FRCI-12 (fibrous refractory composite insulation) rigid tile FRCI-12
Fibre composite of silica (SiO2) fibre and aluminoborosilicate fibre, per the TPSX composition line
Also known as FRCI-12
FRCI-12 is a rigid reusable insulation tile made of fibrous refractory composite insulation (FRCI).
Evidence level
2 of 5
Lab-measured
- 0Predicted only. No one has made it, or no measurement exists.
- 1Calculated. Only calculated or predicted values from sources.
- 2Lab-measured. Measured properties with their conditions stated.
- 3Space-relevant tests. Measured in conditions relevant to space, such as vacuum or atomic oxygen.
- 4Ground-qualified. Qualified for an application on the ground.
- 5Flown or field-proven. Flight or field results exist.
Density
192 kg/m3
Dielectric
1.2 -
Strength limit
1144 K
Recipe, share of the weight
- SiO2 not statedSilica fibre
- not statedAluminoborosilicate fibre
Best for
Reusable insulation on the hot underside of a re-entry vehicle, where low density and low thermal conductivity matter and strength must be higher than the original silica tiles
Weakest at
Few plain-number property values are available for this grade; most TPSX values are printed in exponent form and are not recorded here
Risk at a glance
- People None found. Irritant codes in the PubChem silica record
- If it fails Moderate. Tile damage during ascent or landing
- Corrosion No data. No corrosion data recorded
Quick facts: FRCI-12
| Property | Value | Basis |
|---|---|---|
| Density | 0.08 to 0.48 g/cm³ | 3 sourced values across conditions |
What is the density of FRCI-12 rigid tile?
FRCI-12 rigid tile has a density of 0.08 to 0.48 g/cm³. The range covers 3 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is FRCI-12 rigid tile used for?
Uses recorded in the sources include Space Shuttle orbiter reusable insulation tiles; Orbiter underside tiles, replacing some HRSI tiles; Tiles around door penetrations (replacing LI-2200 tiles).
Why it exists
FRCI-12 is a rigid reusable insulation tile made of fibrous refractory composite insulation (FRCI). It was used on the Space Shuttle orbiters and was designed to be stronger than the original silica tiles while keeping a low density. TPSX says it is 'substantially stronger than the original' silica tile at a low density.
Where it's used
Space Shuttle orbiters
NASA TPSX says FRCI-12 was baselined for use on all of the shuttle orbiters and has flown on the shuttle since shortly after the second orbiter Challenger was built.
Orbiter underside tiles
Wikipedia says FRCI tiles improved strength, durability and resistance to coating cracking, reduced weight, and replaced some HRSI tiles.
Door penetrations
AZoM reports that FRCI replaced LI-2200 tiles around door penetrations, which helped reduce the orbiter's weight.
Recipe
Fibre composite of silica (SiO2) fibre and aluminoborosilicate fibre, per the TPSX composition line
FRCI-12 is a fibre composite, not a single compound. NASA's TPSX record describes it as a silica fibre body with an aluminoborosilicate fibre component, and gives the exact split in its composition line. The patent describes making the tile by washing the silica fibres, dispersing the aluminoborosilicate fibres, mixing both into a water slurry, pressing a billet, drying it and firing it.
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Silica fibre SiO2 | not stated | The bulk of the tile. The patent describes the silica fibres as highly pure, at least 99.6% pure. |
| Aluminoborosilicate fibre | not stated | Adds strength and durability. It carries the boron oxide listed in the TPSX composition line. |
Weight shares are as printed in the sources.
What it can do
Density
192 kg/m3
measured
Insulate the hot underside of a re-entry vehicle at a density of 192 kg/m3 (12 lb/ft3) per the Wikipedia density table.
Dielectric
1.2 -
measured
Keep a dielectric constant of 1.2 at 10GHz and room temperature, per the TPSX record.
