Smart HVAC, IoT & VFD Electronics
H-O Products die-cuts and converts the soft-goods set that lets a connected HVAC product seal, breathe, shed heat, and behave on the bus: silicone and microcellular-urethane enclosure gaskets for controllers and thermostats, ePTFE pressure-equalization vent membranes for IoT sensor nodes, boron-nitride gap pads and graphite spreaders for the VFD heat sink, transfer-tape bond lines and foam dust seals under the display, conductive-elastomer EMI gaskets for the radio module, and PORON battery-holder cushion pads, built to your drawing.
Built for: controller and thermostat enclosure gaskets in IP-framed sealing designs, IoT sensor-node sealing with pressure-equalization venting, VFD heat-sink TIMs, display and touch-panel bonding and dust seals, EMI shielding for radio and comms modules, and battery-holder cushion pads, supporting product designs evaluated to the customer's standards program, with every standard cited by designation.
To outfit the soft-goods set inside a connected HVAC product, work job by job. Controller and thermostat enclosure gaskets: die-cut silicone foam and closed-cell silicone sponge for IP-framed sealing designs (IEC 60529 by designation), with PORON® microcellular urethane where a low-closure-force seal fits a thin snap-fit lid.
IoT sensor-node sealing and venting: perimeter foam gasket plus a die-cut ePTFE pressure-equalization vent membrane that breathes to balance pressure while holding back liquid water and dust. VFD heat-sink TIMs: boron-nitride silicone gap pads across an uneven gap and natural or synthetic graphite spreaders for lateral heat, with thermal impedance per ASTM D5470 at the stated mounting pressure.
Display and touch-panel bonding and dust seals: acrylic transfer tape bond lines and PORON® dust gaskets, validated against the substrate and assembly. EMI shielding for radio and comms modules: SSP502 nickel-graphite silicone, the SSP502-V0 series where a flame class rides along, and fabric-over-foam for low-force runs, with emissions context per CISPR 11 and FCC Part 15 by designation.
Battery-holder cushion pads: die-cut PORON® and HyPUR-cel® PU foam that hold a cell against shock and vibration.
All standards by designation; values per the maker TDS on file; final material selection should be validated in the application. See the quote form for ordering details.
By designation (the evaluation belongs to the customer's tested design or program): IEC 60529 (IP ingress code behind IP-framed sealing designs) · CISPR 11 and FCC Part 15 (emissions frameworks behind radio and VFD EMC work). Material- and method-level, per the maker TDS: ASTM D5470 (TIM thermal-impedance and apparent-conductivity method, reported at a stated mounting pressure) · UL 94 (flammability classes, including V-0 on the listed grades).
Sealing is described as IP-framed: the ingress rating belongs to the customer's tested enclosure, and the gasket is the converted part that helps the design reach it.
- Sealed controller, wide temperature: silicone foam / silicone sponge
- Thin lid, low closure force: PORON® microcellular urethane
- Sensor node that must breathe: ePTFE vent membrane
- Uneven heat-sink gap: boron-nitride silicone gap pad
- Lateral heat spreading: natural / synthetic graphite
- Display bond line: acrylic transfer tape
- Radio-module EMI gasket: SSP502 nickel-graphite / SSP502-V0
- Low-force EMI seal: BISCO® EC-2130 sponge
- Seam bridging & ground paths: conductive foil tape
- Battery-holder cushion: HyPUR-cel® PU foam
Where are you in the spec process?
This page serves engineers who already have gasket, vent, TIM, or shielding callouts on the drawing and engineers still deciding which family carries each job. Pick the path that matches where you are; you don't have to read the rest.
Send a drawing, get a quote
A gasket profile, a vent-disk diameter, a gap-pad thickness and conductivity class, an EMI gasket cross-section, or a complete soft-goods kit on your drawing. Engineering reviews it against the maker TDSs and quotes it.
Skip to the quote form →Work the six jobs in order
Six numbered jobs from the controller enclosure out to the battery holder, each with engineering context, the material families that commonly carry it, and exactly what to put on the drawing.
Start with the controller →
Where H-O parts do the work
Pick a job to see the exposure, the constraint, and the material families H-O converts for it.
Controller & thermostat enclosure gaskets
Engineering context. A smart thermostat, an edge controller, or a building-automation node is a small sealed box mounted on a wall, in a plenum, or on a rooftop unit, and its first job is to keep dust, splash, and condensation out of the electronics. The perimeter gasket between the housing halves is the part that does it: a profile that compresses against a snap-fit or screwed lid, holds its seal across the temperature swing the product sees, and survives the service cycle when the cover comes off.
The sealing intent is described as an IP-framed sealing design, referenced through IEC 60529 by designation; the ingress rating itself belongs to the customer's tested enclosure, and the gasket is the converted part that helps the design get there.
What H-O converts. Die-cut silicone foam and closed-cell silicone sponge perimeter gaskets where a wide temperature span and a flame class matter, including UL 94 V-0 grades such as kSil V-0 super-soft silicone sponge per the vendor TDS; and PORON® microcellular urethane seals where a thin snap-fit lid can only deliver low closure force. Kiss-cut gasket sets ship on liner in assembly order through flatbed die-cutting and CNC knife cutting.
Material-family guidance. Pick by closure force and temperature first. Closed-cell silicone sponge is the wide-temperature default: it seals across the swing a rooftop-adjacent controller sees, and the listed grades carry UL 94 V-0 classes per the vendor TDS [3]. PORON® microcellular urethane earns the job where the lid is thin and the force budget is small: it takes a set slowly and seals at low compression, which is what a snap-fit closure can actually deliver.
