安装方法

1.Methods of Ctting Cast Iron Soil Pipe

There are several methods of successfully cutting cast iron soil pipe.These methods may be placed into two basic categories;those that require external power for their operation and those merhods that require only hand operation.Methods that require external power are usually used for prefabrication work or high volume cutting operations.Examples of this type of equpment would be (1) the abrasive saw (chop saw )(2) power hack saw and (3) an electrically actuated hydraulic snap cutter.Before using electical equipment of this nature,the manufacturer's operating instructions should be carefully reviewed for safe use of the eauipment.
There are two hand operated crtting tools that are used in the industry today (1) The standard steel pipe cutter using cutting wheels specifically designed to cut cast iron soil pipe and (2)the snap cutter.The snap cutter accounts for the majority of all cuts made on cast iron soil pipe in the field.There are several types of snap cutter available,the following procedure has been found to produce consistently good crts:
(1).After marking the pipe length to be cut,positionthe chain cutter squarely around the pipe toassure a straingt cut.The maximum mumber of wheels possible should be im contact with the pipe.
(2).Score the pipe by applying prassure on the handles to make the cutter wheels indent the pipe.
(3).Rotate the pipe a few degrees and then apply quick final pressure to compiete the cut.If a piece of pipe is unusually tough,score the pipe several times before making your final cut.Scoring the pipe before the actual cut is the key to a clean straight cut.
Cast iron soil pipe may also be cut with ahammer and a cold chisel.This method of cutting is very time consuming and should only be used if snap cutters are ont available.Again,protective equipment,such as safety goggles,should be used.The procedure for cutting soil pipe with a hammer and chisel are as follows:
(1).Measure the length to be cut and mark the cut line completely around the circumference of the pipe.
(2).Place the mark to be cut on a 2 x 4 so the edge of the 2x 4is directly under the mark.
(3).By striking the chisel with the hammer,cut a groove following your mark all the way around the circumference of the pipe.
(4).Continue cutting as outlined above in (3) until the pipe is cut.This procedure may take several revolutions of the pipe before it is cut.
installers should be aware of safety considerations,including the need to use protective equipment,such as safety goggles,when cutting cast iron soil pipe.
2.Underground Installation Procedures
The physical properties of cast iron soil pipe make it the best DWV(Drain,Waste and Vent)material for underground installation.The two keys for prpoper underground installation are trench preparation and backfilling.
The trench should be wide enough to saaemble the joints.Total load on the pipe includes both earth load and the truck load.Fot additional information refer to CISPI's"Trenching Recommendations for Cast Iron Soil Pipe"brochure.Safety procedures in trenching should be observed,including provisions to avoid collapse of the trench wall.
The trench bottom should be stable enough to support the complete barrel of the pipe.If possible the barrel should rest on even and undisturbed soil.In certain conditions,i.e.rocky,it becomes necessary to excavate deeper than needed,palce and tamp back fill material to provide an appropriate bed.Holes shoud be provided at each joint for the hub or couplings to allow for continuous support of the barrel along the trench bottom.If the ditch must be excavated deeper than the depth of the drainage pipe,place and tamp backfill material to provide uniform support fot the pipe barrel.
Man times in the installation of underground soil pipe it is necessaryto change the direction of the line.Cast iron soil pipe will allow this through deflection in the joints.Installation should initially be completed in a straight line and then deflected to the appropriate amount.Maximum deflections should not exceed 1/2inch per foot of pipe.This would allow 5 inches of deflection for a 10foot piece of soil pipe and 2 1/2 inches for 5 inches of deflection for a 10 foot piece of soil pipe and 2 1/2 inches for 5 foot pipe.For changes in direction greater than these deflections an appropriate fitting should be used.
No pipe Bedding,Hard Trench Bottom,Continuous Line Support with Hub or Coupling Holes
Once installation (For joining methods refer to Part 3)is completed,the underground section is ready for test.Because this portion of the system is usually the Largest diameter pipe it may be necessary to restrain the system or joints from movement prior to testing.This may be done by partially backfilling and leaving the joints xposed for inspection,or rodding and or bracing.
After testing is completed,the trench can be properly backfilled.When backfilling care should be taken to protect the pipe from large rocks,stones,or frozen fill material etc.,that could damage the pipe.Cast iron soil pipe laid on a solid trench bottom requires no tedious placement of selected backfill materials.Installers should always consider local conditions,codes,manufacturer instructions,and architect/engineer instructions in any installation.
