Furnace Strip Curtains

Silica Strip Curtains Rated to 1800°F for Heat Treat Furnace Openings, Mesh Belt Throats, and Foundry Aisles

Furnace strip curtains from Steel Guard Safety are built in 34 oz vermiculite coated silica for openings where coated fiberglass will not survive. Rated to 1800°F continuous, the HTS-4000 handles the radiant load at heat treat furnace doors, continuous belt furnace throats, and foundry aisle separations — applications well beyond the 500°F range of standard high temperature strip curtains.

Above 1000°F the material changes entirely. E-glass fiberglass, the substrate under every silicone and PTFE coated curtain, gives out around 1000°F regardless of what coating is on it. Amorphous silica takes over from there, with a melting point of 3000°F and a continuous service rating of 1800°F. For openings below 1000°F, see our full High Temperature Strip Curtains range.

Why Vermiculite Coated Silica

Bare silica cloth frays badly when cut and sewn, and sheds fiber in service. The vermiculite coating does three things that matter on a strip curtain:

• Reduces fraying at the cut edge, which makes the fabric workable through cutting, hemming, and grommeting — a real consideration on a curtain built from twenty or thirty individual strips
• Dissipates heat across the fabric surface rather than letting molten slag or splash concentrate in one spot and burn through
• Adds abrasion resistance at the contact faces where parts and personnel pass

The coating carries the same 1800°F rating as the base fabric, so unlike coated fiberglass there is no gap between the coating limit and the substrate limit. The whole assembly holds one number.

Built Heavy on Purpose

At 34 oz the HTS-4000 is the heaviest strip curtain we build — comparable in hand to our 32 oz silicone coated fiberglass, but in a material rated more than three times as hot. Furnace openings see less frequent passage than a conveyor oven door, so the added stiffness costs little, while the mass does real work against molten splash and mechanical contact from loads moving through.

Where Furnace Strip Curtains Are Installed

Continuous mesh belt furnace throats. The strongest application. Entry and exit openings are small, fixed, and product runs through them without stopping. A strip curtain mounts on the throat face and stays there, containing radiant loss at both ends of the line.

Box and batch furnace doors. When the door lifts for charging, the full opening dumps radiant heat into the shop while an operator loads by hand or fork. The curtain hangs inside the door frame so the door still closes over it, holding temperature during the load and shielding the operator.

Heat treat furnace charge and discharge ends. Car bottom and bogie hearth furnaces have large openings exposed during every cycle. Strip configuration depends on what passes through — tell us the load geometry and we’ll spec the overlap.

Foundry aisle separation. Shielding adjacent bays from radiant heat and splash at pour lines, ladle preheat stations, and shakeout transitions.

Induction billet heater entry and exit. Small defined openings with parts moving through continuously — functionally the same as a belt furnace throat.

Furnace Processes and Operating Temperatures

The curtain hangs at the opening, not inside the chamber, so the fabric sees door-plane temperature rather than furnace set point. A furnace running above 1800°F may still be a viable application depending on opening geometry and standoff. Tell us the set point and the opening and we’ll tell you honestly whether it works.

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