Industrial Systems
Joining
General Installation Guidelines for Corzan pipe & fittings
Proper installation of Corzan piping systems is critical to the performance of the system. A few simple guidelines should be followed to ensure long service life and safe operation.
Handling
Proper care should be exercised when transporting or installing Corzan piping to prevent damage. Corzan piping should be stored and shipped only with other non-metallic piping. It should not be dropped or dragged during handling, especially during extremely cold weather. The same treatment should apply to the handling of Corzan fittings.
Prior to actual installation, the pipe and fittings should be thoroughly inspected for cracks, gouges, or other signs of damage. Particular attention should be given to the inside surface of the part. While the outside surface may not exhibit damage, improper handling can result in damage that appears only on the inside surface of the part.
Cutting
Lengths of pipe can be easily and successfully cut by following a few simple guidelines. Best results are obtained by using fine-toothed saw blades (16 to 18 teeth per inch) with little or no offset (0.025” max.). Circular power saws (6,000 rpm) or band saws (3,600 ft./min.) are recommended using ordinary hand pressure. Miter boxes or other guide devices are strongly recommended for manual operation to ensure square cuts. Burrs, chips, and dust should be removed following cutting to prevent contamination of the piping system and facilitate joining.
Joining Methods
Corzan piping can be installed using a number of joining techniques. Solvent welding, flanging, and threading are the more common methods and are covered in greater detail in this section. Back welding of joints using hot gas welders is also covered in some detail. Less common joining methods are also possible with Corzan piping and fittings, including butt fusion and Victaulic techniques. Contact Lubrizol Advanced Materials, Inc. or the Corzan piping manufacturers for assistance with less common joining methods.
Hanging/Laying of Pipe
Corzan piping can be installed above ground or buried underground. Methods to minimize stress on the piping as a result of installation are covered in detail below.
System Stress
Any metal or non-metal piping system is subject to stress-induced corrosion. As a result, special attention should be given to minimizing stress throughout the system. The total stress on a piping system includes not only the known pressure stress, but also stresses from sources such as expansion or installation. Expansion stresses can be minimized with expansion joints or loops. Installational stresses are minimized with careful installation techniques. Pipe and fittings should be properly prepared when joints are made up. Hangers and supports should be properly spaced to prevent sagging and should not cut into the pipe or clamp it tightly, preventing movement. System components should not be forced into place.
Thermal Expansion
Corzan piping has the lowest coefficient of thermal expansion of any thermoplastic piping. However, thermal expansion will be greater than that of metal piping. Typically, expansion loops or offsets in the piping are designed to account for any thermal expansion. These design methods are covered in detail in Section 4.8. Expansion joints can also be installed. Information on expansion joints can be obtained by contacting us or Corzan piping manufacturers.
Testing the Piping System
After the piping system is installed and any solvent cement is fully cured, the system should be pressure tested and checked for leaks using water. Testing using compressed air or inert gas is not recommended. All entrapped air should be allowed to vent as the system is filled with water. Water filling should occur at a velocity not more than 1ft/sec. After filling, the system should be pressured to 125% of the maximum design pressure of the lowest rated part of the system. Pressure should be held for no more than one hour while the system is checked for leaks.
Joining Corzan Pipe and Fittings – Solvent Cementing
Cutting |
 |
Chamfering and Deburring |
 |
| Fitting Preparation |
 |
|
Primer Application |
 |
Primer is applied to both the outside of the pipe end and inside of the fitting socket, redipping the applicator as necessary to ensure that the entire surface of both is tacky. |
 |
|
Solvent Cement Application Solvent cement must be applied when the pipe surface is tacky, not wet, from primer. Joining surfaces must be penetrated and softened. Cement should be applied with a natural bristle brush or swab half the size of the pipe diameter. |
 |
A dauber may be used to apply cement on pipe sizes below 2 inches. A heavy, even coat of cement should be applied to the outside of the pipe end, and a medium coat should be applied to the inside of the fitting socket. |
 |
Pipe sizes greater than 2 inches should receive a second coat of cement on the pipe end. |
 |
|
Assembly |
 |
Cement in excess of the bead may be wiped off with a rag. |
 |
Set and Cure Times
Solvent cement set and cure times are a function of pipe size, temperature, relative humidity, and tightness of fit. Drying time is faster for drier environments, smaller pipe sizes, high temperatures, and tighter fits. The assembly must be allowed to set, without any stress on the joint, per the time shown on the following table. Following the initial set period, the assembly can be handled carefully avoiding significant stresses to the joint. Refer to the following table for minimum cure times prior to testing.
