Data Center Power & UPS Systems

No material is, and no honest supplier will claim otherwise: UL 1973 (batteries for stationary applications), UL 9540 (energy storage systems), and UL 9540A (the thermal-runaway fire-propagation test method) evaluate systems and assemblies, so the listing belongs to the tested system. What the materials on this page carry is their own documentation: material-level classes like UL 94 V-0 on the rated grade TDSs, the test methods behind their properties, and lot-code traceability.

They support designs evaluated to the system standards; H-O supplies the converted layers and the paperwork, and the system designer owns the evaluation. [1]

Typically two layers with two jobs: a PORON® microcellular urethane pad that holds the cells in their compression window as they swell and cycle (specified by compression-force-deflection per ASTM D3574, with the 4701-40V0 grade adding a UL 94 V-0 class), and a mica fire-barrier sheet for cell-to-cell thermal-runaway containment. Some designs combine roles or add a Kapton® dielectric layer. The stack builder on this page assembles the checklist. The cell maker's preload window and the system's barrier-tier strategy fill in the numbers. [6]

By tier. Mica fire-barrier sheet is the cell-to-cell layer: thin, inorganic, die-cut to the cell footprint. ProCell™ EV Firewall Barrier is the module-level layer: walls, lids, and dividers that contain a module-scale event. ArmaGel® aerogel blanket is the thermal-isolation layer between modules and compartments, buying the most temperature drop per millimeter (methods per ASTM C177/E84 on its TDS). A containment strategy usually layers two or three tiers, and the whole strategy is what gets evaluated per UL 9540A on the tested assembly. [3]

Start from the cell maker's preload window (a force or pressure range, usually in kPa) and the expected swell over life. Pick the PORON® firmness grade whose compression-force-deflection curve (per ASTM D3574 on the TDS) delivers that pressure across the deflection span from fresh stack to fully swollen, then set thickness from the gap and the curve, not the other way around. The 4701 family's compression-set resistance is what keeps the window valid over years; ShockSeal® 4790-79 covers pads that double as environmental seals.

Three materials by mechanics: Kapton® HN film (100–500 gauge designations) wraps and lines the busbar where the insulation bends; G10/FR4 glass-epoxy laminate (NEMA LI 1 grades, NP510/NP511 here) makes the supports, standoffs, and barriers that carry load. And Nomex® 410/414 paper insulates the rack's transformers and inductors. At 48V the electrical margins are generous and the mechanical ones are not: gauge to the wrap radius, laminate to the bolt loads, and spacing per the equipment design's IEC 60664 practice. [9]

An electrically insulating TIM: the Bergquist® Sil-Pad® TSP series (TSP 900 through TSP 3500, the current designations of the Sil-Pad 400–2000 line) or Rogers Protect® pads (1500FG class), whose TDSs carry thermal impedance per ASTM D5470 and dielectric data per D149 on the same sheet, with -60 to +180/200 °C ranges by grade. Where the gap is uneven, the Gap Pad® TGP conformable fillers (1.0–5.0 W/m·K classes per TDS) take over. Read every thermal number at your real mounting pressure. [7]

Right: dry, thin, repeatable interfaces that must survive temperature swings without pump-out or cure, cell-to-cold-plate paths and shelf heat spreading, where eGRAF® HITHERM™ grades (the HT-C3200 TDS lists -40 to +400 °C and a UL 94 V-0 class) and SpreaderShield™ sheets excel. Wrong: any interface that must also insulate electrically, because graphite conducts. That duty belongs to the Sil-Pad®/Protect® class. The split is the whole decision, and it is on the TDS of every candidate.

EPDM foam (RE41E–RE45E) is the economical default: closed-cell, weather-tough, compression classes per ASTM D1056 on the grade TDSs. Move to the BISCO® cellular silicone track (HT-870 Soft and the HT series, BF-1000 Extra Soft, RS-800 Medium FR sponge, kSil® V-0 70) when temperature endurance or a flame class drives the joint, with UL 94 listings per the individual grade TDSs. Match the compression class to the real closure force either way. An over-firm gasket holds a door open just as effectively as a missing one. [13]

Rebonded neoprene base pads, classically the 25# and 27# densities, sized by static bearing stress: genset mass over total pad area, placed so each pad's stress sits inside its working range (per-grade data per ASTM D1056 on the TDSs). Switchgear and panels in the same room ride vinyl nitrile (SBE41VN/42VN, ENSOLITE® family) at gentler loads. The room layout supplies the masses and footprints. Send them with the drawing and the sizing is arithmetic, not art.

Diesel. Generator rooms keep a permanent haze of fuel and oil mist, and commodity enclosure foams swell, soften, and lose their seal in it. Epichlorohydrin (C41ECH) is the closed-cell foam whose chemistry shrugs off oil and fuel while still sealing at sheet-metal closure forces (2–5 psi compression class per ASTM D1056 on its TDS). It is the same logic as the oil-and-chemical sealing page, applied to the one room of the data center that runs on hydrocarbons.

Yes. A module's converted layers (compression pads, mica barriers, Kapton® pieces, TIM pads, gaskets) can ship as kitted sets: one kit per module, parts on liner in assembly order, with lot-code TDS records per material. Kitting is how the documentation burden of battery programs gets manageable: every layer in the kit traces to its TDS and lot, which is exactly what a system-level evaluation wants to see.

H-O die-cuts and converts. We take sheet, roll, and blanket stock from the material makers and die-cut, kiss-cut, slit, waterjet-cut, laminate, and kit it to your drawing. Molding and extruding are partner-network processes rather than in-house ones, and we do not manufacture cells or battery systems. Molded or extruded profiles are coordinated through a partner network. Conversion runs in Winsted, Connecticut under an ISO 9001:2015 certified quality management system with material traceability and lot-code TDS records.

By zone: for the battery stack, the cell preload window, swell allowance, barrier-tier strategy, and any per-material flame-class requirement. For rack power, the busbar geometry, wrap radii, support loads, and TIM mounting pressure. For the cabinet, closure force, gap, and flame class. For the room, masses and bearing areas.

Plus quantities for prototype and production, and the standards language you need on the paperwork (material classes per TDS; system standards by designation). "Recommend the stack" is a valid callout: that is what the engineering review is for.

Tolerance depends on the material class, the thickness, and the cut method. Soft foams and sponges move more than rigid laminates or films, so the achievable band is material-specific. Flag the critical dimensions on your drawing. Engineering confirms the achievable tolerance band for your geometry at drawing review, before tooling is committed. That review, not a generic chart, is what goes into the quote.

Yes. Send the sample part and engineering measures it, confirms the geometry back to you at drawing review, and quotes from that confirmed geometry. A drawing is still the fastest path, because nothing has to be reverse-measured. A DXF, STEP, or PDF with the material call-out shortens the review.