City of Ithaca, NY Water and Sewer Main Specifications

The width of the trench shall be ample to permit the pipe to be laid and jointed properly and the backfill to be placed and compacted as specified. Trenches shall be of such extra width, when required, as will permit the convenient placing of timber supports, sheeting and bracing, and handling of fittings.

The minimum width shall be sufficient to give a clearance of at least eight inches on either side of the barrel of the pipe.

Bell holes. Bell holes shall be provided at each joint to permit the jointing to be made properly.

Pipe clearance in rock. Ledge rock, boulders and large stones shall be removed to provide a clearance of at least six inches below and eight inches on each side of all pipe and fittings.

Excavation to grade.

The trench shall be excavated to the depth required so as to provide a uniform and continuous bearing and support for the pipe on solid and undisturbed ground at every point between bell holes. Any part of the bottom of the trench excavated below the specified grade shall be corrected with approved material and thoroughly compacted as directed by the inspector. The finished grade shall be prepared accurately by means of hand tools.

The subgrade beneath the center line of the pipe shall be finished to within 0.03 foot of a straight line between pipe joints or batter boards. All tolerances shall be above specified grade.

If, in the opinion of the inspector, soil conditions are encountered at subgrade which require all or part of the work to be done in accordance with Subsection F of this section, the inspector shall have the authority to order the work to be done.

Excavation in poor soil or rock.

Where the bottom of the trench at subgrade is found to be unstable or to include ashes, cinders, all types of refuse, vegetable or other organic material, large pieces or fragments of inorganic material, or rock, which, in the judgment of the inspector, should be removed, the contractor shall excavate and remove such unsuitable material to the width and depth ordered by the inspector. Before the pipe is laid, the subgrade shall be made by backfilling with an approved material in three-inch uncompacted layers. The layers shall be thoroughly tamped as directed by the inspector so as to provide a continuous bearing and support for the pipe at every point between the bell holes. The finished subgrade shall be prepared accurately by means of hand tools.

The subgrade beneath the center line of the pipe shall be finished to within 0.03 foot of a straight line between bell holes or batter boards, and all tolerances shall be above the specified grade.

Special foundation in poor soil. Where the bottom of the trench at subgrade is found to consist of material which is unstable to such a degree that, in the opinion of the inspector, it cannot be removed and replaced with an approved material thoroughly compacted in place to support the pipe properly, the contractor shall construct a foundation for the pipe consisting of piling, timber or other materials, in accordance with plans approved by the Board of Public Works.

Blasting. Blasting for excavation will be permitted only after securing the approval of the inspector and only when proper precautions are taken for the protection of persons or property. The hours of blasting will be fixed by the inspector. Any damage caused by blasting shall be repaired by the contractor at his/her expense. The contractor's methods of procedure shall conform to state laws and city ordinances and local laws.

Braced and sheeted trenches.

Open-cut trenches shall be sheeted and braced as required by any governing state laws and as may be necessary to protect life, property or the work. When close sheeting is required, it shall be so driven as to prevent adjacent soil from entering the trench either below or through such sheeting. Where sheeting and bracing are used, the trench width shall be increased accordingly.

The inspector reserves the right to order the sheeting driven to the full depth of the trench or to such additional depths as may be required for the protection of the work. Where the soil in the lower limits of a trench has the necessary stability, the inspector, at his/her discretion, may permit the contractor to stop the driving of sheeting at some designated elevation above the trench bottom. The granting of permission by the inspector, however, shall not relieve the contractor in any degree from his/her full responsibility under the contract.

Sheeting and bracing which have been ordered left in place must be removed for a distance of three feet below the established street grade or the existing surface of the street, whichever is lower. Trench bracing, except that which must be left in place, may be removed when the backfilling has reached the respective levels of such bracing. Sheeting, except that which has been left in place, may be removed after the backfilling has been completed or has been brought up to such an elevation as to permit its safe removal. Sheeting and bracing may be removed before flushing the trench but only in such manner as will ensure the adequate protection of the completed water and/or sewer structures and prevent the disturbance of adjacent ground.

Care of surface materials for reuse. All surface materials which, in the opinion of the inspector, are suitable for reuse in restoring the surface shall be kept separate from the general excavation material, as directed by the inspector.

Piling excavated material. All excavated material shall be piled in a manner that will not endanger the work and that will avoid obstructing sidewalks and driveways. Hydrants under pressure, valve pit covers, valve boxes, curb stop boxes, fire and police call boxes or other utility controls shall be left unobstructed and accessible until the work is completed. Gutters shall be kept clear or other satisfactory provisions shall be made for street drainage, and natural watercourses shall not be obstructed.