Extra care should be exercised when systems are assembled in extreme temperature conditions. Extra set and cure times should be allowed when the temperature is below 40°F (4°C). When the temperature is above 100°F (38°C), the assembler should ensure that both surfaces to be joined are still wet with cement before joining them.
Recommended Set Times
After a joint is assembled using solvent cement, it should not be disturbed for a period of time to allow for proper “setting” of the newly prepared joint. Recommended set times are as follows:
| Ambient Temperature | to 1 ¼” | 1 ½” to 2” | 2 ½" to 8" | 10” to 12" | 15” + |
| 60°F to 110°F | 2 min. | 5 min. | 30 min. | 2 hr. | 4 hr. |
| 40°F to 60°F | 5 min. | 10 min. | 2 hr. | 8 hr. | 16 hr. |
| 0°F to 40°F | 10 min. | 15 min. | 12 hr. | 24 hr. | 48 hr. |
Recommended Cure Times
After a joint is assembled using solvent cement, the cement must be allowed to properly “cure” before the piping system is pressurized. Recommended minimum cure times are shown below. These recommendations should only serve as a guide since atmospheric conditions during installation will affect the curing process.
High humidity and/or colder weather will require longer cure times: typically add 50% to the recommended cure time if surroundings are humid or damp.
CURE TIMES FOR OPERATING / TEST PRESSURES TO 180 PSIG
| to 1 ¼” | 1 ¼” to 2” | 2½” to 8” | 10” to 15” | 15” + | ||||
| Ambient Temperature(psi) | >Up to160 | >161 - 370 | >Up to160 | >161 - 315 | >Up to160 | >161 - 315 | >Up to 100 | >Up to 100 |
| 60°F to 110°F | 15 min. | 6 hr. | 30 min. | 12 hr. | 1½ hr. | 24 hr. | 24 hr. | 72 hr. |
| 40°F to 60°F | 20 min. | 12 hr. | 45 min. | 24 hr. | 4 hr. | 48 hr. | 40 hr. | 6 days |
| 0°F to 40°F | 30 min. | 48 hr. | 1 hr. | 96 hr. | 72 hr. | 8 days | 8 days | 14 days |
** DO NOT exceed maximum working pressure of piping for given pipe size and operating temperature.
Dos and Don'ts
While not a complete list, the following is intended to highlight many of the “Dos” and “Don’ts” when joining FlowGuard Gold® and Corzan CPVC piping system.
Dos
- Install product according to the
manufacturer’s installation instructions and this manual.
- Follow recommended safe work practices.
- Follow proper handling procedures.
- Use tools designed for use with plastic pipe and fittings.
- Use proper solvent cement and follow application instructions.
- Cut pipe ends square.
- Deburr and bevel pipe before solvent cementing.
- Rotate the pipe 1/4 to 1/2 turn when bottoming pipe in fitting socket.
- Avoid puddling of solvent cement in fittings and pipe.
- Follow manufacturer’s recommended cure times prior to pressure
testing.
- Visually inspect all joints for proper cementing at end of the shift or day. A visual inspection of the complete system and all joints is also recommended during pressure testing.
Don’ts
- Do not use solvent cement that exceeds its shelf life or has become
discolored or gelled.
- Do not use solvent cement near sources of heat, open flame, or when
smoking.
- Do not pressure test until recommended cure times are met.
- Do not use dull or broken cutting tool blades when cutting pipe.
Threading of Corzan Schedule 80 Pipe
Corzan Schedule 80 pipe up to and including 4” in diameter, and which will operate at 130°F or less, may be threaded. The threads should be in accordance with ANSI B1.20.1 Taper Pipe Thread. Threaded joints are derated to 50% of the pressure rating of the Schedule 80 pipe at the operating temperature. Schedule 40 pipe, Schedule 80 pipe larger than 4," or piping for systems which will operate at a temperature greater than 130°F should not be threaded. Flanges, unions, or Victaulic couplings may be used where occasional disassembly is required.
Pipe to be threaded should be squarely cut with a hand saw or power saw. A mitre box should be used when pipe is cut by hand. A fine-toothed blade (16-18 teeth per inch) works best for cutting plastics. Burrs should be removed from the cut end of the pipe with a knife or similar tool. A slight chamfer on the pipe end will speed threading. A tapered plug should be inserted into the pipe before threading to provide additional support and prevent distortion of the pipe or threads. The pipe should be held in a pipe vise, but saw-toothed jaws should not be used. A rubber sheet or some other type of material may be used to protect the pipe from the rough edges of the pipe vise.
