For HVAC, refrigeration & air-handling equipment engineers

HVAC Vibration & Acoustic Control

Rooftop HVAC unit interior with compressors and blower assemblies mounted on resilient isolation pads, the vibration environment addressed by die-cut NVH materials

H-O Products die-cuts and converts rebonded neoprene, rubberized cork, engineered bearing pads, vinyl nitrile foam, PORON® and HyPUR-cel® microcellular polyurethane, reticulated acoustic foam, mass-loaded sound-barrier silicone, and SAE pressed felt into the compressor isolation pads, fan and blower damping parts, panel damping laminates, acoustic liner die-cuts, piping clamp cushions, and VFD vibration pads inside HVAC equipment, built to your drawing.

Built for: rooftop units, chillers, heat pumps, air handlers, fan coils, condensing units, and the controls cabinets beside them, six vibration and acoustic jobs that decide whether the unit hums politely on the curb or walks its noise into the building below.

Send a drawing Request a material recommendation →
01
f/fn > √2
Where a resilient mount starts to isolate
Isolation only begins once the disturbance frequency is above about 1.4× the mounted natural frequency; below that the pad transmits or amplifies. Compressor and fan pads are sized to that relationship, not to the gap.
02
6 jobs
Six vibration & acoustic jobs in one unit
Compressor isolation, fan and blower damping, panel constrained-layer damping, acoustic lining, piping clamp cushions, and VFD/controls pads, each with its own material logic on this page.
03
9 families
Material families H-O converts for HVAC NVH
Rebonded neoprene, rubberized cork, Atlas bearing neoprene, vinyl nitrile, neoprene foam, PORON® and HyPUR-cel® urethanes, reticulated acoustic foam with the A2 sound barrier, and SAE pressed felt.
04
8
Standards & methods cited by designation
ASTM D1056, D3574, E756, D395, ISO 10846, UL 94 classes per grade TDS, AHRI 575 sound-rating context, and ASTM E90/E413 for transmission-loss vocabulary.
Quick Answer

To control vibration and noise in HVAC equipment, match the material family to the job and the load band. Compressor mounts: rebonded neoprene (25# / 27#), rubberized cork, or engineered Atlas bearing neoprene (258/268), sized so bearing stress sits inside the grade’s working range. Fan and blower assemblies: vinyl nitrile or neoprene foam isolation strips and pads. Cabinet drumming: a lossy damping layer (loss factor per ASTM E756 on the maker TDS).

Acoustic lining: open-cell reticulated foam (10–80 PPI), with UL 94 HF-1 flame-rated versions per vendor TDS (20 PPI HF-1 example).

The remaining duties are mapped in the When-to-spec list. Values are per the TDS on file; see the material reference below for ordering details.

Standards & Test Methods

Cited by designation, with rated results belonging to the tested equipment or assembly: ISO 10846 (vibro-acoustic transfer properties of resilient elements) · AHRI 575 (sound rating of water-chilling packages, design context) · ASTM E90 / E413 (transmission loss and STC vocabulary).

Material-level, per the maker TDS: ASTM D1056 (flexible cellular rubber, compression-deflection classes) · ASTM D3574 (flexible cellular urethane methods) · ASTM E756 (vibration-damping loss factor) · ASTM D395 (compression set) · ASTM D2240 (durometer, solids only) · UL 94 (flammability classes on the rated grades).

H-O does not independently certify materials to these methods unless explicitly stated on the quote.

When To Spec What
LocationMade in Winsted, CT · Family-owned since 1971 · ISO 9001:2015 Certified Organization
Two ways through this page

Where are you in the spec process?

This page serves engineers who already know the pad, liner, or damping grade they want and engineers still working out whether the problem is isolation, damping, or absorption. Pick the path that matches where you are; you don't have to read the rest.

If you know your spec

Send a drawing, get a quote

A rebonded neoprene pad, rubberized cork shim, vinyl nitrile gasket, PORON® grade, reticulated acoustic liner, A2 barrier laminate, or felt cushion on your drawing, with adhesive, liner, and thickness called out.

Skip to the quote form →
If you need a recommendation

Work through the six jobs

Six numbered job sections, compressor isolation through VFD pads, each with the engineering context, the material families that commonly serve it, and exactly what to send with the drawing.

Start with job 01 →
Finished die-cut Rebonded Neoprene parts converted by H-O Products, on release liner ready to ship
How it works
  1. 1
    Send drawing
    Upload a DXF, STEP, or PDF, or describe the unit and the disturbance. A sample part works too.
  2. 2
    Material review
    Engineering checks the goal (isolation, damping, absorption, or cushioning), the static load per pad, the running speed, the temperature, and any flame-class requirement against the maker TDSs, with classes cited per TDS and standards by designation.
  3. 3
    Prototype
    Samples typically ship in 3–5 business days for common configurations on materials we keep on hand. Made-to-order; MOQ varies by material and part.
  4. 4
    Production
    Standard production runs ship about 2 weeks after drawing approval, on flatbed die-cutting, adhesive lamination for absorber-on-barrier acoustic parts, and kitting for unit-level NVH sets. Ongoing parts run with material traceability and lot-code TDS records.
Start where you are

Which noise are you chasing?

Jobs 1, 5 & 6
It hums through the structure
Structure-borne vibration from compressors, piping, and drives: isolation pads, clamp cushions, and precision urethane parts that lower the mounted natural frequency and break the transmission path.
Start spec
Jobs 2 & 3
The cabinet drums and buzzes
Resonating sheet-metal panels and blower housings: free-layer and constrained-layer damping laminates that drain panel resonance as heat, with loss factor per ASTM E756.
Start spec
Job 4
The unit is just loud
Airborne noise: reticulated-foam absorption liners, A2 sound-barrier mass, and the laminated absorber-on-barrier that treat plenum and compressor-compartment walls.
Start spec
Application zones

The six vibration and acoustic jobs, zone by zone

Pick a zone to see the job, the materials that lead it, and what to put on the drawing.

Vibration isolation parts on a light backdrop — two long moulded rubber rail pads with slots, curved and rectangular closed-cell foam pads, four cork-and-rubber mounting pads with slotted holes, four thick rebonded-rubber compressor pads with centre bolt holes, and a rebonded rubber cube

Compressor mount isolation pads

Test methods: ASTM D1056 compression classes; ASTM D2240 durometerContext: compressor mounts — the heaviest, lowest-frequency disturbance

The compressor is the heaviest, lowest-frequency disturbance in the unit, and the pad under it is a spring, not a spacer. Isolation only begins once the running-speed disturbance sits above about √2 times the mounted natural frequency; a pad that is too stiff for the load parks the system near resonance and makes the hum worse.

