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Marinite® I Replacement:
Super Firetemp® X or Promat PROMATECT® – MST

BNZ Materials has permanently discontinued the Marinite product line, and Marinite I is final, non-restocking inventory. AWMCO offers two recommended replacements for Marinite I in calcium silicate insulation applications: Super Firetemp X, a Johns Manville calcium silicate board rated to 1700°F and available with monthly restocking, and Promat PROMATECT MST, a structural calcium silicate board manufactured by Promat and classified to 1000°C (1832°F), sourced to order through AWMCO. Both products are non asbestos, non-combustible calcium silicate boards used in furnace linings, fire doors, kiln construction, industrial insulation, and high-temperature welding protection. Super Firetemp X is the in-stock, on-demand option for operations that need immediate supply. PROMATECT-MST is the option for applications requiring higher classification temperature or EN-compliant structural thermal specifications. Contact AWMCO to discuss which replacement fits your application.

Shop Super Firetemp X Request Promat PROMATECT-MST Info

Marinite® I vs. Super Firetemp® X vs. Promat PROMATECT® – MST : Spec Comparison

Specification BNZ Marinite® I Super Firetemp® X Promat PROMATECT®–MST
Manufacturer BNZ Materials Johns Manville Promat (Etex Group)
Density 46 pcf (~737 kg/m³) 40 pcf (~641 kg/m³) 47 pcf (750 kg/m³)
Max Service Temperature 1200°F (649°C) 1700°F (927°C) 1832°F (1000°C)
Bending Strength 800 psi 1000 psi ≥870 psi (≥6 N/mm²)
Compressive Strength 1350 psi (95 kg/cm²) @ 10% deformation 2000 psi @ 10% deformation ~2611 psi (~18 N/mm²)
Thermal Conductivity 0.13 W/m·K @ 24°C; 0.12 @ 149°C; 0.12 @ 205°C; 0.12 @ 260°C; 0.11 @ 316°C 0.094 W/m·K @ 93°C; 0.101 @ 204°C; 0.108 @ 316°C; 0.115 @ 427°C 0.25 W/m·K @ 20°C (room temp only)
Thermal Shrinkage 0.4% (L/W) @ 1400°F (760°C) / 24h 0.7% (L) / 0.8% (W) @ 1700°F (927°C) / 24h 0.9% @ 1832°F (1000°C) / 24h
Asbestos-Free Yes Yes Yes
Building Material Class Non-combustible Non-combustible A1, Non-combustible (EN 13501)
ASTM / EN Standard ASTM C177 ASTM C656 Type II EN 12467
Sheet Size 48″ × 96″ (1219 × 2438 mm) 48″ × 96″ (1219 × 2438 mm) 47″ × 98″ (1200 × 2500 mm)
Quality System ISO 9002 ISO 9001 ISO 9001
Availability Limited stock — final inventory In stock — monthly restocking Sourced to order — contact AWMCO
Custom Cutting Available Available Available
Supply Status Discontinued — BNZ no longer manufacturing Ongoing supply Currently available

Spec note: Bending and compressive strength for Marinite I are not published in the available BNZ datasheet; Super Firetemp X values are per ASTM test methods. PROMATECT–MST values are per EN 826 (compressive) and EN 12467 (bending). Super Firetemp X thermal conductivity published at four points (93°C through 427°C) per ASTM methods. PROMATECT–MST thermal conductivity is only published at 20°C (room temperature) in the official Promat datasheet — high-temperature values not available. PROMATECT–MST at ~47 pcf is the closest density match to Marinite I (46 pcf); Super Firetemp X at 40 pcf provides 500°F additional temperature headroom. Contact AWMCO to discuss which product fits your application.

Two Replacements for Marinite I — Which Is Right for Your Application?

BNZ Materials — the manufacturer of Marinite — has permanently closed its Marinite production facility. The Marinite I shown on the AWMCO website is our last available inventory. It will not be replenished. Two qualified replacement options are available, and the right choice depends on your supply requirements and application:

  • Super Firetemp X — In stock, monthly restocking, 1700°F rated

    Super Firetemp X is AWMCO's in-stock answer for Marinite I. Available now with monthly restocking, it is rated to 1700°F (927°C) — 500°F higher than Marinite I's 1200°F ceiling. Super Firetemp X meets ASTM C656 Type II, publishes bending strength of 1000 psi and compressive strength of 2000 psi at 10% deformation, and is non-asbestos. Available in 4 ft × 4 ft and 4 ft × 8 ft sheets up to 2" thick, with custom cutting available. It is the practical choice for operations that need a proven, domestically sourced calcium silicate board without lead time risk.

  • Promat PROMATECT-MST — 1000°C classification, EN-compliant

    PROMATECT-MST is Promat's structural calcium silicate board rated to 1000°C (1832°F). At 750 kg/m³ (~47 pcf), it closely matches Marinite I's density, and it publishes bending and compressive strength values (≥6 N/mm² and ~18 N/mm² respectively) under EN standards. PROMATECT-MST carries EN 12467 conformity and A1 (non-combustible) building material class per EN 13501. It is the appropriate choice for applications requiring European standard compliance, higher classification temperature, or documented structural thermal performance under EN test standards.

  • Supply chain certainty

    Marinite I stock at AWMCO is finite. As authorized distributors for both Johns Manville Super Firetemp X and Promat PROMATECT®-MST, AWMCO can supply replacement materials for ongoing production needs. Super Firetemp X is regularly restocked, while PROMATECT® MST is available by order. Both products can be supplied in full sheets or precision-cut 12" × 12" squares.

Is Super Firetemp X a Direct Drop-In for Marinite I?

