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Geothermal Vertical Borehole Heat Exchanger

By Terry Kelly,2014-04-02 04:18
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Geothermal Vertical Borehole Heat Exchangerheat,Heat

    NL Master Specification Guide

    for Public Funded Buildings

    Re-issued 2013/02/28 Section 33 65 47 Geothermal Vertical Borehole Heat Exchanger Page 1 of 6

    PART 1 GENERAL

    1.1 REFERENCES

    .1 American Standard for Testing and Materials (ASTM).

    .1 ASTM D1693, Standard Test Method for Environmental Stress-Cracking of

    Ethylene Plastics.

    .2 ASTM D2447, Standard Specification for Polyethylene (PE) Plastic Pipe,

    Schedule 40 and 80, Based on Outside Diameter.

    .3 ASTM D2513, Standard Specification for Thermoplastic Gas Pressure Pipe,

    Tubing and Fittings.

    .4 ASTM D2683, Standard Specification for Socket-Type Polyethylene Fittings For

    Outside Diameter-Controlled Polyethylene Pipe and Tubing.

    .5 ASTM D2837, Standard Test Method for Obtaining Hydrostatic Design for

    Thermoplastic Pipe Materials or Pressure Design Bases for Thermoplastic Pipe

    Properties.

    .6 ASTM D3035, Standard Specification for Polyethylene (PE) Plastic Pipe (DR-

    PR) Based on Controlled Outside Diameter.

    .7 ASTM D3261, Standard Specification for Butt Heat Fusion Polyethylene (PE)

    Plastic Fittings for Polyethylene Plastic Pipe and Tubing.

    .8 ASTM D3350, Standard Specification for Polyethylene Plastic Pipe and Fittings

    Materials.

    .2 Canadian Standards Association (CSA)

    .1 CSA C448, Design and Installation of Earth Energy Systems. .3 International Ground Source Heat Pump Association (IGSHPA) Installation Manuals.

    1.2 PRODUCT DATA

    .1 Submittals Package: Submit produce data in accordance with Section 01 33 00 -

    Submittal Procedures.

    .2 Product Data: Manufacturer’s catalog sheets, specifications and installation instructions

    for each item specified.

    .3 Quality Control Submittals:

    .1 Geothermal System Installer’s Qualifications Data:

    .1 Name of each person who will be performing the geothermal work and

    their employer’s name, business address and telephone.

    .2 Names and addresses of 3 similar projects that each person has worked

    on.

    .3 Copy of installer’s personal experience demonstrating the use of thermal

    fusion techniques for polyethylene piping.

     .2 Geothermal System Supervisor’s Qualifications Data:

    .1 Name of person overseeing the geothermal work and their name,

    business address and telephone number.

    NL Master Specification Guide

    for Public Funded Buildings

    Re-issued 2013/02/28 Section 33 65 47 Geothermal Vertical Borehole Heat Exchanger Page 2 of 6

    .2 Names and addresses of 3 similar projects that the supervisor has

    overseen during the past 5 years.

    .3 Copy of installer’s personal experience demonstrating the use of thermal

    fusion techniques for polyethylene piping.

     .3 Geothermal System Contractor’s Qualifications Data:

    .1 Names and addresses of 3 geothermal projects that the contractor has

    completed during the past 5 years.

    .4 IGSHPA Installation Manuals: Maintain one copy on site for review. CSA C448:

    Maintain one copy on site for review.

    1.3 CONTRACTOR’S QUALIFICATIONS

    .1 Geothermal System Installer Qualifications: The persons performing geothermal work

    shall be personally trained in polyethylene pipe fusion techniques by IGSHPA or piping

    manufacturer, personally experienced in geothermal work and shall have been regularly

    employed by a Company performing geothermal work for a minimum of 2 years. .2 Geothermal System Supervisor’s Qualifications: The supervisor overseeing the

    geothermal work shall be personally trained in polyethylene pipe fusing techniques by

    IGSHPA or piping manufacturing, personally experienced in geothermal work, and shall

    have been regularly employed by a Company performing geothermal work for a

    minimum of 2 years.

    .3 Geothermal System Contractor Qualifications: The contractor shall have completed

    geothermal work on at least 3 projects with vertical boreholes within the last 5 years.

    1.4 REGULATORY REQUIREMENTS

    .1 Perform field testing of piping systems in complete accordance with the local Utilities

    and other agencies having jurisdiction and as specified.

    1.5 PRODUCT CONDITION

    .1 Protection: During test work, protect adjacent buildings, equipment, vehicles, etc., against

    damage from testing activities.