Phrase the requirement as an IP-framed sealing design and name the target code, the seal channel, and the available closure force; the ingress evaluation stays with the customer's tested enclosure per IEC 60529 framing [2]. Where the gasket is PSA-backed, the adhesive holds the part for assembly: adhesive performance depends on substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, joint geometry, and the assembly process, and tape selections should be validated in the application.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
The gasket profile or seal-channel geometry (a DXF is ideal), material thickness, the IP-framed sealing target if the program names one (IEC 60529 by designation), the available closure force, working-temperature range at the enclosure, any flame class required on the part (UL 94 class per the vendor TDS), and quantities for prototype and production. If the gasket mounts with adhesive, note the substrate so the bond can be validated in the application.
IoT sensor-node sealing & pressure-equalization venting
Engineering context. A wireless sensor node, an air-quality probe, or a duct-mounted transmitter is a sealed box that heats and cools with the equipment around it, and every thermal cycle builds a pressure differential that stresses the perimeter seal and can pump moist air through any leak path. The fix is to let the box breathe on purpose: a ePTFE vent membrane passes air to balance the pressure while holding back liquid water and dust, so the seal stops fighting a load it was not designed to carry.
The node therefore wants two parts working together, a perimeter gasket that seals and a vent that equalizes, kitted so the box seals and breathes. The sealing intent is again an IP-framed sealing design referenced through IEC 60529 by designation, with the rating belonging to the customer's tested enclosure.
What H-O converts. Die-cut Gore ePTFE pressure-equalization vent membranes as vent disks and adhesive patches, sized to the vent port and selected from the membrane maker's airflow and water-entry-pressure data by designation; paired perimeter gaskets in silicone foam or PORON® microcellular urethane for the housing seam; and complete seal-and-breathe kits on liner. The broader sealing-and-venting playbook lives on the HVAC environmental sealing & venting sibling page; this section is its sensor-node edition.
Material-family guidance. The vent membrane is selected by airflow and water-entry pressure, not by guesswork: the membrane maker's data sheet gives the airflow at a stated differential and the liquid-entry pressure the construction holds, and the disk diameter trades airflow against footprint. Expanded PTFE is broadly weather- and UV-stable and chemically inert, which suits the rooftop and plenum environments a sensor node lives in.
Pair it with a perimeter gasket sized for the available closure force so the box seals and breathes as one design. The vent is bonded with a perimeter adhesive: adhesive performance depends on substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, joint geometry, and the assembly process, and the bond should be validated in the application against the membrane maker's mounting guidance.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
The vent-port diameter and the airflow or water-entry-pressure target if the program names one, the enclosure volume and the temperature swing it sees, the perimeter seal-channel geometry, the IP-framed sealing target by designation, the mounting method (adhesive patch vs. snap-in disk), and quantities. "Recommend a vent and gasket pairing" is a valid callout; the engineering review proposes one from the node geometry.
VFD heat-sink thermal interface materials
Engineering context. The smart HVAC product that drives a fan, pump, or compressor carries a variable frequency drive, and the drive's power stage makes heat that has to leave the silicon, cross a joint, and reach a heat sink or chassis. The thermal interface material fills the microscopic air gap at that joint and carries heat across it; air is a poor conductor, so replacing it with a conformable TIM lowers the resistance of the interface.
The number that matters is in-application thermal impedance, which is bulk conduction through the pad plus the contact resistance at both faces, and it is pressure-dependent: higher mounting pressure squeezes out air and lowers the contact term. A pad's thermal impedance is therefore meaningful only with its mounting pressure stated, measured per ASTM D5470 by designation.
What H-O converts. Die-cut boron-nitride silicone gap pads, thickness set to the measured gap, where the pad bridges an uneven or tolerance-stacked joint; natural and synthetic graphite heat spreaders where the job is to move heat laterally across a surface and even out hot spots; thin TIM pads and films for flatter, higher-pressure joints; and dielectric-rated PROTECT-series TIM pads where the interface must also isolate electrically. Kiss-cut TIM kits ship on liner in placement order.
Material-family guidance. Name the job first: conduct heat across a joint (a gap pad or TIM film), or spread it laterally across a surface (graphite). A soft boron-nitride silicone gap pad fills an uneven gap at low pressure and is the default where the gap is wide or varies across the part [5]; a thin TIM film needs flatter surfaces and more pressure but gives the lowest impedance when the joint allows it.
Graphite spreaders carry heat in-plane and are often supplied with a PSA on one face. State the gap and the mounting pressure with the part, because the same pad reports a different thermal impedance per ASTM D5470 at a different pressure [1]: a thin, conformable pad at good contact pressure can beat a thicker pad of higher bulk conductivity. The full electronics-side playbook lives on the power-module thermal management sibling page; this section is its HVAC-drive edition.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
The gap dimension and its tolerance, the mounting or clamp pressure available at the joint (the TIM impedance is meaningless without it), the heat path (through-plane vs. lateral spreading), whether the interface must isolate electrically, the conductivity class or thermal-impedance target if the program names one (per ASTM D5470 on the maker TDS), liner and PSA needs, and quantities for prototype and production.
Display & touch-panel bonding & dust seals
Engineering context. The smart thermostat or controller shows a face to the room: a glass or polycarbonate display, a capacitive touch lens, and the bezel that frames them. Two soft-goods jobs live here. The first is the bond line that holds the lens or display to the bezel in a thin stack-up without a fastener, a job for a carrier-free transfer tape that gives a strong, low-profile bond on flat, close-fitting parts.
