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ManniGlas, Mica, V-0 Sponge, and Rebonded Neoprene: Selecting Data Center Safety-Side Materials
The safety side of a data center is four material problems that share one habit: they fail silently. 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.
This guide walks the four zones the way the parent application page structures them: the cable-tray fire-barrier stack (inorganic layer, compressible V-0 seal, FST layer where indices apply), the generator-room isolation pads sized by bearing pressure, the fuel and acoustic treatments of the same room, and the rack EMI set.
The rule throughout: match the material to the protection function, not to the catalog, with ratings cited per grade TDS and facility-level requirements (NFPA 75, NFPA 76) by designation.
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Zone 1: the fire-barrier stack, inorganic first
Every cable tray that crosses a fire-rated wall leaves a penetration the fire engineering has to close, and the mapping is a stack, not a single sheet. ManniGlas glass-fiber paper (grades 1200/1900/1902/2000, with UL 94 data and ASTM C177 thermal values per grade) is the non-combustible barrier layer, die-cut into wraps, collars, and pads that line the opening. Mica barrier sheet (muscovite and phlogopite) steps in where the compartment sees the highest temperatures: rigid sheet for plates and baffles, flexible sheet for curved penetrations.
The compressible seal that closes the gap around irregular cable bundles is a kSil V-0 or RS-series silicone sponge, rated UL 94 V-0 on its TDS (see the kSil V-0 70 product page), and where the facility specification adds smoke and toxicity indices, an FST-rated neoprene carries those properties. The assembly design belongs to the facility fire engineer per NFPA 75 / NFPA 76; the material ratings stay on the TDS.
Zone 2: isolation pads, sized by bearing pressure
A standby generator is rotating mass bolted to the same structure that carries racks, and the isolation under it is a sizing exercise before it is a material choice. Rebonded neoprene (the classic 25# and 27# density classes) carries generator bases and the heaviest plant: it loads where lighter foams crush solid. ENSOLITE vinyl nitrile and the SBE-series grades isolate switchgear cabinets, transformers, and drive electronics at lower bearing pressures, with UL 94 HF-1 listings per grade.
The discipline is identical for both: state the supported mass and pad footprint on the drawing so the bearing pressure lands inside the grade's working range per its ASTM D1056 compression-deflection data, and re-check after any equipment change. A pad below its range never isolates; a pad above it crushes solid and transmits everything.
Zone 3: fuel-exposed gaskets and acoustic mass
Two more problems live in the generator room. Fuel: day tanks, fuel-polishing skids, and the generator itself put diesel mist and the occasional splash onto gaskets, and standard organic foams swell out of their grooves under that exposure. Epichlorohydrin foam (C41ECH) is the fuel-resistant mapping, a closed-cell chemistry that tolerates diesel exposure with cellular properties per ASTM D1056 on the TDS; classify the room's gaskets by exposure mode (mist, splash, immersion) and let epichlorohydrin take the wet ones.
Noise: generator-room noise is low-frequency, which is mass-law territory, so the effective converted part is a mass-loaded barrier rather than a thin absorber. BISCO A2 sound-barrier sheet, with its fiberglass-reinforced variant for spans and curtains, adds limp mass to panels and doors, die-cut into blankets with airtight penetration cutouts; acoustic design targets stay with the facility acoustician.
Zone 4: the rack EMI set, a continuity system
High-frequency switching in dense compute radiates, and the rack boundary is the practical containment line.
Three families work together, and the shielding result is assembly-level: gasket grade, closure force, joint geometry, and surface plating together.
SSP-series conductive silicones gasket rack doors and removable panels, with conductive-elastomer properties referenced to MIL-DTL-83528 and volume resistivity per ASTM D991 on the TDS, plus dedicated V-0 grades where the flame class applies to the EMI gasket too and corrosion-resistant grades carrying ASTM B117 salt-spray data for harsher rooms.
BISCO EC-2130 conductive sponge takes up irregular sheet-metal mating surfaces at low closure force, the common case on rack doors.
And conductive foil tapes (copper or aluminum with conductive PSA) bridge seams, close lap joints between bays, and ground retrofit panels where an elastomer gasket cannot be retained.