Trenching by hand methods. Hand methods for excavation shall be employed in locations where obstructions are shown on drawings or where, in the opinion of the inspector, property can best be protected by digging by hand. In other locations, the contractor may use trench-digging machinery.

Barricades, guards and safety provisions. To protect persons from injury and to avoid property damage, adequate barricades, construction signs, torches, lanterns and guards, as required, shall be placed and maintained during the progress of the construction work and until it is safe for traffic to use the highway. All material piles, equipment and pipe which may serve as obstructions to traffic shall be enclosed by fences or barricades and shall be protected by proper lights when the visibility is poor. The rules and regulations of the local authorities respecting safety provisions shall be observed.

Maintenance of traffic and closing of streets.

The contractor shall carry on the work in a manner which will cause the least interruption to traffic and may close to travel not more than two consecutive blocks upon the specific permission of the city, including the cross street intersected. Where traffic must cross open trenches, the contractor shall provide suitable bridges at street intersections and driveways.

The contractor shall post, where directed by the inspector, suitable signs indicating that a street is closed and necessary detour signs for the proper maintenance of traffic.

Structure protection. Temporary support, adequate protection and maintenance of all underground and surface structures, drains, sewers and other obstructions encountered in the progress of the work shall be furnished by the contractor at his/her expense and under the direction of the inspector. The structures which may have been disturbed shall be restored upon completion of the work.

Protection of property and surface structures. Trees, shrubbery, fences, poles and all other property and surface structures shall be protected unless their removal is shown on the drawings or authorized by the inspector. When it is necessary to cut roots and tree branches, such cutting shall be done under the supervision of the inspector.

§ 348-55 Backfilling.

Backfill material. All backfill material shall be free from cinders, ashes, refuse, vegetable or organic material, boulders, rocks or stones or other material which, in the opinion of the inspector, is unsuitable. However, from one foot above the top of the pipe to the subgrade of the pavement, material containing stones up to eight inches in their greatest dimension may be used, unless specified otherwise herein.

Use of excavated material as backfill. When the type of backfill material is not indicated on the drawings or specifications, the contractor may backfill with the excavated material, provided that such material consists of loam, clay, sand, gravel or other material which, in the opinion of the inspector, is suitable for backfilling.

Sand or gravel backfill. Where sand or gravel backfill is not indicated on the drawings or specified herein and, in the opinion of the inspector, should be used in any part of the work, the contractor shall furnish and backfill with sand or gravel as directed.

Backfilling under pipe. All trenches shall be backfilled by hand, from the bottom of the trench to the center line of the pipe, with sand, gravel or other approved material placed in layers of three inches and compacted by tamping. Backfilling material shall be deposited in the trench for its full width on each side of the pipe, fittings and appurtenances simultaneously.

Backfilling over pipe.

From the center line of the pipe, fittings and appurtenances to a depth of one foot above the top of the pipe, the trench shall be backfilled by hand or by approved mechanical methods. The contractor shall use special care in placing this portion of the backfill so as to avoid injuring or moving the pipe.

The backfill material from the center line of the pipe to one foot above the pipe shall consist of approved excavated material which shall be placed in three-inch layers and compacted by tamping.

Backfilling in freezing weather. Backfilling shall not be done in freezing weather, except by permission of the inspector, and it shall not be made with frozen material. No fill shall be made where the material already in the trench is frozen.

Backfill sand. All sand used for backfill shall be a natural bank sand, graded from fine to coarse, not lumpy or frozen and free from slag, cinders, ashes, rubbish or other material which, in the opinion of the inspector, is objectionable or deleterious. It shall not contain a total of more than 10% by weight of loam and clay, and all material must be capable of being passed through a three-fourths-inch sieve. Not more than 5% shall remain on a No. 4 sieve.

Backfill gravel. Gravel used for backfill shall consist of natural bank gravel having durable particles graded from fine to coarse in a reasonably uniform combination, with no boulders or stones larger than two inches in size. It shall be free from slag, cinders, ashes, refuse or other deleterious or objectionable materials. It shall not contain excessive amounts of loam and clay and shall not be lumpy or frozen. No more than 15% shall be finer than a No. 200 sieve. Backfill gravel shall be used in the top 18 inches of backfill of all ditches in city streets.

§ 348-56 Water mains.

Materials to be used.

Pipe and fittings.