Scroll and reciprocating compressors in rooftop units, condensing units, and heat pumps commonly sit on dense pads sized by static bearing stress: compressor mass over pad area, placed so each pad works inside the compression range its TDS reports per ASTM D1056.

The compressor deck also smells of refrigerant oil, which favors neoprene-family chemistry over commodity foams.

Rebonded Neoprene (25# / 27#)The classic heavy-equipment base pad: dense rebonded construction that carries sustained bearing stress without creeping flat, with per-grade data per ASTM D1056 on the TDSs. SKUs: 25# · 27#. [1]
Rubberized Cork (BC351-207, DC100 Series)Stiff, thin, very low-creep mount shims and pads where deflection budget is small; cork-elastomer composites to the foot pattern. SKUs: BC351-207 · DC100-312.
Atlas Bearing Neoprene (258 / 268)Engineered solid-neoprene bearing pads for structural duty, base rails, skids, and curb interfaces, specified by Shore A per ASTM D2240 with ozone data per the TDS. SKUs: 258 · 268.
Vinyl Nitrile Foam (SBE41VN / SBE42VN)Closed-cell isolation at gentler loads, small compressors, receivers, and accumulators, with compression-deflection classes per ASTM D1056 on the grade TDSs. SKUs: SBE41VN · SBE42VN.

Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.

What to send H-O: compressor mass and number of feet, pad footprint per foot, running speed (RPM or Hz), mounting temperature range, oil exposure, and the drawing or foot-pattern sketch. Engineering checks bearing stress against the grade's compression range and confirms the chemistry against the TDS. Final material selection should be validated in the application.
Centrifugal blower assembly in an air handler with foam isolation strips between the blower frame and the mounting deck

Fan & blower housing damping and isolation

Test methods: ASTM E756 (damping); ASTM D1056; ASTM D3574Context: fan and blower housings — airborne and structure-borne paths

Fans and blowers make two noises with two fixes. The first is structure-borne: blower frames and motor decks transmit imbalance and blade-pass vibration into the cabinet, and the fix is resilient isolation, foam strips and pads between frame and deck that lower the mounted natural frequency below the blade-pass disturbance.

The second is the housing itself: a scroll or housing panel excited at blade-pass frequency radiates noise directly, and the fix is damping, a lossy layer bonded to the housing that drains the resonance as heat, characterized by loss factor per ASTM E756 on the maker TDS.

The two jobs use nearly opposite materials, soft and resilient versus lossy and dissipative, so the first specification decision is which noise you are actually hearing.

Vinyl Nitrile Foam (ENSOLITE® Family)The general-duty fan and blower isolation foam: closed-cell strips and pads cut to the frame pattern, classes per ASTM D1056. SKU example: ENSOLITE® IG1. [1]
Neoprene Foam (incl. Ribbed)Oil- and ozone-tolerant isolation strips for motor decks and fan frames; ribbed profiles add controlled compliance under bolted joints.
PORON® Industrial Microcellular PUPrecision low-set pads where the blower is small and the deflection window tight; compression behavior per ASTM D3574 on the grade TDSs. [2]
Damping layers (lossy elastomer, by designation)Free-layer damping sheet bonded to housing panels, selected by the loss-factor-versus-temperature curve per ASTM E756 on the vendor TDS; see Job 03 for the constrained-layer construction. [3]

Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.

What to send H-O: blower mass and frame footprint, fan speed and blade count (blade-pass frequency), where the noise reads loudest (frame, deck, or housing skin), temperature at the housing, and the geometry. If the symptom is "the housing rings," send a phone video; the frequency content is usually audible enough to steer the damping choice.
Constrained-layer damping material applied to an HVAC cabinet panel to control resonance

Cabinet panel constrained-layer damping

Test methods: ASTM E756 (loss factor) per damping-material TDSContext: large flat sheet-metal panels — constrained-layer damping

Large flat sheet-metal panels are drums: an access door or cabinet side excited by the compressor or blower resonates and re-radiates the tone, often louder than the source. Damping treatments come in two constructions. Free-layer bonds a lossy elastomer sheet to the panel; the layer strains in bending and dissipates energy, and effectiveness scales with the damping layer's thickness and loss factor.

Constrained-layer adds a stiff facing, foil or thin laminate, over the lossy core, forcing the core into shear, which extracts far more damping per gram and per millimeter; it is the construction of choice on doors and panels where weight and thickness are budgeted. H-O laminates the damping layer, the constraining facing, and the pressure-sensitive adhesive into one part, cut to the panel zone that actually moves rather than wallpapering the whole cabinet.

Because these parts install on adhesive: final adhesive selection should be validated in the application, performance depends on the substrate, surface energy, temperature, exposure, dwell time, applied pressure, surface preparation, part geometry, and assembly method, with painted and powder-coated panels deserving particular attention.

Constrained-layer damping laminates (built to drawing)Lossy elastomer core with a stiff constraining facing and PSA, supplied as one part; core selected by the ASTM E756 loss-factor curve at your panel's temperature and resonance band, per the vendor TDS. [3]
Free-layer damping sheet (by designation)Single-sided lossy sheet with PSA for housings and secondary panels where thickness is available and the resonance is broad; loss factor and use-temperature band per the vendor TDS.
Rubberized Cork CompositesSemi-rigid cork-elastomer sheet used as a damping and de-coupling interlayer between bolted panels and stiffeners, where a soft foam would crush. SKU example: SP52.
SAE Pressed Felt (Anti-Buzz Interfaces)Thin felt strips at panel contact lines and fastener rattle points, the buzz-squeak-rattle companion to the damping layer; felt grades per ASTM D2475/D461 on the TDS. SKUs: F-10 · F-26.

Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.

What to send H-O: panel material and gauge, panel size and the zone that buzzes, the offending frequency or the source (compressor speed, blade-pass), surface finish (bare, painted, powder-coated), service temperature, and whether weight or thickness is budgeted. Engineering proposes free-layer or constrained-layer, the core grade, and the PSA, with the laminate supplied as one part.
Open-cell acoustic foam liner laminated to a mass-loaded barrier sheet inside an HVAC compressor compartment panel

Acoustic liner die-cuts: absorption + barrier mass

Test methods: UL 94 per grade; absorption and barrier mass per liner TDSContext: acoustic liner die-cuts in the airstream and cabinet

"Make the unit quieter" hides two different physical jobs. Absorption converts sound energy to heat inside an open-cell structure; it tames the reflective build-up inside compressor compartments, plenums, and control closets, but does little to stop sound passing through a panel. Blocking stops transmission with limp, heavy, decoupled mass; it quiets the far side of the wall but leaves the inside harsh.

