Heat Shrink Tubing and Sleeving for Aerospace Harnesses
Military and aerospace heat shrink tubing is bought to SAE AS23053, which replaced AMS-DTL-23053, and to the slash sheet for the material: /5 flexible polyolefin, /8 PVDF, /11 FEP, /12 PTFE, /16 elastomeric polyolefin and others. Braided, expandable and fire sleeves are mostly bought to manufacturer data, so the PO has to carry the requirements.
Updated
Types of sleeving and where each one goes
Pick the sleeve by the job it does: insulate and strain relieve a termination, jacket and bundle a harness, resist abrasion where a bundle rubs structure, protect a hose in a fire zone, or carry an identification mark. Heat shrink does the first and last well. Braided and expandable sleeves do bundling and abrasion. Coated fiberglass fire sleeve protects fluid lines near heat.
| Type | Typical use | Usually bought to |
|---|---|---|
| Flexible polyolefin heat shrink | Light duty harness jackets, wire color coding, marking and identification | AS23053/5 (formerly M23053/5) |
| Dual wall, adhesive lined polyolefin | Sealed splices and terminations | AS23053/4, /15 |
| Semi-rigid PVDF heat shrink | Strain relief at solder sleeves, contacts and terminations | AS23053/8, /18 |
| Fluoropolymer heat shrink (PTFE, FEP) | High temperature and chemically aggressive areas | AS23053/12 (PTFE), /11 (FEP) |
| Elastomeric heat shrink | Flexible jackets that see fuel or diesel; fluoroelastomer for harsher fluids | AS23053/16, /13 |
| Expandable braided sleeving | Bundling and abrasion protection over a harness or hose | Manufacturer part number and data sheet |
| Silicone coated fiberglass fire sleeve | Hoses and lines in engine and APU zones | Manufacturer part number, fire test stated |
If the harness is part of a larger build, the wire harness sourcing page covers how sleeving callouts flow from the harness drawing to the shop.
The specifications that govern heat shrink
The general specification is now SAE AS23053. SAE describes it as a conversion of AMS-DTL-23053 into an AS document that includes qualification, and SAE's record for the /17 sheet states the base AMS-DTL-23053 was cancelled because AS23053 replaced it. The slash sheets carry the material requirements. Across all classes AS23053 covers continuous operating temperatures from -80 to +250 °C, with each sheet setting its own range.
| Document | What it covers | Status as verified |
|---|---|---|
| SAE AS23053 | General specification for heat shrinkable electrical insulation sleeving, with qualification | Active; replaced AMS-DTL-23053 (SAE) |
| AMS-DTL-23053 | Former general specification | Cancelled, replaced by AS23053 (SAE) |
| /4 | Polyolefin, dual wall, outer wall crosslinked | AMSDTL23053/4A revised August 2012 |
| /5 | Polyolefin, flexible, crosslinked; Classes 1, 2 and 3 | /5A issued July 2012; SAE also lists /5B |
| /8 | PVDF, semi-rigid, crosslinked | Listed as AS23053/8 by distributors |
| /10 | Silicone rubber, flexible | /10B cancelled December 2018 (SAE) |
| /11 | FEP, non-crosslinked | AMSDTL23053/11A |
| /12 | PTFE | Sold by distributors as SAE AMS-DTL-23053/12 |
| /13 | Fluoroelastomer, flexible | /13A revised August 2012 |
| /16 | Elastomeric polyolefin, crosslinked, flexible | /16A revised August 2012 |
| /17 | Flame retarded modified polyolefin | /17B cancelled February 2019, converted to AS23053/17 |
| SAE AS1055 | Fire testing of flexible hose, tube assemblies and similar components | AS1055E revised October 2017 |
Old drawings still say MIL-I-23053, MIL-DTL-23053 or M23053. The part numbers carried over, so an M23053/5 callout on a legacy drawing is normally filled with AS23053/5 product. Confirm with the design authority before treating them as identical on a flight program.
Have a part like this?Send it in under a minute. A person replies within 1 business day.How an M23053 part number is built
The slash sheet defines the part number as the sheet, then a class digit, a two digit size identifier, then a color code. The worked example printed in MIL-DTL-23053/5C (June 1996) is M23053/5-106-8:
| Field | Value | Meaning per the sheet |
|---|---|---|
| Sheet | M23053/5 | Polyolefin, flexible, crosslinked |
| Class | 1 | Flame resistant (Class 2 is flammable and clear only, Class 3 is highly flame resistant) |
| Size | 06 | 0.250 in minimum as supplied ID, 0.125 in maximum ID and 0.025 ± 0.003 in wall after unrestricted shrinkage |
| Color | 8 | Gray (slate), colors per Class 1 of MIL-STD-104 |
Clear Class 2 tubing carries a C in the color position, for example M23053/5-206-C. Distributors sell -0 as black, so M23053/5-104-0 is 1/8 in black Class 1. Where a sheet has no classes, the class position is 0. The same sheet sets Classes 1 and 2 at -55 to +135 °C continuous and Class 3 at -25 to +125 °C, and requires the supplier to certify a five year storage life at 18 to 35 °C. Those values are from the 1996 revision; check the current AS23053/5 before using them for acceptance.