All pipelines four inches in diameter and larger shall be bell-and-spigot, tar-coated, cement-lined, centrifugally cast pipe to meet American Water Works Association specifications, the class of pipe used to be determined by the operating pressure and conditions of the line. All fittings shall be Class D, tar-coated long pattern to meet American Water Works Association specifications.

The use of mechanical joints and rubber-joint cast-iron pipe will be allowed by approval of the Board of Public Works.

Valves. Main line valves shall be Darling hub-end valves of the type used by the City of Ithaca. Valves shall open left (counterclockwise).

Hydrants.

Hydrants shall be Darling B-50-B, five-inch hydrants of the type used by the City of Ithaca. Hose nozzle threads shall be City of Ithaca standard. Hydrants shall have a two-and-one-half-inch hose nozzle and one four-and-one-half-inch steamer nozzle.

The two-and-one-half-inch hose nozzles shall be the City of Ithaca standard, measuring three inches outside diameter to the top of the thread with 7 1/2 threads to the inch. The four-and-one-half-inch steamer nozzle shall be national standard measuring 5 3/4 inches outside diameter at the top of the thread and threaded four threads per inch.

Valve boxes. Valve boxes shall be the Buffalo screw-type roadway box with the cover marked "water."

Manholes.

Manholes may be built of concrete masonry of 1-2-4 concrete using tight smooth forms or standard cement manhole blocks formed especially for four-foot manholes.

Manholes may be built of masonry using hard-pressed brick. Every fifth course of brick shall be laid as stretchers, the remainders to be headers. Every brick shall have full mortar joints on the bottom and sides which shall be formed at one operation by placing sufficient mortar on the bed and forcing the brick into it. Horizontal joints shall not exceed 3/8 inch, and vertical joints on the inside of manholes shall not exceed 1/4 inch. Joints on the inside face are to be carefully rubbed full and struck as a manhole is built up. In wet trenches, water shall be kept drained away from manholes until the concrete is set.

No backfilling shall be done for 24 hours after completion of the manhole.

(d)

In freezing weather, customary precautions of heating materials and after-protection shall be followed.

Steps. Steps of cast-iron or of galvanized wrought iron 3/4 inch in diameter shall be securely placed in the inside of the manhole during construction not more than 18 inches apart.

[2]

Diameter. Manholes five feet deep or less shall have a minimum inside diameter of four feet at the bottom. Manholes 10 feet deep shall be at least five feet in inside diameter, and at intermediate depths the diameter shall be in proportion.

[3]

Frames and covers. Manhole covers shall be set to the grade given by the inspector. Covers of manholes in streets shall correspond to the type used and approved by the City of Ithaca in 1932, the frame and cover to weigh not less than 480 pounds. The depth of the frame shall be eight inches, and the diameter of the cover shall be 24 inches. Manholes in parking areas where no traffic can be expected may use covers of lightweight type used in the City of Ithaca prior to 1932. The weight of the frame and cover shall be not less than 245 pounds, and the depth of the frame shall be four inches.

Inspection of material.

Field inspection. All pipe and accessories shall be laid, jointed and tested under pressure for defects and leakage in the manner specified and in the presence of and as approved by the inspector.

Disposition of defective material. All material found during the progress of the work to have cracks, flaws or other defects will be rejected by the inspector. All defective materials shall be promptly removed from the site.

Handling of materials.

Hauling. Cast-iron pipe, fittings, valves, hydrants and accessories shall be loaded and unloaded by lifting with hoists or skidding so as to avoid shock or damage. Under no circumstances shall such materials be dropped. Pipe handled on skidways shall not be skidded or rolled against pipe already on the ground.

At the site of the work. In distributing the material at the site of the work, each piece shall be unloaded opposite or near the place where it is to be laid in the trench.

Care of pipe coating and lining. Pipe shall be so handled that the coating and lining will not be damaged. If, however, any part of the coating or lining is damaged, the repair shall be made in a manner satisfactory to the inspector.

Alignment and grade.

General.

The water main shall be laid and maintained to the required lines and grades, with fittings, valves and hydrants at the required locations, spigots centered in bells and all valves and hydrant stems plumb.

Any changes in either line or grade shall be made by using the proper fittings and not by crowding the joints; except that, in laying pipe along a curved line, the inspector may approve a small deviation in alignment at each joint. See Subsection E(7) below.

Depth of pipe. The top of the pipe shall be laid to a minimum depth of four feet below the established grade. Any variations therefrom shall be made only with the approval of the inspector.

Laying.

