Data Center Safety & Generator Systems: Fire Barriers, Generator-Room Isolation & Rack EMI Shielding
H-O Products die-cuts and converts glass-fiber paper, mica barrier sheet, flame-rated silicone sponge, FST-rated neoprene, rebonded neoprene, vinyl nitrile foam, epichlorohydrin foam, mass-loaded silicone sound barrier, and conductive electromagnetic-interference (EMI) elastomers and foil tapes into safety-side parts for data centers: cable-tray fire barriers, generator and switchgear room isolation, and server-rack EMI shielding, built to your drawing.
Built for: fire barriers at cable-tray penetrations, compartment-wall barrier linings, generator base isolation pads, switchgear vibration isolation, diesel-fuel-resistant generator-room gaskets, acoustic damping panels, and rack-level EMI door gaskets, ground pads, and seam tapes.
Specify data-center safety materials by location. At a cable-tray penetration, build an inorganic barrier stack: ManniGlas glass-fiber paper as the non-combustible layer, mica sheet at the hottest walls, and a kSil V-0 or RS-series silicone sponge (UL 94 V-0 per TDS) as the compressible seal, adding FST neoprene where smoke and toxicity indices apply.
In the generator room, carry generator bases on rebonded neoprene, isolate switchgear on ENSOLITE vinyl nitrile, gasket fuel-exposed joints in epichlorohydrin foam, and damp noise with BISCO A2 sound barrier. At the rack, gasket EMI doors with SSP502 conductive silicone. See the list at right for the full when-to-spec-what map.
Fire, smoke, and EMI performance is earned at the assembled-enclosure level — barrier stack, joint geometry, surface treatment, and closure force together; each converted layer carries its own rating, not the assembly's. UL 94 flame classes are per-grade, per-thickness listings; conductive and cellular values are per the TDS on file.
UL 94 · NFPA 75 · NFPA 76 · ASTM C177 · ASTM E162 · ASTM E662 · ASTM D1056 · ASTM D2240 · ASTM D412 · ASTM D624 · ASTM D746 · MIL-DTL-83528 · ASTM D991 · ASTM B117
- Cable-tray penetration barrier: ManniGlas paper + kSil V-0 seal
- Highest-temperature compartment wall: Mica barrier sheet
- Smoke / toxicity indices specified: FST-rated neoprene
- Generator base pads: Rebonded neoprene 25# / 27#
- Switchgear / drive electronics isolation: ENSOLITE vinyl nitrile
- Diesel-fuel-exposed gasket: Epichlorohydrin foam C41ECH
- Generator-room acoustics: BISCO A2 sound barrier
- Rack EMI door / panel gasket: SSP502 EMI silicone (V-0 grades)
- Irregular mating surfaces: EC-2130 conductive sponge
- Seam bridging / retrofit grounding: Conductive foil tape
Where are you in the spec process?
This page serves facility and equipment engineers who already know the material they want and engineers still mapping fire, vibration, fuel, and EMI constraints. Pick the path that matches where you are; you don't have to read the rest.
Send a drawing, get a quote
ManniGlas, mica sheet, kSil V-0 or RS-series sponge, FST neoprene, rebonded neoprene, ENSOLITE vinyl nitrile, epichlorohydrin foam, BISCO A2 sound barrier, SSP502 EMI silicone, EC-2130 conductive sponge, or conductive foil tape on your drawing.
Skip to the quote form →Walk through the selection factors
Six selection factors (barrier function, flammability class, fuel exposure, isolation loading, acoustic mass, EMI continuity), a fire-barrier stack lookup, and twelve material families with TDS-cited test methods.
Start with selection factors →
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1Send drawingUpload a DXF, STEP, or PDF, or describe the assembly. A sample part works too.
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2Material reviewEngineering reviews the location against the vendor TDS: barrier function, required flammability class, fuel or chemical exposure, supported mass for isolation pads, and EMI continuity needs.
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3PrototypeSamples typically ship in 3–5 business days for common die-cut configurations in commonly converted materials. Made-to-order; minimum order quantity (MOQ) varies by material and part.
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4ProductionStandard production runs ship about 2 weeks after drawing approval, including kiss-cut-on-liner and laminated configurations. Expedited service available. Ongoing parts run with material traceability and lot-code TDS records.
What are you protecting?
Application Zones
Four distinct safety problems hide inside a data center's support spaces: the cable-tray penetrations, hundreds of them, each a hole in a fire-rated wall that needs a barrier stack; the generator and switchgear room floor, where rotating mass and electrical cabinets need vibration isolation matched to what they weigh; the fuel- and noise-exposed surfaces of the same room, where gaskets see diesel and walls need acoustic mass; and the server racks themselves, where high-frequency switching in dense compute creates EMI that has to be gasketed, grounded, and bridged at the rack boundary.
Click a tab to see the location, the governing constraints, and the material families H-O converts for that zone.
Cable-tray fire barriers and compartment penetrations
Every data center routes power and data through fire-rated compartment walls, and every tray that crosses one leaves a penetration the fire engineering has to close.
The dossier's mapping for these barriers is inorganic-first: ManniGlas glass-fiber paper is the non-combustible barrier layer, die-cut into wraps, collars, and pads that line the penetration; mica barrier sheet steps in where the compartment sees the highest temperatures; and a kSil V-0 or RS-series silicone sponge, rated UL 94 V-0 on its TDS, provides the compressible seal that closes the gap around irregular cable bundles.
Where the facility specification calls smoke and toxicity indices in addition to flame, an FST-rated low smoke / low flame / low toxicity neoprene carries those properties on its TDS. The facility-level framing for where barriers are required sits in NFPA 75 and NFPA 76, cited here by designation; the mapping to each penetration belongs to the facility fire engineer, and the material ratings stay on the TDS.
