U1A Shaft Spray Removal

Sources are being sought for the planned issuance of a subcontract for construction/installation services for the U1a Shaft Spray Removal and three-product application to the wood lagging in the top 200 feet of the U1a Shaft. This General Service scope supports the improvement of the existing wood lagging fire resistivity, and allows for large equipment to go underground via this shaft. U1a is at the Nevada National Security Site outside Las Vegas, Nevada, and is a Hazard Category 2 complex located in Area 1 of the Nevada National Security Site (NNSS). The NNSS is managed by Mission Support and Test Services (MSTS), and will be the contracting entity. The facility is approximately 25 miles north of Mercury, Nevada, and 90 miles northwest of Las Vegas, Nevada. The objective of this project is to: 1. Remove the existing fire sprinklers from the top 200 feet of the U1a shaft. 2. Improve the fire protection within the “a” Shaft of the U1a complex. This will be accomplished through the application of a penetrant and associated fire tape and filler compound in the top 200 feet of wood lagging. Background The U1a Shaft is a rectangular shaft with dimensions of 12 feet × 18 feet × approximately 963 feet deep. An 18-inch-thick concrete liner extends down 12 feet from surface. The shaft is unsupported the rest of the way. There are three compartments that make up the shaft. These are: Line-of-sight (LOS), which is 10-ft × 10-ft. The LOS is the largest unobstructed opening into the underground at the U1a Complex. Man/hoist skip, which is 5-ft 9-in × 5-ft 7-in. Ladderway ventilation ducting, which is 4-ft 3-in × 5-ft 7-in. Structural steel sets are erected on 6-foot centers. Bearing sets are concreted two feet into the shaft wall and are on 48-foot centers. Wood lagging measuring 3 inches thick × 12 inches wide × 6 feet long is placed vertically between the steel sets. The lagging is not bolted to any structure but rather is held in place by wooden wedges. Initially, these wood planks were pretreated with a fire retardant. The wood lagging serves to hold back any loose material that may spall off the shaft wall and fall down the shaft. The shaft wall profile varies based on the strength of the alluvium, the amount of blasting over-break at the time of excavation, and shaft wall erosion that has taken place over the life of the shaft. Gaps exist between the wood lagging and they vary in sizes from a typical 2-3-inch gap to approximately 6 inches. MSTS, LLC including U1a Systems Engineering with concurrence from Fire Protection Authority Having Jurisdiction recommends the use of FX Lumber Guard XT, 3M Fire Sealant Foam (FIP 1-Step), and 3M Fire and Water Tape (000-76309-98237-9). This will allow the SUBCONTRACTOR to remove the shaft spray system, and install the three products TO meet the fire protection requirement for the wood lagging. Scope We are seeking construction/installation support to apply the three products and remove the shaft spray system. This work may occur during nights and/or weekends to deconflict with other priorities in the U1a underground.

Division 09 -	Finishes.
Division 21 -	Fire Suppression.
Division 31 -	Earthwork, Tunnel Support Systems, Steel Ribs and Lagging.