Handling of water main material into the trench. Proper implements, tools and facilities satisfactory to the inspector shall be provided and used for the safe and convenient prosecution of the work. All pipes, fittings, valves and hydrants shall be carefully lowered into the trench piece by piece by means of a derrick, ropes or other suitable tools or equipment in such manner as to prevent damage to water main materials and protective coatings and linings. Under no circumstances shall water main materials be dropped or dumped into the trench.

Hammer test. The pipe and fittings shall be inspected for defects and, while suspended above grade, shall be rung with a light hammer to detect cracks.

Cleaning pipe and fittings. All lumps, blisters and excess tar-coat coating shall be removed from the bell-and-spigot end of each pipe, and the outside of the spigot and the inside of the bell shall be wire-brushed and wiped clean and dry and free from oil and grease before the pipe is laid.

Laying pipe.

Every precaution shall be taken to prevent foreign material from entering the pipe while it is being placed in the line. If the pipelaying crew can not put the pipe into the trench and in place without getting earth into it, the inspector may require that, before lowering the pipe into the trench, a heavy, tightly woven canvas bag of suitable size shall be placed over each end and left there until the connection is to be made to the adjacent pipe. During laying operations, no debris, tools, clothing or other materials shall be placed in the pipe.

After placing a length of pipe in the trench, the spigot end shall be centered in the bell and the pipe forced home and brought to correct line and grade. The pipe shall be secured in place with approved backfill material tamped under it except at the bells. Pipe and fittings which do not allow a sufficient and uniform space for joints shall be removed and replaced with pipe and fittings of proper dimensions to ensure such uniform space. Precautions shall be taken to prevent dirt from entering the joint space.

At times when pipelaying is not in progress, the open ends of pipe shall be closed by a watertight plug or other means approved by the inspector. Joints of pipe in the trench which cannot be poured shall be caulked with packing to make them as watertight as possible. This provision shall apply during the noon hour as well as overnight. If water is in the trench, the seal shall remain in place until the trench is pumped completely dry.

Cutting pipe.

The cutting of pipe for inserting valves, fittings or closure pieces shall be done in a neat and professional manner without damage to the pipe or cement lining and so as to leave a smooth end at right angles to the axis of the pipe.

When machine-cutting is not available for cutting pipe 20 inches in diameter or larger, the electric-arc cutting method will be permitted using a carbon or steel rod. Only qualified and experienced workers shall be used on this work.

The flame-cutting of pipe by means of an oxyacetylene torch shall not be allowed.

Bell ends to face direction of laying. Pipe shall be laid with bell ends facing in the direction of laying unless directed otherwise by the inspector.

Permissible deflection at joints. Wherever it is necessary to deflect pipe from a straight line, either in the vertical or horizontal plane, to avoid obstruction or plumb stems or where long-radius curves are permitted, the amount of deflection allowed shall not exceed that required for satisfactory caulking of the joint and shall be approved by the inspector.

		Maximum Deflection Length of:			Approximate Radius of Curve With Pipe Produced by Succession of Joints with Pipe Leads of:
Pipe Diameter (inches)	Joint Opening	16 Feet	18 Feet	20 Feet	16 Feet	18 Feet	20 Feet
4	0.41	14.8	16.7	18.5	208	234	260
6	0.58	14.8	16.7	18.5	208	234	260
8	0.65	12.9	14.6	16.2	238	268	297
10	0.75	12.4	14.0	15.5	248	279	310
12	0.75	10.5	11.9	13.2	292	327	363
16	0.75	7.9	8.8	9.7	390	440	488

(8)

Unsuitable conditions for laying pipe. No pipe shall be laid in water or when, in the opinion of the inspector, the trench conditions are unsuitable.

Jointing.

Yarning or packing material. Yarning or packing material shall be molded or tubular rubber rings. The above material shall be handled with care in order to prevent contamination and shall be dry when put into place in the joint. The material shall be free of oil, tar or greasy substances.

Placing of yarning material. The yarning material shall be placed around the spigot end of the pipe and shall be of proper dimensions to center the spigot in the bell. When the spigot is shoved home, the yarning material shall be driven tightly against the inside base or hub of the bell with a suitable yarning tool.

Depth of jointing material. For lead joints, a space not less than 2 1/4 inches in depth shall be left in the bell in pipe having a nominal diameter of 20 inches or less; 2 1/2 inches in twenty-four-, thirty- and thirty-six-inch pipe; and three inches in pipe larger than 36 inches.

Lead.

Lead for caulking purposes shall contain not less than 99.73% pure lead. Impurities shall not exceed the following limits:

Arsenic, antimony and tin together: 0.015%.