Generator base and switchgear vibration isolation
A standby generator is rotating mass bolted to the same structure that carries racks of spinning disks and tuned airflow, and the isolation under it is a sizing exercise before it is a material choice.
The dossier's mapping splits by what sits on the pad: rebonded neoprene, the classic high-density base-pad material (25# and 27# grades), carries generator bases and the heaviest plant; ENSOLITE vinyl nitrile foam and the SBE-series grades isolate switchgear cabinets, transformers, and drive electronics at lower bearing pressures, with UL 94 HF-1 listings per grade on the TDS.
The discipline is the same as any isolation pad: state the supported mass and footprint on the drawing so the bearing pressure lands in the grade's working range per its compression-deflection data, and re-check when the equipment changes. Compression-deflection is reported per ASTM D1056; per-grade values are per the TDS on file. [7]
Diesel-fuel-exposed gaskets and generator-room acoustics
Two more problems live in the same room. First, fuel: day tanks, fuel polishing skids, and the generator itself put diesel mist and the occasional spill onto gaskets that would swell and fail in a standard organic foam. Epichlorohydrin foam (C41ECH) is the dossier's mapping for diesel-fuel-resistant generator-room gaskets: a closed-cell foam whose chemistry tolerates fuel exposure, with cellular properties per ASTM D1056 on the TDS.
Second, noise: a generator room shares walls with occupied and equipment spaces, and the practical converted part is mass: BISCO A2, a mass-loaded silicone sound-barrier sheet, and its fiberglass-reinforced variant add limp-mass damping to enclosure panels, doors, and barrier curtains, with flammability-method data on the TDS. Both are parts: fuel-side gaskets cut to the flange, and barrier sheet cut to the panel with cutouts for penetrations.
Server-rack EMI shielding: gaskets, ground pads, and seam tapes
High-frequency switching in dense compute creates real EMI, and the rack boundary is where it gets contained: the same conductive-elastomer discipline as switchgear EMI, applied at rack level. The dossier maps three families.
SSP502 conductive silicones gasket rack doors and removable panels, with grades spanning the standard range and UL 94 V-0 rated variants, and with conductive-elastomer properties referenced to MIL-DTL-83528 and volume resistivity per ASTM D991 on the TDS; corrosion-resistant grades carry ASTM B117 salt-spray data for harsher rooms.
BISCO EC-2130, a soft electrically conductive silicone sponge, takes up irregular mating surfaces at low closure force, the common case on sheet-metal rack doors. And copper or aluminum conductive foil tape bridges seams, closes lap joints between adjacent bays, and grounds retrofit panels where an elastomer gasket cannot be retained mechanically. Shielding performance is assembly-level: gasket, joint geometry, and surface treatment together; per-grade electrical values stay on the TDS.
Six decisions that drive your safety-systems material spec
Safety-side material selection is not a single-property choice. The right barrier, pad, or gasket satisfies six independent constraints at once, and missing one produces a part that passes inspection on day one and fails its job later: a barrier stack with the wrong layer order, an isolation pad crushed solid under a generator, or an EMI gasket that corroded into an insulator.
Match the material to the protection function, not to the catalog. A flame-rated foam is not a fire barrier, a fire barrier is not an acoustic treatment, and a conductive gasket only shields as part of a continuous joint. Read the six factors below before reaching for a part number.
Inorganic barrier (ManniGlas glass-fiber paper, or mica sheet at the hottest walls) + compressible V-0 seal (kSil V-0 / RS-series sponge) + FST layer where smoke and toxicity indices are specified (FST neoprene). Ordering the layers to the exposure is the design; the lookup tool below walks the common cases.
Read the six factors below in order. Each one constrains the others: the barrier function sets the layer order, the flammability class gates the seal material, and the supported mass sizes the pad before any catalog firmness matters. Selecting one factor at a time and re-checking the others is the discipline.
Show all 6 selection factors tap to expand
Barrier function sets the stack: barrier layer, then seal, then indices
Rule — Specify the stack by function — inorganic barrier layer, then compressible V-0 seal, then an FST layer where smoke and toxicity indices apply — and let each layer's TDS carry its own rating.
A penetration barrier does three jobs, usually as three layers. The inorganic barrier layer stops flame and radiant heat: ManniGlas glass-fiber paper for the general case, mica sheet where the compartment runs hottest. The compressible seal closes the gap around irregular cable bundles: a UL 94 V-0 rated silicone sponge. And where the facility specification adds smoke and toxicity indices, an FST-rated neoprene carries those properties on its TDS.
Specify the stack, not a material: name each layer's function on the drawing and let the TDS carry each rating. The facility-level requirement framing sits in NFPA 75 / NFPA 76, by designation. [2]
Flammability class gates the gasket: V-0 is a TDS listing, not a vibe
Rule — When the spec calls a UL 94 class, pick a grade whose TDS lists it at your thickness and name that grade on the drawing; the rating does not transfer to an unrated grade of the same chemistry.
When a room or enclosure specification calls UL 94 V-0 on seal materials, the rating is a per-grade, per-thickness listing on the material TDS, not a property of "silicone" in general.
The kSil V-0 range and RS-series sponge carry V-0 listings; the SSP502 family includes specific V-0 conductive grades for EMI gaskets that must also meet flame requirements; ENSOLITE grades carry HF-1. Verify the listing at your specified thickness during drawing review, and resist substituting an unrated grade of the same chemistry when supply gets tight; the rating does not transfer. [1]
Fuel exposure moves the gasket chemistry, not the gasket shape
Rule — Classify every gasket in the room by what can reach it: fuel-wetted joints move to epichlorohydrin foam, dry-side doors stay on the economic foams, and a V-0 requirement overlays the whole decision.
Diesel mist and spills around day tanks, fuel skids, and the generator attack standard organic foams: they swell, soften, and lose seal force.