An absorber alone will not fix a transmission problem, and a barrier alone will not fix a reverberant one, which is why most effective HVAC liners laminate both: an absorber face on a barrier layer, as one part with PSA for assembly.

Where the equipment serves occupied spaces, flame behavior joins the spec: the reticulated absorber family carries UL 94 HF-1 flame-rated versions per the vendor TDS, and the A2 barrier TDS reports FAR 25.853-type flammability data; cite the class from the grade TDS, by designation, with any system-level acoustic rating (AHRI 575 sound levels, E90/E413 transmission loss) belonging to the tested equipment, not the material.

[7]

Reticulated PU Foam (10–80 PPI)The open-cell absorber: uncoated, acrylic-coated, and PVC-coated versions, with UL 94 HF-1 flame-rated grades per vendor TDS. SKU example: 20 PPI HF-1. [6]
BISCO® A2 Sound Barrier (+ FG-Reinforced)Mass-loaded silicone blocking sheet, plain and fiberglass-reinforced; FAR 25.853-type flammability data per the TDS. The blocking layer for compressor compartments and equipment-room panels.
Laminated absorber-on-barrier linersReticulated or polyether absorber face laminated to the A2 barrier with PSA, as one liner part per panel, absorption and transmission control in a single install. Built on H-O lamination.
BISCO® Cellular Silicone (Acoustic & Hot-Adjacent Duty)Silicone foams for liner and gasket duty near heat sources (burner-adjacent panels, hot decks) where the use-temperature band on a urethane TDS runs out; flame classes per the individual grade TDSs.

Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.

What to send H-O: panel map with liner zones and cutouts, the dominant noise character (low rumble vs. broadband hiss steers absorber PPI and barrier mass qualitatively), any flame-class requirement and who reviews it, service temperature, airflow or washdown exposure (coated vs. uncoated absorber), and the assembly method. Liner acoustic guidance is qualitative; flammability data comes from each grade's TDS.
Anti-vibration wrap and clamp cushions installed on refrigerant piping lines

Piping anti-vibration wraps & clamp cushions

Test methods: ASTM D1056 compression classes per grade TDSContext: refrigerant-line wraps and clamp cushions — pulsation paths

Refrigerant lines carry compressor pulsation down their whole length, and every rigid clamp is a place where that vibration either enters the structure or chatters the tube against metal. The converter-side fix is small and unglamorous: die-cut clamp cushions and strip wraps that line the clamp saddle, cushion the standoff, and separate tube from sheet metal at pass-throughs.

The material question is chemistry first, geometry second: suction and discharge lines run cold and hot, sweat condensate, and live in a mist of refrigerant oil, so cushion materials are checked against the vendor TDS compatibility tables for the refrigerant-oil family in the system, POE, PAG, or mineral, rather than assumed.

H-O slits and the cushions to the clamp series and supplies them on liner for line installation; compatibility with specific refrigerants and oils is confirmed per the vendor TDS compatibility tables, never as a blanket claim.

Neoprene Foam & Solid Neoprene StripsThe default clamp-cushion chemistry: oil- and ozone-tolerant, in foam for conformability and solid for clamp-saddle duty; classes per ASTM D1056 / Shore A per D2240 on the TDSs. [1]
Vinyl Nitrile Foam (Closed-Cell)Closed-cell wraps and cushions where condensation control matters on cold lines; grade-level fluid data per the vendor TDS. SKU example: ENSOLITE® MLC.
SAE Pressed Felt CushionsFelt strips and washers at tube-to-panel contact points where stick-slip squeak, not energy, is the problem; F-grades per ASTM D2475/D461. SKU: F-10.
Rubberized Cork PadsThin, stiff cushions under line-set supports and equipment feet on the roof curb, where creep over years matters more than softness. SKU example: DC100-314.

Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.

What to send H-O: clamp series and tube diameters, line temperatures (suction/discharge/liquid), the refrigerant and oil family for TDS compatibility review, cushion geometry or the clamp drawing, adhesive/liner preference, and quantities per unit. Strip stock, saddles, and kiss-cut sets on liner are all standard conversions.
Technician assembling controls electronics that ride on cushioning pads

VFD & controls vibration pads

Test methods: ASTM D3574; UL 94 V-0 per gradeContext: VFD and controls vibration pads — electronics-adjacent mounts

Variable-frequency drives, control boards, contactors, and relays live bolted to the same cabinet the compressor shakes, and their failure mode is rarely dramatic: a relay chatters, a connector frets, a display ribbon fatigues. The materials are precision parts at light loads, exactly where coarse rubber pads lose their controlled behavior.

Microcellular polyurethane holds a stable, repeatable compression curve at low stress, specified by compression-force-deflection per ASTM D3574 rather than by durometer, and its low compression set keeps the mount on its design point over years of duty.

Where the pad sits in a classed electrical enclosure, the flame class belongs on the drawing: the PORON® 4701-40V0 grade carries a UL 94 V-0 class per its TDS; other grades report their own classes per TDS, cited by designation only.

PORON® Industrial (4701 / 4790 Series)Precision low-set pads for drive mounts, board standoffs, and anti-rattle duty; CFD grades per ASTM D3574. SKUs: 4701-40V0 (V-0 per TDS) · 4701-50 firm · ShockSeal® 4790-79 for combined seal-and-cushion joints. [2]
HyPUR-cel® Polyurethane FoamThe density-ladder alternative for larger electronics pads and cabinet cushioning; grade data per ASTM D3574 on the TDS. SKU example: I0906.
Vinyl Nitrile Anti-Rattle CushionsSoft closed-cell gap-fillers that stop loose-part rattle in control compartments, wire-bundle contact points, and door panels.
SAE Felt BSR InterfacesThin felt at sliding contact lines, covers, latches, harness clips, where stick-slip squeak starts; to the contact geometry with PSA for line installation.

Grade-level properties, standards and caveats for these families are in the material reference below — one card per family, with the TDS links.

What to send H-O: the mounted mass and footprint (drive, board, or component), the cabinet's vibration source and frequency, any flame-class requirement for the enclosure, temperature at the mount, and the part geometry with adhesive side and liner called out. Kiss-cut multi-part sets on liner are the common format for controls-cabinet NVH kits.
Spec discipline

The decisions that drive an HVAC vibration & acoustic spec

Noise and vibration parts are chosen by the path first — structure-borne or airborne — then tuned to the frequency and load that matter.