The second is the dust seal behind the bezel, a thin compressed foam gasket that keeps airborne dust out of the gap between lens and housing without adding closure force the snap-fit cannot deliver. Both are to a tight kiss-cut outline so they place cleanly on the line.
What H-O converts. Kiss-cut acrylic transfer tape bond lines and mounting tape for lens, display, and bezel attachment in tight stack-ups; double-coated tapes where a carrier suits the build; and PORON® microcellular urethane dust gaskets behind the bezel, with the thin compressed foam set chosen for the small gap. Tight-tolerance kiss-cut outlines on liner run on flatbed die-cutting and CNC knife cutting.
Material-family guidance. The bond line is a thin transfer tape, not a foam tape: a carrier-free acrylic transfer tape gives a strong, low-profile, high-shear bond on flat parts, which is what a display and a lens want. The dust seal is a soft microcellular urethane sized to the gap, compressed enough to exclude dust but not enough to bow the lens.
Because every one of these parts bonds through an adhesive at assembly, the selection has to be earned, not assumed: adhesive performance depends on substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, joint geometry, and the assembly process, and tape selections should be validated in the application against the lens and bezel substrates, particularly where one is a low-surface-energy plastic.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
The bond-line outline and width, both bonded substrates and their surface energy (glass, polycarbonate, painted bezel), the dust-seal gap and geometry, the service temperature, whether the bond is structural or a light hold, and quantities. A drawing of the bezel stack-up lets the review match the tape gauge and the dust-seal thickness to the gap.
EMI shielding for radio & comms modules
Engineering context. A connected HVAC product carries a radio, a Wi-Fi, Zedbee, or cellular module, a wired comms bus, or all of them, sharing a small enclosure with a switching power supply and, often, a VFD. The radio is both a deliberate transmitter and a sensitive receiver, and the switching electronics beside it are a noise source; an unshielded seam or a leaky board-level can lets the two interfere.
The converted parts of this job close those gaps: a conductive-elastomer gasket on a shield-frame joint, a fabric-over-foam strip on a long low-force run, and a conductive foil bridge across a board-level shield seam. The regulatory framing is the emissions environment, referenced through CISPR 11 and FCC Part 15 by designation; the EMC evaluation belongs to the product maker's tested design, and the gasket is the converted part that helps the design get there.
What H-O converts. Die-cut and kiss-cut SSP502 nickel-graphite silicone board-level and shield-frame gaskets; the SSP502-V0 series where the product documentation also wants a flame class on the gasket (UL 94 class per the vendor TDS); BISCO® EC-2130 soft soft conductive solid silicone where a lid or cover closes at low force; fabric-over-foam profiles for long, low-force runs and sliding contacts; and the broader EMI shielding elastomer family for profiles the standard grades do not cover.
The dedicated EMI playbook lives on the HVAC electrical insulation & EMI sibling page.
Material-family guidance. Pick by closure force first, conductivity second. Nickel-graphite silicone is the cost-effective conductive-elastomer default for module-level work; the EC-2130 sponge construction trades some conductivity for a closure force a thin lid can deliver; fabric-over-foam suits long perimeter runs where a soft, low-force seal matters more than maximum attenuation, with construction-specific properties per the vendor TDS.
Galvanic pairing belongs on the drawing: a conductive gasket touches the shield metal by design, so note the mating finish and keep the pairing inside the corrosion guidance on the vendor TDS, particularly where the product lives in condensing air.
Where the gasket is PSA-backed, the adhesive holds the part for assembly and the conductive path comes from compression: adhesive performance depends on substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, joint geometry, and the assembly process, and tape selections should be validated in the application.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
The shield-frame or board-level outline, the gasket cross-section or groove dimensions, the closure force available, the mating-surface finish for galvanic pairing, the emissions context by designation (CISPR 11 / FCC Part 15) if the program names one, any flame-class requirement on the gasket, and quantities for prototype and production.
Battery-holder cushion pads
Engineering context. Many connected HVAC nodes carry a backup cell or a coin or pouch battery for the real-time clock, the radio, or ride-through during a power blip, and the cell has to sit still. A loose cell rattles, fatigues its tabs, and loses contact under the vibration a rooftop unit or an air handler transmits into everything bolted to it.
The cushion pad is a small foam part that takes up the tolerance between the cell and its holder or housing wall, holds the cell against shock and vibration, and absorbs the transient that would otherwise reach the tabs. It is unglamorous and decisive: a node that drops its clock every time a compressor starts is a node with a missing cushion pad.
What H-O converts. Die-cut PORON® microcellular urethane cushion and tolerance-take-up pads where a soft, low-load, set-resistant cushion holds the cell; HyPUR-cel® polyurethane foam for impact and shock cushioning where the node sees a harder transient; and thin foam shims and spacers that locate the cell in its holder. Kiss-cut pad sets ship on liner for line placement.
Material-family guidance. This is a low-load precision-cushion job, which is exactly where microcellular urethane lives: PORON® takes a set slowly, returns reliably, and cushions at low load without bottoming out, which keeps a light cell located across thousands of vibration cycles. HyPUR-cel® steps in where the transient is a shock rather than steady vibration and the pad has to absorb energy and bottom gracefully.
Size the pad to the gap and the cell mass; a pad that is too stiff transmits the very vibration it was meant to absorb. Where the pad mounts with a PSA, adhesive performance depends on substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, joint geometry, and the assembly process, and the bond should be validated in the application.
Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.