Copper: 0.08%.

Zinc: 0.002%.

Iron: 0.002%.

Bismuth: 0.25%.

Silver: 0.02%.

The producer's name or the mark of Lead Industries shall be clearly cast or stamped upon each piece of lead.

Heating and pouring of lead. Lead shall be heated in a melting pot kept in easy reach of the joint to be poured so that the molten metal will not be chilled in being carried from the melting pot to the joint and shall be brought to a proper temperature so that, when stirred, it will show a rapid change of color. Before pouring, all scum shall be removed. Each joint shall be made in one continuous pouring, filling the entire joint space with solid lead. Spongy or imperfectly filled joints shall be burned out and repoured.

Position of joint runner. The joint runner shall fit snugly against the face of the bell, and the outside of the pipe shall be dammed with clay to form a pouring lip to provide for filling the joint flush with the face and to the top of the bell.

Caulking lead joints. After the lead has cooled to the temperature of the pipe, lead joints shall be caulked with pneumatic or hand tools operated by competent workers until such joints are thoroughly compacted and watertight. The finished joint shall show a hard and even hammered surface overall. Care should be taken not to overstrain the bells during caulking.

Setting valves and fittings.

General. Valves, fittings, plugs and caps shall be set and jointed to pipe in the manner heretofore specified for cleaning, laying and jointing pipe.

Valve boxes and manholes. [See Subsection A(4) and (5) above.]

A valve box or manhole shall be provided for every valve.

The valve box shall not transmit shock or stress to the valve and shall be centered plumb over the operating nut of the valve, with the box cover flush with the surface of the ground or such other level as may be directed.

Where valves are in manholes, the operating nut shall be readily accessible for operation through the opening in the manhole, which shall be set flush with the surface of the finished pavement. Manholes shall be so constructed as to permit minor repairs and afford protection to the valve and pipe from impact where they pass through the manhole wall.

Drainage of mains.

Mains shall be drained through drainage branches or blowoffs to dry wells from which the water can be pumped. Drainage branches, blowoffs, air vents and appurtenances shall be provided with gate valves and shall be located and installed as shown on the plans.

Drainage branches or blowoffs shall not be connected to any sewer, submerged in any stream or be installed in any other manner that will permit backsiphonage into the distribution system.

Dead ends. All dead ends on new mains shall be closed with cast-iron plugs or caps, with or without a blowoff cock, as shown on the drawings.[1]

Editor's Note: The drawings are on file and available for inspection at the office of the City Clerk.

Setting hydrants.

Location.

Hydrants shall be located as shown or as directed and in a manner to provide complete accessibility and also in such a manner that the possibility of damage from vehicles or injury to pedestrians will be minimized.

When placed behind the curb, the hydrant barrel shall be set so that no portion of the pumper or hose nozzle cap will be less than six inches nor more than 12 inches from the gutter face of the curb.

When set in the lawn space between the curb and the sidewalk or between the sidewalk and the property line, no portion of the hydrant or nozzle cap shall be within six inches of the sidewalk.

Position. All hydrants shall stand plumb and shall have their nozzles parallel with or at right angles to the curb, with the pumper nozzle facing the curb, except that hydrants having two hose nozzles 90° apart shall be set with each nozzle facing the curb at an angle of 45°. Hydrants shall be set to the established grade, with nozzles at least 12 inches above the ground, as shown or as directed by the inspector.

Connection to main. Each hydrant shall be connected to the main with a six-inch cast-iron branch controlled by an independent six-inch gate valve, except as otherwise directed.

Hydrant drainage in pervious soil. Wherever a hydrant is set in soil that is pervious, drainage shall be provided at the base of the hydrant by placing coarse gravel or crushed stone mixed with coarse sand from the bottom of the trench to at least six inches above the waste opening in the hydrant and to a distance of one foot around the elbow. No drainage system shall be connected to the sewer.

Hydrant drainage in impervious soil. Whenever a hydrant is set in clay or other impervious soil, a drainage pit two feet in diameter and three feet deep shall be excavated below each hydrant and filled compactly with coarse gravel or crushed stone mixed with coarse sand under and around the elbow of the hydrant and to a level of six inches above the waste opening.

Inspector to determine. The inspector shall determine whether Subsection H(4) or (5) of this subsection is applicable.

Anchorage.

Anchorage for hydrants. The bowl of each hydrant shall be well braced against unexcavated earth at the end of the trench with stone or slabs or concrete backing.