Specification principle

Identify the path, then size the part to the disturbing frequency and the equipment load. Isolators and dampers carry their own deflection and damping data per grade TDS.

Show all 5 selection factors tap to expand
Which path — structure-borne or airborneCompressor and fan vibration travels through the structure and is treated with isolation mounts and pads; noise travels through air and is treated with barriers and absorbers.
Isolator by natural frequencyAn isolator only works below the disturbing frequency; size durometer and deflection (neoprene, PORON®) so its natural frequency sits well under the compressor or fan speed.
Damping for panel resonanceRinging cabinet panels are treated with constrained-layer damping chosen by loss factor (ASTM E756), not by mass alone.
Load & environmentThe mount must carry the load without creep; neoprene for oil and weather, silicone near heat, rated for the static stress (D1056 class).
Documentation the review asks forDeflection, damping loss factor, and flame class per grade TDS, to the drawing.
Decision support
Instrumentation·Interactive Selection

Specification Tools

Two tools to take you from "the unit is loud" to here's the material checklist for the drawing set: a duty-driven NVH checklist builder that assembles the part list with its citations, and a side-by-side comparison of every isolation, damping, and acoustic family on this page.

1. HVAC NVH duty checklist builder

Check the vibration and acoustic jobs your unit carries. The builder assembles the corresponding converted parts into a checklist with the family, what to send with the drawing, and the citation language (material classes per TDS; standards by designation, rated results with the tested equipment). The default selection below is pre-built for a typical packaged rooftop unit; every line is also printed in the job sections and material reference, so nothing here exists only behind a script.

NVH part checklist: 3 duties selected

Each checked duty adds its converted part below. The list is the starting bill of materials for the engineering review, not a rating: material classes (UL 94) come from the grade TDS, and acoustic or vibration ratings (AHRI 575 sound levels, ISO 10846 transfer properties) belong to the tested equipment.

  1. Compressor pads: rebonded neoprene 25#/27# (or rubberized cork / Atlas bearing)Send: compressor mass, feet, pad footprint, running speed. Cite: ASTM D1056 classes per TDS.
  2. Fan/blower isolation: vinyl nitrile or neoprene foam stripsSend: blower mass, frame pattern, fan speed and blade count. Cite: ASTM D1056 classes per TDS.
  3. Acoustic liner: reticulated absorber + A2 barrier laminateSend: panel map, noise character, flame-class requirement. Cite: UL 94 HF-1 versions and FAR 25.853-type data per vendor TDS.
Copy line for the RFQ: "Packaged-unit NVH set, 3 duties: compressor pads, fan isolation, acoustic liner. Material classes per TDS; equipment-level ratings by designation."
Quote with this selection →or ask an engineer
The builder assembles converter-side parts only. It does not size mounts, predict sound levels, or substitute for an equipment-level acoustic or vibration measurement; rated results belong to the tested unit. H-O supplies the parts, the TDSs, and lot-code traceability behind them.

2. Side-by-side: HVAC isolation, damping & acoustic matrix

Every family called out on this page, with construction, the metric 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.

Filter
Material Construction Selection metric Standards on the TDS / by designation Job
Isolation: load-bearing resilient families
 Rebonded Neoprene (25# / 27#)Dense rebonded pad Rebonded neoprene granulate Static bearing stress ASTM D1056 (per TDS) Compressor & base pads
Rubberized Cork (BC351-207, DC100, SP52)Cork-elastomer composite Cork + elastomer binder Low creep, thin shims Per-grade TDS data Mount shims, curb pads
Atlas Bearing Neoprene (258 / 268)Engineered solid pad Solid neoprene Shore A (D2240) ASTM D2240; D1149 ozone (per TDS) Rails, skids, structural
Vinyl Nitrile Foam (SBE41VN/42VN, ENSOLITE®)Closed-cell VN foam Closed-cell vinyl nitrile CD class (D1056) ASTM D1056; flame data per grade TDS Fan isolation, cushions
Neoprene Foam (incl. Ribbed)Closed-cell CR foam Closed-cell neoprene CD class (D1056) ASTM D1056 (per TDS) Blower strips, clamp cushions
Precision & damping families
 PORON® Industrial (4701 / 4790)Microcellular PU Microcellular urethane CFD window (D3574) ASTM D3574; UL 94 V-0 (40V0 TDS) VFD & controls pads
HyPUR-cel® PU (Density Ladder)Cellular urethane Open/closed-cell PU Density + CFD (D3574) ASTM D3574 (per TDS) Electronics cushioning
Damping Laminates (Free / Constrained Layer)Lossy core + facing Viscoelastic laminate Loss factor η (E756) ASTM E756 (per vendor TDS) Panels & housings
Acoustic & interface families
 Reticulated PU Foam (10–80 PPI)Open-cell absorber Reticulated open-cell PU PPI + thickness D3574; UL 94 HF-1 versions per TDS Absorption lining
BISCO® A2 Sound Barrier (+ FG)Mass-loaded silicone Mass-loaded barrier sheet Surface mass FAR 25.853-type data per TDS Transmission blocking
SAE Pressed Felt (F-10 / F-26)Wool felt Pressed wool felt F-grade (D2475) ASTM D2475 / D461 (per TDS) BSR & contact lines
Notes. Load bands and acoustic guidance are qualitative; this matrix is a selection aid, not a load-rating table. Specification metrics follow the material class: Shore A durometer per ASTM D2240 for solids, compression-deflection grades per ASTM D1056/D3574 for cellular materials, PPI plus D3574 data for reticulated absorbers, felt grades per ASTM D2475/D461, and loss factor per ASTM E756 for damping materials. UL 94 and FAR 25.853-type flammability entries are as reported on the source maker's TDS for specific grades within each family; equipment-level sound and vibration ratings (AHRI 575, ISO 10846 measurements) belong to the tested unit. The TDS on file governs for the selected grade.
Found your candidate family? The fastest next step is the drawing: H-O reviews it against these selections and comes back with a manufacturable option and the TDS.
Already know your spec?

Skip ahead and request your engineering review now

If your drawing set already calls out a rebonded neoprene density, a cork grade, a PORON® firmness, an absorber PPI, or a barrier laminate, send it over for engineering review against the TDSs and the standards language.

Request engineering review → Call (860) 469-1144
What goes wrong in the field

HVAC vibration & acoustic failures you can prevent at spec

These surface as transmitted noise, a cracked mount, or a panel that drums — all decided at the isolator and damping callout.

Field caution

An isolator tuned wrong can amplify vibration instead of reducing it. Matching the part to the path and the frequency is where these specs go wrong.

