652UNDERGROUND SPRINKLER SYSTEM

652

652.01Description

Provide, install, and test an underground sprinkler system.

652.02Materials

Incorporate new materials and equipment in the system with performance test certifications when requested.

Provide PVC plastic water pipe and fittings. Use standard design fittings appropriate for the type of pipe and pressure rating. Ensure pipe and fittings meet the requirements of ASTM D2241 for SDR 26, PR 160 pipe and stamped N.S.F. approved. Use only standard fittings designed for their specific use, selected and installed to provide the least friction loss of water. Use only the appropriate materials (e.g., cements, solvents, thinners, joint compounds) accepted for use with the kind of pipe used.

Provide sprinkler heads of the sizes, capacities, and types as specified to ensure uniform coverage at the operating water pressure. Provide sprinkler heads with working parts made of sturdy durable materials. Ensure nozzles, orifices, and working parts are precision machined and highly resistant against wear.

nozzles that spray in a full -circle or part -circle, as specified. Provide spray heads with removable and interchangeable orifices or nozzles that can adjust water volume and cov erage area.

adjust water volume and coverage area. Ensure the pop- up portion of the head returns freely to its closed position when it is se t to an angle of 30 degrees. Provide sprinkler heads that are accessible from the top without disturbing the sprinkler housing. Ensure orifices and nozzles are removable and interchangeable from the top of the head without disturbing the sprinkler housing or ground.

without ceasing under the specified operating pressure. Provide a sprinkler assembly with nozzles that are interchangeable and replaceable without disturbing the sprink ler assembly or the ground. Provide pop- up rotary sprinkler heads that are water jet or impulse motivated. Ensure a heavy retractor spring provides positive plate closing when in the off position. Ensure the complete working assembly is removable fr om above the ground as a unit to allow for adjustment and servicing. Ensure part -circle heads are adjustable to any part of a circle from 90 to 360 degrees. 652

Provide pressure type or atmospheric type vacuum breakers (i.e., anti -siphon valves) with machined valve seats, and a working pressure rating of 150 psi. Ensure the vacuum breaker make and design(s) meets Idaho and local sanitary requirements.

Provide heavy duty gate valves meeting the requirements of AS TM B62 (85 -5-5-5) or approved equal. Provide valves with a service rating of 300 psi (for non- shock cold water) and a hydrostatic shell test rating of 450 psi. Ensure the manufactured valve contains a printed or cast identification.

Provide quick coupling valves with self -closing type caps made of a heavy -duty irrigation material that have a service rating of at least 150 psi, and are designed for connection to the water supply l ines. Ensure quick -coupling valves are watertight before and after the coupler is inserted. Ensure the valve seat mechanism is designed to close before the coupler is removed. Provide couplers or keys for quick -coupling valves, portable sprinkler heads, or hose swivel attachments. Provide bayonet type couplers or keys made of highly corrosion- resistant metal, designed for quick -coupling valves. Provide hose swivels with a 90 degree swivel elbow that is free turning and covers a 360 degree swing. Provide watertight washers and seals when in service.

Provide automatic electronic controllers designed to operate on 115- volt, 60 Hz single -phase AC. Provide a controller with a master switchable to shut off irrigation operation without disturbing the timing sequence. Provide a manual setting for each station within the controller to allow independent operation of each station. Provide a controller that controls and operates each station independently within a 14- day cycle. Provide a controller that contains variable and adjustable watering times and separate adjustments for each station that does not affect the timing cycles of other stations. Provide controllers for outdoor installation, when specified. Install a weatherproof cabinet or housing designed specifically for each individual controller. Provide a cabinet that is made from corrosion- resistant metal with a high quality paint or enamel. Provide a cabinet that allows easy removal or part replacement without the use of special tools and that is lockable to prevent tampering and vandalism. Design, install, and adjust the controller to work efficiently with the remote control valves and set watering cycles as designated.

Provide control valves having a service rating of at least 150 psi (for non- shock cold water), designed for underground installation and operating with standard keys. E nsure valves have removable bonnet and stem assembly, adjustable packing gland, rising stem to ensure full valve opening, renewable disc -type washer seating, and hex -nut brass union. Furnish them with an integral union or separate union for adjacent instal lation or in the pipeline. 652

Provide a 24- volt, 60 Hz AC wire conductor system or as specified. Protect solenoids or other actuating mechanisms from moi sture damage.

the main water supply line. Ensure the valves operate at the pressure rating set for the irrigation lines, without creating excess surge pressure.

out by gravity.

Provide solid conductors that can be installed underground, as specified.

Supply electrical power for testing water and power sources required in flushing and balancing the system at no additional cost. If a Department -owned or Department -controlled water supply system is available at the project site, it may be used without charge.

652.03Construction Requirements

Excavate pipeline trenches and areas to be occupied by controllers, bases, valves, protective valve sleeves, drain sumps, and other required facilities. Install pipelines at least 12 inches deep in areas outside the roadways. Under roadways, place the pipe at the ballast bottom. The Engineer will measure pipe cover depth from the pipe top to the finished ground surface. Excavate at least 12 inches square and 12 inches below the drain valve sumps. Hold excavations to the least width practical and work withou t fouling the adjacent topsoil . Dispose of excavated materials not acceptable for backfilling in a satisfactory manner. Ensure trench bottoms and other excavations are true to grade and without protruding stones, roots, or other debris. Construct plastic pipe bedding of earth or sand with at least 2 inches on all sides of the pipe. Protect the pipe with backfill material without stones, clods, or other injurious matter. Place topsoil as required in the upper part of the backfill. Place backfill in layers 8 inches or less in compacted thickness and thoroughly tamp, roll, or puddle each layer. If sufficient acceptable backfill material is not available from required excavations, make up deficiency with acceptable material in a satisfactory manner. Correct backfill settlement as required during the life of the contract . Where pipelines are run under curbs, walks, pavements, and other such improvements, that are to remain in place, preserve such structures from disturbance or damage to the extent practical and install the line by jacking, whenever possible. Repair structures that are disturbed or damaged at no additional cost. Encase all pipes under roadways in a suitable galvanized iron or other approved conduit .