Strength limit
1144 K
measured
Keep its tensile properties relatively constant up to 1144K (1600F), per the TPSX notes.
How it compares
FRCI-12 is lighter than the LI-2200 tiles it was used beside and was used to replace some HRSI tiles, according to the Wikipedia and AZoM sources. TPSX says it is 'equivalent in strength to LI-2200 at a lower density'. The compare rows below show its density, dielectric constant and the patent's laboratory temperature comparison. No comparable figures for other tile grades are recorded here.
The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details.
| Measurement | FRCI-12 |
|---|---|
| Thermal behavior and safety | |
| Temperature below which the aluminoborosilicate fibre does not soften or sinter significantly | 1370 °C9 |
| Physical and electrical | |
| Density, FRCI tile | 192 kg/m32 |
| Density, FRCI tile, imperial units | 12 lb/ft33 |
| Density range of laboratory tiles of the patented composite | 0.08 g/cc7 |
| Temperature behavior | |
| Temperature below which tensile properties stay relatively constant | 1144 K4 |
| Temperature capability, composite of the present invention (patent comparison) | 1540 °C5 |
| Other measurements | |
| Dielectric constant, RF at 10 GHz, room temperature | 1.2 -1 |
| Strain to failure (patent name for elongation), laboratory tile of the patented composite | 0.5 %6 |
| Boron oxide content of the fibre mix, range preferred for re-entry shield applications | 1 %8 |
| Silica fibre share of the FRCI-12 fibre mix, by weight | 78 % wt10 |
| Aluminoborosilicate fibre share of the FRCI-12 fibre mix, by weight | 22 % wt11 |
| Silica fibre purity, raw fibre used in the patented composite | 99.6 %12 |
Why choose it, and why not
Good for
- Low density. The Wikipedia table lists the tile at 192 kg/m3 (12 lb/ft3).
- Reusable insulation on a re-entry vehicle. TPSX says it flew on the Space Shuttle.
Watch out for
- Most flight property values for this grade are printed in exponent form in the TPSX record and are not recorded here.
- The patent temperature figure is for a laboratory tile, not the flight tile.
- Inspection and repair were needed after flights, according to the Wikipedia summary.
FRCI-12 is a documented flight tile with limited plain-number data in the sources we could read. The file is a partial draft.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Other names and standards
The same grade under other systems, as datasheets and standards print them. Each code was checked against the page it comes from.
| System | Codes |
|---|---|
| Trade name | FRCI-12 |
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Dielectric constant, RF at 10 GHz, room temperature | Measured value as listed in the TPSX property table (uncertainty and exponent-form rows not recorded) | frequency 10GHz (as printed in the TPSX note)temperature room temperaturecoating not stated in the row | — |
| 2 | Density, FRCI tile | Value printed in the density table of the Wikipedia weight considerations section (secondary compilation) | tile FRCI (fibrous refractory composite insulation) tilesbasis density column of the Wikipedia weight table; no test method printed | — |
| 3 | Density, FRCI tile, imperial units | Value printed in the same density table row (secondary compilation) | tile FRCI (fibrous refractory composite insulation) tilesbasis same table row as the kg/m3 value; no test method printed | — |
| 4 | Temperature below which tensile properties stay relatively constant | Note on the TPSX property table, based on the NASA Ames record; not a use limit | basis printed as 1144K (1600F) in the TPSX notes for the tensile strength rowsnote gradual strength reduction begins above this temperature | — |
| 5 | Temperature capability, composite of the present invention (patent comparison) | Printed in the comparison table after Example 1 of the patent; a laboratory tile, not a flight tile limit | composite Example 1 tile of the patent (825 grams silica fibres and 175 grams aluminoborosilicate fibre, density 0.32 g/cc)comparator prior-art tile in the same table: 1480° C.test not stated in the table | The patent tile density (0.32 g/cc) differs from the flight density in the Wikipedia table, so do not read this value as the flight-grade limit. |