The dies used for cutting threads on Corzan pipe should be clean, sharp, and in good condition. They should be reserved for use only on plastic materials. Pipe threading dies should have a 5° negative front rake when power threading machines are used, and a 5°-10° negative front rake when pipes are threaded by hand. When power threading equipment is used, the dies should not be driven at high speeds or with heavy pressure.
The threads may be checked with a ring gauge to ensure accuracy. The gauging tolerance is +/- 1 ½ turns.
Threaded parts must be prepared for assembly by brushing away cutting debris from the threads. Degreasing solvents should never be used to clean CPVC threads.
TFE ( Teflon®) thread tape is always safe for making CPVC threaded connections. Some paste-type sealants contain solvents that may be damaging to CPVC. If the use of a paste or pipe dope is preferred, only thread sealants that are included in the FGG/BM/CZ™ System Compatible Program should be used. (Refer to www.corzancpvc.com for a list of products included in the FGG/BM/CZ™ Ssystem Compatible Program.) Use of an improper paste or dope can result in failture of CPVC systems. Solvent cement should never be applied to threaded joints.
After the thread tape has been applied, the threaded fitting may be screwed onto the pipe and tightened hand tight. If desired, a strap wrench may be used to tighten the joint an additional turn. Overtightening of threaded plastic joints will weaken the joint. When Corzan pipe or fittings are connected to metal with a threaded joint, the Corzan pipe or fittings should have male threads, and the metal should have female threads.
Flanging of Corzan Pipe
Flanging can be used to provide temporary disassembly of a piping system or when it is not possible to make up solvent cemented joints at the assembly site.
Flanges are joined to the pipe by solvent cement or threaded joints. Refer to the sections on solvent cementing or threading of Corzan pipe for the proper techniques.
Flanged joints incorporate an elastomeric gasket between the mating faces to provide for a seal. The gasket selected must be full-faced and have a hardness of 55-80 durometer A. Typically, gaskets are 1/8” thick. The gasket material must be resistant to the chemical environment. Many manufacturers of gasketing materials supply this kind of information. If the piping system is for potable water service, the gasket must also be approved for potable water.
The flanges should be carefully aligned and the bolts inserted through matching holes. A flat washer should be used beneath each nut and bolt head. Each bolt should be partially tightened in the alternating sequence indicated in the patterns below. A torque wrench should be used for the final tightening of the bolts. The bolts should be tightened to the torque recommended in the table below in the same alternating sequence used previously.
Flange joints are typically rated to 150 psi at 73°F. For systems operating at higher temperatures, the flange pressure rating should be derated per the manufacturer’s recommendations.
| RECOMMENDED BOLT TORQUE* | |||
| Nominal Pipe Size |
Number of Bolt Holes |
Bold Diameter (in.) |
Recommended Torque (ft-lbs) |
| ½ - 1 ½ | 4 | 1/2 | 10 - 15 |
| 2 - 3 | 4 | 5/8 | 20 - 30 |
| 4 | 8 | 5/8 | 20 - 30 |
| 6 | 8 | 3/4 | 33 - 50 |
| 8 | 8 | 3/4 | 33 - 50 |
| 10 | 12 | 7/8 | 53 - 75 |
| 12 | 12 | 1 | 80 - 110' |
|
*Information given as guidelines only. Consult the manufacturer’s literature for flange requirements. |
|||
Back-Welding of Corzan Pipe Joints
Back-welding may be used to repair minor leaks in solvent cemented or threaded joints. Back-welding is a hot-air welding technique which consists of forcing a welding rod to fuse in the joint fillet while both rod and fillet are softened with hot air.
Before hot-air welding begins, the section of piping where the repair will be made must be emptied. Joints should not be welded with fluid still in the pipe.
All dirt and moisture should be wiped away from the joint to be repaired. Excess dried solvent cement around the joint should be removed with an emery cloth. Residual solvent cement may tend to scorch and burn during welding. If the joint to be welded is a threaded joint, excess threads in the joint area should be removed with a file in order to provide a smooth surface for welding.
If a speed tip will be used for back-welding, refer to this manual’s section on fabrication with high speed hot air welding for the proper conditions and techniques to use.