Epichlorohydrin foam (C41ECH) is the dossier's mapping for fuel-exposed generator-room gaskets: closed-cell, fuel-tolerant chemistry with cellular properties per ASTM D1056 on the TDS. Classify every gasket in the room by what can reach it: fuel-exposed locations move to epichlorohydrin; dry-side doors and panels stay on the economic foams; and a V-0 requirement overlays the whole decision where the specification applies it.
Isolation pads are sized by bearing pressure, not picked by feel
Rule — Put the supported mass and pad footprint on the drawing so bearing pressure lands in the grade's ASTM D1056 working range — rebonded neoprene for heavy plant, vinyl nitrile for cabinets — and re-check after any equipment change.
A generator base pad that is too soft for the mass crushes solid and couples vibration straight into the slab; too firm and it never deflects enough to isolate. Rebonded neoprene (25# / 27#) carries the heavy plant: generator bases and transformers at high bearing pressures.
ENSOLITE vinyl nitrile and the SBE grades carry switchgear cabinets and drive electronics at lighter loads. Put the supported mass and pad footprint on the drawing so the bearing pressure lands in the grade's working range per its ASTM D1056 compression-deflection data, and re-check after any equipment change. [7]
Acoustic treatment is mass first: limp-mass barriers beat thin absorbers here
Rule — Treat the barrier as added panel mass: specify a mass-loaded sheet (reinforced variant for spans and curtains), put coverage area and penetration cutouts on the drawing, and leave acoustic targets with the facility acoustician.
Generator-room noise is low-frequency and structure-adjacent, which is mass-law territory: the practical converted part is a mass-loaded barrier, not a thin absorber foam. BISCO A2 is a mass-loaded silicone sound-barrier sheet, with a fiberglass-reinforced variant where the sheet spans framing or hangs as a curtain; both cut cleanly into panel blankets with penetration cutouts. Flammability-method data is on the TDS, which matters because the same sheet often ends up inside an equipment enclosure.
Treat the barrier as added mass on the panel and put the coverage area and penetrations on the drawing; acoustic design targets stay with the facility acoustician. [9]
EMI shielding is a continuity system: gasket, gap-filler, and seam tape together
Rule — Specify the joint, not just the gasket: a conductive elastomer on engineered doors, a soft conductive sponge where flatness runs out, and foil tape on seams, with the mating-surface plating named so the filler is matched to it.
A rack shields when the conductive path around every opening is continuous. That takes three parts working together: a conductive elastomer gasket (SSP502, with V-0 grades where flame class applies) on doors and panels with engineered compression; a soft conductive sponge (EC-2130) where sheet-metal flatness will not give a solid elastomer its working range; and conductive foil tape bridging seams, lap joints, and retrofit panels.
Electrical properties per grade reference MIL-DTL-83528 and ASTM D991 on the TDS, with ASTM B117 salt-spray data on the corrosion-resistant grades. Specify the joint, not just the gasket: mating surface treatment and closure force decide whether the TDS numbers show up in the assembly. [5]
Specification Tools
Two tools to take you from "I have a protection problem" to here's what to put on the drawing: a fire-barrier stack lookup that maps your location and requirement to an ordered material stack, and a side-by-side comparison matrix of every material family on this page.
1. Fire-barrier layer-stack lookup by location and requirement
Pick where the barrier goes and what the specification asks of it. The lookup returns the ordered layer stack the dossier maps to that case, each layer with its function and its citation. Qualitative guidance; ratings are per-grade TDS listings, and the requirement mapping belongs to the facility fire engineer per NFPA 75 / NFPA 76.
location + requirement → ordered layer stackStack mapping per the H-O dossier; each layer's rating is a per-grade TDS listing.
2. Side-by-side: safety-systems material matrix
Every material family called out on this page, with its construction, protection role, flame data as reported on its TDS, and the zone it fits. Click a column header to sort. Click any material name to jump to its accordion entry and full TDS reference.
| Material | Construction | Flame data (TDS) | Key test methods | Form factor | Best for | |
|---|---|---|---|---|---|---|
| Fire-barrier stack | ||||||
| ManniGlas Glass-Fiber Paper (1200/1900/1902/2000)Non-combustible barrier layer | Inorganic paper | UL 94 per grade (TDS) | ASTM C177, UL 94 | Penetration liners, walls | ||
| Mica Barrier Sheets (Muscovite / Phlogopite)Highest-temperature walls | Mineral sheet | Inorganic (per TDS) | Per maker TDS | Hottest compartments | ||
| kSil V-0 Silicone SpongeCompressible penetration seal | Closed-cell sponge | UL 94 V-0 (TDS) | ASTM D1056, UL 94 | Seals around bundles | ||
| RS-Series Silicone Sponge (RS-800/820/840/870)General FR sponge | Closed-cell sponge | UL 94 V-0 (TDS) | ASTM D1056, D746 | Compartment gaskets | ||
| FST Neoprene (Low Smoke / Flame / Toxicity)Indices-rated layer | Elastomer sheet | FST per TDS | Per grade TDS | FST-specified barriers | ||
| Generator-room isolation, fuel & acoustics | ||||||
| Rebonded Neoprene (25# / 27#)High-density base pads | Rebonded cellular | Per TDS | ASTM D1056 | Generator bases | ||
| ENSOLITE Vinyl Nitrile (SBE41VN/42VN, IV1/IV2/IV3)Cabinet / electronics isolation | Closed-cell foam | UL 94 HF-1 (TDS) | ASTM D1056, D2240 | Switchgear, drives | ||
| Epichlorohydrin Foam (C41ECH)Diesel-fuel-resistant gaskets | Closed-cell foam | Per TDS | ASTM D1056, D412 | Fuel-exposed seals | ||
| BISCO A2 Sound Barrier (A2 + Fiberglass-Reinforced)Mass-loaded acoustic sheet | Mass-loaded silicone | Per TDS | Flammability methods per TDS | Room acoustics | ||
| Server-rack EMI | ||||||
| SSP502 EMI Silicone (Standard + V-0 Grades)Conductive elastomer gaskets | Conductive silicone | V-0 grades per TDS | MIL-DTL-83528, D991 | Rack doors, panels | ||
| BISCO EC-2130 Conductive SpongeSoft, irregular-surface EMI seal | Conductive sponge | Per TDS | Per BISCO TDS | Low closure force doors | ||
| Conductive Foil Tapes (Cu / Al + Conductive PSA)Seam bridging, grounding | Foil + conductive PSA | Per TDS | Per maker TDS | Seams, lap joints | ||
| SSP502 Corrosion-Resistant GradesHarsh-room EMI gaskets | Conductive silicone | Per TDS | ASTM B117, D991 | Plant-adjacent racks | ||
Skip ahead and request your engineering review now
If your drawing already calls out a glass-fiber, mica, silicone-sponge, neoprene, vinyl nitrile, epichlorohydrin, sound-barrier, or conductive-elastomer grade, send it over for engineering review.
