7-08 General Pipe Installation Requirements

7-08.2 Materials

(PUD July 2020)

Section 7-08.2 is supplemented with the following:

Gravel Borrow: 9-03.14 (1)
Crushed Surfacing Base Course: 9-03.9 (3)
Quarry Spalls: 9-03.1 (5)
Ballast: 9-03.9 (1)
Locate Devices: 9-03.30

7-08.3(1)A Trenches

(PUD July 2020)

The last line in the third paragraph is deleted.

The last sentence of the sixth paragraph is revised to read:

The trench foundation shall be backfilled to the bottom of the pipe zone with gravel backfill for pipe zone bedding, crushed surfacing base course, ballast, or quarry spalls with a maximum size of 4 inch, or as directed by the Engineer, and compacted to form a uniformly dense, unyielding foundation.

7-08.3(1)B Shoring

(PUD July 2020)

Supplement this section with the following:

Shoring shall be designated as “Trench Safety System”.

Add the following new section:

7-08.3(1)D Dewatering
(PUD July 2020)

When groundwater is present, the Contractor shall provide a dewatering system of sufficient size and capacity necessary to lower and maintain the groundwater table to an elevation of at least 1 foot below either the lowest foundation subgrade or the bottom of trench, whichever is lower, to permit the Work to be performed under dry conditions.

The Contractor shall submit a dewatering plan that includes the following:

  • Site plan that includes the proposed layout of the temporary dewatering system including discharge location(s)
  • Manufacturer data sheets for proposed temporary dewatering equipment and piping

The Contractor shall be responsible for complying with all dewatering requirements as described in RCW 18.104.

7-08.3(3) Backfilling

(PUD July 2020)

Delete the second paragraph.

Supplement this section with the following:

The Contractor shall submit maximum density and optimum moisture content data as required in section 2-03.3(14)D at least 7 calendar days prior to any backfilling operations. Test results shall not be more than 2 months old.

Trench backfill shall be capped with cold mix AC or temporary HMA at the end of each work day. Thickness of temporary pavement patching material shall be a minimum of 2 inches. Use of temporary steel sheeting, pinned and set with cold mix edge transitions may be allowed by authorization of the Skamania County permit and inspector.

Add the following new sections:

7-08.3(5) Tracer Wire
(PUD July 2020)

Tracer wire systems must be installed as a single continuous wire. No looping or coiling of wire is allowed. Tracer wire shall be attached to the top of all water lines regardless of pipe material. Include tracer wire on service piping, hydrant leads, and air release valve piping. Tracer wire shall be secured (taped / tied) at 5-foot intervals. Lay mainline tracer wire continuously, by-passing around the outside of valves and fittings on the north or east side. All mainline tracer wires shall be interconnected at intersections (e.g. mainline tees and crosses) without cutting of mainline tracer wire by stripping back insulation and using a mainline-to-service connector. Tracer wire must be properly grounded at all dead-ends / stubs. Grounding of tracer wire shall be achieved by using a 1.5-lb, drive-in, magnesium ground rod. Ground rods shall be driven into virgin soil directly beneath and in-line with the utility.

Any damage occurring during installation of the tracer wire must be immediately repaired by removing the damaged wire and installing a new section of wire with approved connectors. Taping and/or spray coating shall not be allowed.

Mainline tracer wire shall not be connected to existing conductive pipes. Treat as a mainline dead-end ground using an approved waterproof connector to a ground rod. In occurrences where an existing tracer wire is encountered on an existing utility that is being extended or tied into, the new tracer wire and existing tracer wire shall be connected using approved connectors.

All new tracer wire installations shall be located using typical low frequency (512 Hz) line tracing equipment, witnessed by the Contractor and Owner’s representative, prior to acceptance of ownership. This verification shall be performed upon completion of rough grading and again prior to final acceptance of the project. Continuity testing in lieu of actual line tracing shall not be accepted.

7-08.3(6) Locator Stations

(PUD July 2020)

Where shown on the Contract Plans, the Contractor shall install locator stations. See Division 9 for details. Maintain 2 feet of excess tracer and grounding wire above final grade at all locator access points.

7-08.4 Measurement

(PUD July 2020)

Section 7-08.4 is supplemented with the following:

Trench safety system will be measured per linear foot, for trench over four feet in depth where an adequate trench safety system is provided.

There will be no separate measurement for trench excavation and backfill. This will be considered incidental to other bid items.

Locator stations will be measured per each.

7-08.5 Payment

(PUD July 2020)

Section 7-08.5 is supplemented with the following:

“Trench Safety System”, per linear foot.

The unit contract price per linear foot for “Trench Safety System” shall be full compensation for all work involved to furnish and install trench safety systems per local, state, and federal requirements.

The costs of trench safety systems shall not be considered as incidental to any other contract item. Any bid under $1 per linear foot will be considered unrealistic. If the Contractor’s bid is less than the minimum specified amount, the Contracting Agency will unilaterally revise the bid amount to the minimum specified amount and recalculate the Contractor’s total bid amount. The corrected total bid amount will be used by the Contracting Agency for award purposes and to fix the amount of the contract bond.

“Locator Station”, per each.

The unit Contract price for “Locator Station” shall be full pay for all work to furnish and construct the locator station in-place, including but not limited to excavating, backfilling, valve box and cover, and cleanup. Fire hydrant tracer wire access points shall be included in the fire hydrant bid item.