Standards
The standards printed on a shrink tube datasheet, decoded
>20 kV/mm, 12 kV/mm, 14.3 kV/mm — one property, one manufacturer, two test methods behind it. Read the method column before the value.
Twelve references sit on the GSC thin wall sheet: seven ASTM methods, IEC 216, UL 224, two MIL specs and CSA C22.2. One row on it, heat shock at 250 °C for four hours, carries no method at all.
They are not one list. Sort them by what each governs and four groups fall out. Two were run on the compound you are buying. One is checkable without asking the manufacturer for anything. One is about the factory.
Four groups, and the one a specification should name
Type specifications fix what the tube must be. MIL-I-23053/5 and IEC 60684-3-247 are the two here. One document carries the dimensions, the tolerances and the property set, which is why a utility or defence clause names one of these and not a test method.
A listing is the flame evidence. UL 224 with a VW-1 rating is the only reference in this range tied to an outside body's file number, and a file number can be looked up.
Bench methods are everything else: nine ASTM methods across the heat shrink range, plus IEC 216, ESI 09-11 and MIL-I-7444. Each returns one figure from one specimen under one stated condition. None of them rates a joint.
Company certificates describe the factory, not the tube. ISO 9001:2015, ISO 14001:2015 and ISO 45001:2018 cover how it is run. CPRI certified 33 kV heat shrink joints and terminations in August 2012, ERDA reported on a busbar sleeve, and MSEDCL approved supply to 11 kV in 2015 and 11–33 kV in 2016. AEO status is customs. None belongs in a clause specifying a length of tube.
What each named reference governs
- MIL-I-23053/5, Class 2 and Class 3
- The United States defence specification for heat-shrinkable electrical insulation sleeving; /5 is the crosslinked polyolefin slash sheet. Two sheets in this range declare it — GSC and Finotube — and both name Class 2 and Class 3 together, as a pair. Neither says what separates the classes, and no qualification reference sits beside the declaration. The GLC sheet, on the same geometry, does not carry it at all.
- UL 224, and what VW-1 is
- UL 224 is the standard for extruded insulating tubing. VW-1 is its vertical flame rating, run on finished tube rather than on the compound. The rating belongs to a listing, and a file number is the only thing tying one reel to one. GSC prints 125 °C VW-1 against File E328193. Finotube prints the same rating against File E328538.
- IEC 60684-3-247
- IEC 60684-3 holds the individual specifications in the flexible insulating sleeving series, one sheet per type. Sheet 247 is the one the medium and heavy wall, red insulation and CATV tubes are declared against. The declaration is a single bullet with no report number. Not one property row on those sheets cites it: every value is referred to an ASTM method, to ESI 09-11 or to IEC 216.
- ANSI C119.1
- Both cold shrink sheets claim the water seal requirements of ANSI C119.1, not the standard entire. That is a clause-level sealing claim with no clause named. Worked through on the cold shrink tubing page.
- CSA C22.2
- Printed on the GSC sheet with nothing after it, and absent from the Finotube sheet that carries the same MIL and UL lines. C22.2 is a series of Canadian standards, not one document, so the line names a family and stops. For a Canadian job, ask which standard in the series, which certification body and which certificate number.
- MIL-I-7444 and ASTM G-21
- Two fungus tests, and they do not convert. The thin wall and dual wall sheets rate fungus resistance inert to MIL-I-7444. Both cold shrink sheets report 28 days of exposure with no growth to ASTM G-21. A specification naming one is not met by a sheet carrying the other.
- IEC 216, and the heat shock row
- IEC 216 carries every temperature band on the heat shrink side. -55 °C to +125 °C on GSC, -40 °C to +110 °C on GMW and GHW, -40 °C to +100 °C on the GDLT double layer tube. The cold shrink band of -40 °C to 105 °C is printed with no method beside it, so the two do not compare as they stand. Heat shock is the row to watch. Thin wall: 250 °C for four hours, no method. Medium and heavy wall, GDLT and the 5:1 tube: 250 °C for 30 minutes to ESI 09-11. Red insulation tube: the same 30-minute row, referred to ASTM D2671. Same condition, same acceptance wording, three different backings.
Dielectric strength: one property, two methods, split by wall class
| Sheet | Printed value | Method |
|---|---|---|
| GSC thin wall | >20 kV/mm | ASTM D2671 |
| GSC 3X thin wall, 3:1 | >15 kV/mm | ASTM D2671 |
| GLC thin wall | >15 kV/mm | ASTM D2671 |
| GDW dual wall | >15 kV/mm | ASTM D2671 |
| Vented thin wall | >15 kV/mm | ASTM D2671 |
| GMW / GHW medium and heavy wall | 12 kV/mm min., 2 mm wall | ASTM D149 |
| GMW 5x, 5:1 | 12 kV/mm min., 2 mm wall | ASTM D149 |
| GMWR / GHWR co-extruded | 12 kV/mm min. | ASTM D149 |
| GDLT double layer, inner layer | 20 kV/mm min. | ASTM D149 |
| GRT red insulation | 22 kV/mm min. | ASTM D149 |
| GCTE cold shrink, EPDM | 14.3 kV/mm | ASTM D149 |
| GCTS cold shrink, silicone | 18.0 kV/mm min. | ASTM D149 |
Values as printed on the manufacturer's own sheets. The thin wall family is referred to ASTM D2671 throughout and states no specimen thickness. Everything from medium wall upward, and both cold shrink compounds, go to ASTM D149. Only the GMW/GHW and 5:1 sheets name the specimen — 2 mm. Sources: thin wall and cold shrink.
