Installation Information | Pipe

ORDERING, RECEIVING AND HANDLING

Although the ordering of materials is the contractor's responsibility, supplier and engineer familiarity with the contractor's proposed schedule will enable better coordination to avoid mistakes and possible delays in pipe deliveries.  We stock a wide range of pipe sizes and strengths, but production facilities must frequently be adapted to meet specific project requirements, particularly when large quantities and/or special types of pipe are involved.

Information required to initiate a pipe order should be in writing and include:           

• name and location of project
• pipe size, laying length and strength
• total footage of each type and size of pipe
• type of joint
• size and quantity of manhole base sections,  riser sections, cone sections and grade rings
• list of fittings and specials including radius pipe with laying sequence
• material test requirements
• joint material and quantity
• invoicing instructions
  

The pipe should be checked for the following information, clearly marked on each pipe section: 

• specification designation
• pipe class or strength designation
• span, rise, table number, top of box and design earth cover for ASTM C 789 (M) box
• sections, and span, rise, top of box and table number for ASTM C 850 (M) box sections
  date of manufacture
• name or trademark of the manufacturer for reinforced pipe with elliptical or quadrant reinforcement orientation, the letters E or Q, respectively.

UNLOADING

Unloading of pipe should be coordinated with the construction schedule and installation sequence to avoid re-handling and unnecessary equipment movement. Access to the jobsite shall be provided by the contractor to ensure that the pipe manufacturer's trucks can deliver pipe to the unloading area under their own power.

Each shipment of pipe is loaded, blocked and tied down at the plant to avoid damage during transit.  However, it is up to the receiver to make certain, damage has not occurred in delivery from the plant to the construction site.  An overall inspection of each pipe shipment should be made on arrival, before the pipe is unloaded.  Total quantities of each item should be checked against the delivery slip and any damaged or missing items recorded on the delivery document.

If a pipe is damaged during delivery or unloading, the pipe should be set aside. Damaged ends, chips or cracks which do not pass through the wall can usually be repaired.

Our trucks are equipped with automatic unloaders which further expedite the unloading of circular pipe.  These automatic unloaders consist of a fork lift type of apparatus mounted at the rear of a flat bed truck.  The forks rotate vertically rather than move up and down, such that, when the forks are in a vertical position they extend above the truck bed.  This provides a backstop and cushion for the pipe sections as they are rolled to the rear of the truck for unloading.  A cradle formed by the forks and unloader frame securely retains the pipe section being unloaded as the forks are rotated downward and lowered to the ground.

Unloading of the pipe should be controlled so as not to collide with other pipe sections or fittings, and care should be taken to avoid chipping or spalling, especially to the spigots and sockets. Caution should be exercised to be sure other working personnel are out of the path of the pipe as it is lowered.

If the pipe has to be moved after unloading, the sections should be rolled or lifted and should never be dragged.  Pipe sections should not be rolled over rough or rocky ground.

The use of mechanical equipment is necessary for unloading elliptical and box sections and larger size circular pipe, and can usually simplify and speed up the unloading of smaller pipe. When using mechanical equipment for unloading, the lifting device which connects to the pipe should enable proper and safe handling without damage to the pipe. Lifting devices such as slings, chain, steel wire, cable and rope should be placed around the pipe, or arranged so that the pipe is lifted in a horizontal position. If the lifting device could chip or damage the pipe, padding should be provided between the pipe and lifting device. These types of lifting devices should not be passed through the pipe. Other devices which are designed to pass into or through the pipe should not touch the spigot or socket jointing surfaces, and should extend far enough beyond the end of the pipe for adequate clearance of lifting lines.

When pipe is provided with lifting holes, the lifting device should pass through the wall and distribute the weight along the inside barrel of the pipe. Lifting holes or devices for box sections should be located as near to the wall as is practical and not in the central portion of the top slab.

The most common lifting device for use with lifting holes consists of a steel threaded eye bar with a wing type nut and bearing plate.  If a specially designed lifting device is not readily available, a single looped sling can be passed through the lift hole into the bore of the pipe and then around a piece of timber of adequate length and cross-section to assure structural stability. For manhole sections, cone sections, bases, fittings and other precast appurtenances, the lifting holes or lifting eyes provided should be used. 

Regardless of the method used to unload pipe, precautions should be taken to avoid damage to the pipe and assure the pipe is unloaded in a safe manner.

STOCKPILING

Any stockpiling of pipe should be as near as possible to where the pipe will be installed.  Small diameter pipe should be layered in the same manner as they were loaded on the truck.  The bottom layer should be placed on a flat base and more adequately blocked to prevent shifting as more layers are added.  Each layer of bell and spigot pipe should be arranged so that all of the bells are at the same end.  The bells in the next layer should be at the opposite end, and projecting beyond the spigots of the pipe sections in the lower layer. Where only one layer is being stockpiled the bell and spigot ends should alternate between adjacent pipe sections.  All pipe should be supported by the pipe barrel so that the joint ends are free of load concentrations.

Pipe sections generally should not be stockpiled at the job site in a greater number of layers than would result in a height of 2m(6'). Box sections may be stockpiled in the same general manner as pipe.

All flexible gasket materials including joint lubrication compounds should be stored in a cool dry place to be distributed as needed.  Rubber gaskets and preformed or bulk mastics should be kept clean, away from oil, grease, excessive heat and out of the direct rays of the sun.

JOINTING

In laying the pipe, it is general practice to face the bell end of the pipe in the direction of the pipe laying. This helps prevent bedding material from being forced into the socket during jointing and enables easier coupling of pipe sections.

Several types of joints and sealant materials are utilized for concrete pipe to satisfy a wide range of performance requirements. 

