Heat Shrink Coupler for Post-Tensioning Duct Joints
A cross-linked polyolefin coupler that joins post-tensioning duct sections with a hot-melt-lined, IP68-sealed connection for prestressed-concrete construction.
- ASTM D638
- ASTM D2671
- ASTM D2240
Installation instructions
Full dimensional specifications and technical data, ready to download.
Choose a size
Selection Chart
- D (min.)
- Internal diameter as supplied (minimum)
- d (max.)
- Internal diameter after free recovery (maximum)
- T
- Wall thickness after recovery (±10%)
| Code | D(min.) | d(max.) | T(±10%) | Length per piece |
|---|---|---|---|---|
| GMW 70/22 | 70 | 22 | 2.7 | 300 |
| GMW 90/28 | 90 | 28 | 3.0 | 300 |
| GMW 105/30 | 105 | 30 | 3.0 | 300 |
| GMW 115/34 | 115 | 34 | 3.2 | 300 |
| GMW 130/36 | 130 | 36 | 3.2 | 300 |
| GMW 140/42 | 140 | 42 | 3.2 | 300 |
| GMW 160/50 | 160 | 50 | 3.3 | 300 |
| GMW 180/55 | 180 | 55 | 3.3 | 300 |
| GMW 200/60 | 200 | 60 | 3.5 | 300 |
| GMW 250/70 | 250 | 70 | 3.5 | 300 |
| GMW 320/90 | 320 | 90 | 3.5 | 300 |
| GMW 375/110 | 375 | 110 | 3.5 | 300 |
| GMW 425/125 | 425 | 125 | 3.5 | 300 |
| GMW 550/157 | 550 | 157 | 3.5 | 300 |
| GMW 680/200 | 680 | 200 | 3.5 | 300 |
| GMW 760/215 | 760 | 215 | 3.5 | 300 |
| GMW 863/250 | 863 | 250 | 3.5 | 300 |
Source: GALA Heat Shrink Coupler for Post Tensioning Duct Joint catalogue sheet, Issue 2, July 2024.
Material properties
Technical Specification
| Properties | Value | Standard |
|---|---|---|
| Physical | ||
| Tensile Strength | 12 Mpa (N/mm²) (min.) | ASTM D638 |
| Ultimate Elongation | 350% (min.) | ASTM D638 |
| Longitudinal Change | -10% (max.) | ASTM D2671 |
| Hardness | 45 ± 10 Shore D | ASTM D2240 |
| Water Absorption | 0.5% (max.) | ASTM D570 |
| Thermal | ||
| Accelerated Ageing | (120 °C for 500 hrs.) | ASTM D2671 |
| Tensile Strength | 10 Mpa (N/mm²) (min.) | ASTM D638 |
| Ultimate Elongation | 300% (min.) | ASTM D638 |
| Low Temperature Flexibility (-40 °C for 4 hrs.) | No Cracking | ASTM D2671 |
| Heat Shock (250 °C for 30 min.) | No Cracking or Flowing | ESI 09-11 |
| Shrink Temperature | 125 °C | IEC 216 |
| Continuous Temperature Limit | -40 °C to +110 °C | IEC 216 |
| Electrical | ||
| Dielectric Strength | 12kV/mm. (min.) | ASTM D149 |
| Volume Resistivity | 1 x 10¹⁴ Ohm.cm (min.) | ASTM D257 |
| Dielectric Constant | 5 (max.) | ASTM D150 |
Source: GALA Heat Shrink Coupler for Post Tensioning Duct Joint catalogue sheet, Issue 2, July 2024.
Heat Shrink Coupler is a Tubing used for jointing the posttensioning ducts to ensure leak tightness of connections between two consecutive portion of duct.
These tubes are manufactured from cross-linked polyolefin. Hot melt adhesive lining provides 100% sealing according to IP 68 (Ingress Protection). Heat Shrink Couplers ensure a tight seal around the pre-stressing duct connections.
Covered on this page
- Pipeline / Corrosion Protection Products
- Heat Shrink Sleeve for Post-tensioning
Features & Benefits
- Tensile strength 20 N/mm² min, elongation 350% min (ASTM D638)
- Hardness 45±10 Shore D (ASTM D2240); continuous temperature limit -40°C to +110°C (IEC 216)
- Dielectric strength 12 kV/mm min, volume resistivity 1×10¹⁴ Ω·cm min (ASTM D149 / D257)
- Hot-melt adhesive lining seals to IP68; 3:1 shrink ratio
- Resistant to heat, UV rays, vibration and sand-blasting
Applications
- Jointing post-tensioning duct sections in prestressed-concrete construction
- Wet and dry underground duct connections
Standards & Compliance
- ASTM D638
- ASTM D2671
- ASTM D2240
- ASTM D570
- ESI 09-11
- IEC 216
- ASTM D149
- ASTM D257
- ASTM D150
FAQs
Frequently Asked Questions
What is the Heat Shrink Coupler for Post-Tensioning Duct Joints used for?
It is used for:
- Jointing post-tensioning duct sections in prestressed-concrete construction
- Wet and dry underground duct connections
How do I choose the right size?
A heat-shrink part is chosen by two diameters. As supplied (D (min.)) it must open wider than the largest thing it has to slide over; after shrinking (d (max.)) it must close smaller than the smallest thing it has to grip. Measure both on your cable or busbar and pick the first code in the selection chart that satisfies both.
How is it installed?
Clean and degrease the surface, position the part, then shrink it with a gas torch or a hot-air gun: keep the heat moving round it with a smooth, brushing motion so it recovers evenly without scorching. Start at one end and work steadily along to the other.
Which standards and test methods are quoted for it?
These, with the values in the Technical Specification on this page:
- ASTM D638
- ASTM D2671
- ASTM D2240
- ASTM D570
- ESI 09-11
- IEC 216
- ASTM D149
- ASTM D257
- ASTM D150
Where can I download the datasheet?
From the "Download datasheet" button at the top of this page, or here:
Can I get a quote, a sample or a size that is not listed?
Send your cable details, quantity and application with the "Request a Quote or Sample" form at the foot of this page. For a size or variant that is not in the chart, describe what you need there, or use Technical support at the top of the page, and the technical team will confirm what can be supplied.
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