Anchorage for plugs, caps, tees and bends. All plugs, caps, tees and bends deflecting 22 1/2° or more on mains eight inches in diameter or larger shall be provided with a reaction backing.

Reaction backing. Reaction backing shall be concrete of a mix not leaner than one cement to 2 1/2 sand to five stone and having a compressive strength of not less than 2,000 pounds per square inch at 28 days. Backing the area of bearing on the pipe and on the ground in each instance shall be that shown or directed by the inspector. The backing shall, unless otherwise shown or directed, be so placed that the pipe and fitting joints will be accessible for repair.

Hydrostatic tests.

Pressure test. After the pipe has been laid and partially backfilled as directed by the inspector, all newly laid pipe or any valved section thereof shall be subject to a hydrostatic pressure equal to a pressure 50% greater than the computed working pressure of the section under test based on the lowest point in the section under test and corrected to the elevation of the test gauge.

Duration of pressure test. The duration of each pressure test shall be at least one hour.

Procedure. Each valved section of pipe shall be slowly filled with water, and the specified test pressure, based on the elevation of the lowest point of the line or section under test and corrected to the elevation of the test gauge, shall be applied by means of a pump connected to the pipe in a manner satisfactory to the inspector.

Expelling air before test. Before applying the specified test pressure, all air shall be expelled from the pipe. If hydrants or blowoffs are not available at high places, taps at points of highest elevation shall be made before the test is made and plugs inserted after the test has been completed.

Examination under pressure. All exposed pipes, fittings, valves, hydrants and joints shall be carefully examined during the open-trench test. Joints showing visible leaks shall be recaulked until tight. Any cracked or defective pipe, fittings, valves or hydrants discovered in consequence of this pressure test shall be removed and replaced with sound material, and the test shall be repeated until satisfactory to the inspector.

Leakage test.

A leakage test shall be conducted after the pressure test has been satisfactorily completed. The duration of each leakage test shall be two hours; and during the test, the main shall be subject to a pressure equal to the computed working pressure of the lowest point in the section and corrected to gauge elevation, except that the test pressure shall be a minimum of 100 pounds per square inch in the lowest point in the section.

"Leakage" is defined as the quantity of water to be supplied into the new laid pipe or any valved section thereof necessary to maintain the specified leakage test pressure after the pipe has been filled with water and the air expelled.

No pipe installation will be accepted until the leakage is less than the number of gallons per hour as determined by the formula:

	L = ND ** P/1,850
Where
	L	=	The allowable leakage in gallons per hour.
	N	=	The number of joints in the length of pipe tested.
	D	=	The normal diameter of the pipe in inches.
	P	=	The average test pressure during the leakage test in pounds per square inch gauge.

Variation from permissible leakage. Should any test of pipe laid disclose leakage greater than that specified in Subsection J(6) of this section, the defective joints shall be located and repaired until the leakage is within the specified allowance.

(8)

Time for making test of pipe.

Lead-jointed pipe may be subjected to hydrostatic pressure and inspected and tested for leakage at any convenient time after the trench has been partially backfilled, except at the joints.

Where any section of a main is provided with concrete reaction backing, the hydrostatic pressure test shall not be made until at least five days have elapsed after the concrete reaction backing was installed. If high-early-strength cement is used in the concrete reaction backing, the hydrostatic pressure test shall not be made until at least two days have elapsed.

(9)

Interruption of service. No valve or other control on the existing system shall be operated for any purpose by the contractor. The city will operate all valves, hydrants, blowoffs and curb stops.

Disinfection.

Form of chlorine and means of application. Before being placed in service, all new water distribution systems and repaired portions of or extensions to existing systems shall be chlorinated. If the available water is more alkaline than pH eight, the holding time in the main shall be increased at the discretion of the Engineer.

Form of applied chlorine. Any of the following methods of procedure (arranged in order of preference) shall be followed, subject to the approval of the Engineer:

Liquid chlorine gas-water mixture.

Direct chlorine feed.

Calcium or sodium hypochlorite and water mixture.

(d)

Chlorinated lime and water mixture.

Liquid chlorine. A chlorine gas-water mixture shall be applied by means of a solution-feed chlorinating device, or, if approved by the Engineer, the dry gas may be fed directly through proper devices for regulating the rate of flow and providing effective diffusion of the gas into the water within the pipe being treated. Chlorinating devices for feeding solutions of the chlorine gas or the gas itself must provide means for preventing the backflow of water into the chlorine cylinder.

Chlorine-bearing compounds in water. On approval of the Engineer, a mixture of water and a chlorine-bearing compound of known chlorine content may be substituted as an alternative for liquid chlorine.

