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PVC Pipe Restraints.
For crews, distributors and engineers on PVC lines. Find the PV-LOK or ONE-LOK model for the joint, then download the catalog.
✓ 2 through 60 in. ✓ C900/C905 and IPS PVC
✓ Domestic models: D-PWP and D-SLCE
Which restraint does your PVC joint need?
PV-LOK clamps a serrated ring on the pipe at a bell joint, a ductile iron fitting or a PVC fitting. ONE-LOK SLCE grips the pipe with wedges at a mechanical joint.
Also called joint restraints, bell restraints or restraint glands.
PV-LOK
Serrated restraints for C900/C905 and IPS PVC pipe at bell joints, ductile iron fittings and PVC fittings.
2 to 48 in.
ONE-LOK SLCE
Wedge-action restraint for PVC pipe at a mechanical joint. UL listed and FM approved, 4 to 12 in.
Import 3 to 60 in. · domestic D-SLCE 3 to 36 in.
ONE-LOK SLCEH
Bell harness for C900 PVC: an SLCE gland on the spigot, tied with rods to a ring behind the bell.
4 to 12 in.
ONE-LOK SLCS
Wedge-action restraint for C900, C909 and IPS PVC pipe. UL listed and FM approved, 4 to 12 in.
3 to 12 in.
On ductile iron pipe?
At a mechanical joint on ductile iron pipe, use ONE-LOK SLDE and its family. PV-LOK PWP also fits ductile iron bell joints, 4 to 12 in.
Length of pipe requiring restraint.
The Restraint Calculator works out the length of pipe requiring restraint at each fitting.
- DIPRA thrust restraint design method
- Ductile iron, polywrap ductile iron and PVC pipe
Have ready: pipe size, fitting, depth of bury, soil type, trench type and test pressure.
Start with the fitting
Pick the pipe and the fitting. The calculator opens beside this page for the rest.
Open the full calculator page ›Restraint Calculator
Restrained length for each fitting, by the DIPRA method.
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Projects stay in this browser. Use Save file to keep a copy or move it to another computer.
Inputs
Restrained length
Lengths are calculated with the DIPRA thrust restraint design method used in SIGMA's original Restraint Length Calculator. They apply to fittings whose restrained lengths do not overlap those of other fittings. Where they overlap, the designer evaluates the combination as a whole.
A qualified engineer should review every result before it is used in design.
Saved to this project
- DIPRA, "Thrust Restraint Design for Ductile Iron Pipe," Second Edition, 1986.
- Potyondy, J.G., "Skin Friction Between Various Soils and Construction Materials."
- ASTM D 2487, "Classification of Soils for Engineering Purposes."
- Uni-Bell PVC Pipe Association, "Handbook of PVC Pipe, Design and Construction," Dallas, Texas.
- Lambe, T. William, and Whitman, Robert V., "Soil Mechanics," Series in Soil Engineering, Massachusetts Institute of Technology.
Catalogs, sheets and price lists.
One row per model. The PDF stays the document of record.
