Loading...
HomeMy WebLinkAboutPN_Project_Narrative_180426_v1.pdfRenton Mitigation Hangar Project Narrative – April 25, 2018 1 Global Project Information Title: 4-87 Mitigation Hangar Location: Renton, Between Buildings 4-81 and 4-20 Boeing Permit Contact: Mark Clement Contact Phone: (206) 617-2944 Overview The Boeing Company is looking to construct a hangar structure measuring approximately 338’x173’ in plan on Apron R as an extension to their existing final assembly building 4-81/82; the height is proposed to be approximately 88’ ft. High. This new hangar will house two 737 aircrafts for the purpose of performing manufacturing activities currently performed in the final assembly building 4-81/82. The new hangar will consist of high bay and low bay buildings. High bay will be located on the northern portion of the building and will house two 737 MAX (Unfueled aircraft). The low bay which is located on the south will house airplane equipment service and storage area on the first floor and work area and lockers on the second floor. There will be a 10’ separation between the existing building 04-81 and the new hangar structure. Existing utilities within the footprint of the proposed hangar will be relocated and re- established, with existing lines abandoned in place. The project will require a comprehensive re-evaluation and revision of the existing storm water conveyance system including installation of new combined bypass, oil/water separator and new modular wetland water quality treatment vault. The project will install a new electrical unit substation dedicated to this building. Mechanical system includes new air handling system located at roof of the hangar. All proposed work for this project will be performed outside the 200 foot shoreline buffer. No change in impervious surface area or use is proposed. Area will be restored to current condition following completion of the hangar project. See Utility and Grading Elevation Plans for more information See the attached Site Plans and Vicinity Map for location information. A smaller version of the Vicinity Map is included below as Figure 1; not to scale. Renton Mitigation Hangar Project Narrative – April 25, 2018 2 Summary Program · Overall Size: ~63,000 Square Feet (SF) · Assumed Displaced Impervious SF: ~63,000 SF · Building Components: o Mitigation Hangar (High Bay) – 173’x290’ o Manufacturing/Work Area – 48’x133’ · Assumed Occupancy: S-1 · Major Design Components: o Structural Figure 1 – Vicinity Map Renton Mitigation Hangar Project Narrative – April 25, 2018 3 o Architectural o Mechanical o Electrical o Civil/Site o Geotechnical o Fire Protection Detailed Summary of Work Building Summary · High Bay Hangar: o High bay on the north, approximately 290’L x 173’D x 88’H will be a steel frame building supported by steel trusses spanning E-W direction. o Roof will be single ply roofing system on metal decking; Parapet wall provided for minimum height of 42”above roof surface for fall protection. o Exterior siding - Prefinished metal insulated panels and architectural metal panels with interplay of horizontal and vertical lines to create different planes, shadow lines and flavors but need to work as a whole. o Wall base, approximately 7’-2” concrete wall base panel at exterior. o Two (2) large hangar doors on west wall for airplane ingress and egress. o One (1) roll up door opening at the north wall for future use. o One (1) roll up door at the west wall and align with existing roll up door location in 04-81 building for equipment moving purposes across the two (2) buildings. o Building canopies will be provided at entrances for added architectural markings. o Existing signage and paint striping to be reconfigured within the proximity area impacted from by the new hangar location. · Low Bay Hangar Support Building: o The low bay, approximately 48’D x 133’D x 52’H will be a steel frame building supported by steel trusses spanning E-W direction. o Roof will be single ply roofing system on metal decking; Parapet wall provided for minimum height of 42”above roof surface for fall protection. o Exterior siding - Prefinished metal insulated panels and architectural metal panels with interplay of horizontal and vertical lines to create different planes, shadow lines and flavors but need to work as a whole. o Wall base, approximately 7’-2” concrete wall base panel at exterior. o Building canopies will be provided at entrances for added architectural markings. Renton Mitigation Hangar Project Narrative – April 25, 2018 4 o There will be airplane equipment storage on the first floor and work area that include lockers on the second floor. See below for additional detail: o Low bay hangar 1st Floor: Low bay 1st floor area will be used for equipment service, machine parts and storage function. Minimum height clearance of 25’ (TBD) above slab for equipment. An electrical substation will be located at the east end of the building with code compliant wall and ceiling enclosure/room that includes doors and hardware. One roll up door at the west wall. One roll up door at the south wall. o Low bay hangar 2nd Floor: Code compliant occupancy load analysis will be performed including, exiting requirements and stairway system for the Low Bay building area. Work Area to be ADA compliant. Boeing will be