3.Above Ground Installation Procedures
with attention to a few basic rules the installation of cast iron soil pipe and fittings is easily accomplished.
soil pipe and fittings is easily accompilshed.
(1).Cast iron soil pipe installed in the horizontal position shall be
supported at every hub (Hub & Spigot)or coupiling (Hubless).The hanger shall be palced within 18"of the hub or coupling.Joints used for connecting cast iron soil pipe possess sufficient shear strength to require one hanger perjoint or hub.
(2).Installations requiring multiple joints within a four foot developed length shall be supported at every other or alternating hubs or couplings.
Vertical components shall be secured at each stack base and at sufficiently colse intervals to keep the systme in alignment and to adequately support the pipe and its contents.Riser clamps,sometimes called floor or friction clamps are required for vertical piping in multistory strctures in order for each floor not to exceed 15'O"
Horizontal pipe fittings five (5) inches and larger shall be suitably braced to prevent horizontal movement.This shall be done at every branch opening or change of direction by the use of braces,blocks,rodding or other suitable method,to prevent movement.
Closet bends,traps,trap-arms and similar branches must be secured against movenent in any direction.Clset bends installed above ground shall be stabilized by firmly strapping and blocking.Where vertical closet stubs are used they must be stabilized against horizontal or vertical movements.
4.General Installation Instructions
(1).Vertical piping:
1.Secure vertical piping at sufficiently close intervals to keep the pipe in alignment and to support the weight of the pipe and its contents.Support stacks at their bases and at sufficient floor intervals to meet the requirements of local codes.Approved metal clamps or hangers should be used for this purpose.
2.If vertical piping is to stand free of any support or if on structural element is available for support and stability during construction,secure the piping in its proper position by means of adequate stakes or braces fastened to the pipe.
(2).Horizontal Piping,Suspended;
1.Support horizontal piping and fittings at sufficiently close intervals to maintain alignment and prevent sagging or grade reversal.Support each length of pipe by an approved hanger located not more than 18 inches from the joint.
2.Support terminal ends of all horizontal runs or branches and each change of direction or alignment with an approved hanger.
3.Closet bends installed above ground should be firmly secured.
(3).Horizontal Piping,Underground:
1.To maintain proper alignment during backfilling,stabilizepipe in proper position by partial backfilling and cradling.
2.Piping laid on grade should be adequately secured to prevent misalignment when the slab is poured.
3.Closet bends installed under slabs should be adequately secured.
(4).Installation Inside the Building:
1.Installation suggestions.According to most authorities and plumbing codes,it is sufficient to support horizontal pipe at each joint,i.e.5' pipe should be supported at five foot intervals,10' in length may be supported at ten foot intervals.Supports should be adequate to maintain alignment and prevent sagging and should be placed within eighteen inches of the joint.
When the system is filled with water,sufficient beam strength is provided by cast iron soil pipe to carry the load with hangers every ten feet. Any of the horizontal supports of clamps illustrated in Figures 1and 2 may be used, depending of conditions or what is regarded as essentil by the conteractor,architect or engineer.Whatever method of support or clamp is used for the horizontal line,care should be exercised to make certain that the line has a proper grade (1/4 inch or more per foot).
Hangers may be fastened to wood members or beams with wood scr ews,lagscrews or large nails.For fastening to "I" beams,bar joists,junior beams or other structural members,beam clamps or "C" clamps may be used.Fasteners for masonry walls may be expansion bolts or screws,or where a void is present, the toggle bolt may be used.Studs shot into the masonry by the explosion method may also be used.Along a wall,a bracket made of structural members or a cast bracket may be used.
Adequste provision should be made to prevent "shear".where components are suspended in excess of eighteen (18)inches by means of mon-rigid hangers they should be suitably braced against movement horizontally,oftenclled sway bracing.Examples of sway bracing are illustrated in figures 3 and 4.
(5).Horzontal Installation of Large Diameter Pipe.
Horizontal pipe and fittings five (5) inches and larger must be suitab braced to prevent horizontal movement.This must be done at every branch opening or change of direction by the use of braces,blocks,rodding or other suitable method,to prevent movemnt or joint separation.Figure 5 illustrates severa methods of bracing.
(6).Suggested Installation of Horizontal Fittings.
1.Hangers should be provided as necessary to provide alignment and grade.Hangers should be provided at each horizontal branch connectiong. Hangers should be adequate to maintain alignment and rpevent sagging and should be placed adjacent to the coupling.By placing the hangers properly,the proper grade will be maintained.Abequate provision should be made to prevent shear.Where pipe and fittings are suspended in excess of sighteen inches by means of non-rigid hangers they should be suitably braced against movement horizontally,often called sway bracing .Refer to Figures 3 and 4 for illustrations.