Safety-systems failures you can prevent at spec
Safety-side material failures are quiet because the systems they protect are rarely tested by a real event. A barrier stack with a missing layer passes every walkthrough until the day it matters; an isolation pad crushed solid still looks like a pad; an EMI gasket that corroded into an insulator still looks like a gasket. Five patterns cover most of what goes wrong in this zone, and each is a specification decision made before commissioning.
Protection systems fail silently. Unlike a leaking gasket, a compromised fire barrier or a set-collapsed isolation pad gives no day-to-day signal. The fix is at spec and at periodic inspection, not at the incident review.
Show all 5 failure modes tap to expand
1. A flame-rated foam standing in for a fire-barrier stack
Fix — Specify by function, layer by layer: an inorganic barrier layer plus the V-0 compressible seal, with the facility fire engineer owning the assembly per NFPA 75 / NFPA 76. A flammability class is not a barrier function.
A V-0 rated foam gasket gets installed at a cable-tray penetration and everyone moves on: the material is "fire rated," after all. But a flammability classification is not a barrier function. The UL 94 listing says the material itself resists ignition and self-extinguishes under the test method; it says nothing about stopping flame and radiant heat from crossing a compartment boundary.
The dossier's mapping for penetrations is a stack: an inorganic, non-combustible barrier layer (ManniGlas glass-fiber paper; mica sheet at the hottest walls) plus the V-0 compressible seal that closes the gap around the bundle. The fix: specify by function, layer by layer, and let the facility fire engineer own the assembly per NFPA 75 / NFPA 76; the TDS carries each layer's rating, not the assembly's.
2. Smoke and toxicity indices discovered after the material is installed
Fix — Pull the full materials clause from the facility specification before freezing the barrier stack; when smoke and toxicity indices appear, add the FST layer at design time and note it on the drawing.
The barrier passes the flame requirement, then the facility specification, or the AHJ, turns out to call smoke-density and toxicity indices too, and the installed material has no FST data on its TDS. Now the penetration gets reworked at commissioning prices. FST-rated low smoke / low flame / low toxicity neoprene exists for exactly this case and carries the indices on its TDS.
The fix: pull the full materials clause from the facility specification before freezing the barrier stack, and when indices appear, add the FST layer at design time. A one-line note on the drawing ("FST indices per facility spec section X") saves the rework.
3. The generator pad that crushed solid and started transmitting
Fix — Treat the pad as a spring and size it by bearing pressure: rebonded neoprene for generator bases, vinyl nitrile for cabinets, with mass, footprint, and layout on the drawing and a re-check after any equipment change.
A pad that felt comfortably firm under a corner of the genset crushes to near-solid under the full wet mass, and a solid pad is just a spacer: vibration couples straight into the slab and shows up as reads in the white space. The reverse error, an oversized soft pad that never loads into its working range, isolates nothing either.
The fix: treat the pad as a spring and size it by bearing pressure. Rebonded neoprene (25# / 27#) is the high-density family for generator bases; ENSOLITE vinyl nitrile carries cabinets and electronics at lighter pressures. Put the supported mass, footprint, and pad layout on the drawing, check the bearing pressure against the grade's ASTM D1056 compression-deflection data, and re-verify after any equipment change.
4. A standard foam gasket dissolving in the fuel room
Fix — Classify the room's gaskets by fuel exposure at spec: epichlorohydrin foam on the wetted joints, standard foam economics on the dry side, and the exposure mode (mist, splash, immersion) named on the drawing.
A general-purpose foam gasket on a day-tank access cover or generator enclosure door sees diesel mist daily and the occasional splash during fueling. Organic foams swell and soften under that exposure; the gasket grows out of its groove, loses compression, and the enclosure starts weeping fuel vapor. The fix: classify the room's gaskets by fuel exposure at spec.
Epichlorohydrin foam (C41ECH) is the dossier's fuel-resistant mapping for generator-room gaskets, with cellular properties per ASTM D1056 on the TDS; standard foam economics stay on the dry-side doors.
Confirm against the fuel-exposure mode (mist, splash, immersion) named on the drawing.
5. The rack EMI gasket that corroded into an insulator
Fix — Match the gasket grade to the environment and the mating surface: specify a corrosion-resistant grade with ASTM B117 data, name the plating on the drawing so the filler is chosen against it, and inspect gasketed joints on the room's protection-system schedule.
An EMI gasket only works while the conductive path stays conductive. In a plant-adjacent room, galvanic mismatch between the gasket's conductive filler and the rack's plating, plus humidity, grows an oxide film that turns yesterday's low-impedance joint into today's insulator, and emissions that passed at commissioning quietly return. The fix: match the gasket grade to the environment and the mating surface.