Materials and the trade-offs
Polyolefin is the default because it is flexible, cheap and shrinks at a moderate temperature. Move up the material ladder only for a reason the drawing can state.
- Polyolefin (/5). Flexible and easy to install. Rated to +135 °C for Classes 1 and 2. The 1996 sheet warns that Class 2 is not flame retarded and will burn readily, so never accept Class 2 where flame resistance is required.
- PVDF (/8, /18). Semi-rigid, which is the point when you want strain relief at a termination. A distributor lists /8 at -55 to +175 °C continuous with a 2:1 shrink ratio. It is stiff, so it is a poor choice for a jacket that must flex.
- PTFE (/12). For heat and chemical exposure. A distributor lists /12 Class 2 at -67 to +250 °C. Shrink temperatures are high, published values vary between listings, and the installer needs the right heat tools. Sea Wire lists 2:1 standard, light and thin wall versions and a 4:1 thin wall.
- FEP (/11). A non crosslinked fluoropolymer. Sea Wire lists it at shrink ratios of about 1.3:1 and 1.6:1, well below PTFE, so size it carefully against the largest and smallest diameters.
- Elastomeric polyolefin (/16) and fluoroelastomer (/13). Flexible jackets with fluid resistance. A distributor lists /16 as diesel resistant, -75 to +120 °C, shrinking at 150 °C.
Shrink ratio drives size selection. The tubing must slide over the largest feature, a connector or splice, and still recover tight on the smallest diameter. On the M23053/5 example above, size 06 goes from at least 0.250 in to at most 0.125 in, so it will not grip anything under 0.125 in.
Braided, expandable and fire sleeving
These products rarely have a single governing military specification, so the purchase order has to state the material, size range, temperature rating and any flammability, smoke or fluid requirement, and ask for the data sheet and test reports. Expandable polyester braid is the common choice for bundling and abrasion; fiberglass and aramid braids are used where heat or cut resistance matters. Order by the manufacturer part number the drawing names, or by a source control drawing.
Fire sleeve is typically a braided fiberglass sleeve with a silicone rubber coating slipped over hoses and lines in fire zones. Ratings in catalogs are marketing numbers until tied to a test method. For hose and tube assemblies, SAE AS1055 is the fire test standard, so ask whether the sleeved assembly or the sleeve alone was tested and to which method. The tube and fluid systems page covers how sleeved hose assemblies are sourced as a unit.
Space programs: outgassing limits for sleeving
Sleeving inside a spacecraft is a polymer in vacuum, so it is screened by ASTM E595 like any other nonmetal. The test reports total mass loss (TML) and collected volatile condensable material (CVCM), and historically 1.0 percent TML and 0.10 percent CVCM have been used as rejection screening levels. Results change with the formulation, the color and the vendor, so a value for one red polyolefin does not cover a black one from another maker.
Look up the exact product in the NASA outgassing database, and if it is not listed, require an E595 report on the lot or a bakeout that your materials engineer approves. The engineering plastics page explains the test conditions, and the satellite manufacturers page covers how materials lists flow down to suppliers.
Marking sleeves
The /5 sheet names marking and identification as an intended use, and many harness shops print wire and bundle identifiers on heat shrink sleeves. The print is part of the requirement. Specify the marking content, character height, ink or print method, and that marks must remain legible after the fluid and abrasion exposure the harness will see. Ask the harness shop which sleeve and printer combination it has qualified rather than letting a substitution happen at the bench. Item level identification of the harness itself is covered on the part marking and labels page.
What to put on the purchase order
- Full part number with sheet, class, size and color, and the specification revision, for example AS23053/5 at the revision on the drawing.
- A qualified source: AS23053 includes qualification, so ask the manufacturer to show the product is qualified to the sheet.
- Manufacturer name and lot or batch number on the certificate of conformance, and the date of manufacture.
- Storage life remaining at delivery, stated against the sheet's storage requirement.
- For space hardware: E595 data or database reference for the exact product and color.
- For braided and fire sleeve: manufacturer part number, data sheet revision, and the test method behind any fire or flammability claim.
- Packaging: spools or cut lengths, labeled with part number, lot and quantity on each package.
