Loop Field Installation

Vertical Drilling

Vertical loops are installed using vertical well drilling equipment.

UMR Vertical DrillingEach hole is drilled to the desired depth – typically between 80 and 300 feet. The loop and a tremie pipe (grout pipe) are then inserted into the hole.

U-bend pipe separators are added to the pipes every ten feet as the loop is inserted into the well. These spacers will spring open as the tremie pipe is removed. The spacers increase the performance of each loop by pushing the pipes apart and against the walls of the hole.

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UMR uses spacers in all of its vertical drilled loop fields.

Once the loop is inserted into the hole, grout is pumped through the tremie pipe and into the hole. As the pipe is removed the grout fills the hole and the spacer’s spring open.

Drilling Mud and Grout

Bentonite, an absorbent aluminum phyllosilicate, is used for both drilling mud and grout. Bentonite is essentially impure clay consisting mostly of montmorillonite. The drilling mud formulation of bentonite lubricates and cools the equipment. The grout formulation expands and is used to drive out any air pockets and seal the pipes in the ground.

Advantages
  1. Vertical drilling is often the only option when space is limited. On a small city lot, for example, a loop field can be installed in the driveway.
  2. Vertical wells can reach higher thermal conductivity soil that may be deeper in the earth.
Disadvantages
  1. Vertical drilling requires heavy equipment that will damage lawns and landscaping during installation. The amount of damage varies widely depending on a variety of factors. The most damage is typically done when the equipment has to work on wet or saturated dirt and grass.
  2. Vertical loops are the most expensive to install due to the equipment required for drilling.

Trenching

UMR Vertical DrillingHorizontal loops were historically installed in trenches dug with a back hoe. The depth of the loop field is limited to 6 to 10 feet by the equipment.

Advantages
  1. Flexibility in design. A loop field could, for example, be installed in a large square around the perimeter of a smaller lot.
  2. Less expensive to install
Disadvantages
  1. Increased risk of pulling frost into ground in severe weather due to shallow depth.
  2. May not be able to reach higher thermal conductivity soil that may be present slightly deeper in the earth.
  3. Does considerable damage to the yard. Filled in trenches can take a year or more of settling before the ground stops sinking due to the compaction of the soil.

Horizontal Boring

UMR Horizontal BoringToday most horizontal loop fields are installed with horizontal boring machines. This equipment has the ability to bore down and install loops 15 to 20 feet deep in the ground. This allows the loops to be installed under obstructions such as trees and buildings without doing damage to them.

This equipment also has the ability to follow the contour of the ground while keeping the depth the same level below the surface.

Advantages
  1. Less expensive than vertical drilling
  2. Minimal damage to landscaping
  3. Can go under obstacles such as trees and buildings without damaging them
  4. Faster to install
Disadvantages
  1. Requires large space to install – a minimum of 300 feet

Pond Installations

Pond_Loop_Being_SunkPond installations require minimal excavation and are therefore typically the least expensive and easiest.

The loop field is submerged and anchored to the floor of the pond. The header connections are all made on the loop field before it is submerged.

The final step is to bring supply and return lines from the pond to the building. This is typically done with trenching.

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UMR uses Bergerson-Caswell, Inc. as it’s primary driller.