Heat Shrink Polyolefin Tube for U-Bolt Coating
A 3:1-shrink polyolefin tube rated -40°C to +110°C that coats the U-bolt/pipe contact point on refinery, chemical-plant and offshore pipe supports, where excessive corrosion is the leading cause of process pipe failure.
- ASTM D638
- ASTM D2671
- ASTM D570
Installation instructions
Full dimensional specifications and technical data, ready to download.
Choose a size
Selection Chart
- D min.
- Minimum internal diameter as supplied
- d max.
- Maximum internal diameter after free recovery
- T
- Recovered wall thickness (±10 %)
| Code | D min.(mm) | d max.(mm) | T ±10%(mm) |
|---|---|---|---|
| GMWR 10/3 | 10 | 3 | 1.5 |
| GMWR 12/4 | 12 | 4 | 1.8 |
| GMWR 16/6 | 16 | 6 | 2.0 |
| GMWR 19/6 | 19 | 6 | 2.0 |
| GMWR 22/6 | 22 | 6 | 2.3 |
| GMWR 27/8 | 27 | 8 | 2.5 |
| GMWR 30/8 | 30 | 8 | 2.6 |
| GMWR 33/10 | 33 | 10 | 2.6 |
| GMWR 40/12 | 40 | 12 | 2.7 |
| GMWR 50/16 | 50 | 16 | 2.7 |
Source: GALA Heat Shrink Polyolefin Tube for U-Bolt Coating catalogue sheet, Issue 2, January 2024.
Material properties
Technical Specification
| Properties | Value | Standard |
|---|---|---|
| Tensile Strength | 12 N/mm² (Mpa) (min.) | ASTM D638 |
| Ultimate Elongation | 350 % (min) | ASTM D638 |
| Longitudinal Change | -10 % (max) | ASTM D2671 |
| Water absorption | 0.5 % (max.) | ASTM D570 |
| Accelerated ageing | (120 °C for 500 hrs) | ASTM D2671 |
| Tensile Strength | 11 N/mm² (Mpa) (min.) | ASTM D638 |
| Ultimate Elongation | 300 % (min.) | ASTM D638 |
| Heat Shock (250 °C for 30 min.) | No cracking or flowing | ESI 09-11 |
| Continuous Temperature Limit | -55 to +110 °C | – |
| Dielectric Strength | 12 kV/mm.(min) | ASTM D149 |
| Volume Resistivity | 1 x 10¹⁴ Ohm.cm (min) | ASTM D257 |
| Dielectric Constant | 5 (max.) | ASTM D150 |
Source: GALA Heat Shrink Polyolefin Tube for U-Bolt Coating catalogue sheet, Issue 2, January 2024.
Dimensions & Drawings
Pipes running through refineries, chemical plants and offshore platforms rest on, or are secured to, structural beam supports using U-bolts. The uncoated U-bolt/pipe contact area deteriorates in the presence of moisture, and this corrosion at the support point is the leading cause of process pipe failure, eventually developing into pinhole leaks.
The heat shrink polyolefin tube shrinks smoothly over the U-bolt shank to give corrosion and mechanical protection at that contact point, with high resistance to impact and abrasion and good strain relief. Technical Qualification Report: QR 1025.
Covered on this page
- Market Segment: Electrical, Offshore, Marine, Industrial Oil and Gas Utilities
Features & Benefits
- 3:1 shrink ratio; continuous temperature limit -40°C to +110°C (IEC 216)
- Tensile strength 12 N/mm² min, elongation 350% min (ASTM D638)
- Dielectric strength 12 kV/mm min (ASTM D149); volume resistivity 1×10¹³ Ω·cm min (ASTM D257)
- Heat shock 250°C for 30 min: no cracking or flowing (ESI 09-11)
- Shrinks over the U-bolt shank without wrinkles, reducing paint-film cracking as the bolt is torqued down
- Hardness and durability protect the pipe paint without setting up a capillary crevice around the pipe circumference
- Elastomeric conformance over irregular contours without splitting; good strain relief
- Unaffected by heat, UV rays, vibration or sandblasting
- GMWR sizes 9/3 to 50/16; GHWR sizes 12/3 to 50/16
- Technical Qualification Report QR 1025
Applications
- Corrosion and mechanical protection at U-bolt/pipe contact points on structural beam supports
- Refinery, chemical-plant and offshore-platform pipe supports
- Electrical, marine, industrial, oil and gas utility installations
Standards & Compliance
- ASTM D638
- ASTM D2671
- ASTM D570
- ASTM D149
- ASTM D257
- ASTM D150
- IEC 216
- ESI 09-11
FAQs
Frequently Asked Questions
What is the Heat Shrink Polyolefin Tube for U-Bolt Coating used for?
It is used for:
- Corrosion and mechanical protection at U-bolt/pipe contact points on structural beam supports
- Refinery, chemical-plant and offshore-platform pipe supports
- Electrical, marine, industrial, oil and gas utility installations
How do I choose the right size?
A heat-shrink part is chosen by two diameters. As supplied (D min. (mm)) it must open wider than the largest thing it has to slide over; after shrinking (d max. (mm)) 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 D570
- ASTM D149
- ASTM D257
- ASTM D150
- IEC 216
- ESI 09-11
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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Years manufacturing
100+
Countries served
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Products in range
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