| 6 | Strain to failure (patent name for elongation), laboratory tile of the patented composite | Printed in the comparison table after Example 1 of the patent, row 'Strain to failure'; a laboratory tile, not the flight FRCI-12 tile | tile Example 1 tile of the patent, density 0.32 g/cc, silicon carbide opacifiedcomparator prior-art silica fibre and colloidal silica matrix tile at 0.32 g/cc: 0.2-0.3%test not stated in the table | — |
| 7 | Density range of laboratory tiles of the patented composite | Printed in the patent description of the final density ('prepared in densities ranging from about 0.08 to 0.48 g/cc') | tile Patented fibrous refractory composite (silica and aluminoborosilicate fibres), laboratory tilesbasis range of densities the patent says the insulation has been prepared in; the flight FRCI-12 density is in the density rows above | — |
| 8 | Boron oxide content of the fibre mix, range preferred for re-entry shield applications | Printed in the patent description of boron oxide content; a composition specification for the composite, not a test result | basis percent of the total fibre weight; boron oxide added as aluminoborosilicate fibre or as free boron oxiderange printed 0.5 to 30% of the total weight of fibres in general | — |
| 9 | Temperature below which the aluminoborosilicate fibre does not soften or sinter significantly | Printed in the patent description; a statement about the fibre, not a tile use limit | fibre aluminoborosilicate fibre component of the compositebasis patent statement of the lower limit of the temperature range without significant softening or sintering | — |
| 10 | Silica fibre share of the FRCI-12 fibre mix, by weight | Composition line of the TPSX record, printed as approximately 78% wt. | basis approximate weight share printed in the TPSX composition line; the balance is aluminoborosilicate fibre | — |
| 11 | Aluminoborosilicate fibre share of the FRCI-12 fibre mix, by weight | Composition line of the TPSX record, printed as approximately 22% wt. | basis approximate weight share printed in the TPSX composition line; the balance is silica fibre | — |
| 12 | Silica fibre purity, raw fibre used in the patented composite | Printed in the patent description of raw materials; a raw-fibre specification, not a tile test | fibre silica fibre (Microquartz 108 type)basis minimum purity printed for the raw fibre before tile forming | — |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
The safety information found here is for the pure compounds, not for the bound tile. No safety data sheet for FRCI-12 was found.
- Silica
- PubChem's silica record lists skin, eye and respiratory irritation codes from company reports, and says most reports do not meet GHS criteria.
- Boron oxide
- PubChem's boron oxide record lists a reproductive toxicity hazard (H360FD) for the pure oxide. Its presence in the tile is as bound fibre.
If a tile is damaged
These are handling and inspection points from the sources, not from test data.
- Ascent damage
- The Wikipedia summary says the tiles needed close inspection and repair after each landing, because they could be damaged during ascent.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Tile damage during ascent or landingmoderate severity | Debris strikes or other impacts during launch, and handling after landingThe Wikipedia summary says the tiles, 'originally specified never to take debris strikes during launch, in practice also needed to be closely inspected and repaired after each landing'. |
Handling and storage
- The Wikipedia summary says the tiles were glued to Nomex felt strain-isolation pads with room temperature vulcanizing (RTV) silicone adhesive rather than mechanically fastened, to avoid heat transfer through attachment points.
Supply and geography
How common the raw materials are and where they come from.
Boron (boric oxide in the aluminoborosilicate fibre)
- Critical mineral lists
- US: listed
- Recycling
- Not found in the USGS boron chapter we hold.
Aluminium (alumina, Al2O3, in the aluminoborosilicate fibre)
- Recycling
- Not found in the USGS bauxite and alumina chapter we hold.
- Substitutes
- USGS: 'Bauxite is the only raw material used in the production of alumina on a commercial scale.'
Silicon dioxide (silica fibre)
- Critical mineral lists
- US: listed
- Recycling
- Not found in the USGS silicon chapter we hold.