2.Clset bends,traps,trap-arms and similar branches must be firmly secured against movement in any direction.Closet bends installed above ground should be stabilized.Where vertical closet studs are used they must be stabilized against horizontal or vertical movement.In Figures 6 and 7 see illustration for strapping a closet bend under a sub-floor and how a clevis type hanger has been used to an advantage.
3.When a hulbess blind plug is used for a required cleanout,the complete coupling and plug must be accessible for removal and replacement.
4.The connection of closet rings,floor and shower drains and similar"slip-over"fittings and the connection of hubless pipe and fittings to soil pipe hubs may be accompilshed by the use.of caulked lead and oakum or compression joints.
(7).Seismic Restraints
The following recommendations are some of the factors to consider when installing cast iron pipe in seismically active areas.All installations must comply with local codes and instructions of architects or engineers who are responsidle for the piping design.
1.Brace all pipe 2"and larger.Exceptions:
Seismic braces may be omitted when the top of the pipe is suspended 12"or less from the supporting structure member and the pipe is suspended by an individual hanger.
2.Vertical Piping Attachment-
Vertical piping shall be secured at sufficiently close intervals to keep the pipe in alignment and carry the weight of the pipe and conltents. Stacks shall be supported at their bases and if over two stories in height at each floor by approved floor clamps.At vertical pipe risers,whenever possible,support the weight of the riser at a point or point or points above the center of gravity of the riser.Provide lateral guidesat the top and bottom of the riser,and at intermediate points not to exceed 30'0"on center.
3.Horizontal Piping Supports-
Horizontal piping shall be supported at sufficiently close intervals to prevent sagging.Trapeze hangers may be used.Pipe,where top of the pipe is 12"or more from supporting structure shall be braced on each side of a change of direction of 90 degrees or more.
4.Traverse bradcing
40'-0"o.c.maximum spacing unless otherwise onted.One pipe section may act as longitudinal bracing for the pipe section conneced perpendicular to it ,if the bracing is installed with 24"of the elbow or tee of similar size.
5.Longitudinal bracing
80"-0"o.c.maximum spacing unless otherwise noted.
6.Miscellaneous
Provide large enough pipe sleeves through walls or floors to allow for anticipated differential movements.
5.Jointing Methods for Cast Iron Soil Pipe
(1).The Compession Joint
The compression joint is the result of research and development to provide an efficient,lower-cost method for joining cast iron soil pipe and fittings.The jiont is not unique in application to cast iron soil pipe,since similar compression-type gaskets have been successfully used in pressure ipipe joints for years.As showmn in Figure 1,(B)the compression joint rses hub and spigot pipe as does the lead and oakum joint.The major difference is the onepiece robber gasket.
When the spigot end of the pipe or fitting if piushed.or drawn,into the gasketed hub,the gasdet displaces and compresses to seal the joint. The resulting joint is leak-proof and root*proof.It absorbs vibration and can be deflected up to 5 degrees without leakage or failure.
(2).The Leal and Oakum Joint
Cast iron soil pipe joints made with oakum fiber and molten lead are leak-proof,strong,flexible and root-proof.The waterproofing characteristics of oakum fiber have long been recognized by the plumbing rtades,and when molten lead is poured over the oadum in a cast iron soil pioe joint,it completely seals and locks the joint.This is bue to the fact that the hot metal fills a groove in the bell end of the pipe,firmy anchoring the lead in place after cooling.When the lead has cooled sufficiently,it is caulked into the joint with a caulking tool to form a solid metal insert.The result is a lock-tight soil pipe joint with excellent flexural characteristics.
(3).Soundproofing Qualitise of Cast Iron wiht Rubber Gasket Joints
One of the most significant features of the compression gasketed joint and hubless couplings is that they assure a quieter plumbing drainage system.The problem of noise is particularly acute in multiple dwelling units.Although soundproffing has become a major concern in constructonion design,certain plumbing products have been introduced which not only transmit noise but in some cases actually amplify it .The use of neoprene gaskets and cast iron soil pipe reduces noise and vibration to an absolute minimum.Because of the density and wall thickness of the pipe,sound is muffled rather than transmitted or amplified,and the neoprene gaskets separate the lengths of pipe and the units of fittings so that they suppress any contact-related sound.The result is that objectionable plumbing noises are minimized.