Show all 5 failure modes tap to expand

1. An isolator too stiff for the frequency

Fix — size deflection so the isolator’s natural frequency sits well below the disturbing frequency.

2. Elastomer creep under compressor load

Fix — use a neoprene or PORON® grade rated for the static load (D1056 class per TDS).

3. Airborne treatment used for a structure-borne path (or the reverse)

Fix — match the treatment to the path — isolation for vibration, barrier / absorber for noise.

4. Material degraded by oil, UV, or heat

Fix — choose the chemistry for the environment: neoprene for oil and weather, silicone near heat.

5. Field-cut pads with inconsistent preload

Fix — die-cut isolation pads and shims to the drawing so every mount sees the same load.

Reference

Material reference

Detailed notes for the families referenced on this page: the load-bearing isolation set (rebonded neoprene, rubberized cork, Atlas bearing neoprene), the general-duty foams (vinyl nitrile and neoprene), the precision urethanes (PORON® and HyPUR-cel®), the damping laminates, and the acoustic and interface set (reticulated absorber, A2 sound barrier, SAE felt).

Values are per the maker TDS on file for each grade with the method named; flame classes and equipment-level ratings are cited by designation. H-O die-cuts, kiss-cuts, slits, laminates, and kits every family to drawing.

Rebonded Neoprene (25# / 27# Densities)Compressor & equipment base pads · ASTM D1056 data per TDS · sized by static bearing stress
CompositionGranulated neoprene re-bonded under pressure into dense pad stock
Grades here25# and 27# density designations
Defining propertyCarries sustained bearing stress for years without creeping flat
MethodsASTM D1056 cellular-rubber data per the grade TDSs
EnvironmentNeoprene chemistry tolerates the oil mist of a compressor deck; per-grade fluid data on the TDS
Form factorsDie-cut and waterjet-cut base pads, strips, and foot pads
Where it lives in this application: under the compressor and under the unit. The classic heavy-equipment isolation pad, sized so each foot's bearing stress (mass over pad area) sits inside the grade's working compression range, which is what keeps the mounted natural frequency where the design put it. [1]

Specify mass, feet, and footprint, not "a rubber pad." A pad loaded too lightly does not deflect into its working range; loaded too heavily it bottoms and transmits. Both read as "the pads did nothing."

View all rebonded neoprene → View this product → Browse the materials catalog →
Rubberized Cork Composites (BC351-207, DC100 Series, SP52)Thin, stiff, very low-creep mount shims · per-grade TDS data
CompositionGranulated cork in an elastomer binder, sheet and pad stock
Grades hereBC351-207; technical DC100-312 / DC100-314; SP52
Defining propertyVery low creep in thin sections; deflection stays predictable for years
MethodsPer-grade values per the maker TDS
Form factorsDie-cut shims, washers, foot pads, and de-coupling interlayers
Where it lives in this application: where the deflection budget is millimeters, not centimeters: under compressor rails and curb interfaces as thin mount shims, between bolted panels and stiffeners as a damping and de-coupling interlayer, and under line-set supports on the roof.

Cork-rubber is the answer to "we need a pad, but the stack-up only has 3 mm." It trades softness for stability; if the job needs real deflection, step to rebonded neoprene or a foam.

View all rubberized cork → View this product → Browse the materials catalog →
Atlas Bearing Neoprene (258 / 268 / 278)Engineered structural bearing pads · Shore A per ASTM D2240 · ozone data per TDS
CompositionSolid engineered neoprene bearing-pad stock
Grades here168 / 258 / 268 / 278 designations
Specification metricShore A durometer per ASTM D2240 (solids spec by durometer; foams by CD class)
EnvironmentOzone testing (ASTM D1149) reported on the TDS; suited to rooftop exposure
Form factorsDie-cut and waterjet-cut bearing pads, rail strips, curb interface pads
Where it lives in this application: at the structural interfaces, between unit rails and roof curbs, under skids, and anywhere the pad carries the whole unit rather than one component. Solid construction trades resilience for load capacity and weather endurance.

Specify solids by Shore A and cellular materials by compression-deflection class; the two metrics do not convert, and "40 durometer foam" is a callout procurement cannot fill. [1]

View all Atlas bearing pads → View this product → Browse the materials catalog →
Vinyl Nitrile Foam (SBE41VN / SBE42VN, ENSOLITE® Family)Fan & blower isolation, cushions, wraps · ASTM D1056 classes per TDS
CompositionClosed-cell vinyl nitrile (PVC-NBR blend) foam
Grades hereSBE41VN / SBE42VN; ENSOLITE® IG1, MLC, and siblings
Selection metricCompression-deflection class per ASTM D1056 on the grade TDS
Flame dataSpecific ENSOLITE® grades report flame-class data per their TDSs, cited by designation
Form factorsDie-cut pads, strips, gaskets, clamp cushions, kiss-cut sets on liner
Where it lives in this application: everywhere the loads are gentler than the compressor deck: blower-frame isolation strips, anti-rattle cushions in control compartments, cold-line clamp wraps, and general gasket-and-cushion duty across the cabinet. [1]

The general-duty workhorse of HVAC NVH: one family covers isolation, cushioning, and sealing at foam closure forces, with the grade picked by CD class against the actual load.

View all vinyl nitrile foam → View this product → Browse the materials catalog →
Neoprene Foam (incl. Ribbed Profiles)Oil-tolerant strips, clamp cushions · ASTM D1056 classes per TDS
CompositionClosed-cell chloroprene (CR) foam; ribbed sheet available
Selection metricCompression-deflection class per ASTM D1056
EnvironmentOil and ozone tolerance is the family's reason for being; per-grade fluid data on the TDS
Form factorsStrips, pads, saddles, ribbed mounting sheet
Where it lives in this application: motor-deck and blower strips, refrigerant-line clamp cushions, and the oily corners of the unit where commodity foams swell and soften. Ribbed profiles add controlled compliance under bolted joints.

For specific refrigerant-oil exposure (POE, PAG, mineral), confirm the grade against the vendor TDS compatibility tables; chemistry varies by grade and no blanket compatibility claim is made.