The cell size and mass, the gap between cell and holder, the geometry of the cushion (pad, shim, or wrap), the vibration or shock environment, any PSA or liner need, the service temperature, and quantities. "Recommend a cushion family" is a valid callout; the engineering review proposes one from the cell and the gap.
The decisions that drive a smart-HVAC electronics spec
A smart-HVAC control assembly is four jobs in one enclosure — sealing, thermal, EMI, and cushioning. The first decision is which one a given part is really doing.
Name the dominant physics for each part first — seal, heat path, shield, or cushion — then size it to the rating the design review asks for. Grades carry their own IP, thermal, and flame class per TDS.
Show all 5 selection factors tap to expand
Specification Tools
Two tools to take you from "we're building a connected HVAC product" to here's the soft-goods checklist for the drawing set: a job-driven checklist builder that assembles the part list with its citation language, and a side-by-side comparison of every family on this page.
1. Smart-HVAC soft-goods checklist builder
Check the jobs your product carries. The builder assembles the corresponding parts into a checklist with the family, what to send with the drawing, and the citation language (material classes per the maker TDS; ingress, thermal, and EMC standards by designation). The default selection is pre-built for a typical connected controller with a sealed enclosure and a radio; every part is also printed in the material reference section, so nothing here exists only behind a script.
Smart-HVAC soft-goods checklist: 3 parts selected
Each checked job adds its part below. The list is the starting bill of materials for the engineering review, not a certification: material classes (UL 94) come from the grade TDS, and ingress, thermal, and EMC standards (IEC 60529, ASTM D5470, CISPR 11, FCC Part 15) are cited by designation with the evaluation belonging to the customer's tested design or program.
- Enclosure gasket: silicone foam/sponge or PORON® microcellular urethaneSend: seal-channel geometry, closure force, IP-framed target, flame class. Cite: IEC 60529 by designation; UL 94 class per the vendor TDS.
- Display set: acrylic transfer-tape bond line + PORON® dust sealSend: bond-line outline, both substrates and surface energy, dust-seal gap. Cite: properties per the vendor TDS; bond validated in the application.
- EMI gaskets: SSP502 nickel-graphite or EC-2130 spongeSend: cross-section, closure force, mating finish. Cite: emissions context per CISPR 11 / FCC Part 15 by designation.
2. Side-by-side: smart-HVAC soft-goods family comparison
Every family called out on this page, with construction, the property that drives its selection, the standards its TDS cites, and the job it serves. Click a column header to sort. Click any material name to jump to its accordion entry.
| Material | Construction | Selection driver | Standards on the TDS / by designation | Job | |
|---|---|---|---|---|---|
| Sealing & venting (close the box, let it breathe) | |||||
| Closed-Cell Silicone Foam & SpongeCellular silicone grades | Closed-cell silicone | Wide-temperature sealing; V-0 grades | UL 94 V-0 per vendor TDS; IP-framed per IEC 60529 (by designation) | Controller / thermostat gaskets | |
| PORON® Microcellular UrethaneMicrocellular PU | Microcellular urethane foam | Low closure force, slow set | Compression set per ASTM D395 on the vendor TDS | Low-force seals, dust seals, cushions | |
| HyPUR-cel® Polyurethane FoamCellular PU | Cellular polyurethane | Impact & shock cushioning | Per vendor TDS; shock methods where required | Battery-holder cushion pads | |
| Gore ePTFE Vent MembraneExpanded PTFE | Expanded-PTFE membrane | Breathes; holds back liquid & dust | Airflow & water-entry pressure per the membrane TDS | Sensor-node pressure equalization | |
| Thermal interface (move the heat, spread the heat) | |||||
| Boron-Nitride Silicone Gap PadConformable TIM | Filled silicone gap pad | Fills uneven gap at low pressure | Thermal impedance per ASTM D5470 at stated pressure | VFD heat-sink TIM (through-plane) | |
| Natural & Synthetic Graphite SpreadersGraphite TIM | Thin graphite sheet | High in-plane lateral spreading | In-plane conductivity per the maker TDS | Lateral heat spreading | |
| TIM Pads & Films (incl. dielectric-rated)Through-plane TIM | Thin filled-elastomer pad / film | Lowest impedance on flat, higher-pressure joints | Thermal impedance per ASTM D5470; dielectric per grade TDS | Flat-joint TIM, electrical isolation | |
| Bonding & conductives (hold the face, close the seams) | |||||
| Acrylic Transfer Tape & Mounting TapePSA bonding family | Carrier-free acrylic / coated tape | Thin, high-shear bond line | Per vendor TDS; bond validated in the application | Display / lens / bezel bonding | |
| SSP502 Nickel-Graphite + SSP502-V0 + EC-2130 + Fabric-Over-FoamConductive elastomers | Filled silicone / sponge / metallized fabric | Shielding at the available closure force | UL 94 on the V-0 grades per vendor TDS; emissions context per CISPR 11 / FCC Part 15 (by designation) | Radio / comms module EMI gaskets | |
| Conductive Foil Tape + BISCO® EC-2265 SolidGrounding set | Cu/Al foil with conductive PSA / solid conductive silicone | Low-impedance bonding through joints | Per vendor TDS; pairing per galvanic guidance | Shield seam bridging, ground bonds | |
Skip ahead and request your engineering review now
If your drawing set already calls out a gasket profile, a vent-disk diameter, a gap-pad thickness, a transfer-tape bond line, or an EMI gasket cross-section, send it over for engineering review against the TDSs and the standards language.
