Y1NZ--659-24-903 | Steam Line Replacement | Salisbury, NC 28144 W.G. Hefner VA Medical Center

nd specifications. Estimated construction duration is 365 days. Additionally, the contractor will provide one (1) year of construction warranty. The construction duration will remain at 365 days with the acceptance of bid items 1 and 2, as these items would be performed in conjunction with other construction. Civil EXISTING CONDITIONS Steam Distribution for the site is currently supplied by a steam line constructed back in 1989 which was to replace the older and now abandoned 1965 steam line. During the initial site visit during the hazmat survey of the 1989 (and later 1965) line s insulation materials, it was determined that a new line could be constructed along the pathway of the old 1965 steam line. The scope of work is to replace a portion of this steam line from buildings 10 to 18 (or Manholes 17B through 15), while keeping existing manholes 17B and 16A. DEMOLITION & TRENCH WORK Portions of the 1965 steam line will need to be abated and removed from the ground so that the new proposed steam line can be laid in place. This will require site prep, traffic control and trenching of the existing landscape, including demolition and replacement of concrete sidewalk panels. During demolition, any good in-situ soil shall be kept to reduce the amount of off-site fill required to fill in the trench. All existing utilities that are not a part of the scope that are encountered while excavating the trench shall be left alone and left in place. When encountering roadways, the path will be bored through and a 24-inch steel jacket (with supports for the steam line) will be installed so that the steam line can be brought through and connected to the other side. NEW WORK A new proposed steam line that connects manhole 17-B to manhole 15 shall be installed within the trench and bore hole provided during the demolition and trench work of the construction. Once the new steam line has been installed, tested, and commissioned, the trench will require backfilling back to existing grade. Additionally, the 1989 steam line will be decommissioned and abandoned in place at this time. Three (3) new manholes will be constructed along the path of the old 1965 steam. See the structural section for more details. Structural EXISTING MANHOLES There is one existing manhole that will be re-used as a part of the current redesign, MH-D (renamed MH-10B). There will be a new opening created for both condensate and steam piping in the existing walls. The new openings will need to be larger than the pipe penetration and squared with additional rebar reinforcement installed around the opening. After service has been transferred to the new steam line, the existing steam line will need to be removed and the existing holes repaired. When the manhole sides are exposed for pipe installation, new waterproofing should be provided prior to backfilling. Additionally, the existing rebar ladder rungs have become corroded and need to be removed and patched with a new rung ladder added. There are also (2) existing manholes that will be removed in their entirety (MH-C & MH-10A) and (2) existing manholes that will be replaced (MH-A & MH-B) as they are too small to accommodate the new piping required. EXISTING BUILDING CONNECTIONS New penetrations through the below grade walls to the Building 16 Laundry and Building 17 Facilities will be required for both condensate and steam piping. After service has been transferred to the new lines, the existing lines will need to removed and the existing holes repaired. Both Building 16 and 17 were part of the original construction of the campus, designed in 1949 by Walter, Hook & Associates (VA Project #2448). The foundation for Building 16 has a basement wall that extends to about 8 -0 below grade and is comprised of 12 thick concrete with #4 at 12 o.c. each way each face. The foundation for Building 17 does not have a basement and it is indicated that the wall extends at least 2 -0 below grade and is comprised of 12 ½ thick concrete with #4 at 14 o.c. each way each face. NEW MANHOLES There are (5) new manholes planned in the current redesign, MH-15A, MH-15B, MH-16A (previously MH-A), MH-17B (previously MH-B) and MH-17C. These manholes will be cast-in-place concrete and meet or exceed the requirements as indicated in the VA Concrete Steam Manhole with Typical Piping Detail (SD336300-01). The concrete walls, floors, and lid will be 12 thick concrete reinforced with #5 at 12 o.c. each face horizontal and vertical, except for lid reinforcing will be #5 at 10 o.c. Plumbing EXISTING CONDITIONS Condensate from the steam piping distribution and end-use equipment is currently returned to the boiler plant in Building 18 through the existing condensate return branches and main distribution piping. The existing condensate piping will be replaced with this project scope of work, so the temporary discharge of this condensate to the nearest sanitary connection at each location will need to be accommodated. TEMPORARY FACILITIES AND PHASING The existing condensate return piping will be maintained until the new condensate return piping is installed. Once the new condensate return main is installed, tested, and commissioned, the existing condensate return branch piping will need to be connected to this new condensate return main. During this construction period, the condensate generated from the existing steam main and end-use equipment shall be quenched and indirectly discharged to the nearest sanitary main. Once the new condensate return branch piping is installed, tested, and commissioned with the new main, these temporary condensate discharge connections shall be demolished. NEW WORK New indirect sanitary connections will be made at each branch connection to the existing condensate return main. The indirect connections will also incorporate a domestic cold water quench valve to temper the condensate discharge to 140°F before discharge into the sanitary main. These indirect sanitary connections shall be demolished once the new condensate return branch connections have been made with the new condensate return mains. Mechanical EXISTING CONDITIONS The 1965 Steam Distribution As-Built Drawings show 12 high-pressure steam and 6 condensate return piping routed to Manhole #17, where a branch of 2 steam and 1-1/2 condensate return piing serves the Utility Shops & Warehouse. The 12 steam and 6 condensate return piping then extends from Manhole #17 to Anchor A-4, where it branches off to serve the laundry facility with 5 steam and 3-1/2 condensate return piping. From Anchor A-4, 10 steam and 6 condensate return piping extends past Manhole #1 to Anchor A-7. From Anchor A-7, branch piping is distributed at 8 steam and 4 condensate return piping to serve Building 10. Another branch extends from Anchor A-7 at 3-1/4 steam and 1-1/4 condensate return piping to serve the Engineering facility. The 10 steam and 6 condensate return mains extend downstream of Anchor A-7 to serve the remainder of the campus. The 1989 Steam Distribution Model shows 10 steam and 6 condensate return piping from the boiler plant to Manhole A . A branch of 2 steam and 1-1/2 condensate return piping serves the Utility Shops & Warehouse. The mains continue at 10 steam and 6 condensate return piping from Manhole A to Manhole B . A branch of 4 steam and 2-1/2 condensate return piping serves the laundry facility. Downstream of Manhole B ,