The same property, two families, two methods
ASTM D149, D257 and D2240 appear in both columns. Everything else differs, so a heat shrink sheet and a cold shrink sheet cannot be read side by side row for row.
| Property | Heat shrink tube | Cold shrink tube |
|---|---|---|
| Tensile strength | ASTM D638. GSC 9 N/mm² min. on one issue and 16 on two others, GMW and GHW 12 N/mm² min. as supplied | ASTM D-412. GCTE 9.6 MPa ultimate, GCTS 6.0 MPa min. |
| Elongation | ASTM D638. 300% min. on GSC, 350% min. on GMW and GHW | ASTM D-412. GCTE 750%, GCTS 400% min. |
| Tear strength | No tear row on any heat shrink tube sheet in this range | ASTM D-624C 26.3 kN/m on GCTE, ASTM D-624 25.0 kN/m min. on GCTS |
| Hardness | ASTM D2240. 45 ± 10 Shore D on GMW and GHW | ASTM D2240. 40 ± 10 Shore A on GCTS, no hardness row on GCTE |
| Water | ASTM D570 water absorption. 0.15% max. on GSC, 0.5% max. on GMW and GHW | Manufacturer's internal method. GCTE 1.8% weight gain, 7 days at 90 °C |
| Fungus | MIL-I-7444. Inert | ASTM G-21. 28 days exposure, no growth |
| Flammability | UL 224 VW-1 pass on GSC, ASTM D2671 pass on GDW, no row at all on GLC | No flammability row on either cold shrink sheet |
| Sealing | No sealing standard. IP68 is claimed where hot melt adhesive is fitted | ANSI C119.1, water seal requirements only |
| Temperature | IEC 216. -55 °C to +125 °C on GSC, -40 °C to +110 °C on GMW and GHW | -40 °C to 105 °C, no method printed |
Which claim carries which backing
| Claim | Where it is published | What backs it |
|---|---|---|
| Electrical insulation up to 3.3 kV, GSC thin wall | General product properties, thin wall sheet | The sheet alone. No report number, and a third issue of the same sheet rates the series at 600 volts |
| 36 kV, GHW heavy wall | Opening paragraph, medium and heavy wall sheet | The duty wording — mechanical protection and outer sealing of a joint of that class, not insulation to it |
| VW-1 at 125 °C, GSC | Flammability row and the specifications block | A UL file number, E328193. The manufacturer's certifications page lists the heat shrink tubes under E328538 instead; the sheet-to-sheet split is on the thin wall page |
| Conforms to IEC 60684-3-247 | One bullet each on the medium and heavy wall, red insulation and CATV sheets | Nothing beside it. No clause list, no report number, and no property row on those pages cites it |
| IEC, ASTM, Ul224 and MIL-SPEC | Specifications block, both dual wall sheets | Four families and not one document number. The flammability row on the same sheet is referred to ASTM D2671, not to UL 224 |
| Water seal to ANSI C119.1 | Features list, both cold shrink sheets | A claim scoped to the water seal requirements. No clause and no report |
| IP68 with hot melt adhesive | Optional adhesive bullet, medium and heavy wall and 5:1 sheets | An ingress class, not a test result. No immersion depth and no hold time stated |
| Technical Qualification Report QR 1013 | Foot of the medium and heavy wall sheet and of the 5:1 sheet | The manufacturer's own report, by number — and the same number on two different products. Ask for the document; a number is a reference |
| ISO 9001:2015, CPRI, ERDA, MSEDCL, AEO | The manufacturer's certifications page | Company level. None is a property of a tube and none should be quoted as one |
Every claim below is one this site repeats from the manufacturer's published sheets. The third column is what stands behind it, including where that is nothing.
One value, two row labels, and a method that is not the one used elsewhere
ASTM D2671 is the test-methods document for heat-shrinkable tubing — a battery of procedures, not one breakdown test — and the whole thin wall family refers dielectric strength to it. The manufacturer's Finotube web page then repeats the >20 kV/mm figure on a row labelled volume resistivity. Beneath it sits a second volume resistivity row, 1 × 10¹⁴ ohm.cm to ASTM D257. Two rows, one label, and the upper one carries a kV/mm figure. Establish which procedure produced >20 kV/mm before setting it against a D149 result.
Not published — six product pages in this range carry no property table and no standards line
The anti-tracking tube, the non-tracking GAT tube, the GVOT integrated stress control tube, the GLC3 commercial grade tube, the combined thin wall page and the fibre splice protection sleeve publish neither. For some of them a datasheet fills the gap. For GVOT it does not: its sheet carries a six-row selection chart from GVOT 30/12 to GVOT 85/32 and nothing under it. Where a job needs a declared method, ask for the qualification report by number before the part reaches a schedule.
Questions this page gets asked
Which reference should a utility specification name for a heavy wall joint tube?
Is a tube declared to MIL-I-23053/5 the same as a qualified MIL-spec tube?
Does a VW-1 rating settle the flammability requirement for my panel?
Does the CPRI certificate cover the tube?
Two issues of the same sheet give different numbers. Which one applies?
Where each of these is actually applied
- Thin wall tubeMIL-I-23053/5, UL 224 VW-1, CSA C22.2, and the three-way split between sheet issues
- Medium and heavy wall tubeIEC 60684-3-247, ESI 09-11 and the 12 against 15 kV/mm question
- Dual wall tubeThe specifications line that names four families and no document number
- Cold shrink tubingANSI C119.1, ASTM D-412, D-624C and G-21 on EPDM and silicone
- MaterialsThe four base polymers these methods were run on
- Heat shrink or cold shrinkTwo recovery mechanisms, and why the two datasheets share only three methods
Ask for the sheet by issue, not by product name
Send the size, the substrate and the standard your specification names. A reply quoting an issue number and a report number is worth more than one quoting a code.