Import Restraint Products
Price list. Effective 12/9/24, rev. 4/14/26
Domestic Pipe Restraint Products
Price list. Effective 1/19/26
| Model | Document | What it is | PVC pipe | Sizes |
|---|---|---|---|---|
|
PV-LOK PWM |
Submittal (PDF) Sep 2026 Catalog (PDF) Jun 2022 |
Restraint to a ductile iron fitting |
C900/C905 |
4 to 48 in. |
|
PV-LOK PTM |
Catalog (PDF) May 2023 |
Bi-directional, to a ductile iron fitting |
DI OD PVC (C900) |
4 to 12 in. |
|
PV-LOK PWP |
Submittal (PDF) Sep 2026 Catalog (PDF) Jun 2024 |
Bell joint restraint |
C900/C905 |
4 to 48 in. |
|
PV-LOK PWH |
Submittal (PDF) Sep 2026 Catalog (PDF) Apr 2014 |
Bell joint harness |
C900 |
4 to 12 in. |
|
PV-LOK PTP |
Catalog (PDF) May 2023 |
Bi-directional bell joint restraint |
DI OD PVC (C900) |
4 to 12 in. |
|
PV-LOK PWPF |
Catalog (PDF) Aug 2024 |
Restraint to a PVC fitting |
C900/C905 |
4 to 48 in. |
|
PV-LOK PTPF |
Catalog (PDF) May 2023 |
Bi-directional, to a PVC fitting |
DI OD PVC (C900) |
4 to 12 in. |
|
PV-LOK PVM |
Catalog (PDF) Apr 2014 |
Restraint to a ductile iron fitting |
IPS |
2 to 12 in. |
|
PV-LOK PVP |
Catalog (PDF) Apr 2014 |
Bell joint restraint |
IPS |
2 to 12 in. |
|
PV-LOK PVPF |
Catalog (PDF) Aug 2020 |
Restraint to a PVC fitting |
IPS |
2 to 8 in. |
|
ONE-LOK SLCE |
Submittal (PDF) Sep 2026 Sales flyer (PDF) Apr 2024 |
Wedge-action MJ restraint |
C900; IPS 3 to 12 in. |
3 to 60 in. |
|
ONE-LOK SLCEH |
Submittal (PDF) Sep 2026 Catalog (PDF) Apr 2014 |
Bell harness |
C900 |
4 to 12 in. |
|
ONE-LOK SLCS |
Submittal (PDF) Sep 2026 Catalog (PDF) Sep 2024 |
Wedge-action MJ restraint |
C900, C909 and IPS |
3 to 12 in. |
|
C909 PVCO pipe |
Info sheet (PDF) May 2026 |
PWP-C, PWM-C and SLCE 4 to 30 in.; SLCS 4 to 12 in. |
C909 |
4 to 30 in. |
From the spec to the trench.
The engineer sets the pressure rating and coating in the spec. The distributor supplies the restraint, plus the fitting, bolts and gasket at a mechanical joint. The crew sets it at the joint.
PV-LOK bell joint restraint on a PVC main.
2:1
Minimum safety factor in the PV-LOK PWP and ONE-LOK SLCS catalog specifications.
305 psi
PV-LOK PWP rating on C900 DR14 pipe, 4 to 24 in. PV-LOK is rated to the pipe it is on, within each catalog's table.
UL · FM
ONE-LOK SLCS is UL listed and FM approved from 4 through 12 in., FM on C900 DR14, DR18 and DR25 pipe.
Figures from the PV-LOK PWP and ONE-LOK SLCS catalogs. Ratings by size and pipe class are in the PDFs.
Questions crews ask about PVC.
Short answers. The PV-LOK page has the detail.
It keeps a joint from pulling apart under thrust at bends, tees and dead ends. A thrust block does that with poured concrete. A restraint does it at the joint: it grips the pipe and ties it to the bell or the fitting.
Both restrain PVC pipe. PV-LOK clamps a ring with machined serrations around the pipe and ties it back with rods or bolts: at a bell joint, a ductile iron fitting or a PVC fitting. ONE-LOK SLCE is a wedge-action gland for the mechanical joint itself. The Selection Tool narrows it by pipe, size and pressure.
C900/C905 PVC is made to the ductile iron pipe OD: the PV-LOK models with -C before the size, as in PWM-C8. IPS PVC is made to the steel pipe OD: PVM, PVP and PVPF, with -S, as in PVM-S8. ONE-LOK SLCE fits C900 pipe, and IPS pipe from 3 to 12 in.: its two-piece spacer comes off, and a transition gasket is needed.
That is the restrained length. It depends on pipe size and material, fitting, depth of bury, soil, trench type and test pressure. The Restraint Calculator works it out for each fitting, for PVC or ductile iron pipe.
Yes. D-PWP, the PV-LOK bell joint restraint for C900 PVC, 4 to 12 in., and D-SLCE, 3 to 36 in., are on the Domestic Pipe Restraint Products price list.
PWP-C and PWM-C do, from 4 to 30 in., per SIGMA's sheet for AWWA C909 pipe (May 2026). The sheet also lists ONE-LOK SLCE (4 to 30 in.) and SLCS (4 to 12 in.). The restraint's rated pressure is limited to the pipe's, and the sheet rates them at 165 and 235 psi; for higher, ask your regional team. On C909 pipe, do not over-tighten the T-bolts.
Have the spec in hand?
Your regional team can match it to the right model and size.