Buttermilk Mountain – Midway Trail 2006

In 2004 Aspen Skiing Company (ASC) initiated a research study into other pipe systems, which would extend the longevity of steel pipe, and reduce the recurring costs to replace steel pipe in all snowmaking systems, on all ASC mountains.  In late 2005 this study was completed.  The VRS®-T high pressure Ductile Iron (DI) system from TRM Austria, was selected to replace large sections of steel pipe on the Midway and Columbine trails.

Project Background:

In the late ‘90’s and early 2000’s, pipe leakage was becoming a major problem in steel snowmaking lines at all ASC resorts. This corrosion was not unusual because a large portion of this pipe had been installed between 1977 and 1981.   In 2004 ASC began a research study with the mission of finding other pipe systems that would provide better longevity than steel pipe.   This study also included steps to define the market for snowmaking pipe in the North American Ski Industry.   In late 2005 ASC decided to use high pressure DI pipe, and TRM Austria was selected as the manufacturer, because of extensive field experience and expertise in similar snowmaking applications in Europe.  In 2006 VRS®-T pipe and fittings were used to replace all existing air/water pipes on Midway Trail; and, install new DI air/water pipes from a Compressor/Pump Station, on the mountain, to existing steel lines on Columbine Trail.   Because of the high incidence of leakage in areas close to the Compressor/Pump Station, ASC wanted to take whatever steps necessary to minimize the corrosion of pipe in this area.  To minimize pipe corrosion in this area, ASC selected a design to eliminate any steel pipe outside of any buildings.   All new DI pipe was taken inside the Compressor/Pump Station, and transitioned to flanged fittings on valves in the existing operating system.   Refer to the photos below.

The Photo below shows the four (4) pipelines on the back wall of the valve pit inside the Compressor/Pump Station.   This also shows how the DI pipes are transitioned to flanged fittings on valves in the existing operating system.

Project Challenges:

Find a piping system that: would satisfy the pressures required in all pipe sizes; would improve the longevity of the new pipe system compared with steel, to reduce costly system repairs in the future; could be installed easily and quickly; would provide flexibility to deal with constraints adjacent to and entering buildings; caused by major utility systems; and, would minimize environmental damage throughout the project region.    More specifically:

OPERATING PRESSURES:

Operating pressures in the process water system in lower sections of the Midway Trail are 500 psig, with surge pressures up to 650 psig.

LONGEVITY:   Corrosion of any material is based on the corrosivity of the environment surrounding the material. Steel snowmaking pipe in normal alpine environments has a longevity ranging from 20 to 35 years, depending on the corrosivity of the soil.  Other materials are available that will provide superior longevity than steel.

UTILITY SYSTEMS:  There were complex networks of utility systems adjacent to the Compressor/Pump Station, where new piping would be installed, which created constraints that had to be dealt with.

ENVIRONMENTAL SUSTAINABILITY:  A primary goal with all pipe installations in all alpine regions is to select/use materials which protect ecosystems, and maximize the integrity and sustainability of the natural resources.   Ductile Iron (DI) materials from TRM have unique characteristics, not available with other pipe systems, including:

  • DI pipe is produced using +98% recyclable materials.
  • Joint design requires no welding or open flames at any time during assembly/installation.
  • Joint design requires much less force to assemble; and, much smaller/lighter construction equipment to complete installation.
  • Easier assembly and smaller/lighter construction equipment make it possible to: complete installation using a much smaller construction footprint, reducing cleanup requirements; and complete assembly/installation in much shorter timelines, providing much longer periods for terrain clean-up/restoration.

Project Solution:

ASC completed an indepth product research to study/review/evaluate other pipe systems, to find an option with longevity superior to steel pipe.  As part of this study ASC contacted Engineers at Alford Design Group (ADG), a Consulting Engineering Firm with 3+ decades of experience worldwide, in snowmaking pipeline design.   ADG contacted several clients in Europe, to discuss the use of DI pipe in high pressure applications.   Based on these discussions, ADG recommended that ASC use the VRS®-T lock restraint system from TRM in Austria.   ASC selected this high pressure DI pipe system for several reasons.

Advantages of the VRS®-T System:

  • The VRS®-T joint design in this system satisfies a wide range of operating pressures from 25 bar (360 psig) to 100 bar (1450 psig).
  • The corrosion rate of steel is +3 times faster than the rate for DI; the longevity of VRS®-T pipe is +3 times greater than steel pipe.
  • The DUPLEX coating on all pipe provides active and passive corrosion protection, and a unique sacrificial repair mechanism for any pipe damage exposing bare metal.   These characteristics extend the longevity of this pipe even more.
  • The VRS®-T joint requires ±38% less force to assemble each joint; and, with the soft flexible gasket used in this joint, alignment of the pipe is not as critical.   Both issues make it much easier to assemble this pipe in shorter timelines; and, because alignment is not as critical at each joint, it is much easier, faster and less costly to assemble/install this pipe system in shorter timelines
  • Each VRS®-T joint has angular joint deflection, providing flexibility to deal with the tight constraints of the utility systems encountered in regions close to the Compressor/Pump Station. To install steel pipes through this region would have made it necessary to cut/mitre/weld extensively.  DI joint flexibility eliminated this.   The photos below show how the flexibility of this DI system was valuable.
  • In the left photo, four (4) lines from the Compressor/Pump Station; in the right photo, two (2) left lines continue to serve Columbine Trail, and two (2) right lines go uphill to serve Midway Trail, with no fittings required.
  • The VRS®-T joint requires smaller lighter construction equipment; and, a smaller construction footprint to complete the entire project in a much shorter timeline.   This shorter construction timeline provided more time for site cleanup and restoration; considered to be an important environmental benefit.

Project Team Members:

CLIENT: Buttermilk Mountain
DESIGN ENGINEER: Alford Design Group LLC Master Plan
DIP DESIGN/SALES/FIELD SERVICS: PNP Supply LLC
GENERAL CONTRACTOR: In-house Personnel

PROJECT

Midway Trail Piping - 2006

PIPE TYPES
DN080 High Press MDR DI Air/Water
DN150 High Press MDR DI Water
DN150 Low Press MDR DI Air
DN200 High Press MDR DI Water
DN200 Low Press MDR DI Air
DN250 High Press MDR DI Water
DN250 Low Press MDR DI Air

LOCATION
Buttermilk Mountain,
Aspen, CO

PHYSICAL CHARACTERISTICS
9,300 ft of pipe

PROJECT TYPE
Snowmaking Pipelines
Multiple Trails

CHALLENGES

Physical Constraints
Rocky Terrain
Stray Electric Currents