Anacortes Lateral Upgrade

Coffman provided comprehensive engineering design and project management services for the upgrade and replacement of 11 miles of eight inch high pressure gas main with a new 20 inch gas main in Anacortes, Washington. Our civil, structural, mechanical, electrical, and land surveying teams from three Coffman offices collaborated to provide coordination for over 130 land owners and overcome challenges including crossing certified organic farmland, crossing Interstate 5 and a Burlington Northern Railway, assistance with easement acquisition, horizontal directional drilling (HDD), hot taps, utility and irrigation canal crossings, assistance with wetlands permitting, cathodic protection, and design of pipeline weights for buoyancy control in areas with high groundwater.

The pipeline is regulated by the Washington Utilities Transportation Commission (WUTC) and designed to WUTC and PHMSA/DOT CFR 49 CFR Part 192 requirements. The HDD for seven areas ranged from 220 LF to over 1400 LF and ten conventional bores ranged from 100 LF to 150 LF. The design included three valve sites, two of which have temporary pig launcher/receiver facilities, and all will be cross connected to an existing 16 inch pipeline. Nine regulation stations will be upgraded and switched off the existing 8 inch 36 psig pipeline and tied into both the new 20 inch 500 psig line and an existing 16 inch 500 psig pipeline.