View all neoprene foam → Browse the materials catalog →
PORON® Industrial (4701 / 4790) + HyPUR-cel® PolyurethanePrecision VFD & controls pads · CFD per ASTM D3574 · V-0 class on the 40V0 TDS
CompositionMicrocellular polyurethane (PORON® industrial line); HyPUR-cel® cellular PU density ladder
Grades here4701 firmness series; 4701-40V0; ShockSeal® 4790-79; 4790-92 slow rebound; HyPUR-cel® I0906
Flame classUL 94 V-0 on the 4701-40V0 TDS; other grades list their own classes per TDS
Defining propertyLow compression set: the pad stays on its design point through years of duty
MethodsASTM D3574 cellular methods; D395 set data where reported
Form factorsDie-cut and kiss-cut pads, strips, and multi-part sets on liner
Where it lives in this application: under the electronics. VFD mounts, control-board standoffs, relay and contactor anti-rattle pads, and small-blower isolation, the light-load precision duty where a coarse rubber pad loses its controlled curve. [2]

Specify the compression window, not just the thickness; the CFD curve on the TDS is the spec. Use the 40V0 grade where the enclosure design wants a V-0 class on the pad itself, cited per its TDS.

View all PORON® industrial PU → View this product → Browse the materials catalog →
Panel Damping Laminates (Free-Layer & Constrained-Layer)Cabinet & housing resonance control · loss factor per ASTM E756 on the vendor TDS
ConstructionFree-layer: lossy elastomer sheet + PSA. Constrained-layer: lossy core + stiff facing + PSA, supplied as one laminate
Selection metricLoss factor η versus temperature and frequency, per ASTM E756 on the vendor TDS
Design noteEffective damping depends on the construction (free vs. constrained), not the material alone
Form factorsDie-cut panel zones with PSA and liner, ready for line installation
Where it lives in this application: on the panel zones that actually move: access doors, cabinet sides, blower housings. Constrained-layer construction extracts more damping per millimeter where weight and thickness are budgeted; free-layer suits broad, low-cost coverage. [3]

These parts install on adhesive, so the framing applies in full: final adhesive selection should be validated in the application, performance depends on substrate, surface energy, temperature, exposure, dwell, pressure, surface preparation, geometry, and assembly method.

See H-O lamination capability → Browse the materials catalog →
Acoustic Set: Reticulated PU (10–80 PPI) + BISCO® A2 Sound BarrierAbsorption + blocking, laminated as one liner · flame data per grade TDS
AbsorberReticulated open-cell PU, 10–80 PPI; uncoated, acrylic-coated, PVC-coated; UL 94 HF-1 flame-rated versions per TDS
BarrierBISCO® A2 mass-loaded silicone sheet, plain and fiberglass-reinforced; FAR 25.853-type flammability data per TDS
Combined formAbsorber face laminated to barrier layer with PSA, as one liner part
UV noteCoated reticulated grades report ASTM G154 UV testing on the TDS for exposed locations
Form factorsDie-cut liner panels, baffles, laminated absorber-on-barrier parts
Where it lives in this application: lining compressor compartments, plenum walls, and equipment-room panels: the absorber tames the reverberant build-up inside, the barrier carries the transmission loss through, and the laminate does both as one installed part. SKUs: A2 · A2 FG · 20 PPI HF-1. [6]

Absorption and blocking are different mechanisms; an absorber alone will not stop sound passing through a panel. Acoustic guidance here is qualitative; equipment sound ratings (AHRI 575 context) belong to the tested unit.

View all reticulated foam → View this product → Browse the materials catalog →
SAE Pressed Felt (F-10 / F-26)BSR interfaces, clamp lines, sliding contacts · felt grades per ASTM D2475 / D461
CompositionPressed wool felt, SAE F-grades
Grades hereF-10; F-26
MethodsASTM D2475 specification and D461 test methods per the TDS
Defining propertyLow, stable friction at contact lines: the classic stick-slip squeak fix
Form factorsDie-cut strips, washers, and pads with PSA for line installation
Where it lives in this application: at the contact lines, tube-to-panel pass-throughs, cover edges, latches, harness clips, anywhere two parts grip and release as the unit breathes. Thin, precisely placed, and to the contact geometry.

Felt fixes squeak, not energy: it is an interface material, not an isolator. Pair it with the isolation and damping families above when the problem is more than noise at a contact point.

View all SAE pressed felt → View this product → Browse the materials catalog →
Silicone Sponge — Sound Barrier (BISCO® A2)BISCO® Cellular Silicone (Acoustic & Hot-Adjacent Duty)
ColorLight Gray
Polymer TypeVMQ
Areal Density0.20 lb/ft², 0.31 lb/ft², 0.61 lb/ft² per ISO 2286-2
Hardness, Shore A62 per ISO 868
Temperature Stability-58°F to 356°F
Form factorsSheet stock, Slit rolls, Precision die-cut components, Kiss-cut parts, Laminated constructions
Values above are the published product data for this family. Verify the exact grade and thickness against the technical data sheet before release — download the TDS.
View all Silicone Sponge — Sound Barrier (BISCO® A2) →Browse the materials catalog →
Engineering questions

HVAC vibration & acoustic materials: engineer-grade FAQ

Ten of the questions we hear most from HVAC, refrigeration, and air-handling equipment teams. If your question isn't here, send a drawing or call, engineering picks up.

10 questions · click a question to expand its answer

What pad goes under an HVAC compressor, and how is it sized?

Commonly rebonded neoprene in the 25# or 27# density, rubberized cork where the deflection budget is thin, or Atlas bearing neoprene at structural rail and curb interfaces. Sizing is a static bearing-stress calculation: compressor mass over total pad area, placed so each pad's stress sits inside the working compression range its TDS reports per ASTM D1056. Send the mass, the number of feet, the footprint per foot, and the running speed; the firmness and thickness fall out of those numbers. [1]

Why did adding isolation pads make the vibration worse?

Because isolation only begins above the √2 crossover. A single-degree-of-freedom mount transmits roughly the full input below its natural frequency, resonates at f/fn=1, and only drops below unity transmissibility above f/fn=√2. A pad that is too stiff for the load parks the compressor's running speed near resonance and amplifies the hum instead of cutting it. The fix is softer pads, more deflection, or more supported mass per pad, sized so the disturbance lands comfortably in the isolation region. [5]

What is the difference between vibration isolation and panel damping?

They solve the problem in opposite ways. Isolation uses a soft, resilient, low-loss element, a spring, to lower a system's natural frequency so the disturbance falls in the isolation region; it works by mismatching frequencies. Damping uses a lossy, high-hysteresis material to convert resonant panel vibration into heat, characterized by loss factor per ASTM E756; it works precisely by absorbing energy. A good isolator and a good damper are nearly opposite materials, so the first thing to get right is which job the noisy part actually needs. [3]

When does a cabinet panel need constrained-layer damping instead of a free-layer sheet?

When weight or thickness is budgeted. A free-layer sheet damps by straining in bending, and its effectiveness scales with its own thickness, cheap but bulky. A constrained-layer laminate adds a stiff facing that forces the lossy core into shear, extracting far more damping per gram and per millimeter, which suits access doors and visible panels.

