- ENGINEERING INFO
- CASE STUDIES
The United States territory of Guam is located 3,300 miles west of Hawaii in the Pacific Ocean and serves as an important strategic hub for the United States Military in its efforts to rebalance the defense needs of the Asia-Pacific region in conjunction with our allies. Apra Harbor is located on the western side of Guam and serves as a deep-water port for both commercial shipping and U.S. military operations.
Efforts have been underway since 2006 to relocate U.S. Marine Corps members and their families from Okinawa, Japan to the U.S. territories of Guam and the Mariana Islands. The relocation effort has required expansion of the U.S. military presence in Guam, which is the largest deep water port in the Western Pacific.
|Pipeline Details and Apra Harbor Summary|
|Property Owner:||U.S. Navy/Department of Defense|
|Utility Owner:||U.S. Navy|
|Project:||Water and Sewer Upgrades 2007 - 2015|
|Location:||Apra Harbor/Naval Base Guam|
|Pipe:||11,600 LF of 12 to 18-inch Fusible PVC® pipe|
|Installation:||Pipe Burstin, Open Cut, Sliplining|
Naval Base Guam is currently the home of Commander Naval Forces Marianas, Commander Submarine Squadron Fifteen, Coast Guard Sector Guam, Naval Special Warfare Unit One, and 28 other tenant commands.
Naval Base Guam, like most other military installations, contains a significant amount of aging infrastructure. The Navy facilities' planning and engineering groups have been tasked with assuring they can support current needs and future growth. Fusible PVC® pipe has played an important role in solving their water and wastewater pipeline needs and continues to be used for a variety of ongoing projects. Fusible PVC® pipe has been selected for water and sewer projects based on the following criteria:
Naval Base Guam was experiencing infiltration in their cast Iron and asbestos cement gravity sewer pipelines that were nearing the end of their service lives. Sections of the existing sewer were located under the water table, making open cut replacement a difficult and undesirable option. In addition to reducing infiltration, the Navy needed additional capacity in the sewer line to accommodate growth. A combination of pipe bursting and traditional open cut methods using Fusible PVC® was deemed the best available approach to meet the project needs. Pipe bursting proved to be the best option in areas where dewatering and stabilizing soils would make open cut construction time consuming and cost prohibitive.
Open cut installation was used in areas where reduced ground water and installation depth made excavation more cost efficient.
Fusible PVC® pipe has a favorable outside diameter (OD) to inside diameter (ID) relationship compared to other thermoplastic pipe materials. Selection of pipe bursting equipment and open cut trench width are based in part on the outside diameter of the replacement pipe, including in any applicable bells.
A comparison of 14" Fusible PVC® pipe to HDPE pipe with a similar ID and critical buckling pressure is depicted on the right.
Naval Base Guam Apra Harbor was one of three Guam locations that were included in an $89 million design-build project designed to expand utilities and provide other site improvements. Phase one of the project was awarded in August, 2011. One of the components of the 2011 project included installing a new water main in an underground utility corridor containing multiple utilities. The water main needed to be fully restrained for this application, making a fused pipe system desirable since it would ensure leak-free performance in shifting and unstable soils. HDPE pipe was evaluated during the design phase for the application however Fusible PVC® pipe was ultimately selected based on performance considerations and lower overall installed cost. HDPE pipe would have required additional fittings, upsized valves, and other connection hardware to accommodate the increased pipe OD required to achieve comparable ID and flow capacity.
Fusible PVC® pipe proved to be an excellent fit for the application due to the potential for hydrocarbon impacted soils and groundwater. Fusible PVC® pipe provides high performance in maintaining water quality in hydrocarbon contaminated areas. Additionally, PVC pipe is highly resistant to oxidative degradation in the presence of disinfectants commonly used in potable water distribution systems. Oxidative degradation has repeatedly proven to lead to early life failure of HDPE in potable water distribution systems, particularly in higher temperature geographies, further reinforcing the decision to select Fusible PVC® pipe for the project.
Fusible PVC® pipe has proven itself in the rigorous operating conditions on Guam through its ongoing performance and has earned a position as an important design element for future underground utility replacement and expansion projects.