Link Seal Calculator
Estimate pipe penetration seal fit from actual pipe OD, sleeve or core hole ID, annular space, model size, segment count, bolt torque, pressure rating, and elastomer material.
1 Job Presets
Use a preset to load realistic starting values, then replace them with measured dimensions and the approved seal catalog values for the job.
2 Seal Inputs
3 Link Seal Spec Grid
Radial annular space between pipe OD and sleeve ID.
Average center spacing implied by selected segment count.
Distance from current annular gap to the model upper range.
Approximate clamp per bolt from torque, nut factor, and bolt diameter.
| Model | Radial Gap Range | Pitch | Rubber Width | Typical Torque | Base Pressure |
|---|
4 Reference Tables
| Material | Best Use | Pressure Factor | Watch Item |
|---|---|---|---|
| EPDM | Water, weather, many utilities | 1.00 | Not for petroleum oils |
| Nitrile | Oil mist, fuel splash, shop service | 0.95 | Check ozone exposure |
| Neoprene | General industrial service | 0.90 | Confirm fluid compatibility |
| Silicone | High or low temperature service | 0.75 | Lower tear resistance |
| Fluoroelastomer | Chemical and heat service | 0.85 | Higher cost, catalog only |
| Annular Result | Meaning | Action | Risk |
|---|---|---|---|
| Below model range | Gap is too tight for the chosen links | Choose smaller links or verify sleeve size | Hard install, rubber over-compression |
| Inside model range | Chosen model can span the radial gap | Check segment count and pressure | Normal catalog review |
| Above model range | Gap is too wide for the chosen links | Choose larger links or reduce opening | Leak path or poor compression |
| Negative gap | Pipe OD is larger than opening ID | Correct the sleeve or pipe data | Impossible fit |
| Preset | Pipe OD | Sleeve ID | Model | Material |
|---|---|---|---|---|
| 2 in water pipe | 2.375 in | 4.000 in | LS325 | EPDM |
| 4 in steel pipe | 4.500 in | 6.000 in | LS325 | EPDM |
| 8 in PVC conduit | 8.625 in | 10.000 in | LS400 | Neoprene |
| 12 in process pipe | 12.750 in | 15.000 in | LS500 | Nitrile |
| 24 in sanitary pipe | 24.000 in | 30.000 in | LS625 | EPDM |
| Install Check | Target | Why It Matters | Field Note |
|---|---|---|---|
| Pipe centered | Uniform annular gap | Links compress evenly | Shim or support pipe before tightening |
| Clean sleeve | Smooth, round, deburred surface | Prevents rubber cuts and leak paths | Grind sharp weld beads and rough cores |
| Even torque | Stage torque in a cross pattern | Prevents one side from bottoming early | Use a calibrated torque wrench |
| Visible plates | Pressure plates aligned with links | Maintains compression around ring | Recheck after first full torque pass |
| Pressure test | Use approved test procedure | Confirms seal before concealment | Record pressure, hold time, and leakage |
5 Tips and Safety Note
A link seal is a device that is used to seal the gap between a pipe and a sleeve or a core hole. The link seal form a compression ring within the annular gap between the pipe and the sleeve. This compression ring allows the link seal to hold the contents of that pipe, whether it contains water, gas, or chemicals.
Rather than using caulk or grout within the gap between the pipe and the sleeve, workers use link seal. The reason for using link seals instead of caulk and grout is because those materials will eventually crack. There are many factors that affect the performance of a link seal.
What Affects Link Seals
Such factors includes the size of the gap between the pipe and the sleeve, the material of the link seal, the torque of the bolts of the link seal, and the condition of the sleeve. The first important factor that affect the performance of the link seal is the radial space between the pipe and the sleeve. The radial space is the distance between the outside diameter of the pipe and the inside diameter of the sleeve.
If the radial space between the pipe and the sleeve is too small, there will not be enough room for the rubber component of the link seal to compress. If the radial space is too large, the links of the link seal will not be able to reach full compression. You must measure the outside diameter of the pipe because the nominal pipe size may not be the actual outside diameter of the pipe.
Additionally, the condition of the sleeve may affect the performance of the link seal. If the sleeve is made of smooth steel or PVC, the link seal will perform different than if it is made of rough concrete. The second important factor is the segment count of the link seal.
The segment count is the number of links in the link seal ring. The segment count is based upon the circumference of the annular gap between the pipe and the sleeve. If the segment count is too high or too low, the spacing between the links may deviate from the pitch of the link seal.
If the pitch of the link seal is different from the recommended pitch, the link seal’s rubber components will not be compressed evenly. If the link seal is hydrostatically test, the link seal may leak due to the even compression of the rubber components. The third important factor is the amount of torque that is applied to the bolts of the link seal.
Each model of link seal will have a target torque value. If the torque applied to the link seal is too low, the link seal will not be fully seat into the annular gap between the pipe and the sleeve. If the torque applied to the link seal is too high, the rubber component of the link seal may be crushed or the threads of the bolt may be stripped.
The torque applied to the link seal should be consistent around the circumference of the link seal so that the link seal will compress evenly. The fourth important factor is the material that is used to make the link seal. The link seal may be made of many different materials.
One material that maintains the pressure rating of the link seal is EPDM, which is used for link seals in water service. Nitrile and neoprene are materials that have a higher resistance to oil but have a lower pressure rating than EPDM. Silicone link seals can endure higher temperatures but have a lower pressure rating than EPDM and nitrile link seals.
You must select the material used to make the link seal based off the requirements of the service into which the link seal will be install. The fifth important factor is the condition of the sleeve into which the link seal will be installed and the exposure of the link seal. If the sleeve into which the link seal will be installed is a split sleeve or is out of round, the link seal will have a lower pressure rating.
If the link seal will be continuously exposed to water, the exposure must be considered in the requirements for the link seal. Additionally, the length of the link seal may have to be considered in the installation of the link seal. Longer link seals will better distribute the load of the link seal.
There are many mistakes that are made in the installation of link seals. One mistake is using the nominal pipe size instead of the outside diameter of the pipe. Second, the condition of the sleeve is often skip.
Third, the bolts are often tightened in a single pass instead of in stages around the link seal. If the bolts are tightened in a single pass, the link seal may not be correctly centered on the pipe. If the link seal is not centered, the link seal may leak or the rubber component may fail after the link seal experiences temperature cycles.
Link seals are a compression device and not a filler material for the gap between the pipe and the sleeve. If the gap, link seal material, link seal torque, link exposure are within the limits of the link seal model, the link seal will act as a permanent solution to the gap. If any of those variables are outside the limits of the model, the link seal may only act as a temporary patch to the gap between those two component.
In order to install the link seal correctly, a calculator that determines the size of the gap between the pipe and the sleeve and the link seal torque is require.