The most common compression joint sealants and joint fillers used for sanitary sewers, storm sewers and culverts are:

• rubber, attached or separate
• mastic, bulk or preformed mortar
• external bands, cement or rubber

Regardless of the specific type of joint sealant used, each joint should be checked to be sure all pipe sections are in a home position, it is important to assure that the gasket is properly positioned and under compression. 

There are numerous types of rubber gaskets and they all require the following:

Clean Bell

Carefully clean all dirt and foreign substances form the jointing surfaces of the bell or groove end of the pipe.  Improperly prepared bell jointing surface may prevent homing of the pipe.

Clean Spigot

Carefully clean spigot or tongue end of pipe, including the gasket recess. Improperly prepared spigot and gasket recess may prevent gasket from sealing correctly.

Lubricate Bell

Lubricate bell jointing surface liberally.  Use a brush, cloth, sponge or gloves to cover entire inside surface.  Only approved lubricant should be used.  A bell not lubricated or improperly lubricated may cause the gasket to roll and possibly damage the bell.

Lubricate Spigot

Lubricate the spigot or tongue end of the pipe, especially the gasket recess. Gasket may twist out of recess if lubricant in recess is lacking or insufficient. 

Lubricate Gasket

Lubricate the gasket thoroughly before it is placed on the spigot or tongue. Excessive force will be required to push the pipe to the home position if the gasket is not well lubricated.

Install Gasket

Fit the gasket carefully. Equalize the rubber gasket stretch by running a smooth, round object, inserted between gasket and spigot, around the entire circumference several times.  Unequal stretching of the gasket may cause bunching of the gasket and may cause leaks in the joint or a crack in the bell.

Align Pipe

Align bell and spigot of pipes to be jointed.  Before homing the joint, check that the gasket is in contact with the entry taper around the entire circumference.  Make sure pipe is aligned.  Improper alignment can dislodge gasket causing leaks or possibly break the bell.

Mastic

Mastic sealants consist of rubber compounds or bitumen and inert mineral filler which are usually cold applied.  A sufficient amount of sealant should be used to fill the annular joint space with some squeeze out.  During cold weather, better workability or the mastic sealant can be obtained if the mastic and joint surfaces are warmed.

Mortar

Cement sealants consist of portland cement paste or mortar made with a mixture of portland cement, sand and water. The joint surface is thoroughly cleaned and soaked with water immediately before the joint is made. A layer of paste or mortar is placed in the lower portion of the bell or groove end of the installed pipe and on the upper portion of the tongue or spigot end of the pipe section to be installed.  The tongue or spigot is then inserted into the bell or groove of the installed pipe until the sealant material is squeezed out. Any annular joint space between the adjacent pipe ends is filled with mortar and the excess mortar on the inside of the pipes wiped and finished to a smooth surface.

Geotextile Filter Fabrics

As an alternative measure, where groundwater and joint configurations warrant, a band of geotextile filter fabric, usually 1 to 2 feet wide may be wrapped around the exterior of the pipe joint and secured with either tape or stitching to prevent soil infiltration into joints of storm and culvert pipe.

External Bands

Portland cement mortar bands are sometimes specified around the exterior of the pipe joint.  A slight depression is excavated in the bedding material to enable mortar to be placed underneath the pipe.  The entire external joint surface is then cleaned and soaked with water.  Special canvas or cloth diapers can be used to hold the mortar as it is placed.  Backfill material should be immediately placed around the pipe. 
   
Rubber-mastic bands also can be used around the exterior of the pipe joint.  The bands are stretched tightly around the barrel of the pipe and held firmly in place by the weight of the backfill material.

JOINTING PROCEDURES

Joints for pipe sizes up to 24" in diameter can usually be assembled by means of a bar and wood block.  The axis of the pipe section to be installed should be aligned as closely as possible to the axis of the last installed pipe section, and the tongue or spigot end inserted slightly into the groove or bell.  A bar is then driven into the bedding and wedged against the bottom bell or groove end of the pipe section being installed. A wood block is placed horizontally across the end of the pipe to act as a fulcrum point and to protect the joint end during assembly.  By pushing the top of the vertical bar forward, lever action pushes the pipe into a home position.

When jointing larger diameter pipe, and when granular bedding is used, mechanical pipe pullers are required. Several types of pipe pullers or come along devices have been developed but the basic force principles are the same.

When jointing small diameter pipe, a chain or cable is wrapped around the barrel of the pipe a few feet behind the tongue or spigot and fastened with a grab hook or other suitable connecting device.  A lever assemble is anchored to the installed pipe, several sections back from the last installed section, and connected by a means of a chain or cable to the grab hook on the pipe to be installed.  By pulling the lever back, the tongue or spigot of the pipe being jointed is pulled into the bell or groove of the last installed pipe section.  To maintain close control over the alignment of the pipe, a laying sling can be used to lift the pipe section slightly off the bedding foundation. 

Large diameter pipe can be jointed by placing a did man blocking inside the installed pipe, several sections back from the last installed section, which is connected by means of a chain or cable to a strong back placed across the end of the pipe section being installed.  The pipe is pulled home by lever action similar to the external assembly.
Mechanical details of the specific apparatus used for pipe pullers or come along devices may vary, but the basic lever action principle is used to develop the necessary controlled pulling force.   The use of excavating equipment to push pipe sections should be avoided.  The force applied by such equipment can damage the pipe.

SERVICE CONNECTIONS

When a pipe connects to a rigid structure such as a building, manhole or junction chamber, the bedding and foundation for the connecting pipe section should be highly compacted to minimize differential settlement.  Differential settlement can result in the pipe being sheared or cracked at the connection. Special connectors are available which provide flexibility between the connecting pipe and the structure.