High-Temperature Sleeving for Industrial Equipment

Motors, transformers, sensors and control cabinets do not all get hot the same way. Steady ambient heat, direct contact, radiant load, splash and short excursions each favor a different construction. This guide separates the heat modes first, then maps the sleeving constructions to them. Single "temperature ladder" tables are avoided on purpose: catalogue values without a grade and a test method are not selection data.

Continuous vs short-term: read the right number

Two different figures appear on high-temperature sleeving datasheets, and mixing them is the classic sizing error. The continuous rating is what the construction tolerates for hours at a stretch. Size on this figure with margin. The short-term peak is overload tolerance for brief excursions (a bake cycle, a momentary overload), not a normal running condition. A construction quoted with a high flash rating has not thereby earned that number continuously; when comparing two datasheets, compare the continuous columns, and confirm both against the exact grade you plan to cite.

First: which heat mode are you protecting against?

• Continuous ambient. The whole part sits in hot air (inside an enclosure near a drive, a transformer bay). What matters is the continuous rating of the exact grade.
• Contact heat. The sleeve touches a hot part (a bus run, a heater element). Contact demands both temperature rating and dimensional stability, because softening against the part changes the fit.
• Radiant heat. A hot source nearby, not touching (furnace walls, exhaust runs). A reflective face or a low-absorption construction changes what the sleeve experiences versus what the source emits.
• Splash. Intermittent molten material or hot oil hitting the sleeve. The construction needs enough mass and surface behavior to shed the drop before it soaks through.
• Short-term exposure. Brief excursions above the continuous level (a bake cycle, a brief overload). Grades differ in what excursion they tolerate without damage; the datasheet states the difference.

The constructions, and what each is for

Silicone-coated fiberglass

Silicone-coated fiberglass sleeving is the general-purpose continuous-ambient and contact construction: the fiberglass braid carries the heat load and the silicone coating supplies dielectric and surface behavior. Continuous rating depends on coating grade. Take it from the datasheet, not from a category value.

Inner fiber / outer silicone

Inner-fiber / outer-silicone sleeving reverses the emphasis: a braided glass core sits under the silicone skin. The glass core gives the wall more body and abrasion resistance while the silicone outside keeps the dielectric surface. The construction to compare when a coated build wears through on a rubbing or vibrating hot point but a rigid tube cannot follow the route.

Extruded fiberglass

Extruded fiberglass sleeving is the rigid construction of the family: a bonded, non-flexible wall for fixed bus runs and terminal protection where the route never moves and the highest temperature class of the fiberglass builds is the requirement. Rigidity is the trade. It does not follow movement, so keep it off flexing sections.

Corrugated fiberglass

Corrugated fiberglass sleeving adds mechanical compliance: the corrugation flexes and insulates across a moving or vibrating hot point where a smooth-wall tube would fatigue.

Double-layer braid

Double-layer braided sleeving doubles the textile barrier where abrasion and heat arrive together, motor lead exits and point-of-contact zones.

Aluminum-foil reflective constructions

Radiant sources are handled by a reflective face rather than by thickness. Two constructions: aluminum foil fiberglass fire pipe and aluminum foil textile crimped sleeving. The foil face reflects radiant load; the carrier supplies the mechanical and temperature base. Reflective constructions protect against radiation specifically. They are not general contact insulation.

Polyimide-fiberglass and spiral constructions

Polyimide-fiberglass sleevings pair a high-temperature film with a fiberglass carrier for compact, high-dielectric applications; construction-specific ratings are being confirmed and are flagged on the product page. Spiral fiberglass bellows tube serves where the sleeve must follow a moving or irregular route; its continuous rating is likewise under verification on the product page.

Matching, not ranking

The failure pattern in industrial buying is picking "the highest temperature" sleeving when the actual threat is radiation or splash. Identify the heat mode, match the construction, then verify the grade datasheet. Within the silicone-and-glass family the routing is mechanical first: moving or bent sections take the coated or inner-fiber/outer-silicone builds; fixed high-heat bus takes the extruded construction. Scenario routing is under the Industrial solution page; construction definitions are on the Materials hub.

Heat mode to construction shortlist

Match the heat mode first, then verify the grade. This is a routing table, not a ranking; the temperature number always comes from the exact grade's datasheet.

Frequently asked questions