Either way the core is selected by its ASTM E756 loss-factor curve at your panel's temperature and resonance band, and the treatment is to the panel zone that actually moves rather than covering the whole cabinet. [3]

Which acoustic liner quiets an HVAC unit, and what about flame ratings?

Split the duty first. Absorption, open-cell reticulated foam (10–80 PPI), tames the reverberant build-up inside compressor compartments and plenums; blocking, the mass-loaded A2 sound-barrier silicone, stops transmission through the panel. Most effective liners laminate both as one part. On flame behavior: the reticulated family carries UL 94 HF-1 flame-rated versions and the A2 TDS reports FAR 25.853-type data, cited from the grade TDS by designation; any equipment-level sound rating belongs to the tested unit. [6]

Can a vibration pad or acoustic liner carry an AHRI 575 or ISO 10846 rating?

No. AHRI 575 describes sound measurement and rating of water-chilling packages, equipment, not materials, and ISO 10846 is a laboratory method for measuring the vibro-acoustic transfer properties of a resilient element under a stated preload; a mount can be characterized by an ISO 10846 measurement, but the result attaches to that part at that preload.

The honest framing: H-O materials are evaluated against and support compliance with these methods through the maker TDS; H-O does not independently certify materials to them unless explicitly stated on the quote, and rated results belong to the tested equipment. [5]

What cushions refrigerant piping clamps, and does the refrigerant oil matter?

Die-cut clamp saddles and strip wraps of neoprene foam or solid neoprene are the common choice, with closed-cell vinyl nitrile on cold lines and SAE felt at squeak-only contact points. The oil matters: suction and discharge lines live in a mist of POE, PAG, or mineral oil, and cushion chemistry is confirmed against the vendor TDS compatibility tables for that fluid family rather than assumed. Send the clamp series, tube diameters, line temperatures, and the refrigerant-oil pair, and the grade gets checked per its TDS.

Do vibration pads under a VFD or control panel actually do anything?

Yes, when the failure mode is what they address: relay chatter, connector fretting, and fastener loosening driven by cabinet vibration. Precision microcellular polyurethane (PORON® 4701/4790, HyPUR-cel®) holds a stable compression curve at the light loads electronics impose, specified by compression-force-deflection per ASTM D3574, and its low compression set keeps the mount on its design point for years. Where the pad sits in a classed enclosure, the 4701-40V0 grade carries a UL 94 V-0 class per its TDS. [2]

Should I specify foam firmness by durometer?

Only for solids. Shore A durometer per ASTM D2240 measures surface indentation of a solid elastomer (Atlas bearing pads, solid neoprene) and says nothing useful about how a cellular foam carries load.

Cellular materials, rebonded neoprene, vinyl nitrile, PORON®, HyPUR-cel®, reticulated foam, are specified by their compression-deflection grade per ASTM D1056 or D3574, the stress at a standard deflection. "40 durometer foam" is a callout suppliers cannot fill consistently; write the right metric for the material class and the quotes come back comparable. [1]

Does H-O make the raw foam and rubber, and what are lead times and minimums?

H-O is a precision converter, not a raw-material producer: we buy sheet, slab, and roll stock from the material makers and convert it to your drawing by die-cutting, kiss-cutting, waterjet cutting, slitting, adhesive lamination, and kitting, with material traceability and lot-code TDS records, under an ISO 9001:2015 certified quality management system in Winsted, Connecticut.

Every part is made to order; samples typically ship in 3–5 business days for common configurations, standard production runs about 2 weeks after drawing approval, and MOQ varies by material and part.

Definitions

Glossary: terms used on this page

Quick reference for the vibration, damping, and acoustic terminology used throughout. Each entry links to the relevant standard or test method where applicable.

Transmissibility (T)

The ratio of force or motion transmitted through a mount to the force or motion applied to it, plotted against the frequency ratio f/fn. Above 1 the mount amplifies; below 1 it isolates. Measured on resilient elements per ISO 10846 [5] under a stated preload.

Natural frequency (fn)

The frequency at which a mounted mass on a resilient pad oscillates when disturbed, set by the pad's stiffness and the supported mass. The design goal of an isolation pad is to put fn well below the disturbance frequency.

Isolation region (the √2 rule)

Transmissibility crosses 1 at f/fn=√2 for every damping value; only above that ratio does a mount transmit less than the input. A pad too stiff for its load parks the disturbance near resonance and amplifies it.

Damping loss factor (η)

A dimensionless measure of how much vibration energy a material dissipates per cycle relative to the energy stored, measured by the damped cantilever-beam method per ASTM E756 [3]. Temperature- and frequency-dependent; the TDS gives the curve.

Constrained-layer damping (CLD)

A damping construction in which a lossy viscoelastic core is sandwiched between the vibrating panel and a stiff constraining facing, forcing the core into shear. Extracts more damping per unit weight and thickness than a free layer.

Free-layer damping

A single lossy elastomer layer bonded to a panel, damping by extension and compression as the panel bends. Simpler and lower-cost than CLD; effectiveness scales with the damping layer's thickness relative to the panel.

Compression force deflection (CFD)

The pressure a cellular material exerts at a given compression, the curve that turns a foam pad into a specifiable spring. Reported per ASTM D3574 [2] for urethanes and per ASTM D1056 [1] classes for cellular rubbers.

Compression set

The permanent thickness a material loses after sustained compression, per ASTM D395 [4]. A pad that sets thins out, stiffens, raises the mounted natural frequency, and can push the disturbance back toward resonance, the quiet way an isolation design expires.

Absorption vs. barrier mass

The two airborne-noise mechanisms: absorption converts sound to heat inside an open-cell structure (reticulated foam); blocking stops transmission with limp, heavy, decoupled mass (the A2 barrier). Transmission-loss vocabulary follows ASTM E90/E413 [8].

PPI (pores per inch)

The cell-count designation of reticulated foam (10–80 PPI on this page). Together with thickness, it sets the absorber's qualitative frequency character: coarser cells and more thickness reach lower; finer cells suit higher-frequency hiss.

Blade-pass frequency

Fan speed times blade count: the tonal disturbance a fan or blower injects into its frame and housing. The frequency that fan isolation strips are sized against and that panel damping treatments are tuned to.

BSR (buzz, squeak & rattle)

The noise an assembly makes against itself: squeak is stick-slip friction (fix: felt or low-friction interface), rattle is a loose part knocking (fix: soft foam gap-filler), buzz is a panel resonating (fix: damping layer or stiffener). Thin, precisely placed parts.