exploring the option to take advantage of using building 04-81 West Tower existing floor elevation, exiting and elevator system to provide those horizontal and vertical movement system requirement between the two (2) buildings. Where infeasible to take advantage of using the Building 4-81 West Tower existing floor exiting and elevator system, a code compliant ADA Accessibility system will be utilized in this low bay. Depending on the location of the horizontal movement between the two (2) buildings, Boeing may explore utilizing a sky-bridge to link them. Exterior sun shade device and interior roller window shades will be utilized as required. ADA compliant restroom facility, that includes lockers, will be provided. · Egress Corridor Between New Hangar and 4-81 Building: o Corridor between building 4-81 and the new hangar will have a “service level” mezzanine” floor at second level with stair access located at the N- E corner of the new hangar. o Mezzanine floor will house electrical and VFD panels; Floor elevation is determined by the height of the existing Engine Build Up area (EBU) door at the 4-81 building. o Mezzanine floor structural farming will consist of concrete composite metal deck flooring supported by hangar columns at the west face and W Renton Mitigation Hangar Project Narrative – April 25, 2018 5 columns at the east face independent of the existing building 4-81 framing. Existing Site Features Summary: The project site is located at the northern extent of The Boeing Renton Production Plant, directly adjacent to the northwest corner of Building 4-81 and just south of Apron R. Utility improvements, drainage improvements, re-grading, and repaving of Apron R are proposed as a part of a separate project. The Mitigation Hangar project site is currently used for parts storage directly adjacent to Building 4-81 on the eastern extent of the site. Aircraft staging stalls are located on the western end of the project site. A two-way vehicular drive aisle and a dedicated pedestrian path separates these two main areas of use. An existing employee parking area is located at the southern end of the project site. Existing canopies along the western face of Building 4-81 currently provide covered storage and will be removed to construct the new building extension. Site Improvements Summary: In addition to construction of the hangar building extension, other site improvements planned as a part of this project will include: o Abandonment of an existing 80,000-gallon combined oil/water separator o Abandonment of and existing wet vault o Constructing a new combined bypass and oil/water separator vault o Providing a new modular wetland water quality treatment vault o Abandonment of existing storm conveyance pipe o Abandonment of existing utilities within the proposed building extension footprint o Constructing new connections to the existing fire protection system o Preloading the building extension site o Relocation of an existing private campus roadway running north-south along the west side of the existing 4-81 Building, which provides use as a fire lane as well as support for vehicle and parts movement around the campus. Renton Mitigation Hangar Project Narrative – April 25, 2018 6 Existing Drainage Conditions Summary: The entire project site is impervious in its current condition. Site runoff from the project site generally flows to the north and discharges to Lake Washington via a closed conveyance system. Drainage improvements constructed as a part of the Apron R project just north of the project site will include replacing outdated stormwater infrastructure between the Mitigation Hangar project site and Lake Washington. An 80,000-gallon existing combined oil/water separator and wet vault system constructed in the 1990s is located centrally within the project site. This vault was designed to provide water quality treatment for the paved area between Building 4-81 and Building 4-20/21 and bypass flows above the required design flow via a diversion vault. This system will be demolished and abandoned as a part of the Mitigation Hangar project and will be replaced with a combined oil/water separator and bypass vault and a manifold modular wetland vault system that will provide oil control and enhanced water quality treatment to this area. See Technical Information Report for additional information. Drainage System Update Summary: Stormwater improvements proposed within the limits of this project will include new collection and conveyance piping south of the building extension, a new oil control facility, a new water quality treatment facility, and the demolition and abandonment of an existing combined oil/water separator and wet vault. Although no new pollution-generating area will be created by the proposed improvements, the project will remove an existing combined oil/water separator and wet vault. New oil control and treatment facilities will be constructed to provide treatment and oil control for high-use portion of this tributary area. Clean-way catch basin inserts will be installed to provide replacement water quality treatment for an additional 4.78-acre area upstream of the vault. This upstream tributary area includes landscaped areas, pedestrian walkways, gravel areas, and employee parking lot/driveway areas. No high-use