Documents
Datasheets, safety data sheets, papers and standards you can open.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0. Images keep the licence shown with each one.
Show the full YAML
spore: profile
id: frci-12-tile
spore_version: 0.2
family: silica
name: FRCI-12 (fibrous refractory composite insulation) rigid tile
abbreviation: FRCI-12
role: Reusable rigid insulation tile of fibrous refractory composite insulation on the Space Shuttle orbiters
category: thermal-protection
type: reusable-tiles
summary: |
FRCI-12 is a rigid reusable insulation tile made of fibrous refractory composite insulation (FRCI). It was baselined for all Space Shuttle orbiters. The NASA Ames TPSX record gives its dielectric constant as 1.2 at 10GHz and room temperature, and the Wikipedia density table lists FRCI tiles at 192 kg/m3 (12 lb/ft3). The TPSX record says its mechanical properties stay relatively constant up to 1144K (1600F).
best_for: Reusable insulation on the hot underside of a re-entry vehicle, where low density and low thermal conductivity matter and strength must be higher than the original silica tiles
weakest_at: Few plain-number property values are available for this grade; most TPSX values are printed in exponent form and are not recorded here
identity:
formula: Fibre composite of silica (SiO2) fibre and aluminoborosilicate fibre, per the TPSX composition line
source: tpsx-frci
where: 'Composition line of the FRCI-12 Rigid Tile record (TPSX Material id=3): Approximately 78% wt. silica (SiO2), 22% wt. aluminoborosilicate (62% Al2O3, 24% SiO2, 14% B2O3)'
designations:
- system: Trade name
code: FRCI-12
source: tpsx-frci
where: Name line, FRCI-12 Rigid Tile
tags:
environments:
- re-entry
stresses:
- extreme-heat
applications:
- heat-shields
properties:
- benchmark: dielectric_constant
label: Dielectric constant, RF at 10 GHz, room temperature
value: 1.2
unit: '-'
scope: material
conditions:
frequency: 10GHz (as printed in the TPSX note)
temperature: room temperature
coating: not stated in the row
method: Measured value as listed in the TPSX property table (uncertainty and exponent-form rows not recorded)
status: ground
source: tpsx-frci
where: Properties at Standard Conditions table, Dielectric Constant row; note 15
- benchmark: density
label: Density, FRCI tile
value: 192
unit: kg/m3
scope: material
conditions:
tile: FRCI (fibrous refractory composite insulation) tiles
basis: density column of the Wikipedia weight table; no test method printed
method: Value printed in the density table of the Wikipedia weight considerations section (secondary compilation)
status: ground
source: wiki-tps
where: Weight considerations, density table, row 'Fibrous refractory composite insulation tiles'
- benchmark: density
label: Density, FRCI tile, imperial units
value: 12
unit: lb/ft3
scope: material
conditions:
tile: FRCI (fibrous refractory composite insulation) tiles
basis: same table row as the kg/m3 value; no test method printed
method: Value printed in the same density table row (secondary compilation)
status: ground
source: wiki-tps
where: Weight considerations, density table, row 'Fibrous refractory composite insulation tiles' (lb/ft 3 column)
- benchmark: mechanical_stability_limit_temperature
label: Temperature below which tensile properties stay relatively constant
value: 1144
unit: K
scope: material
conditions:
basis: printed as 1144K (1600F) in the TPSX notes for the tensile strength rows
note: gradual strength reduction begins above this temperature
method: Note on the TPSX property table, based on the NASA Ames record; not a use limit
status: ground
source: tpsx-frci
where: Notes 8 and 9 of the Properties at Standard Conditions table
- benchmark: temperature_capability
label: Temperature capability, composite of the present invention (patent comparison)
value: 1540
unit: °C
scope: material
conditions:
composite: Example 1 tile of the patent (825 grams silica fibres and 175 grams aluminoborosilicate fibre, density 0.32 g/cc)
comparator: 'prior-art tile in the same table: 1480° C.'