Clamp cushion

The elastomer or felt liner between a refrigerant line and its clamp or standoff, breaking the metal-to-metal path that lets pulsation enter the structure and tube chatter start. Chemistry checked against the refrigerant-oil family per the vendor TDS compatibility tables.

Rated results belong to the tested equipment

The honesty rule for standards claims on this page: equipment-level sound and vibration ratings (AHRI 575 sound data, ISO 10846 measurements, E90 transmission loss) attach to the tested unit or assembly. A material carries its own TDS classes and supports a rated design without inheriting its rating.

Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).

Citations

Standards, test methods & technical references

The standards and test methods cited throughout this page, by designation. Equipment-level standards evaluate units and assemblies, and rated results belong to the tested equipment. 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 D1056

Standard Specification for Flexible Cellular Materials — Sponge or Expanded Rubber (ASTM International). The classification system behind the compression-deflection classes on the rebonded neoprene, vinyl nitrile, and neoprene foam TDSs cited on this page.

[2] ASTM D3574

Standard Test Methods for Flexible Cellular Materials — Slab, Bonded, and Molded Urethane Foams (ASTM International). The force-deflection procedures behind the PORON®, HyPUR-cel®, and reticulated-foam data cited per TDS.

[3] ASTM E756

Standard Test Method for Measuring Vibration-Damping Properties of Materials (ASTM International). The damped cantilever-beam method behind the loss-factor curves that select the free-layer and constrained-layer damping cores on this page.

[4] ASTM D395

Standard Test Methods for Rubber Property — Compression Set (ASTM International). The method behind the set data that decides whether an isolation pad's design point survives years of sustained load.

[5] ISO 10846 (by designation)

Acoustics and vibration — Laboratory measurement of vibro-acoustic transfer properties of resilient elements (International Organization for Standardization). A measurement method, not a material rating: a mount is characterized under a stated preload, and the result attaches to that part and condition.

[6] UL 94 (classes per grade TDS)

Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances (UL). Flammability classes (V-0 on the PORON® 4701-40V0 TDS, HF-1 on the rated reticulated-foam versions) are cited from the specific grade's TDS, by designation; listings belong to the rated grade and the customer's evaluated assembly.

[7] AHRI 575 (by designation)

Method of Measuring Machinery Sound Within an Equipment Space (Air-Conditioning, Heating, and Refrigeration Institute). Cited as design context for equipment sound levels: the rating describes the tested machine in its space, and the materials on this page are converter-side ingredients of that result, not holders of it.

[8] ASTM E90 / E413

Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements, and Classification for Rating Sound Insulation (ASTM International). The transmission-loss and STC vocabulary behind barrier-mass discussions; measured results belong to the tested partition or panel assembly.

Updated . Standards editions 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.

Quote request

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Send a drawing set, panel map, or unit spec. We typically respond within one business day with a material recommendation, prototype lead time, and TDS verification against your loads, frequencies, flame-class requirements, and standards language.

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Continue reading

See also: related H-O application pages

Engineering content for the adjacent NVH and vibration sub-applications, the parent application overview, and the owning industry hub. Each page covers material selection, failure modes, and converter-side process detail for its application family.

Vehicle suspension and driveline underbody, the vibration environment addressed by isolation, damping and cushioning materials. Parent application NVH, shock & vibration control The cross-industry overview this page belongs to: isolation vs. damping vs. cushioning, the transmissibility logic, and the full material-family reference. Read the page Open-cell acoustic foam and mass-loaded barrier sheet laminated inside an equipment enclosure panel Sibling sub-application Vibration, shock & acoustic control (electromechanical) The same NVH playbook applied to transformers, relays, drives, and switchgear, including the durometer-vs-CD-grade spec discipline this page borrows. Read the page Stretch-wrapped equipment on shipping pallets Sibling sub-application HVAC wear pads & dunnage Slide pads, wear strips, and shipping dunnage that protect HVAC equipment in service and transit. Read the page HVAC ductwork and air handling Sibling sub-application HVAC thermal insulation Duct, coil, and condensation insulation that manages heat and moisture across HVAC assemblies. Read the page HVAC sheet-metal panel and ductwork Sibling sub-application HVAC panel bonding & stiffeners Structural tapes and stiffener bonding for HVAC sheet-metal panels and assemblies. Read the page Wide reference photo of a data center generator and electrical room, with a standby generator set on isolation pads, switchgear cabinets along the wall, and cab Sibling sub-application Data center safety & generator systems Generator-room base isolation and the absorber-plus-barrier acoustic treatments at building-equipment scale, the heavy cousin of this page's compressor deck. Read the page Centrifugal blower assembly in an air handler with foam isolation strips between the blower frame and the mounting deck Sibling sub-application Aircraft vibration, NVH & shock isolation The flight-hardware edition of the same material logic: PORON®, silicone, and felt isolation where the spec sheet adds FST data lines. Read the page Rooftop HVAC unit interior with compressors and blower assemblies mounted on resilient isolation pads Industry hub Industrial HVAC The owning industry hub: sealing, thermal, electrical, fire, and NVH application families across HVAC equipment, with this page as the vibration and acoustic member. Read the page Open-cell acoustic foam liner laminated to a mass-loaded barrier sheet inside an HVAC compressor compartment panel Capability Laminating & material bonding The process behind this page's absorber-on-barrier liners and constrained-layer damping parts: multi-layer laminations with PSA, supplied as one part. Read the page

Material data & standards. All compression, set, damping, felt, and flammability values on this page are taken from the source maker's technical data sheets with the method named (ASTM D1056, D3574, D395, E756, D2240, D2475/D461; UL 94 classes per the listed grade TDSs).

Equipment-level standards and methods (ISO 10846 measurements, AHRI 575 sound ratings, ASTM E90/E413 transmission loss) are cited by designation only: they evaluate parts, units, and assemblies under stated conditions, the rated result belongs to the tested equipment, and the materials on this page support designs evaluated to them.

Acoustic and load-band guidance is qualitative. Refrigerant and oil compatibility is confirmed per the vendor TDS compatibility tables for the specific grade and fluid; no blanket compatibility claim is made. H-O converts materials; H-O does not design mounting systems or certify equipment, and does not independently certify materials against the standards unless explicitly stated on the quote. Final material selection should be validated in the application; verify against the maker TDS and your equipment-level test plan.

Conversion scope. H-O and converts sheet, slab, and roll stock to drawing in Winsted, Connecticut: die-cut and kiss-cut pads, strips, saddles, and liner panels, slit strip stock, waterjet-cut thick sections, multi-layer laminations, and kitted unit-level NVH sets, 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 process strip and the quote form above.

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