The SSP502 family includes corrosion-resistant grades with ASTM B117 salt-spray data on the TDS; conductive-elastomer properties reference MIL-DTL-83528, and volume resistivity is reported per ASTM D991. Specify the mating-surface plating on the drawing so the filler system is chosen against it, and inspect gasketed joints on the same schedule as the room's other protection systems. [8]
Material reference
Detailed reference for the twelve material families on this page: the fire-barrier stack (ManniGlas glass-fiber paper, mica barrier sheets, kSil V-0 and RS-series flame-rated silicone sponge, FST neoprene); the generator-room isolation pads (rebonded neoprene, ENSOLITE vinyl nitrile); the fuel and acoustic treatments (epichlorohydrin foam, BISCO A2 sound barrier); and the rack EMI set (SSP502 EMI silicones including V-0 and corrosion-resistant grades, BISCO EC-2130 conductive sponge, conductive foil tapes).
Flame ratings are per UL 94 listings on each TDS, compression-deflection per ASTM D1056, thermal values per ASTM C177, and conductive-elastomer properties per MIL-DTL-83528 / ASTM D991 as cited per grade. H-O and converts all of them to drawing; per-grade values are per the TDS on file, not headline numbers.
ManniGlas Glass-Fiber Paper (1200 / 1900 / 1902 / 2000)Non-combustible barrier layer · penetration liners & compartment walls · UL 94 / ASTM C177 per TDS
ManniGlas is the layer that makes the stack a barrier rather than a gasket: inorganic, non-combustible, and stable against radiant heat. Specify the grade per the TDS data for your wall and pair it with a V-0 compressible seal; the assembly design belongs to the facility fire engineer per NFPA 75 / NFPA 76.
Mica Barrier Sheets (Muscovite / Phlogopite)Highest-temperature compartment walls · rigid & flexible sheet · values per maker TDS
Mica is the step-up barrier layer: specify it where the wall or baffle sees the highest temperatures in the room, and keep ManniGlas for the general penetrations. Rigid sheet suits plates and baffles; flexible sheet wraps curved penetrations. Values are per the maker's TDS on file.
kSil V-0 Flame-Resistant Silicone SpongeUL 94 V-0 per TDS · compressible penetration & door seals · super-soft to firm
The V-0 rating is the gate for this layer: it keeps the compressible seal from becoming the flammable link in an otherwise inorganic stack. The wide firmness ladder lets the same chemistry conform around bundles and still latch on doors. Ratings and values are per the TDS on file.
RS-Series Silicone Sponge (RS-800 / 820 / 840 / 870)General-purpose FR sponge · UL 94 V-0 per TDS · medium / firm / very firm / soft
RS-800 is the medium default; step softer (RS-870) for low-closure-force covers and firmer (RS-820 / RS-840) for bolted panels. kSil V-0 and RS-series share the rating class and split by firmness range and format. Verify the V-0 listing at your thickness during drawing review.
FST Neoprene (Low Smoke / Low Flame / Low Toxicity)Smoke & toxicity indices per TDS · FST-specified barriers & enclosed rooms
FST is a specification trigger, not an upgrade: when the indices appear in the materials clause, this layer joins the stack, and when they don't, the standard V-0 sponge carries the seal. Pull the full clause before freezing the stack; the indices are per the TDS on file.
Rebonded Neoprene (25# / 27#)Generator & heavy-plant base pads · high-density · ASTM D1056 per TDS
Rebonded neoprene wins this location on density: it loads where lighter foams crush solid. The failure mode to design out is bottoming (failure 3 above); size by bearing pressure against the D1056 data, and re-check when the genset or skid changes.
ENSOLITE Vinyl Nitrile (SBE41VN / SBE42VN, IV1 / IV2 / IV3)Switchgear & electronics isolation · UL 94 HF-1 per TDS · ASTM D1056 ladder
Vinyl nitrile gives a fine-celled, conformable isolation layer at cabinet-scale loads with HF-1 flame listings on the TDS. Same sizing discipline as every pad on this page: mass and footprint on the drawing, bearing pressure into the grade's D1056 working range.
Epichlorohydrin Foam (C41ECH)Diesel-fuel-resistant gaskets · day tanks & generator enclosures · ASTM D1056 per TDS
Classify gaskets by fuel exposure and let epichlorohydrin take the wet ones; a standard foam in a fuel path swells out of its groove (failure 4 above). Name the exposure mode (mist, splash, immersion) on the drawing and confirm against the TDS on file.
BISCO A2 Sound Barrier (A2 + Fiberglass-Reinforced)Mass-loaded silicone sheet · generator-room acoustics · flammability methods per TDS
Acoustic treatment here is mass first: the barrier sheet works by adding limp mass to the panel, so coverage area and airtightness of cutouts matter more than any thin absorber. Use the reinforced variant for spans and curtains; acoustic targets stay with the facility acoustician.
SSP502 EMI Silicone (Standard, V-0 & Corrosion-Resistant Grades)Rack EMI door & panel gaskets · MIL-DTL-83528 / ASTM D991 per TDS
Conductive elastomer is half of the shielding result; closure force, joint geometry, and the mating surface's plating are the other half. Specify the plating on the drawing so the filler system is matched to it, and verify electrical values per grade against the TDS on file.
BISCO EC-2130 Conductive SpongeSoft EMI seal for irregular surfaces · low closure force · per BISCO TDS
Pick EC-2130 by the joint, not the spec sheet: if the door cannot deliver the compression a solid grade needs, the soft sponge is what keeps the conductive path closed. Values per the BISCO TDS on file; pair with foil tape for seams the gasket cannot reach.