areas, such as areas receiving heavy truck traffic, are located in this upstream tributary area; therefore, no new oil control measures will be provided. See attached Utility Plans for additional information. Renton Mitigation Hangar Project Narrative – April 25, 2018 7 Earthwork Quantities: Total area grading on the project site will be approximately 130,522 sf (2.996 acres) Types of excavation cut and fill, including quantities: · Utility trench and stormwater vault excavation, bedding and backfill o 1,100 cubic yards cut o 695 cubic yards fill · Structural fill at demolished storm vaults o 1,711 cubic yards fill · Preload soils installation and Removal o 18,806 cubic yards cut/fill · General Site Grading o 295 cubic yards cut o 1,175 cubic yards fill · Excavation and Backfill for Building Pile Cap, Grade Beam and Pile Foundations o 5,750 cubic yards cut o 1,150 cubic yards fill Total earthwork quantities for the project are estimated to be approximately 26,000 cubic yards of cut and 23,500 cubic yards of fill. Roadway Relocation Summary An existing private two-way vehicular roadway running north-south to the west of the existing 4-81 Building is proposed to be relocated further west to allow for the placement of the new hangar building. This roadway currently provides support as a fire lane and roadway for vehicle and parts movement around the campus. Parking required to support the surrounding buildings is proposed to be maintained in the area immediately south of the new hangar. The existing roadway immediately west of the 4-81 Building (one-way headed north) will be maintained as currently configured in order to provide continuing access for fire trucks and parts delivery to the 4-81 Building. Extents of the roadway relocation, illustration of fire truck movements accommodated by the new roadway alignment and Phase I parking layout are included in the Traffic Plan. A preliminary Phase II parking layout has been provided as a concept for maintaining required parking as later phases of the Apron R construction take place. Renton Mitigation Hangar Project Narrative – April 25, 2018 8 Other Utility Work & Site Prep Summary: · General: o NO active buried utilities are assumed to remain underneath the new hangar building footprint. · Utility Trenches: o E-W trench between building 4-81 and the new hangar (Final Location TBD) o N-S trench between aircraft main gear and building columns (Final Location TBD) · Site Preload: o Soil Preload will be utilized over the full footprint of the new hangar to better ground conditions prior to installation of the foundation system for the new hangar. o Preload extents assumed to be approximately 6 to 8 feet of soil over the full footprint, in place for approximately 8 to 10 weeks. o See Draft Geotechnical Report and Grading Elevation Plan for additional information related to site Preload. · Electrical: o Install a new 1500 KVA electrical unit substation in the southeast corner of the lower production and work area portion of the new hangar o Demolition of all the electrical in Apron R change incorporation stalls (R5, R6, and R7). (West of proposed hangar) o 480V power to new HVAC. o 480V power and controls for hangar doors. o Power, data, and lighting for work area in the second floor of the two- story bump out building. o High bay lighting of the mitigation building and the work area on the first floor of the bump out building o 120V power to the VESDA system. o 480V power to the hydraulic cart and 400HZ system. o 480V, 30A to charging stations. · Mechanical/Fire Protection: o Compressed air; air piping will be run in newly constructed floor trenches which are connected to the existing floor trenches in the 4-81 building. Renton Mitigation Hangar Project Narrative – April 25, 2018 9 o Relocate existing fire water supply line from within footprint of new hangar. o Establish temporary line to provide ongoing fire protection to the existing 4-81/82 building during pre-load o Fire protection to hangar space and 2nd floor work area. o Fire protection requirements intended to meet standards of NFPA 409 and other applicable code criteria. o Ventilation and heating to hangar space. Heating, ventilating, and air conditioning to the 2nd floor work area. o Potable water to a floor location centrally positioned between the two airplane positions and stub up. This potable water piping will be run in floor trenches which are connected to the existing floor trenches in the 4- 81 building. o Industrial waste water drainage connection at a floor location centrally positioned between the two airplane positions. This industrial waste water piping will gravity drain to sumps in floor trenches which are pumped to the existing industrial waste water system in the 4-81 building. o Relocated wall PIVs and fire alarm check valves on two risers located on the West wall of the 4-81 building. o Relocate/Reroute and reconnect, underground mechanical utilities piping to be displaced by the new hangar complex footprint. o Relocate outside air louvers and associated supply ducts on the 4-81 building West wall which will be displaced by constructing the new hangar complex. o Provide steam supply to door heaters at hangar openings. o Provide steam supply to HVAC units. o Provide plumbing stub up to 2nd floor work area.