6.Testing and Inspection
Once the roughing-in is completed on a cast iron piping project,it is important to test and inspect all piping for leaks.The installer usually is required to notify the plumbing inspector of the administrative.authority having jurisdiction.over plumbing work before the rests are made,concedledwordk should remain uncovered until the required rests are made and approved.When testing,the system should be properly restrained at all bends,changes of direction,and ends of runs.
There are various types of tests used for the installed cast iron soil pipe and fittings.These are water or hydrostatic,air,smoke and peppermint.Proper safety procedures and protective equipment should be employed during all testing procedures.Installers should always consider local conditions,codes,manufacturer installation instructions,and architect/engineer instructions in any installatioo.
A water test,also called a hydrostatic test is maede of all parts of the drainage system before the pipe is concealed or fixtures are in place.This test is the most representative of operating conditions of the system.Tests expelled,all parts of the system are subjected to 10 feet of hydrostatic pressure (4.3PSI)and checked for leaks.Air test:
Air tests are sometimes used instead of the water or hydraostatic tests of completed installations.Cast Iron Soil Pipe and Fittings joined with rlbber compression joints or hubless mechanical couplings are expected to have a reduction in air pressure during a 15 minute test.This drop in air pressure does not indicate a failure of the system or an indication the system sill leak water.Because molecules of air are much smaller than water molecules a cast iron system is expected tl have a reduction in air pressure buring the 15 minute test period.
Cauton:Materials under pressure can explode causing serious personal jijury or death.Extreme care should be exercised in conducting any air test.Persons conducting an airtest must exercise care to avoid application of pressure above 6 psig to the system under test by using appropriate pressure regulation and reief devices.Persons conducting the test are cautioned to inspect for tightness of all system components prior to beginning the test and to avoid adjustment of the system whle under pressure.Proper protective equipment should be worn by individuals in any area where air test is being conducted.
(1).Test PRocedures:
1.Water Test-A wster or hydrostatic test is the most common of all tests used to inspect a completed cast iron soil pipe installation.The purpose of the test is to locate any leaks at the joints and correct these prior to putting the system in sservice.Since it is important to be able to Visually inspect the jionts,water tests should be conducted prior to the "closing in"of the piping or back fill of the underground piping.
As water fills a Vertical cylinder or vertical pipe it creates hydrostatic pressure.The pressure incresases as the height of water in the Vertical pipe increases.The Cast Iron Soil Pipe Institute recommends 10 feet of hydrostatic pressure (4.3 pounds per square inch).This is the recommended test by most plumbing codes.To isolate each floor or section being tested,test plugs are inserted through test tees installed in the stacks.All other openings should be plugged or capped with test plugs or test caps.
Prior to the beginning of the test.all bends,changes of direction and dnds of runs should be prlperly restrained.During the test,thrust forces are exerted at these locations.Thrust is equal to the nydrostatic preasure mutiplied by area.Thrust preasares.if not restraimed,will resulf in joint movement ort separation causing filare of the test.all air entrapped in the system should be expelled prior to beginning the tests.
Once the stack is filled to ten feet ,an inspector makes a visual inspection of the section being tested to check for joint leaks.In most cases,where these leaks are found,hudless couplings have not been torqued to the recommended 60 in ,pounds.Proper torquing will correct the Problem.If leaks occur during testing of hub and spigot materials the joint should be disassembled and checked for proper installation.
Fifteen minutes is a suitable time for the water test.Once the system has been successfully tested it should be drained and the next section should be prepared for test.
2.Smoke Test-When a smoke test is required by engineers,architects,or plumbing codes,it is applied to alll the parts of the diainage and venting systems after all fixtures have been permanently connected and all traps filled with water.A thick,penetrating somke produced by one or more smoke machinse,not by a chemical mixture,is introduced into the system through a suitable opening .AS smoke appears at the stack opening on the roof,the opening is closed off and the introduction of smoke is continued until a prassure of 1 inch of water has been built up and maintained for 15 minutes or longer as required for the system.Under this pressure,smoke should not be visble at any point,Connection or fixture.All windows in the building should be closed until the test is completed.
3.Peppermint Test- Some engineers,architects,and plumbing codes require a peppermin
7.Thrust Forces:
Thrust or displacement forces are encountered as the pipe or cylinder is filled with water.The higher the fill the greater the force acting to separate a joint.Table 1 shows the pounds of force tending to cause joint separation when using pipe from 1 1/2 "to 10"and a head of water from 10' to 120'.