Conductive Foil Tapes (Copper / Aluminum + Conductive PSA)Seam bridging & retrofit grounding · slit rolls & · per maker TDS
Foil tape is the continuity patch of the EMI set: fast to apply, thin, and right for seams and retrofits, with the gasket families carrying the engineered joints. Adhesion and through-PSA resistance are per the maker's TDS; surface prep governs the field result.
Data center safety systems: engineer-grade FAQ
Twelve of the questions we hear most from facility engineers, generator-room builders, and rack integrators. If your question isn't here, send a drawing or call, engineering picks up.
What materials make up a cable-tray fire barrier at a penetration?
A stack, not a single sheet. The dossier's mapping: ManniGlas glass-fiber paper as the non-combustible barrier layer lining the opening, mica barrier sheet where the compartment runs hottest, and a kSil V-0 or RS-series silicone sponge (UL 94 V-0 per TDS) as the compressible seal closing the gap around the cable bundle. Where the specification adds smoke and toxicity indices, an FST-rated neoprene layer carries those properties.
The assembly design belongs to the facility fire engineer; the facility-level framing sits in NFPA 75 / NFPA 76 by designation. [2]
Is a UL 94 V-0 foam the same thing as a fire barrier?
No, and the distinction prevents the most common spec failure on this page. A UL 94 V-0 listing says the material itself resists ignition and self-extinguishes under the test method; a fire barrier's job is stopping flame and radiant heat from crossing a compartment boundary, which is the inorganic layer's role (glass-fiber paper, mica). The V-0 sponge is the compressible seal in the stack, not the barrier. Specify by function: barrier layer + V-0 seal + FST layer where indices are called. [1]
When do ManniGlas grades give way to mica sheet?
At the hottest walls. ManniGlas glass-fiber paper (1200 / 1900 / 1902 / 2000) is the general non-combustible barrier layer for penetration liners and compartment walls, with UL 94 data and ASTM C177 thermal values per grade on its TDS.
Where the compartment face runs hotter than the glass-paper envelope, adjacent to high-energy plant or heat-producing equipment, the dossier steps up to mica barrier sheet, with phlogopite mica mapped where temperature extremes govern. State the wall's exposure temperature on the drawing and let the TDS data make the call. [4]
What goes under a standby generator to keep vibration out of the white space?
Rebonded neoprene base pads (25# / 27# density classes), the classic heavy-plant isolation material, sized by bearing pressure. Put the supported wet mass and the pad footprint on the drawing so the pressure lands in the grade's working range per its ASTM D1056 compression-deflection data: a pad crushed solid transmits everything, and an underloaded pad isolates nothing. Switchgear lineups and drive electronics, at lighter pressures, take ENSOLITE vinyl nitrile instead. Re-verify the sizing after any equipment change. [7]
Which gasket survives diesel exposure in the generator room?
Epichlorohydrin foam (C41ECH), the dossier's mapping for diesel-fuel-resistant generator-room gaskets. Standard organic foams swell and soften under fuel mist and splash, grow out of their grooves, and lose compression; epichlorohydrin's chemistry tolerates the exposure, with cellular properties per ASTM D1056 / D412 / D624 on the TDS.
Classify the room's gaskets by exposure: fuel-wetted locations (day tanks, fuel skids, enclosure doors in the drip zone) move to C41ECH, and dry-side panels keep standard foam economics. Name the exposure mode on the drawing.
How do I quiet a generator room with converted parts?
With mass, mostly. Generator-room noise is low-frequency, which is mass-law territory: the effective converted part is a mass-loaded barrier sheet, BISCO A2, into panel blankets with cutouts for penetrations, with the fiberglass-reinforced variant where the sheet spans framing or hangs as a curtain. Thin absorber foams do little against low-frequency energy. Coverage area and airtight cutouts matter more than material exotica; flammability-method data is on the TDS, and acoustic design targets stay with the facility acoustician. [9]
Why does a GPU-dense rack need EMI gasketing at all?
Because high-frequency switching at kilowatt scale radiates, and the rack is the practical containment boundary. Dense compute concentrates fast power conversion (point-of-load regulators, high-speed serial links) whose harmonics leak through every unsealed seam in the rack skin.
The dossier maps the same conductive-elastomer discipline used on switchgear EMI to the rack: SSP502 gaskets on doors and panels, a soft conductive sponge for irregular gaps, and conductive foil tape on seams. The shielding result is assembly-level: gasket grade, closure force, joint geometry, and surface plating together. [5]
When do I use conductive sponge vs solid conductive elastomer on a rack door?
Let the joint decide. A solid conductive elastomer (SSP502 family) needs a defined compression range to make its TDS numbers, which assumes the door delivers real closure force against a reasonably flat flange. Sheet-metal rack doors often deliver neither, and that is the soft conductive sponge's case: BISCO EC-2130 maintains conductive contact across waviness and low closure force.
Use the solid grades on engineered joints, the sponge where flatness or hinge force runs out, and foil tape on seams neither can live in. Values per grade are on the BISCO and SSP TDS. [9]
Do EMI gaskets in a data center need a flame rating too?
Often, yes: when the room or enclosure specification applies a UL 94 class to gasket materials, the EMI gasket is not exempt just because it is conductive. The SSP502 family includes specific V-0 listed grades for exactly this case, so the flame requirement and the EMI function ride the same part. The listing is per grade and per thickness on the TDS; verify it at your gauge during drawing review, and resist substituting an unrated conductive grade when supply gets tight. [1]
What do NFPA 75 and NFPA 76 mean for these materials?
They are the facility-level fire-protection standards for information technology equipment (NFPA 75) and telecommunications facilities (NFPA 76), and this page cites them by designation only. They frame where compartmentation and barriers are required in the facility; the mapping from those requirements to a specific penetration design belongs to the facility fire engineer and the AHJ.
