Custom Interior NVH, HVAC Insulation & Cabin Filtration for Electric Vehicles

Because the masking noise is gone. In a combustion vehicle, engine and exhaust noise covers a great many small interior sounds, so a minor buzz, squeak or rattle is rarely noticed. An electric powertrain removes that broadband masking, and the cabin gets much quieter, which means the same small rattle at a trim interface, the same squeak between two panels, is now clearly audible to the occupant.

So anti-rattle and acoustic parts that were marginal before become important, and the interfaces that need a resilient cushion multiply. The materials are the familiar ones, thin microcellular-polyurethane pads and soft lining foams, but they are specified more widely and to a higher quiet standard, and they still need to meet the occupant-compartment flammability requirement.

FMVSS 302 is the U.S. motor-vehicle safety standard for the flammability of interior materials; it sets a maximum horizontal burn rate for materials in the occupant compartment. Most soft trim, cushioning, lining and insulation materials in the cabin are expected to meet it.

The important framing is that the burn-rate result is a property of the specific material and construction, not a blanket property of a foam family, so the right move is to select a grade that carries the FMVSS 302 result and confirm it on the data sheet for the thickness and construction you are using.

H-O converts grades chosen to meet the requirement; the rated result belongs to the tested material.

Reach for polyimide foam when you want light weight, a wide temperature range and strong flammability behavior together. Polyimide foam is very light, holds its properties across a broad temperature span, and carries good flammability performance, which makes it well suited to HVAC duct and plenum insulation and thermal runs in the occupant compartment, and many grades also screen well for low outgassing.

A flexible polyurethane foam can be a lower-cost choice for a moderate-temperature duct quiet-and-seal layer, but where temperature, weight and flammability all matter at once, polyimide is the move. Confirm the continuous-service temperature, the FMVSS 302 result and any outgassing requirement on the data sheet.

By pore size, airflow and dirt-holding. A reticulated (open-cell) polyurethane foam filter is described by its pore size, usually given in pores per inch, which together with density sets two competing properties: a finer pore traps smaller particulate but resists airflow more, while a coarser pore passes more air but catches less. So the spec balances the filtration target against the allowable pressure drop across the HVAC airflow, and adds the dirt-holding capacity needed for the service interval.

Tell us the airflow, the particulate target and the housing geometry, and a reticulated grade and element shape can be matched; flame-rated reticulated grades are available where the air path needs added flammability performance.

Sometimes the same family appears in both jobs, but the grade is usually different. Microcellular polyurethane leads for anti-rattle and cushioning because of its controlled low-stress curve, while a lightweight polyimide or a soft lining foam leads for insulation and acoustic absorption. Vinyl nitrile can serve as both a firm anti-rattle part and an acoustic lining, so it is the most likely single family to cross over.

The honest approach is to define each job at its location, NVH, acoustic, insulation or filtration (for a noise, the BSR triage names the mechanism first), point each one at its lead family, then see where one grade can reasonably cover two adjacent jobs to simplify the build. Send the locations and we will look for sensible consolidation.

Five things move a recommendation from a guess to a real direction: the job at each location (NVH and anti-rattle, acoustic lining, HVAC and thermal insulation, or air filtration), the FMVSS 302 flammability requirement, any outgassing limit near glass or optics, the operating temperature, and the environment (dry interior, HVAC air path, humid).

Add the part geometry or a drawing, the adhesive and liner needs, and the prototype and annual volume, and engineering can match a family, a grade direction and a converting approach, then confirm the grade-level values against the manufacturer's data sheet.

The What to send H-O box on the page lists these.

H-O is a precision converter, not a raw-material producer. We do not extrude or mold the foam; we buy sheet, slab and roll stock from the material manufacturers and convert it to your drawing, by die-cutting, kiss-cutting, laser and waterjet cutting, adhesive lamination, slitting and kitting, with material traceability and lot-level data-sheet records.

Every interior pad, lining, insulation and filter part is made-to-order; we do not carry finished parts in stock and we do not advertise a no-minimum policy, though prototype quantities through full production runs are equally welcome and the minimum varies by material and part.

Prototype and production timing is summarized in the process strip near the top of the page and on the quote form.

Yes — most anti-rattle pads, cushioning parts, and insulation layers on this page can be supplied with pressure-sensitive adhesive and delivered kiss-cut on liner for line installation. Interior parts add one consideration: the adhesive and foam together should be reviewed against the program’s flammability and fogging requirements, since the adhesive layer is part of the installed stack.

Fogging is the film that volatiles from interior materials can deposit on glass; automotive programs commonly limit it through outgassing and fogging test requirements. Material families differ — polyimide foam is notably low-outgassing, and several microcellular polyurethane grades are formulated for low fogging per their manufacturers’ data — so state the program’s fogging or outgassing limit on the RFQ and the material data sheets are checked against it at review.

The usual presentation is kiss-cut on liner, so installers peel and place pads at the interface points identified in a squeak-and-rattle review. Achievable thickness and cut tolerance depend on the specific foam grade and part geometry, so they are confirmed at drawing review rather than quoted generically.

Yes — material swatches and cut samples are available on request, subject to material availability. For evaluation builds, the usual path is to send the part drawing so prototype parts are cut from the actual grade and thickness under consideration; that puts representative parts in your fixture instead of a generic swatch.

Minimums depend on the material and format rather than a single policy. Prototype quantities are quoted case-by-case, and production minimums are typically driven by the vendor’s sheet or roll purchase unit for the specific material. Stating your target annual volume on the RFQ lets H-O quote realistic break points up front.