor are shown in this photo. There are four (4) total (one per ozone contactor). Below, each of the checker plates (in the same slab opening) is a secondary gastight hatch which provides access to the interior of the ozone contactors. There are four (4) total gastight hatches. For all checker plate/gastight hatch pairs opened by the Contractor during the course of the Work, Contractor shall replace gasket materials, replace hardware as required, and perform and provide all other requirements as noted or specified. NOTES: 1. Contractor shall provide replacement gaskets for checker plate covers and gastight hatches opened during the Work. 2. The number of checker plates and gastight hatches opened shall be at the Contractor s discretion based on their means and methods for demolishing the existing dissolved ozone sample piping inside the Ozone Contactors, installing new piping, and providing for a safe work environment per state and federal guidelines while working inside the ozone contactors. 3. Gasket materials shall be ozone compatible. 4. If plates and hatches in the Generator Room are to be opened by the Contractor, the following submittals shall be provided for Engineer review and approval prior to gasket fabrication: a. Summary of existing checker plates and gastight hatches, including: make, model, dimensions, and hardware summary ( hardware quantity, type, size, spacing, and material). b. Photographs of the existing installation for both checker plates and gastight hatches before and after opening. c. Photographs and summary of existing gaskets (for checker plate and gastight hatch), including dimensions, bolt patterns, materials, and thickness. d. Documentation from the gastight hatch manufacturer including recommendations for gasket materials and thickness. e. Submit gasket fabrication drawings and quantities for gaskets to be replaced. Include material types and replacement hardware to be provided. 5. Existing hardware may be reused unless it is worn or otherwise degraded such that a gastight seal cannot be achieved with the existing hardware and/or the hardware will not allow for future disassembly and access. Hardware replacements shall match existing. 6. Replacement gaskets and sealant shall be of the following materials: a. Replacement gaskets for the checker plates on the generator slab shall be one piece and fully molded solely of 1/8 thick Viton with bolt patterns to match existing. Viton gasket strips shall also be provided between the checker plates and the cast-in frame, cut to fill the void space between the checker plates and the cast-in frame, and flush with the operating floor to eliminate potential trip hazards. Apply silicone caulk around the perimeter and atop mounting bolts. Typical of four checker plate hatches. b. Replacement of gastight hatch gaskets located below the checker plates in the Ozone Generator Room, each one piece and fully molded solely of 1/4 thick PTFE (GARLOK GYLON Style 3505, or equal). No photo or detail of the hatch are available. Figure 25. Gastight/Watertight Door Resealing Requirments GWINNETT COUNTY DWR LFP Ozone System Safety Improvements -26- BV September 2014

7 Valve shall be closed. Temporary connections for compressed air. Contaminant and oil-free, filtered compressed air shall be introduced to the headspace of the Ozone Contactors to achieve positive pressure. The Ozone Contactors shall be pressurized to achieve positive 5 inches of water column during the duration of the test. Compressed air shall be introduced via temporary connections to the Ozone Contactors off-gas piping. Figure 26. Gastight Testing END OF SECTION GWINNETT COUNTY DWR LFP Ozone System Safety Improvements -27- BV September 2014