The materials on this page then carry their own per-grade ratings (UL 94 listings, FST indices, thermal data) on their TDS. H-O converts the materials; it does not certify assemblies. [2]
Can H-O cut these materials to our drawing, and how do orders run?
Yes. H-O Products is a precision converter: we die-cut, kiss-cut on liner, slit, and laminate glass-fiber paper, mica sheet, sponge, foam, sound-barrier sheet, and conductive elastomer and foil stock to your drawing as an ISO 9001:2015 certified organization in Winsted, Connecticut. Everything is made-to-order against the drawing, with material traceability and lot-code TDS records; MOQ varies by material and part.
H-O does not extrude or mold raw material in-house; extruded or molded profiles are coordinated through a partner network. Lead-time details are on the process strip above and in the quote form below.
Why frame ratings and electrical values as "per the TDS on file"?
Because every number on this page is a per-grade, per-thickness, per-condition value that belongs to a specific manufacturer document: UL 94 listings change with gauge, compression-deflection with grade, volume resistivity with filler system and compression, and FST indices with the exact compound. Quoting one headline number would flatter one condition and mislead the rest.
This page names the governing methods (UL 94, ASTM D1056, ASTM C177, MIL-DTL-83528, ASTM D991, ASTM B117) and keeps the values on the TDS, which H-O reviews against your drawing during quoting.
We're building generator rooms for several sites. Can the material set standardize?
Yes, and it should. The protection functions repeat site to site even when the room geometry doesn't: the same barrier stack at penetrations (sized per wall), the same two isolation families split by bearing pressure, the same fuel-side gasket chemistry, the same acoustic barrier sheet, and the same three-part rack EMI set. A drawing package standardized on this page's families turns each new site into a dimensions problem instead of a materials problem, with one TDS layer and one converter behind every site. Send the package for a standing review.
Glossary: terms used on this page
Quick reference for the fire-barrier, isolation, acoustic, and EMI terminology used throughout. Each entry links to the relevant test method or section where applicable.
Fire barrier vs flame rating
A fire barrier stops flame and radiant heat from crossing a compartment boundary; a flame rating (a UL 94 [1] class) describes how a material itself behaves under an ignition test. The two are different jobs: the inorganic layer is the barrier, and the rated sponge is the seal that refuses to become the flammable link.
Penetration (cable-tray)
Any opening where a cable tray, conduit, or busway crosses a fire-rated wall or floor. Each one interrupts the compartment boundary and needs a barrier treatment; a data center has hundreds. The converted parts are the stack layers: barrier liner, compressible seal, and an FST layer where indices are specified.
FST (fire / smoke / toxicity)
A specification pattern that limits not just flame spread but the smoke density and toxic-gas yield of a burning material, relevant wherever people and equipment share enclosed air. FST-rated neoprene carries these indices on its TDS; the trigger is the facility specification's materials clause, not the installer's judgment.
Non-combustible (inorganic) barrier layer
The layer of a barrier stack made from material that does not burn: glass-fiber paper (ManniGlas) or mineral mica sheet. It carries the barrier function itself, with thermal transmission characterized per ASTM C177 [4] on the TDS, while organic layers in the same stack carry ratings, not the barrier duty.
UL 94 V-0 / HF-1
Flammability classifications under UL 94 [1], the standard for flammability of plastic materials in devices and appliances. V-0 is a vertical-burn rating; HF-1 a horizontal-burn rating for cellular foams. Listings are per grade and per thickness on each TDS; verify at your gauge, and never assume the rating transfers across grades of one chemistry.
Bearing pressure (isolation pads)
Supported mass divided by pad area: the number that sizes every isolation pad on this page. Each grade has a working deflection range in its ASTM D1056 [7] compression-deflection data; a pad below the range never isolates, and one above it crushes solid and transmits. Mass and footprint go on the drawing; the grade follows.
Rebonded neoprene
High-density pad stock made by bonding neoprene granulate under pressure, graded by density (25# / 27# classes here). Its density carries bearing pressures that crush lighter foams, which is why it is the classic base-pad material under transformers and generators.
Mass-loaded barrier / mass law
The acoustic principle that a panel's transmission loss rises with its surface mass, dominant at the low frequencies a generator produces. A mass-loaded barrier sheet (BISCO A2) adds limp mass to a panel or curtain, which is why it outperforms thin absorber foams against room noise; coverage and airtight cutouts decide the field result.
Epichlorohydrin (ECH) foam
A closed-cell rubber foam whose chemistry tolerates oil and fuel exposure that swells standard organic foams. On this page it is the diesel-side gasket (C41ECH) for day tanks, fuel skids, and generator enclosures, with cellular properties per ASTM D1056 [7] on the TDS.
Conductive elastomer (EMI gasket)
A silicone elastomer filled with conductive particles so a compressed gasket carries current across the joint, closing the shielding boundary at doors and panels. Properties are referenced to MIL-DTL-83528 [5] and volume resistivity to ASTM D991 [6] per grade; compression and mating-surface plating decide what the assembly achieves.
Galvanic compatibility (EMI joints)
The electrochemical pairing between a gasket's conductive filler and the mating surface's plating. A poor pairing plus humidity corrodes the joint into an insulator over months, the silent EMI failure. Corrosion-resistant gasket grades carry ASTM B117 [8] salt-spray data; the drawing should name the plating so the filler is chosen against it.
Seam bridging (foil tape)
Closing an EMC leak path by laying a conductive foil tape (copper or aluminum with conductive PSA) across a seam, lap joint, or retrofit panel edge where a compressed gasket cannot be retained. The continuity patch of the rack EMI set; adhesion and through-PSA resistance are per the maker's TDS.