If welding will be done by feeding the rod manually, the following conditions and procedures should be used:
The welding temperature should be approximately 550-600°F. Only welding rod made of Corzan CPVC should be used for back welding CPVC joints.
The end of the welding rod should be inserted into the junction of the pipe and fitting, and the rod should be held at a 90° angle to the joint. The rod and base material should be preheated with the welding torch 1/4 to 3/4 inch away from both the rod and the base material and fanning back and forth in the immediate welding area. While preheating, the rod can be moved up and down until it is soft enough to stick to the base.
When the materials are softened enough to fuse, the rod should be advanced by the application of a slight pressure. The fanning motion of the torch should be continued throughout the welding process. When the weld is finished, another inch of rod material should be lapped over the bead.
When large diameter pipe is welded, three beads may be required to fill the joint adequately. The first bead should be laid directly into the joint fillet, and the subsequent beads on either side of the first bead.
Corzan Pipe & Fittings Underground Installation Guidelines
References
These guidelines are based upon the following:
1. ASTM D2774: Standard Recommended Practice for Underground Installation of Thermoplastic Piping
2. Piping Manufacturer’s Installation Instructions
3. Industry Experience
For additional information and data, consult ASTM standards D2774, D2321, or F645.
Installation Procedures
This procedure will cover the typical steps encountered in underground installations: trench design, trench preparation, piping assembly, laying of pipe, and backfilling.
Trench Design
| Width: | The trench should be of adequate width to allow for convenient installation, but as narrow as possible depending on whether the piping will be assembled inside or outside of the trench. |
| Depth: | The trench depth should be sufficient to place the pipe deep enough to meet frost, above-ground load, and any trench bedding requirements. |
| Frost: | Piping at least 12 inches below the frost line. |
| Loads: | Piping should be deep enough to keep external stress levels below acceptable design stress. Design stress will be determined by pipe size and operating temperature and may be governed by various codes. |
| Bedding: | 4 to 6 inches underneath piping, if necessary (see below) |
Trench Preparation
The trench bottom should be continuous, relatively smooth and free of rocks. If ledge rock, hardpan, boulders, or rocks that are impractical to remove are encountered, it will be necessary to pad the trench bottom to protect the piping from damage. 4 to 6 inches of tamped earth or sand bedding will be sufficient in such situations.
Piping Assembly/Placement
Piping may be assembled using conventional solvent cementing techniques either inside or outside of the trench depending on the specific installation requirements. Solvent cement usually requires at least 12 to 24 hours for the cemented joint to cure properly. During this critical curing process, every effort should be made to minimize the stress on any joints. As a result, the piping should not be moved during the curing period, nor should the pipe be backfilled, or otherwise constrained during curing. See the recommendations on joint curing time to determine the exact curing requirements for a specific installation.
If the piping was assembled outside of the trench, the pipe may be placed into the trench after proper curing, but MUST NOT be rolled or dropped into place. Long lengths of joined piping should be properly supported as the piping is put into place to prevent excessive stress.
After proper curing and before backfilling, the piping should be brought to within 15°F of the expected operating temperature. Backfilling can proceed while the piping is maintained at this temperature in order to minimize stress on the system due to thermal expansion/contraction. If this step is impractical, then stress calculations must be done to determine the loads that will be created due to constrained using the formula below:
| S = EyΔT | |
| Where | S = stress induced in the pipe |
| E = Modulus of elasticity at maximum temperature | |
| y = coefficient of thermal expansion | |
| ΔT = total temperature change of the system |
These loads must then be compared to the design stress of the particular piping system.
Backfilling
Backfilling should only proceed after all solvent cement joints have been properly cured and the piping brought close to normal operating temperature, if operation will be more than 15°F different than the current ambient temperature. The piping should be uniformly supported over its entire length on firm, stable material.
Backfill material should be free of rocks and have a particle size no greater than 1/2.” Piping should initially be surrounded with backfill to provide between 6” and 8” of cover. The backfill should be compacted using vibratory or water flooding methods. If water flooding is used, additional material should not be added until the water flooded backfill is firm enough to walk on. Backfill containing a significant amount of fine-grained material, such as silt or clay, should be hand or mechanically tamped.
The remainder of the backfill should be placed and spread in approximately uniform layers to completely fill the trench without voids. Particle size for this final fill should not exceed 3." Rolling equipment or heavy tampers should only be used to consolidate the final backfill.
