FieldEngineersKitEngineering Reference & ASME Code Basis
1. Core Formula & Variable Definitions
GPT Industries Link-Seal Modular Sealing System (manufacturer catalog) · Century-Line / wall sleeve pairing practice · ASME B36.10M — pipe OD reference
C = Sleeve ID − Pipe OD2
Dp = OD + 2 · tfree · N = round(π · Dp / wbelt)
GPT Link-Seal modular mechanical seal screening · Century-Line sleeve pairing
Select a Link-Seal model whose free (unexpanded) thickness is slightly less than the annular clearance C and whose screening envelope covers C. Pitch diameter Dp is the link-bolt / belt centerline (OD + 2·t_free) used only to compute N. Ideal minimum sleeve ID uses the same geometry to seat free thickness (C ≈ t_free) — do not confuse Dp with a procurement sleeve catalog size when the entered hole differs. Hardware suffixes: C (zinc CS), S316, T (silicone HT). Continuous service screening ≈ 0.14 MPa (1.38 bar) / 12.2 m H₂O · 20 psig / 40 ft head — confirm the current GPT catalog. Link-Seal® is a registered trademark of GPT Industries; this app is an independent screening tool.
- C (Annular clearance) — Radial gap between pipe OD and sleeve/hole ID: C = (ID − OD)/2 (mm or in).
- t_free (Free thickness) — Unexpanded Link-Seal rubber thickness for the selected model (mm or in).
- w_belt (Belt width / link pitch) — Center-to-center pitch used for link count (mm or in).
- D_p (Pitch diameter (bolt centerline)) — Dp = OD + 2·t_free — diameter through link-bolt / belt centers used to compute N. Not a substitute label for the entered sleeve ID.
- ID_ideal (Ideal minimum sleeve ID) — OD + 2·t_free — minimum sleeve/hole bore that seats free thickness when C ≈ t_free. Compare to the entered sleeve ID.
- N (Number of links) — N = round(π·Dp / w_belt), minimum 3 for a closed belt.
- OD (Pipe outside diameter) — Carrier pipe OD (from NPS Sch 40/STD or manual override).
- ID (Sleeve / hole ID (entered)) — Steel sleeve inside diameter or finished core-drilled hole diameter as entered.
2. Allowances, Tolerances & Standards
Model matching uses screening envelopes ≈ 0.80–1.20 × free thickness. Outside ~12–85 mm annular space, resize the sleeve or consider Century-Line oversized sleeves.
Must be positive. Free thickness should be slightly less than C so expansion seals the annulus.
UI warns when annular space is outside the standard Link-Seal chart. Resize sleeve or use Century-Line.
Screening N = round(π·Dp / belt width). Confirm even-count or chart counts on the GPT sheet when required.
Typical continuous modular-seal screening (≈ 1.38 bar · 12.2 m H₂O · 40 ft head). Higher heads need manufacturer confirmation. Live results follow the Metric/Imperial navbar toggle.
Dp = link-bolt centerline for N. Ideal minimum sleeve ID = OD + 2·t_free seats free thickness. Entered sleeve ID may differ; always compare both.
Model free-thickness / belt chart is shown once under Calculation Results (Link-Seal model chart). Confirm values on the current GPT catalog before purchase.
3. Material & Code Limitations
Hardware suffix and elastomer compound set corrosion and temperature capability. This calculator does not derate for fire, hydrocarbons, or vacuum.
| Material Group | Temperature Range | Allowable Stress / Limit | Engineering Notes |
|---|---|---|---|
| C — Carbon steel zinc hardware | EPDM / standard compound (typical ≤ ~121 °C / 250 °F) | 0.14 MPa / 20 psig screening | Default plant hardware for buried / wet walls when stainless is not specified. |
| S316 — Stainless 316 hardware | Same elastomer family unless specified | 0.14 MPa / 20 psig screening | Use in corrosive or coastal atmospheres where zinc CS is inadequate. |
| T — Silicone high-temperature | Silicone service (confirm GPT sheet; often > standard EPDM) | Confirm catalog | Not a substitute for fire-stop listed assemblies. Check chemical compatibility. |
| Century-Line / oversized sleeves | N/A | When C out of chart | If annular space is too large/small for LS-200–LS-575, resize the sleeve or use manufacturer Century-Line guidance. |
Code Applicability & Safety Boundaries
- Screening Purpose Only: preliminary sizing from published reference data — not a substitute for official engineering calculations, design review, or manufacturer certification.
- Verification Required: always confirm model, link count, and clearances against the current official GPT Industries Link-Seal® sizing chart and installation manual before procurement or installation.
- No Warranty: this tool is provided AS IS. FieldEngineersKit assumes no liability for errors, omissions, or damages arising from use of these results.
- Trademark Notice: Link-Seal® and Century-Line® are registered trademarks of GPT Industries. This application is an independent utility and is not affiliated with, sponsored, or endorsed by GPT Industries.
- Do not use above manufacturer temperature / chemical limits (e.g. continuous > 250 °F / 121 °C without the correct compound).
4. Step-by-Step Worked Example
Field VerificationShowHide
Size a Link-Seal for NPS 4 Sch 40 carrier pipe (OD = 114.3 mm) through a steel wall sleeve with ID = 190 mm, carbon-steel zinc hardware.
Compute annular clearance
Within the 12–85 mm screening window.
Match Link-Seal model
LS-425 free t = 28.4 mm is farther from C; LS-400 is the closest valid match.
Pitch diameter (bolt centerline)
Dp drives N only — it is not the entered sleeve catalog ID.
Number of links
Hero shows LS-400-C × 9 Links.
Ideal minimum sleeve ID vs entered ID
Screening rating 0.14 MPa (1.38 bar) · 12.2 m H₂O — confirm GPT sheet.
5. Frequently Asked Questions & Technical References
ShowHide
Tighten in a star / criss-cross pattern until the rubber links bulge slightly and seal against both the pipe and the sleeve. Do not drive bolts to metal-to-metal crush. Follow the GPT installation sheet for the model.
Standard EPDM compounds are typically limited near 250 °F (121 °C). For higher temperatures, select the T (Silicone) hardware/elastomer option and confirm the GPT chemical/temperature chart — this tool does not replace manufacturer limits.
If C < 12 mm or C > 85 mm (≈ 0.47–3.35 in), the UI warns that the gap is outside the standard Link-Seal chart. Resize the sleeve, change the core-drill diameter, or use a Century-Line / manufacturer oversized sleeve solution.
No. This is a field screening calculator using published free thickness / belt width. Always verify model and link count on the current GPT Link-Seal sizing chart before procurement. Link-Seal® is a registered trademark of GPT Industries — this app is not affiliated with or endorsed by GPT Industries.