Specialty metals rules under DFARS rarely touch polymer sleeving, but if a sleeve includes a metal braid on a defense contract, check the DFARS specialty metals rules.
Counterfeit and quality risks, and how to receive it
The common failure is commercial tubing sold as mil spec: correct color and size, wrong compound, no qualification. It looks identical on the spool. The defense is buying from the manufacturer or its authorized distribution and requiring a certificate that names the manufacturer, the sheet and the lot.
At receiving:
- Match spool labels to the certificate and the PO, including class and color code.
- Measure as supplied ID on a sample against the sheet's minimum.
- Shrink a sample freely (the /5 sheet uses 200 °C for 3 minutes for its unrestricted shrinkage test) and check recovered ID and wall.
- Check date of manufacture against storage life.
- Quarantine anything without a traceable lot.
The receiving inspection page covers sampling, and counterfeit parts avoidance covers source selection.
How we source heat shrink and sleeving
We do not hold inventory or publish prices. We buy sleeving with traceability through the manufacturer or its authorized and franchised distribution, flow the sheet, class, revision and documentation requirements down, and deliver it with the certificate package. We can put sleeving, clamps and protective caps on the same PO as machined or fabricated parts, build harness or installation kits, and chase discontinued sheets and colors under counterfeit avoidance controls through our obsolete parts process. Related protection parts: cushion clamps and caps, plugs and protective covers, or browse all protection parts.
Request heat shrink or sleeving
Send the part numbers, quantities, lengths and any outgassing or fire requirements, and we will come back with one quote that covers the sleeving and anything else on the bill. Request a hardware quote. A person replies within one business day, and mutual NDA terms are on the confidentiality page.
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Questions
Is M23053 heat shrink the same as AS23053?
In most cases the part number carried over. SAE converted AMS-DTL-23053 into AS23053, which includes qualification, and the slash sheets kept their numbers, so M23053/5 tubing is normally supplied as AS23053/5. On flight hardware, confirm with the design authority that the drawing accepts the AS document, and state the revision on the purchase order so the certificate can be checked against it.
What do the numbers in M23053/5-106-8 mean?
Per the /5 sheet, the first digit after the dash is the class (1 is flame resistant), the next two digits are the size (06 is 0.250 in minimum as supplied ID, shrinking to 0.125 in maximum), and the final character is the color code (8 is gray). Clear Class 2 tubing uses C in the color position. Distributors sell color code 0 as black.
Which heat shrink should I use above 135 °C?
Flexible polyolefin to /5 is rated to +135 °C for Classes 1 and 2 in the 1996 sheet. Above that, look at PVDF to /8, which a distributor rates to +175 °C continuous, or PTFE to /12, which a distributor rates to +250 °C. Each step up costs flexibility and needs higher shrink temperatures, so confirm the installer has the right heat tools.
Can I use heat shrink inside a spacecraft?
Yes, if the exact product passes your program outgassing screen. ASTM E595 reports total mass loss and collected volatile condensable material, and 1.0 percent and 0.10 percent have historically been used as screening levels. Results vary with formulation and color, so look up the specific product in the NASA outgassing database or require test data or an approved bakeout.
Is there a military spec for expandable braided sleeving?
Expandable braided sleeving is usually bought by manufacturer part number or a source control drawing rather than a single military sheet. Put the material, size range, temperature, flammability and fluid requirements on the PO, ask for the data sheet and test reports, and do not accept a substitute brand without engineering approval.
How do I spot counterfeit or non qualified heat shrink?
You usually cannot by eye. Buy from the manufacturer or authorized distribution, require a certificate naming manufacturer, sheet, class and lot, and check spool labels against it. At receiving, measure as supplied ID, shrink a sample and check recovered ID and wall against the sheet, and check the manufacture date against storage life.
Related
Sources
- MIL-DTL-23053/5C detail specification sheet, polyolefin heat shrinkable sleeving (PDF)
- SAE AS23053 Insulation Sleeving, Electrical, Heat Shrinkable, General Specification
- SAE AMSDTL23053/17B record (base specification replaced by AS23053)
- SAE AMSDTL23053/4A polyolefin dual wall
- SAE AMSDTL23053/16A elastomeric polyolefin
- SAE AMSDTL23053/13A fluoroelastomer
- SAE AMSDTL23053/10B silicone rubber
- Sea Wire and Cable: M23053 slash sheets and shrink ratios
- Wiremasters: M23053/8 PVDF series
- AWC: M23053/12-205 PTFE heat shrink
- AWC: M23053/16-002 elastomeric polyolefin
- SAE AS1055E fire testing of flexible hose and tube assemblies
- NASA outgassing database
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