Smart-HVAC soft-goods failures you can prevent at the drawing
Five failure modes that show up in the field on connected HVAC products, and the drawing note that prevents each. None of them is a material defect; all of them are spec decisions made or missed before the part was cut.
Show all 5 failure modes tap to expand
Condensation inside a sealed sensor node
A box that seals but cannot breathe builds a pressure differential on every thermal cycle and pumps moist air through any leak path, then condenses inside. The fix is designed-in venting: a ePTFE vent membrane equalizes pressure while holding back liquid and dust, so the seal stops carrying a load it was not designed to. Spec the vent alongside the gasket.
A gasket the snap-fit cannot close
A silicone sponge sized for a screwed lid will not seal under a thin snap-fit that delivers only a few psi: the lid bows before the gasket compresses. The fix is to match the material to the closure force, dropping to a low-force microcellular urethane where the force budget is small. Put the available closure force on the drawing.
A TIM specified without its mounting pressure
Thermal impedance per ASTM D5470 is pressure-dependent: the same pad reports a different impedance at a different clamp pressure, and a thin pad at good pressure can beat a thicker, higher-conductivity pad at low pressure. A TIM callout that omits the mounting pressure cannot be evaluated. State the gap and the pressure together.
A display bond that lets go on a low-energy plastic
A transfer tape that holds on glass can release on an untreated low-surface-energy bezel. Adhesive performance depends on substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, joint geometry, and the assembly process; the bond has to be validated in the application. Name both substrates and their surface energy on the drawing.
A galvanic couple at the EMI gasket
A conductive gasket touches the shield metal by design, and a dissimilar pairing in condensing air corrodes the very contact the EMC design depends on. The fix is to name the mating finish and keep the pairing inside the vendor TDS corrosion guidance. Put both mating metals and finishes on the drawing, particularly for products in humid or rooftop air.
Material reference
Detailed notes for the families referenced on this page: the sealing and venting set (closed-cell silicone foam and sponge, PORON® microcellular urethane, HyPUR-cel® PU foam, and the ePTFE vent membrane), the thermal interface set (boron-nitride silicone gap pads, natural and synthetic graphite spreaders, and through-plane TIM pads and films), and the bonding and conductives set (acrylic transfer and mounting tapes, conductive-elastomer EMI gaskets, and the conductive foil-tape grounding set).
Values are per the maker TDS on file for each grade with the method named; ingress, thermal, and EMC standards are cited by designation only, with the evaluation belonging to the customer's tested design. TIM thermal impedance is reported at a stated mounting pressure. H-O die-cuts, kiss-cuts, slits, and kits every family to drawing.
Closed-Cell Silicone Foam & SpongeWide-temperature enclosure gaskets · UL 94 V-0 grades per vendor TDS · IP-framed sealing designs
Specify the seal channel, closure force, temperature range, and any flame class. Where the lid delivers little force, PORON® microcellular urethane takes over; final material selection should be validated in the application.
PORON® Microcellular UrethaneLow-closure-force seals, display dust seals, cushion pads · compression set per ASTM D395 on the TDS
Specify thickness, the gap or seal channel, and the closure force. Commonly used for low-force sealing and precision cushioning; may be suitable depending on temperature and fluid exposure. Final material selection should be validated in the application.
HyPUR-cel® Polyurethane FoamImpact & shock cushioning for battery holders · per vendor TDS
Size the pad to the cell mass and the gap. Often specified for shock cushioning; may be suitable depending on the transient and temperature. Final material selection should be validated in the application.
Gore ePTFE Pressure-Equalization Vent MembraneSensor-node venting · airflow & water-entry pressure per the membrane TDS
Specify the vent-port diameter, the airflow or water-entry-pressure target, and the mounting method. The vent and gasket are designed as one seal-and-breathe pairing.
Boron-Nitride Silicone Gap PadConformable VFD heat-sink TIM · thermal impedance per ASTM D5470 at stated pressure
Specify the gap and its tolerance, the mounting pressure, and any conductivity-class or impedance target. The deep electronics-side playbook lives on the power-module thermal management sibling page.
Natural & Synthetic Graphite Heat SpreadersIn-plane lateral heat spreading · in-plane conductivity per the maker TDS
Specify the outline, the heat path (lateral spreading), and any PSA need. Final material selection should be validated in the application against the thermal model.
AeroZero® Graphite-Faced Aerogel Film (Blueshift)Spread + insulate in one part · VFD & controller enclosures, rooftop sun-load boxes
- AZ-TPS GR 100 · DualZero TPS GR 201 · QuadZero TPS GR 400 graphite-faced constructions — spread heat along the face while insulating through the thickness (UL 94 VTM-0 film; V-0 laminates)
- AZ-TPS 100 · AZ-TPS 101 single- and double-sided silicone-PSA aerogel film, 190–216 µm, UL 94 VTM-0
- AZ-TPS PI 100 polyimide-faced aerogel film, 240 µm, UL 94 VTM-0 — durable outer skin for handling and wear
Through-Plane TIM Pads & Films (incl. dielectric-rated)Flat-joint TIM, electrical isolation · thermal impedance per ASTM D5470
Specify the joint flatness, mounting pressure, and whether electrical isolation is required. A thin film and a soft gap pad solve different joints; the gap and pressure decide.
Acrylic Transfer Tape & Mounting TapeDisplay, lens & bezel bonding · per vendor TDS; bond validated in the application
Name both bonded substrates and their surface energy. Adhesive performance depends on substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, joint geometry, and the assembly process; tape selections should be validated in the application.