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 vendor technical data sheets cited throughout this page. Standards editions current as of June 2026; verify against the publishing body before final spec. H-O converts materials that are tested to these methods on the source manufacturer's TDS; H-O does not independently certify materials or assemblies unless explicitly stated on the quote.
UL 94
Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances. The V-0 and HF-1 ratings cited on the silicone-sponge, vinyl nitrile, and EMI-silicone TDS; listings are per grade and thickness. shopulstandards.com (UL 94)
NFPA 75
Standard for the Fire Protection of Information Technology Equipment. The facility-level framing for compartmentation and barrier requirements in IT spaces, cited by designation; mapping to specific penetrations belongs to the facility fire engineer and the AHJ. nfpa.org (NFPA 75)
NFPA 76
Standard for the Fire Protection of Telecommunications Facilities. The companion facility-level standard where the build is a telecom or carrier space; cited by designation on this page. nfpa.org (NFPA 76)
ASTM C177
Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus. The thermal-conductivity method on the glass-fiber paper TDS. astm.org/c0177
MIL-DTL-83528
Detail Specification: Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI. The reference specification for conductive-elastomer EMI gasket properties cited on the SSP502-family TDS. quicksearch.dla.mil (MIL-DTL-83528)
ASTM D991
Standard Test Method for Rubber Property: Volume Resistivity of Electrically Conductive and Antistatic Products. The volume-resistivity method behind the conductive-elastomer electrical values on the TDS. astm.org/d0991
ASTM D1056
Standard Specification for Flexible Cellular Materials, Sponge or Expanded Rubber. The compression-deflection classification behind the sponge, vinyl nitrile, epichlorohydrin, and rebonded-neoprene grades on this page. astm.org/d1056
ASTM B117
Standard Practice for Operating Salt Spray (Fog) Apparatus. The corrosion-exposure method behind the salt-spray data on the corrosion-resistant conductive-elastomer grades. astm.org/b0117
BISCO technical data sheets
Manufacturer technical data sheets for the BISCO A2 sound-barrier sheet and EC-2130 conductive sponge cited on this page: flammability-method data, cellular properties, and electrical values per grade, reviewed against your drawing during quoting.
SSP conductive-elastomer technical data sheets (TDS on file)
Per-grade TDS on file with H-O for the SSP502-family conductive silicones: filler systems, durometer per ASTM D2240, volume resistivity per ASTM D991, MIL-DTL-83528 references, UL 94 listings on the V-0 grades, and ASTM B117 data on the corrosion-resistant grades.
Glass-fiber paper & mica sheet technical data (TDS on file)
Per-grade TDS on file for the ManniGlas glass-fiber papers (UL 94 data, ASTM C177 thermal values, REACH / RoHS statements) and the muscovite / phlogopite mica barrier sheets (thermal and dielectric values per the maker's documents).
ASTM E162 / ASTM E662
Standard Test Method for Surface Flammability of Materials Using a Radiant Heat Energy Source (E162) and Standard Test Method for Specific Optical Density of Smoke Generated by Solid Materials (E662). The surface-flammability and smoke-density methods cited on silicone-foam and FST-material TDS. astm.org/e0162 · astm.org/e0662
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; lot-specific documentation available on request.
Get a safety-systems materials engineering quote
Send a drawing, BOM, or spec sheet. We typically respond within one business day with a material-family recommendation, prototype lead time, and TDS verification against your barrier function, flammability class, supported mass, fuel exposure, and EMI continuity needs.
See also: related H-O application pages
Engineering content for the adjacent product and application categories. Each page covers material selection, failure modes, and converter-side process detail for its application family.
Application page
Data center cooling & liquid infrastructure
CDU sealing, RDHx gaskets, coolant pipe insulation, containment seals, and immersion cooling materials for the same facility.
Read the page
Application page
Data center power & UPS
Rack power distribution insulation and UPS / Li-ion battery-backup materials, the electrical systems these safety treatments protect.
Read the page
Application page
Arc-flash zones, barriers & chutes
The switchgear-side fire and arc barrier page: structural laminates, mica, and inorganic papers inside the gear itself.
Read the page
Application page
EMI shielding for switchgear & power systems
The full EMI reference: conductive elastomers, ground-contact gaskets, and foil tapes across switchgear, VFDs, and racks.
Read the page
Application page
Vibration, shock & acoustic control
The deeper dive on isolation and damping: transformers, reactors, relays, and acoustic materials across electromechanical equipment.
Read the page
Industry hub
Electromechanical & switchgear materials
The full industry directory: every electromechanical sub-application H-O converts for, from insulation to EMI to data center infrastructure.
Open the hub
Material data & standards. All material properties and ratings referenced on this page are taken from the source manufacturer's technical data sheets and the cited standards: UL 94 flammability listings per grade and thickness, compression-deflection per ASTM D1056, thermal transmission per ASTM C177, surface flammability and smoke density per ASTM E162 / E662 where cited, conductive-elastomer properties per MIL-DTL-83528 with volume resistivity per ASTM D991, and salt-spray exposure per ASTM B117.
NFPA 75 and NFPA 76 are cited by designation as the facility-level fire-protection framing; assembly and penetration design belong to the facility fire engineer and the AHJ. This page frames performance qualitatively and keeps per-grade values on the TDS, where they belong. H-O converts materials tested to these methods; H-O does not independently certify materials or assemblies against the standards unless explicitly stated on the quote.
Conversion scope. H-O and converts sheet, roll, and pad stock to drawing in Winsted, Connecticut: die-cut and kiss-cut-on-liner barrier layers, gaskets, and seals, slit strip, waterjet-cut base pads, and multi-layer laminations, with material traceability and lot-code TDS records, as an ISO 9001:2015 certified organization. H-O does not extrude or mold raw material in-house; extruded or molded profiles are coordinated through a partner network. Lead-time and MOQ details are on the process strip and in the quote form above.