Chlorine-bearing compounds. The chlorine-bearing compounds which may be used are:

Calcium hypochlorite (comparable to commercial products known as "HTH," "Perchloron" and "Pittchlor").

[2]

Chlorinated lime (frequently called "chloride of lime" and known to industry as "bleaching powder").

[3]

Sodium hypochlorite.

Proportions of mixtures. A five-percent solution of the powder shall be prepared, consisting of 5% of powder to 95% of water by weight, due attention being given to the chlorine content of the product used. This calcium hypochlorite or chlorinated lime and water mixture, first made into a paste and then thinned to a slurry with clean water, shall be injected or pumped into the newly laid pipe after preliminary flushing. If sodium hypochlorite is used, mix the solution as purchased with water to obtain the desired concentration of chlorine and feed into the pipe under treatment in the same manner as is used for feeding other hypochlorites.

Point of application. The preferred point of application of the chlorinating agent shall be at the beginning of the pipeline extension or any valved section of it and through a corporation stop inserted by the owner (except in new distribution system) in the top of the newly laid pipe. The water injector for delivering the chlorine-bearing water into the pipe should be supplied from a tap on the pressure side of the gate valve controlling the flow into the pipeline extension. In a new system, application of chlorine may be made advantageously at the pumping station, the elevated tank, the standpipe or the reservoir. When properly cleaned first, these units are thus chlorinated adequately.

Rate of application. Water from the existing distribution system or other source of supply shall be controlled so as to flow slowly into the newly laid pipeline during the application of chlorine. The rate of chlorine mixture flow shall be in such proportion to the rate of water entering the pipe that the chlorine dose applied to the water entering the newly laid pipe shall be at least 40 to 50 parts per million. This may require as much as 100 parts per million of chlorine in the water left in the line after chlorination. A convenient method of determining the rate of flow of water into the line to be treated is to start with the line full of water and measure the rate of discharge at a hydrant with a pilot gauge. Great flexibility is made possible by providing a series of orifices to give good gauge readings at high and low flows.

Preventing reverse flow. Valves shall be manipulated so that the strong chlorine solution in the line being treated will not flow back into the line supplying the water.

(8)

Retention period. Treated water shall be retained in the pipe long enough to destroy all non-spore-forming bacteria. This period should be at least 24 hours and preferably longer, as may be directed. After the chlorine-treated water has been retained for the required time, the chlorine residual at the pipe extremities and at other representative points should be at least 25 parts per million.

(9)

Chlorinating valves and hydrants. In the process of chlorinating newly laid pipe, all valves or other appurtenances shall be operated while the pipeline is filled with the chlorinating agent.

(10)

Final flushing and test. Following chlorination, all treated water shall be thoroughly flushed from the newly laid pipeline at its extremities until the replacement water throughout its length shall, upon test, be proved comparable to the quality of water served the public from the existing water supply system. This quality of water delivered by the new main should continue for a period of at least two full days as demonstrated by laboratory examination of samples taken from a tap located and installed in such a way as to prevent outside contamination.

(11)

Repetition of procedure. Should the initial treatment fail to result in the conditions specified in Subsection K(10) of this section, the chlorination procedure shall be repeated until such results are obtained.

§ 348-57 Sewer mains.

Materials to be used.

Pipe and fittings.

All sewer mains shall be cement-asbestos with a minimum inside diameter of eight inches.

No other specifications for concrete or cement-asbestos sewers are herein contained. The use of other materials is not prohibited and may be done under standard specifications submitted to and approved by the Board of Public Works.

Manholes.

Manholes shall be constructed at every change of line or grade of the sewer main, at every main intersection or branch (except branches for house connections) and in straight runs of main so that the distance between manholes shall not exceed 300 feet; except that, where the grade of the sewer is more than five feet in 100 feet, the distance between the manholes shall not exceed 250 feet.

Manholes may be precast of concrete masonry of 1-2-4 concrete using tight smooth forms or standard cement manhole blocks formed especially for four-foot manholes.

Manholes may be built of brick masonry using hard-pressed brick. Every fifth course of brick shall be laid as stretchers, the remainder to be headers. Every brick shall have full mortar joints on the bottom and sides which shall be formed at one operation by placing sufficient mortar on the bed and forcing the brick into it. Horizontal joints shall not exceed 3/8 inch, and vertical joints on the inside of the manholes shall not exceed 1/4 inch. Joints on the inside face are to be carefully rubbed full and struck as a manhole is built. The outside of the manhole shall be smoothly and evenly plastered with cement mortar 1/2 inch thick. Such plaster coat shall be applied in one operation after all brick has been placed and must not be applied by the mason working within the manhole as the brick courses are laid up. Plaster shall be proportioned one part portland cement to 2 1/2 parts mortar sand.

