PVC Restrained Joint Comparison

Certa-Lok™ vs. Bulldog™

All restrained joint systems are

NOT created equal

Sharp metal teeth create potential failure points

Uni-directional restraint allows for overbelling

Metal joint restraint is permanent and susceptible to corrosion

Spline groove aligns with groove in bell and prevents over-insertion

Nylon spline creates bi-directional restraint

Gradual taper lessens required pull-in forces

Certa-Lok™ Integral Bell

Bulldog™

Certa Lok

Key Design and Installation Considerations: The Certa-Lok Advantage

Avoid Over-Insertion / Over-Belling If a pipe is inserted past the manufacturer’s recommended insertion point and into the tapered throat of the bell, stress can occur and lead to failure of the restrained joint.

Bulldog does not include a design element to prevent over-belling (over-insertion), and if this occurs the joint must be replaced. Bulldog pipe manufacturers recommend that as the joint strings are being assembled the leading pipe joints (belled ends) should be physically held back as a new joint is being inserted to prevent over-insertion of joints ahead in the string (which have already been assembled). During this process it is necessary to carefully watch and limit insertion depth as each joint is assembled.

With CertainTeed’s Certa-Lok self-aligning restrained joint system, the nylon spline can only be inserted when the pipes are lined up properly. Certa-Lok is engineered to prevent the spigot end of the pipe from over-inserting during assembly. Once the nylon spline is inserted, both pipes are solidly held in place and will not move apart, eliminating the possibility of over-belling of joints that have already disappeared into the borehole.

Bi-directional Design Allows Pushing and PullingIn trenchless applications, PVC piping can experience both pulling (primary) and pushing (secondary) forces during installation. These forces can contribute to over-belling and over-insertion.

The Bulldog restrained joint system is a uni-directional system and “will only be allowed to be pulled.”1 In horizontal directional drilling applications, additional steps must be taken to prevent over-insertion.

When the nylon spline is inserted into the Certa-Lok restrained joint, the pipe position is locked into place and can be pushed and pulled at force levels typically experienced with traditional trenchless applications, thanks to Certa-Lok’s bi-directional design.

The Certa-Lok™ restrained joint PVC pipe system is uniquely designed to offer significant cost,

performance, safety and environmental advantages over Bulldog™ joint options and materials.

Read on to learn why Certa-Lok is the smart choice for PVC restrained joint applications.

Spline groove aligns with groove in bell

Gradual taper lessens required pull-in forces

Leak-free O-ring

Spline groove

Spline groove

Nylon locking spline

Less Drilling and FluidOn average, Bulldog joints require drilling a 6-11% larger borehole than Certa-Lok, which results in an increased amount of drilling fluid to complete the job.

While there are many similarities, like I.D. and PVC, the differences are striking as far as the potential for costly misalignment and product failure. Most notable is the inability of the Bulldog system to be repositioned if over-inserted or misaligned.

Nominal Pipe Size Type

Nominal Pipe

O.D. (in)

Maximum Pipe

O.D.* (in)

Borehole Up-size for Bulldog (%)

4"Bulldog 4.80 6.504

9%Certa-Lok 4.80 5.96

6"Bulldog 6.90 9.254

11%Certa-Lok 6.90 8.36

8"Bulldog 9.05 11.754

7%Certa-Lok 9.05 10.95

10"Bulldog 11.10 14.254

7%Certa-Lok 11.10 13.36

12"Bulldog 13.20 16.754

6%Certa-Lok 13.20 15.84

*Outside dimension of coupled RJ

1JM Eagle, Eagle Loc 900 Submittal and Data Sheet, page 12JM Eagle, Eagle Loc 900 Internal Joint Restraint System Installation Guide, page 17

3Diamond Plastics, Diamond Lok-21® AWWA C900 Specification Data, page 4 and JM Eagle, Eagle Loc 900 Brochure

4Diamond Plastics, Diamond Lok-21 AWWA C900 Specification Data, page 4 and JM Eagle, Eagle Loc 900 Internal Joint Restraint System Installation Guide, page 15

Visual Verification of Bell and Spigot PositioningThe integrity of the PVC piping system is dependent upon the sustained proper positioning of the bell and spigot within the restrained joint.

The metallic split ring teeth within the Bulldog restrained joint do not become embedded in the spigot end of the pipe until the joint experiences a significant tensile force. If a spigot has been inserted too far during assembly, the uni-directional design of the Bulldog does not allow the pipe to be pulled back and repositioned. More importantly, the final positioning of the bell and spigot will not occur until after the pipe is pulled underground, at which point a visual and physical verification cannot occur.

Certa-Lok products become fully restrained and locked into position the moment the spline is inserted. This point of visual and physical verification occurs before the pipe is pulled underground.

Easy DisassemblyBulldog pipe systems cannot be disassembled. Once two pieces of pipe are joined together, the only way to separate them is to cut them apart. “Eagle Loc 900™ may not be separated once assembled. It is locked.”1 If a joint is misaligned or over-inserted, the joint must be cut out and replaced using specialized fittings.

Certa-Lok piping systems can be quickly disassembled and reassembled by removing the nylon spline as many times as needed.

Certa-Lok™ Bulldog™

11

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ax

Pip

e O

.D.

Nominal Pipe Size 8" DR 14

10

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ax

Pip

e O

.D.

7.7

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CertainTeed Corporation P.O. Box 860

Valley Forge, PA 19482

866-CT4-PIPE 866-284-7473

© 06/13 CertainTeed Corporation, Printed in the U.S.A. Code No. 40-60-02A

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For additional product application and performance information, visit: certa-lok.com/pvccomparison

High Tensile Strength for Trenchless ApplicationsHorizontal Directional Drilling (HDD) and pipe bursting require high tensile strength for both short and long duration loading. PVC piping is deflected and repositioned to enter the bore hole to pull the pipe. CertainTeed Certa-Lok piping and restrained joints are designed to meet the rigorous design and installation requirements for trenchless applications. These engineering design requirements are published in the product technical data sheets. CertainTeed uses a safety factor of 2.0 for all Certa-Lok piping when estimating the recommended maximum pull force.

According to the published maximum allowable pull force data compared with the load at failure testing2, the Eagle Loc 900 has variable published safety factors.

CertainTeed Certa-Lok™ Restrained Joint Piping System

Nominal Pipe Size

Maximum Pull Force (lbs.)

DRCerta-Lok

RJ (coupled)Certa-Lok

RJIB (integral bell) DRCerta-Lok

RJ (coupled)Certa-Lok

RJIB (integral bell)4" 18 7,800 10,300 14 9,800 11,9006" 18 16,000 20,100 14 18,900 22,3008" 18 23,100 27,500 14 24,300 31,00010" 18 40,500 - 14 48,700 -12" 18 50,500 - 14 53,800 -14" 18 61,500 - 25 52,500 -16" 18 68,500 - 25 68,500 -

Bulldog™

Nominal Pipe Size DR

Maximum Allowable Pull Force Straight Alignment (lbs.)3 Load at Failure (lbs.)2

Calculated Safety Factor

Normalized Max Allowable Pull Force

with Safety Factor of 2.04" 18 15,000 20,358 1.36 10,1796" 18 20,000 36,952 1.85 18,4768" 18 30,000 54,215 1.81 27,108

10" 18 40,000 72,700 1.82 36,35012" 18 45,000 110,100 2.45 55,050

Certa Lok