Layout the sprinkler system as specified. The Engineer may allow minor alterations to distribute adequate water coverage. Before proceeding with the installation of any system section, verif y the specified measurements with the available water supply and pressure. If there are apparent discrepancies, obtain approval before making changes. 652

of drain valves. The Engineer will inspect installations that have been tested and are ready to be accepted for compliance with contract before being covered by backfill material. Do not move or install plastic pipe when the pipe is wet or the ambient temperature is below 40°F. Join plastic pipe and plastic fittings with solvent cement, except put threaded j oints together with an approved non- hardening, putty -type joint compound. Make cuts square and clean. If pipe is chucked or clamped, protect it from nicks and scarring by wrapping in canvas, emery paper, or other suitable material. In making solvent cemented joints , the procedures are as follows:

In making joints with threaded fittings, exercise care to avoid undue strain on plastic material. On plastic -to-iron connections, make the iron connections first, using a non- hardening joint putty type. Tighten threaded joints about 1 turn past hand- tight with a strap wrench. Place plastic pipe in continuous contact with the trench bottom and lay the lines alternating from side-to-side of the trench to provide for possible length contraction due to temperature changes. When testing the lines for water tightness, center load the pipe between joints with backfill material as necessary to prevent pipe arching or whipping under pressure. Before installing sprinkler heads and valves, thoroughly flush pipelines and blow out dirt and foreign matter. Install quick -coupling valves 4 inches above the planting bed finished grade. Assemble gate valves with a union.

section control valves to sprinkler heads, for water tightness by sections at the highest operating pressure obtainable for each system section, in the Engineer’s presence, , before trenches are 652

test, with valves tested in open and closed positions. Repair and remedy leaks or defects. Make tests and repairs on each unit or system section, repeating the process until the pipelines and valves are completely watertight and leak proof. Correct damage to existing facilities caused by the testing, by leakages, or by repairs to the system at no additional cost.

Except for shrubbery heads, set sprinkler heads 4 inches away from curbs, walks, and pavements and flush with the lawn finished grade. Set shrubbery sprinkler heads on risers above finished grade at the heights as specified or as directed, and 12 inches away from curbs, walks, and pavements.

consist of 1 or more controllers working as a unit. The controllers and cabinets are to be firmly mounted on a substantial and firm concrete pedestal or base , on a heavy, galvanized iron pipe stanchion set in concrete, or on faces of walls or structures . When wall -mounted, ensure bottom of controller is at least 4 feet above the floor. Adjust an d set controllers to provide specified station cycles and timing. Install meter bases at the power source. Contact the local utility company t o determine their requirements before performing any electrical installations. Ensure power source connections meet the requirements of the company or agency providing the power supply, and their representative is contacted and given sufficient notice before making such connections. Ensure wiring is in accordance with the schematic wiring diagram as specified or as approved. Ensure the wire sizes

The Engin eer may allow placing the electrical conductors in the same trench as the water pipe as long as contact with the pipe is avoided. If allowed, protect wires by placing the conductors under the pipelines. Place a 2- inch soil cushion without rocks or hard lumps in the trench bottom before placing the conductors and then firmly tamp and backf ill with the same material. Twist and solder wire connections. Ensure wire splices are watertight and to the Engineer’s satisfaction. Provide a U -loop approximately 12 inches wide and deep in the direct burial conductor at eac h conduit entrance bushing to prevent the conductor from pulling on conduit due to settling subgrade material. Co nductors through conduit are to be separate runs and not twisted, braided, or banded in a group or groups. At section control v alves, the conductor may be placed under the protective sleeve with clearances of at least 3 inches below the sleeve.

sleeves with lock caps, furnished in lengths sufficient to enclose and clear the bonnet portion of the valve as installed. Provide protective sleeves with integral fl anges to resist sleeve removal or with 12-gauge copper wire for fastening the sleeve to valve or pipe. Protect automatic control valves with 12- inch concrete sewer pipe with concr ete plug cover, standard cast iron sleeves and covers, or approved equal. Provide sufficient lengths to enclose the valve assem bly and extend to the water supply line top. A concrete or cast iron box may be substituted with a suitable cover and large enough to house grouped valves and couplings when more than 1 valve is installed at 1 location. 652

well graded, and containing material retained on a ¾ inch sieve. Set boxes, sleeves, pipe covers, and caps at valves with the tops flush with the final finished grade.

valve operation. Provide keys with T -handles and shafts of sufficient length to allow the operator to work from a standing position. Provide tools and accessories necessary for irrigation system adjustment , normal field repair, and operation. Also provide manuf acturer’s or dealer’s written installation instructi ons, parts lists, maintenance, and operation manuals and instructions, and similar available data.

The Engineer will use the following criteria for final inspection:

652.04Method of Measurement

The Engineer will measure accept ably completed work by the lump sum.

652.05Basis of Payment

The Department will pay for accepted work as follows: Pay Item Pay Unit Underground Sprinkler System ............................................................... LS 653