Safety-Side Families by Protection Function
| Function | Family | Key data on the TDS | Where it goes |
|---|---|---|---|
| Non-combustible barrier layer | ManniGlas paper / mica sheet | UL 94 per grade; ASTM C177 thermal values | Penetration liners; hottest walls |
| Compressible rated seal | kSil V-0 / RS-800 sponge | UL 94 V-0 listing per grade and thickness | Gaps around cable bundles, doors |
| Smoke / toxicity indices | FST neoprene | FST indices per TDS | Where the materials clause specifies them |
| Heavy-plant isolation | Rebonded neoprene 25#/27# | ASTM D1056 compression-deflection | Generator bases |
| Cabinet-scale isolation | ENSOLITE vinyl nitrile / SBE grades | ASTM D1056; UL 94 HF-1 per grade | Switchgear, drive electronics |
| Fuel-exposed sealing | Epichlorohydrin C41ECH | ASTM D1056 / D412 cellular data | Day tanks, fuel skids, drip zones |
| Acoustic mass | BISCO A2 sound barrier | Flammability methods per TDS | Room panels, doors, curtains |
| EMI continuity | SSP-series + EC-2130 + foil tape | MIL-DTL-83528 refs; ASTM D991; B117 on CR grades | Rack doors, irregular gaps, seams |
Illustrative and functional only; per-grade values and listings stay on the maker TDS, verified at your thickness during drawing review. Assembly and penetration design belong to the facility fire engineer and the AHJ.
How H-O Products helps
H-O Products is a precision die-cut converter, not a raw-material producer and not a certifier of assemblies. 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: barrier liners and collars, penetration seals, waterjet-cut base pads, acoustic blankets with cutouts, and EMI gasket sets, with material traceability and lot-code TDS records under our ISO 9001:2015 certified quality management system in Winsted, Connecticut.
Everything is made to order. We recommend family and grade direction against your barrier function, flammability class, supported mass, fuel exposure, and EMI continuity needs, and we verify ratings per grade TDS; extruded or molded profiles are coordinated through our partner network.
Frequently asked questions
What materials make up a cable-tray fire barrier at a penetration?
A stack, not a single sheet: 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 framing sits in NFPA 75 / NFPA 76 by designation.
What goes under a standby generator to keep vibration out of the white space?
Rebonded neoprene base pads (25# / 27# density classes), sized by bearing pressure: supported wet mass over pad footprint, landed inside 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, ride ENSOLITE vinyl nitrile instead. Re-verify the sizing after any equipment change.
Which gasket survives diesel exposure in the generator room?
Epichlorohydrin foam (C41ECH). 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 on the TDS. Classify the room's gaskets by exposure: fuel-wetted locations move to C41ECH, dry-side panels keep standard foam economics, and the exposure mode goes on the drawing.
When do I use conductive sponge instead of solid conductive elastomer on a rack door?
Let the joint decide. A solid conductive elastomer (SSP-series family) needs a defined compression range against a reasonably flat flange to make its TDS numbers. Sheet-metal rack doors often deliver neither, and that is the soft conductive sponge's case: EC-2130 maintains conductive contact across waviness at low closure force. Use solid grades on engineered joints, the sponge where flatness or hinge force runs out, and foil tape on seams neither can live in.
Get a safety-side material recommendation
Tell us the barrier locations, the flammability and FST clauses, the supported masses, the fuel exposure, and the EMI joints, and we will recommend families and grades and quote die-cut parts on your drawings.
Samples typically ship in 3 to 5 business days for common die-cut configurations; standard production runs about two weeks; special orders are quoted to the job. MOQ varies by material and part.
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Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).
References
- UL 94 (V-0 / HF-1 listings per grade and thickness); NFPA 75 and NFPA 76 (facility-level fire protection for IT and telecom spaces, by designation); ASTM C177 (thermal transmission, glass-fiber paper TDS).
- ASTM D1056 (compression-deflection on sponge, vinyl nitrile, epichlorohydrin, and rebonded-neoprene grades); MIL-DTL-83528 (conductive-elastomer EMI gasket reference specification); ASTM D991 (volume resistivity); ASTM B117 (salt-spray, corrosion-resistant EMI grades); ASTM E162 / E662 (surface flammability and smoke density where cited).
- Maker technical data sheets: ManniGlas papers; muscovite / phlogopite mica sheets; kSil V-0 and RS-series sponge; FST neoprene; rebonded neoprene; ENSOLITE / SBE vinyl nitrile; C41ECH; BISCO A2 and EC-2130; SSP-series family incl. V-0 and corrosion-resistant grades; conductive foil tapes.
This article summarizes safety-side material selection using the published standards and material families named above. Ratings and indices are per-grade, per-thickness TDS listings; assembly and penetration design belong to the facility fire engineer and the AHJ, and shielding results belong to the assembled joint. H-O converts materials tested to the cited methods; it does not certify materials or assemblies.
All parts are custom manufactured to order; minimum production run quantities vary by material and part. H-O is a die-cut converter, not a raw-material producer.