SSP502 Nickel-Graphite Silicone + SSP502-V0 + EC-2130 Sponge + Fabric-Over-FoamRadio & comms module EMI gaskets · UL 94 on the V-0 grades per vendor TDS
Pick by closure force first, conductivity second. Note the mating finish so the galvanic pairing stays inside the vendor guidance, particularly in condensing air.
Conductive Foil Tape (Cu / Al) + BISCO® EC-2265 Solid Conductive SiliconeShield seam bridging, ground bonds · conductive PSA per vendor TDS
Treat foil tape as a manufactured electrical part: width, foil thickness, and adhesive system come off the drawing.
Smart HVAC, IoT & VFD electronics: engineer-grade FAQ
Ten of the questions we hear most from connected-HVAC, controls, and building-automation teams. If your question isn't here, send a drawing or call, engineering picks up.
Are these gaskets and seals rated to an IP ingress code?
An IP ingress rating belongs to the tested enclosure, not to the gasket inside it, so we describe these as IP-framed sealing designs rather than making an unqualified ingress claim. What the materials carry is their own documentation: cellular silicone and microcellular urethane with compression-set data per ASTM D395 on the grade TDS, flame classes such as UL 94 V-0 on the listed grades, and lot-code traceability.
They support enclosures designed to an IP target framed by IEC 60529, cited by designation; the customer's tested enclosure owns the rating. [2]
Why does a sealed IoT sensor node need a vent membrane if it is supposed to be sealed?
Because a fully sealed box heats and cools and builds a pressure differential that stresses the perimeter seal and pumps moist air through any leak path, where it condenses inside. A ePTFE vent membrane lets the box breathe on purpose: it passes air to balance pressure while holding back liquid water and dust, so the seal stops carrying a load it was not designed to. The node is designed as a pairing, a perimeter gasket that seals and a vent that equalizes, kitted so the box seals and breathes.
How is an ePTFE vent membrane selected?
By airflow and water-entry pressure off the membrane maker's data sheet, not by guesswork. The data sheet gives the airflow the membrane passes at a stated pressure differential and the liquid-entry pressure the construction holds, and the disk diameter trades airflow against footprint. Expanded PTFE is broadly weather- and UV-stable and chemically inert, which suits the rooftop and plenum environments a sensor node lives in. Pair it with a perimeter gasket sized for the available closure force so the box seals and breathes as one design.
Why do you keep asking for the mounting pressure on a TIM?
Because a TIM's in-application thermal impedance is pressure-dependent, and a callout without the pressure cannot be evaluated. Thermal impedance per ASTM D5470 is the bulk conduction through the pad plus the contact resistance at both faces, and higher mounting pressure squeezes out air and lowers the contact term. The same pad reports a different impedance at a different pressure, and a thin, conformable pad at good pressure can beat a thicker pad of higher bulk conductivity. State the gap and the mounting pressure together. [1]
Gap pad vs graphite spreader vs TIM film: which thermal interface fits a VFD heat sink?
By the job and the joint. A boron-nitride silicone gap pad fills an uneven or tolerance-stacked gap at low pressure and carries heat through-plane, which makes it the default where the gap is wide or varies. A thin TIM film gives the lowest impedance but needs flatter surfaces and more pressure. A graphite spreader does a different job entirely, moving heat laterally across a surface to even out hot spots, often paired with a gap pad that takes the heat through-plane afterward. Name the heat path and the gap, and the family follows.
What holds a display or touch lens to the bezel, and will it stay bonded?
A carrier-free acrylic transfer tape gives a strong, low-profile, high-shear bond line for a display, lens, or cover glass in a thin stack-up, with a thin foam dust gasket behind the bezel to keep dust out of the gap. Whether it stays bonded depends on the substrate: adhesive performance depends on substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, joint geometry, and the assembly process, and the bond should be validated in the application.
A tape that holds on glass can release on an untreated low-surface-energy plastic, so name both substrates on the drawing.
Why does a smart HVAC product with a radio need an EMI gasket?
Because the radio is both a deliberate transmitter and a sensitive receiver, and the switching power supply or VFD sharing its enclosure is a noise source; an unshielded seam or a leaky board-level can lets the two interfere. A conductive-elastomer gasket on the shield frame, a fabric-over-foam strip on a long low-force run, or a conductive foil bridge across a board-level seam closes those gaps electrically.
The emissions framing is commonly CISPR 11 or FCC Part 15, cited by designation; the EMC result belongs to the product maker's tested design. [4]
Nickel-graphite solid vs soft conductive solid vs fabric-over-foam: which EMI gasket?
Pick by closure force first. SSP502 nickel-graphite solid silicone is the cost-effective conductive-elastomer default where the frame can compress it; the SSP502-V0 series adds a UL 94 V-0 class per the vendor TDS where the documentation wants one. BISCO® EC-2130 soft conductive solid trades some conductivity for a closure force a thin lid can deliver.
Fabric-over-foam suits long, low-force perimeter runs and sliding contacts where a soft seal matters more than maximum attenuation. Either way, note the mating finish on the drawing so the galvanic pairing stays inside the vendor guidance.
What cushions a backup battery or coin cell in a connected HVAC node?
A small foam cushion pad that takes up the tolerance between the cell and its holder and holds it against the shock and vibration a rooftop unit or air handler transmits. PORON® microcellular urethane is the low-load precision-cushion default: it cushions at low load, takes a set slowly, and returns reliably across many cycles. HyPUR-cel® PU foam steps in where the duty is a shock rather than steady vibration and the pad has to absorb energy and bottom gracefully.