For most applications, yes. Marinite I and Super Firetmemp X are both:

•      Non-asbestos, non-combustible calcium silicate boards

•      Machinable — cut, drilled, and fabricated using standard tools

•      Available in 4 ft × 4 ft and 4 ft × 8 ft sheets up to 2" thick, with custom cutting through AWMCO

•      Rated for industrial high-temperature use (Super Firetemp X at 1700°F — exceeds Marinite I's 1200°F ceiling)

The primary differences are density (40 vs. 46 pcf) and temperature ceiling (1700°F vs. 1200°F). In most furnace lining, fire door, kiln, and welding protection applications where Marinite I has been the specified material, Super Firetemp X performs as a compatible substitution. For applications with strict density specifications above 40 pcf, contact AWMCO — PROMATECT-MST at ~47 pcf more closely matches Marinite I's density.

Is PROMATECT-MST a Direct Drop-In for Marinite I?

For applications requiring a closer density match, EN standard compliance, or higher classification temperature, PROMATECT-MST is the technically stronger substitution for Marinite I:

•      Density match: PROMATECT-MST at 750 kg/m³ (~47 pcf) closely mirrors Marinite I's 46 pcf

•      Temperature headroom: PROMATECT-MST is classified to 1000°C (1832°F) — well above Marinite I's 1200°F operational ceiling

•      EN compliance: For specifications requiring EN 12467 conformity or A1 non combustible classification per EN 13501, PROMATECT-MST satisfies these requirements

•      Published mechanical data: Bending strength ≥6 N/mm² and compressive strength ~18 N/mm² are available for engineering documentation

PROMATECT-MST is sourced to order through AWMCO — contact us for lead times and confirm sheet format and thicknesses for your application.

Common Applications

Super Firetemp X and PROMATECT-MST replace Marinite I in the following applications:

•      Industrial furnace wall panels and backup insulation

•      Fire door cores and assemblies

•      Kiln furniture and sidewall lining

•      Welding and torch protection panels

•      Marine and shipboard fire insulation

•      Aerospace ground support heat shields

•      Petrochemical and refinery insulation panels

•      Structural insulation for high-temperature industrial equipment

•      Load-bearing thermal separation components

Order Super Firetemp X or PROMATECT-MST from AWMCO

AWMCO is an authorized distributor for Johns Manville Super Firetemp X and Promat PROMATECT - MST. Contact us for lead times, pricing, and custom cutting to your part dimensions.

Shop Super Firetemp X Request Promat PROMATECT - MST Quote — Contact AWMCO

Frequently Asked Questions — Marinite I, Super Firetemp X and Promat PROMATECT - MST

What is the best replacement for BNZ Marinite I?

AWMCO offers two recommended replacements for BNZ Marinite I. Super Firetemp X, manufactured by Johns Manville, is the in-stock option — rated to 1700°F, ASTM C656 Type II compliant, bending strength 1000 psi, compressive strength 2000 psi at 10% deformation, and available with monthly restocking in 4 ft × 4 ft and 4 ft × 8 ft sheets. Promat PROMATECT - MST is the option for applications requiring higher classification temperature (1000°C / 1832°F), closer density match (~47 pcf vs. Marinite I's 46 pcf), or EN 12467 / EN 13501 compliance. Contact AWMCO to discuss which product fits your application.

Is Super Firetemp X the same density as Marinite I?

No. Super Firetemp X has a density of 40 pcf; Marinite I has a density of 46 pcf. Super Firetemp X exceeds Marinite I's maximum service temperature (1700°F vs. 1200°F). For applications requiring a closer density match, Promat PROMATECT - MST at ~47 pcf (750 kg/m³) is the better match.

What is Promat PROMATECT-MST and how does it compare to Marinite I?

PROMATECT - MST is a structural calcium silicate board manufactured by Promat (Etex Group) and classified to 1000°C (1832°F). Its density of ~47 pcf (750 kg/m³) closely matches Marinite I's 46 pcf. It publishes bending strength ≥6 N/mm² and compressive strength ~18 N/mm² per EN standards, carries A1 non-combustible classification per EN 13501, and conforms to EN 12467. For applications requiring density matching, EN compliance, or higher temperature classification, PROMATECT - MST is the stronger technical substitution.

What is the temperature limit of Super Firetemp X compared to Marinite I?

Super Firetemp X is rated to 1700°F (927°C) continuous service — 500°F higher than Marinite I's 1200°F (649°C) ceiling. This gives operations additional thermal headroom with no change in product category.

Why is Marinite I no longer available from BNZ Materials?

BNZ Materials, the manufacturer of the Marinite product line, has permanently closed its production facility. AWMCO has limited Marinite I inventory and is no longer able to reorder any Marinite I due the closure. This stock will not be replenished once sold. AWMCO stocks Super Firetemp X and sources Promat PROMATECT-MST as the recommended replacements. Contact AWMCO for availability and lead times.

Does AWMCO still have Marinite I in stock?

Yes — as of the date this page was published, AWMCO has limited quantities of BNZ Marinite I remaining. This is final inventory and will not be restocked. Order now to secure remaining supply, or transition to Super Firetemp X (in stock, monthly restocking) or Promat PROMATECT-MST for long-term sourcing.

Can AWMCO cut Super Firetemp X or PROMATECT-MST to custom dimensions?

Yes. AWMCO offers custom fabrication for both Super Firetemp X and PROMATECT-MST — cut to length, width, thickness, shape and design to your specified dimensions. Contact AWMCO with your specs to request a quote.

 Does PROMATECT-MST have EN building compliance?

Yes. PROMATECT-MST carries A1 (non-combustible) building material class per EN 13501-1 and conforms to EN 12467. For projects requiring European standard compliance in passive fire protection or structural thermal insulation applications, PROMATECT-MST meets these requirements.

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