Manhole bottoms.

[a]

Inverts of manholes shall be formed by running the sewer pipe through the manhole cutting pipe after the manhole has been completed. Concrete bottoms of manholes shall be placed in two layers. The top of the bottom layer shall be level with the horizontal diameter of the pipe, and upon this layer the brick masonry shall be started. The depth of this concrete shall be everywhere at least six inches thick. Particular care must be exercised to ensure this depth under the invert. After the top of the pipe has been cut off and the invert left in the concrete base, a second concrete floor must be applied on top of the original bottom to the height of the top of the sewer pipe leaving the manhole. This floor shall be neatly shaped to meet the cut half of the sewer pipe and shall serve to confine the sewage from overflowing on the manhole bottom if the sewer should flow more than half full.

[b]

Where the invert of the manhole is below groundwater level, manholes shall be waterproof on the outside of the plaster coat with suitable bituminous waterproofing to a line one foot higher than the apparent groundwater level. In wet trenches, water shall be kept drained away from manholes until the concrete work is set.

[c]

No backfilling shall be done until the plaster coat on the outside of the manhole shall have set for 24 hours.

[d]

In freezing weather, customary precautions of heating materials and after-protection shall be followed.

[2]

Steps. Steps of cast-iron or of galvanized wrought iron 3/4 inch in diameter shall be securely placed in the inside of the manhole during construction not more than 18 inches apart.

[3]

Diameter. Manholes five feet deep or less shall have an inside diameter of four feet at the bottom. Manholes 10 feet deep shall be five feet in inside diameter, and at intermediate depths the diameter shall be in proportion.

[4]

Frames and covers. Manhole covers shall be set to the grade given by the inspector. Covers of manholes in streets shall correspond to the type used and approved by the City of Ithaca in 1932, the frame and cover to weigh not less than 480 pounds. The depth of the frame shall be eight inches, and the diameter of the cover shall be 24 inches. Manholes in parking areas where no traffic can be expected may use covers of the lightweight type used in the City of Ithaca prior to 1932. The weight of the frame and cover shall be not less than 245 pounds, and the depth of the frame shall be four inches.

Disposition of defective material. All material found during the progress of the work to have cracks, flaws, blisters or other defects shall be rejected by the inspector. All defective material shall be promptly removed from the site.

Alignment and grade.

Sewers shall be laid straight to line and grade between manholes.

The alignment and grade of the sewer line shall be checked from a string line stretched along the center of the pipe between batter boards at every 25 feet. The batter board grades are taken from the engineer's grade stakes. The elevation of the batter boards above the invert of the pipe shall be constant for adjacent batter boards. Batter boards shall be set at every change in line and grade.

Laying.

Handling main material into trench. Proper implements, tools and facilities satisfactory to the inspector shall be provided and used for the safe and convenient prosecution of the work. All pipe and fittings shall be carefully lowered into the trench piece by piece by means of a derrick, ropes or other suitable tools or equipment in such a manner as to prevent damage to sewer main materials. Under no circumstances shall sewer main material be dropped or dumped into the trench.

Pipelaying. All pipe shall be laid with ends abutting and true to line and grade, so fitted and matched that a smooth uniform invert will be formed. The bottom of the trench shall be shaped so as to conform as nearly as possible to the outside of the pipe, particular care being taken to recess the bottom of the trench in such a manner as to relieve the bell of all load.

Depth. In streets or highways, sewers shall be laid to a minimum depth of three feet, grade permitting.

Unsuitable conditions for laying pipe. No pipe shall be laid in water or when, in the opinion of the inspector, trench conditions are unsuitable.

Jointing.

Joints. Pipe joints shall conform to both the materials and methods of installation of the manufacturer of the particular cement-asbestos pipe furnished for the job.

Joints in cold weather. No joints shall be poured when pipe is at a temperature below freezing. When the air temperature is below 40° F., the part of the pipe to be joined shall be heated, and a paint coat of G-K primer, or equal, shall be applied both to the spigot end and the inside of the bell before pipes are joined preparatory to pouring.

Testing.

Cleaning and flushing.

The interior of the sewer shall, as the work progresses, be cleared of all dirt, surplus joint material and superfluous material of every description.

No sewer main shall be finally joined to the city system until it has been satisfactorily cleaned and flushed.