Size the pad to the cell mass and the gap; a pad that is too stiff transmits the vibration it was meant to absorb.
What should I put on the drawing set so the quote comes back right the first time?
By job: for enclosure gaskets, the seal-channel geometry, closure force, IP-framed target, and any flame class; for sensor venting, the vent-port diameter and the airflow or water-entry target; for TIMs, the gap and the mounting pressure together; for display bonding, both substrates and their surface energy plus the dust-seal gap; for EMI gaskets, the cross-section, closure force, and mating finish; for battery cushions, the cell mass and the gap.
Plus quantities for prototype and production. "Recommend the family" is a valid callout: that is what the engineering review is for.
Glossary: terms used on this page
Quick reference for the sealing, venting, thermal, bonding, EMC, and standards terminology used throughout. Each entry links to the relevant standard or test method where applicable.
IoT sensor node
A small connected device, a wireless sensor, air-quality probe, or duct transmitter, that measures a condition and reports it over a network. In HVAC it is a sealed box mounted where the air is, so it defines a coupled sealing-and-venting problem: keep liquid and dust out while letting the box breathe through thermal cycles.
VFD (variable frequency drive)
The power-electronics controller that varies motor speed by synthesizing a PWM waveform. In a smart HVAC product it drives the fan, pump, or compressor for part-load efficiency, and it defines both the thermal problem (heat off the power stage) and the EMI problem (fast switching edges beside a radio) on this page.
IP-framed sealing design
A sealing design intended to help an enclosure reach an ingress-protection target framed by IEC 60529 [2], described this way to keep the rating attached to the customer's tested enclosure rather than to the gasket. H-O converts the seal; the IP rating belongs to the tested product.
IEC 60529 / IP code (by designation)
The standard defining the ingress-protection (IP) code, the two-digit rating for protection against solids and liquids, per [2]. Cited here by designation; the rating is assigned to the tested enclosure, so on this page sealing is described as an IP-framed sealing design.
Pressure equalization (venting)
Letting a sealed enclosure breathe through a membrane so the internal and external pressures balance as the box heats and cools, instead of loading the perimeter seal and pumping moist air through leak paths. A ePTFE vent membrane passes air while holding back liquid water and dust.
ePTFE (expanded PTFE)
A microporous expanded-PTFE membrane whose pore structure passes air vapor while blocking liquid water and dust. Broadly weather- and UV-stable and chemically inert; selected by airflow at a stated differential and liquid-entry pressure off the membrane maker's data sheet.
Thermal interface material (TIM)
A conformable material placed between a hot component and a heat sink or chassis to fill the microscopic air gaps at the joint and carry heat across it. Air is a poor conductor, so replacing it with a TIM lowers the thermal resistance of the interface. Gap pads, TIM films, and graphite spreaders are all TIMs.
Thermal impedance (per ASTM D5470)
The in-application measure of how much a TIM resists heat flow across the joint, including both bulk conduction through its thickness and the contact resistance at each surface, measured per ASTM D5470 [1]. It is pressure-dependent: a thin, conformable pad at good contact pressure can beat a thicker pad of higher bulk conductivity, which is why mounting pressure is stated with every value.
Gap pad
A soft, conformable filled-silicone TIM, often boron-nitride-filled, sized to a measured gap so it fills an uneven or tolerance-stacked joint at low pressure and carries heat through-plane. The default where the gap is wide or varies across the part; thickness is set to the gap.
Closure force
The force a lid, door, or frame applies to compress a gasket. A thin snap-fit closure delivers only a few psi, so a gasket sized for a screwed lid will not seal under it. Matching the material to the available closure force, dropping to a low-force microcellular urethane where the budget is small, is the first gasket decision.
Microcellular urethane
A fine-celled polyurethane foam (PORON® family) that seals and cushions at low closure force, takes a set slowly, and returns reliably across many cycles, with compression set reported per ASTM D395 on the grade TDS. The default for low-force seals, display dust seals, and precision cushion pads on this page.
Fabric-over-foam
A metallized-fabric-wrapped foam EMI gasket for long, low-force runs and sliding contacts, where a soft, conformable conductive seal matters more than maximum shielding. Construction-specific properties come from the vendor TDS; cited here as a generic family.
Galvanic pairing
The corrosion relationship between a conductive gasket's filler or a foil tape's metal and the shield surface it touches. Dissimilar pairings in condensing air corrode the very contact the EMC design depends on; name both metals on the drawing and keep the pairing inside the vendor TDS guidance.
CISPR 11 / FCC Part 15 (by designation)
Emissions frameworks for industrial, scientific, and medical equipment (CISPR 11) and for unintentional radiators in the US regulatory context (FCC Part 15), per [4]. Cited here by designation as the EMC context behind radio-module and VFD shielding work; the emissions result belongs to the product maker's tested design.
UL 94 (per the grade TDS)
The flammability classification for plastic materials (HB, V-2, V-1, V-0, 5V classes), per [3]. The class belongs to the listed material grade per its TDS at the tested thickness; it is a material property, not an equipment listing.
Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).
Standards, test methods & technical references
The standards, test methods, and maker technical data sheets cited throughout this page. Ingress, thermal, and EMC standards are cited by designation: they evaluate enclosures, joints, and programs, and the evaluation belongs to the customer's tested design. Standards editions current as of June 2026; verify against the publishing body before final spec. H-O converts materials tested to the material-level methods on the source maker's TDS; H-O does not certify systems or independently certify materials unless explicitly stated on the quote.