    1.6 SEQUENCING AND SCHEDULING

    .1 Transmit written notification of proposed date and time of tests to the Owner’s

    Representative at least 2 days in advance of such tests.

    .2 Perform cleaning and testing work in the presence of the Owner’s Representative.

    1.7 WARRANTY

    .1 Manufacturer’s Warranty:

     .1 Minimum 50 years warranty for polyethylene piping from the date of Substantial

    Completion.

    .2 Special Warranty:

    NL Master Specification Guide

    for Public Funded Buildings

    Re-issued 2013/02/28 Section 33 65 47 Geothermal Vertical Borehole Heat Exchanger Page 3 of 6

     .1 25 years for butt fusion welds in polyethylene piping against leakage from the

    date of Substantial Completion.

    1.8 WATER, SILT AND SOIL CONTAINMENT AND REMOVAL

    .1 The Contractor shall submit a detailed proposal outlining his proposed methodology for

    containing and removing and runoffs created by the well drilling and piping installation. .2 Dewater each borehole during drilling utilizing an interceptor and water sump tank

    arrangement. Remove water from site in a manner accountable to all authorities having

    jurisdiction.

    PART 2 PRODUCTS

    2.1 HIGH DENSITY POLYETHYLENE (P.E.) PIPE AND FITTINGS

    .1 Pipe and fittings shall be manufactured based on polymers made with ethylene as the sole

    monomer, which meet the requirements of PE Type III for water distribution. .2 PE Type III pipe shall have a 23.2 kPa (160 PSI) design stress at 23?C (73.4?F) which is

    listed by the Plastics Pipe Institute (PPI).

    .3 The piping shall be PE3408 (high density polyethylene) with minimum cell classification

    345434C per ASTM D 3350. Resistance to environmental stress cracking is critical to

    long life expectancy. Therefore, as a more stringent requirement, the piping shall

    experience zero failures (Fo) after 5,000 hours under condition “C” (100% reagent @

    100?C) when tested in accordance with ASTM D1693. A 50 year limited warranty (in

    writing) must be issued by the pipe manufacturer. U-type fittings shall be shop fabricated

    under quality controlled conditions of the same material designation and shall be ASTM

    D-3261 certified.

    .4 Pipe shall conform to ASTM D3035 and ASTM D3261 for butt fusion fittings. U-bend

    joints shall be butt head fused or socket welded.

    .5 Pipe must be designed and fabricated by manufacturer specifically for geothermal heat

    pump applications.

    .6 The complete assembly of piping within the borehole must be continuous without any

    joints except at the bottom U-BEND located where only a thermally fused joint or socket

    welded joint will be acceptable.

    .7 All piping shall be sealed at the factory and contain a compressed air charge. The

    presence of the air charge must be witnessed at the site prior to hydrostatic testing.

    Piping without an air charge will not be accepted.

    2.2 ANTI-FREEZE

    .1 Provide a 25% by volume solution of polypropylene glycol charge and water for all the

    entire ground source heat pump closed loop piping.

    .2 The performance characteristics shall be as follows:

    NL Master Specification Guide

    for Public Funded Buildings

    Re-issued 2013/02/28 Section 33 65 47 Geothermal Vertical Borehole Heat Exchanger Page 4 of 6

    .1 Viscosity shall be no more than 5.00 centipoise at 1.1?C with blend for 9.4?C

    freeze protection;

    .2 Specific heat shall be 1.05 at 21?C with blend for 9.4?C freeze protection.

    .3 Specific gravity shall be 0.982 at 10?C with blend for 9.4?C freeze.

    .4 Pressure drop and Reynolds Number for a 11.3 l/m flow in NPS ? IPS SDR-11

    PE pipe of a 1.1?C mixture for a 9.4?C freeze protected blend shall be no more

    than 0.86 m of HD per 30.0 m of pipe and no less than Re=2028 respectively. .3 The fluid shall mix easily and readily with water and shall not damage or corrode

    common tools.

    .4 The fluid shall have a good or excellent material compatibility with iron, copper, red and

    yellow brass, Polyethylene, PVC, Viton, Buna “N” neoprene and nylon and shall include

    an oxygen scavenger blend to reduce any corrosion capability. The fluid shall not have a

    low surface tension to prevent leakage.

    .5 The fluid shall have a NFPA Health rating of 0 (least risk).

    .6 The Contractor shall provide a certified test report from a recognized lab stating glycol

    concentration.

    .7 The product shall be available in plastic 19 liter (5 gallon) pails, plastic 208 liter (55

    gallon) drums, or bulk tanker.