[1] ASTM D5470
Standard test method for thermal transmission properties of thermally conductive electrical insulation materials: the method behind a TIM's thermal-impedance and apparent-conductivity values, reported at a stated mounting pressure. Cited by designation as a test method, not as a pass. store.astm.org (ASTM D5470-17)
[2] IEC 60529 (by designation)
Degrees of protection provided by enclosures (the IP code): the framework behind ingress-protection ratings against solids and liquids. Cited by designation; the rating is assigned to the tested enclosure, so sealing on this page is described as an IP-framed sealing design. webstore.iec.ch (IEC 60529)
[3] UL 94 (per the grade TDS)
Standard for tests for flammability of plastic materials for parts in devices and appliances. Classes (HB through V-0 and 5V) attach to the listed material grade at the tested thickness per the maker TDS; they are material properties, not equipment listings. ul.com/services/combustion-fire-tests-plastics
[4] CISPR 11 / FCC Part 15 (by designation)
Emissions frameworks for industrial, scientific, and medical radio-frequency equipment (CISPR 11) and for unintentional radiators in the US regulatory context (FCC Part 15). Cited by designation, by name only, as the EMC context behind radio-module and VFD enclosure shielding work; the emissions result belongs to the product maker's tested design.
[5] Boron-nitride gap-pad TDS (by maker)
Maker technical data sheets for the boron-nitride silicone gap-pad family: the source for thermal impedance and apparent conductivity (reported per ASTM D5470 at a stated mounting pressure), hardness, and deflection data used to select a pad to a measured gap. Values per the maker TDS on file; cited by name only.
Updated . Standards editions and links current at publication; verify against the publishing body before final spec. H-O converts materials tested to the methods cited; H-O does not certify systems. Lot-specific documentation available on request.
Get a smart-HVAC soft-goods engineering quote
Send a drawing set, gasket profile, vent-port detail, or thermal-stack drawing. We typically respond within one business day with a material recommendation, prototype lead time, and TDS verification against your IP-framed sealing targets, thermal-impedance requirements, EMC context, and standards language.
See also: related H-O application pages
Engineering content for the adjacent HVAC sub-applications, the supporting capabilities, the parent application, and the owning industry hub. Each page covers material selection, failure modes, and converter-side process detail for its application family.
Parent application
Thermal management & insulation
The cross-industry thermal overview: TIMs, gap pads, graphite spreaders, and insulation, with the impedance logic this page's heat-sink job draws from.
Read the page
Sibling sub-application
HVAC electrical insulation & EMI
The dedicated EMI and insulation playbook behind this page's gasket and shielding jobs: conductive elastomers, foil tapes, and grounding hardware at panel scale.
Read the page
Sibling sub-application
HVAC environmental sealing & venting
The full sealing-and-venting playbook this page's enclosure and sensor-node jobs draw from: door and panel gaskets, roof-curb seals, and vent membranes.
Read the page
Sibling sub-application
HVAC thermal management & insulation
The equipment-side thermal playbook: duct and plenum insulation, anti-condensation liners, heat-exchanger gaskets, and high-temperature families.
Read the page
Capability
Flatbed die-cutting
The converting line behind the gaskets, dust seals, TIM kits, and EMI parts on this page: steel-rule and rotary die-cutting to drawing and tolerance.
Read the page
Capability
CNC knife cutting
Digital, tool-free cutting for prototypes and short runs: kiss-cut gasket and TIM sets on liner in assembly order, no steel-rule die required.
Read the page
Industry hub
Industrial HVAC
The full HVAC application family: sealing, vibration, thermal, electrical, fire protection, and the converter-side process detail behind each.
Read the page
Send the drawing set for your smart-HVAC soft-goods parts
Enclosure gaskets, vent membranes, heat-sink TIMs, display bond lines, EMI gaskets, and battery-holder cushions, in Winsted, Connecticut with material traceability and lot-code TDS records. Typical response in one business day.
Material data & standards. All sealing, thermal, flammability, and conductivity values on this page are taken from the source maker's technical data sheets with the method named (compression set per ASTM D395, TIM thermal impedance per ASTM D5470 at a stated mounting pressure, UL 94 classes per the listed grade TDSs, vent airflow and water-entry pressure per the membrane maker's TDS, shielding and conductivity data per the vendor TDSs).
Ingress and EMC standards (IEC 60529, CISPR 11, FCC Part 15) are cited by designation only: they evaluate enclosures, products, and programs, the evaluation belongs to the customer's tested design, and the materials on this page support designs evaluated to them. Sealing is described as an IP-framed sealing design rather than as an unqualified ingress claim; the IP rating belongs to the customer's tested enclosure.
TIM thermal-impedance values are pressure-dependent. Performance depends on grade, geometry, compression, adhesive system, and environment; final material selection should be validated in the application. H-O converts materials; H-O does not build products, perform ingress, thermal, or EMC evaluation, or certify systems, and does not independently certify materials against the standards unless explicitly stated on the quote. Verify against the maker TDS and your product-level evaluation plan.
Conversion scope. H-O and converts sheet, roll, and membrane stock to drawing in Winsted, Connecticut: die-cut and kiss-cut gaskets, vent disks and patches, TIM pads and kits, transfer-tape bond lines, EMI gaskets, and cushion pads, slit films and tapes to width, and CNC knife-cut and flatbed die-cut sets on liner, with material traceability and lot-code TDS records. H-O does not mold or extrude in-house; molded or extruded profiles are coordinated through a partner network.
Lead-time and MOQ details are in the quote form above. Renderings and diagrams on this page are representative illustrations, not product photographs.