    2.3 BOREHOLE GROUT

    .1 Provide grout for each of the boreholes as indicated on the drawings.

    .2 Grout to be a single component bentonite grout consisting of 25% solids and polymer

    free mixed with water as follows: 68L water per 22.7 kg bentonite grout.

    PART 3 EXECUTION

    3.1 GEOTHERMAL BOREHOLE PIPING INSTALLATION

    .1 The contractor shall obtain all necessary permits associated with the described work. .2 The borehole drilling contractor shall be experienced in deep bore hole drilling and shall

    have a minimum of 10 years drilling experience within the geographic vicinity of the

    project or shall subcontract to an approved drilling contractor with equivalent experience. .3 The vertical holes shall be drilled no closer than 8.0 m apart and shall be held open by a

    “mud” casing so that the piping can be inserted. The piping shall be tested in accordance

    with other sections of this specification prior to insertion. Loops must be installed from

    or by a mechanical device so that the pipe is not rolled out on the ground before

    installation.

    .4 Install polyethylene piping in accordance with details on drawings.

    .5 The piping shall be capped and protected for future connection.

    .6 Approved borehole seals should be tightened to manufacturer’s specifications.

    NL Master Specification Guide

    for Public Funded Buildings

    Re-issued 2013/02/28 Section 33 65 47 Geothermal Vertical Borehole Heat Exchanger Page 5 of 6

    .7 The entire piping system shall be pressure tested in accordance with other sections of this

    specification before any backfilling of trench is permitted.

    .8 The Owner’s Representative shall be notified 24 hours prior to the test and shall, at this

    discretion, witness the test.

    .9 The contractor shall maintain an accurate record of all borehole locations and at the

    completion of the work, deliver to the owner a set of “as-builts” site plans.

    3.2 GROUNTING BOREHOLE

    .1 Bore holes in vertical heat exchangers shall be tremi-grouted. Grouting of vertical heat

    exchangers shall be done in accordance with jurisdictional requirements of IGSHPA

    standards. Grouting shall immediately follow the completion of drilling and installation

    of each borehole piping. A large capacity grout mixer/separate holding tank are required

    and a minimum of 25 mm diameter polyethylene tubing shall be used as the tremi-grout

    pipe. The tremi-grout pipe shall be attached to the u-bend heat exchanger before it is

    lowered into the ground.

    .2 Grouting procedures to be as follows:

    .1 Monitor the grouting operation to ensure grout is being adequately mixed in

    correct proportions and that the viscosity is adequate for pumping down the

    borehole.

    .2 The grout contractor should have spare grout pipes, hoses, fittings, readily

    available on site.

    .3 A screw-type pump or a piston pump shall be used to pump grouts down the

    boreholes.

    .4 A 75 to 100 mm inside diameter suction line and a 25 to 50 mm discharge line

    shall be used.

    .5 Bentonite based grout shall be used mixed with water in proportions

    recommended by manufacturer. For Volclay Grout II (25% solids) utilize a

    mixture of 68L per 22.7 kg of grout. Cement based grout will not be used.

    3.3 PIPING SYSTEMS TEST

    .1 The contractor shall provide all necessary equipment and shall perform all work required

    in connection with all piping system tests.

    .2 At the water working pressure of the pipe installed, all water piping systems shall be

    tested. Each section tested shall be slowly filled with water. Care shall be taken to expel

    all air from pipes. If necessary, the pressure, as measured at the point of lowest elevation,

    shall be applied for not less than ? hour. When the test pressure has fallen over 5%, the

    point of leakage shall be found, repaired and tested repeated. This procedure shall be

    followed until the piping systems have been proved absolutely tight. The use of any

    chemicals, any “Stop-Leak” compounds, any mastic or any other temporary means shall

    not be used for repairing leaks during or subsequent to these tests.

    .3 Polyethylene pipe testing:

    .1 Prior to insertion of the vertical pipe, the contractor shall assembly the “U Bend”

    and piping, cap both ends, and air pressure test the piping to a pressure of 862

    NL Master Specification Guide

    for Public Funded Buildings

    Re-issued 2013/02/28 Section 33 65 47 Geothermal Vertical Borehole Heat Exchanger Page 6 of 6

    kPa (125 PSI). The test must be maintained for 8 hours minimum without the

    pressure falling more than 20 kPa (3 PSI).

    .2 Loops shall pass the test at the following milestones:

    .1 Before insertion into hole.

    .2 After insertion into hole.

    .3 Contractor is responsible to provide evidence of and certification of

    pressure testing, and acceptance of all work performed by signature of

    Owner’s Representative.

    END OF SECTION

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