test: not stated in the table
method: Printed in the comparison table after Example 1 of the patent; a laboratory tile, not a flight tile limit
status: ground
note: The patent tile density (0.32 g/cc) differs from the flight density in the Wikipedia table, so do not read this value as the flight-grade limit.
source: patent-frci
where: 'Comparison table after Example 1, row ''Temperature capability'' (Tile: Present Invention)'
- benchmark: elongation
label: Strain to failure (patent name for elongation), laboratory tile of the patented composite
value: 0.5
unit: '%'
scope: material
conditions:
tile: Example 1 tile of the patent, density 0.32 g/cc, silicon carbide opacified
comparator: 'prior-art silica fibre and colloidal silica matrix tile at 0.32 g/cc: 0.2-0.3%'
test: not stated in the table
method: Printed in the comparison table after Example 1 of the patent, row 'Strain to failure'; a laboratory tile, not the flight FRCI-12 tile
status: ground
source: patent-frci
where: 'Comparison table after Example 1, row ''Strain to failure'' (Tile: Present Invention)'
- benchmark: density
label: Density range of laboratory tiles of the patented composite
value: 0.08
value_high: 0.48
unit: g/cc
scope: material
conditions:
tile: Patented fibrous refractory composite (silica and aluminoborosilicate fibres), laboratory tiles
basis: range of densities the patent says the insulation has been prepared in; the flight FRCI-12 density is in the density rows above
method: Printed in the patent description of the final density ('prepared in densities ranging from about 0.08 to 0.48 g/cc')
status: ground
source: patent-frci
where: Description, paragraph on the final density of the tile (sentence beginning 'The insulation of the present invention has been prepared in densities')
- benchmark: boron_oxide_content
label: Boron oxide content of the fibre mix, range preferred for re-entry shield applications
value: 1
value_high: 6
unit: '%'
scope: material
conditions:
basis: percent of the total fibre weight; boron oxide added as aluminoborosilicate fibre or as free boron oxide
range_printed: 0.5 to 30% of the total weight of fibres in general
method: Printed in the patent description of boron oxide content; a composition specification for the composite, not a test result
status: ground
source: patent-frci
where: Description, paragraph beginning 'Boron oxide, it has been pointed out earlier' (sentence giving the preferred range)
- benchmark: fibre_softening_onset_temperature
label: Temperature below which the aluminoborosilicate fibre does not soften or sinter significantly
value: 1370
unit: °C
scope: material
conditions:
fibre: aluminoborosilicate fibre component of the composite
basis: patent statement of the lower limit of the temperature range without significant softening or sintering
method: Printed in the patent description; a statement about the fibre, not a tile use limit
status: ground
source: patent-frci
where: Description, paragraph beginning 'Silica fiber is highly reactive' (sentence on the aluminoborosilicate fibres)
- benchmark: silica_fibre_fraction
label: Silica fibre share of the FRCI-12 fibre mix, by weight
value: 78
unit: '% wt'
scope: material
conditions:
basis: approximate weight share printed in the TPSX composition line; the balance is aluminoborosilicate fibre
method: Composition line of the TPSX record, printed as approximately 78% wt.
status: ground
source: tpsx-frci
where: Composition line, FRCI-12 Rigid Tile record (Approximately 78% wt. silica (SiO2))
- benchmark: aluminoborosilicate_fibre_fraction
label: Aluminoborosilicate fibre share of the FRCI-12 fibre mix, by weight
value: 22
unit: '% wt'
scope: material
conditions:
basis: approximate weight share printed in the TPSX composition line; the balance is silica fibre
method: Composition line of the TPSX record, printed as approximately 22% wt.
status: ground
source: tpsx-frci
where: Composition line, FRCI-12 Rigid Tile record (22% wt. aluminoborosilicate)
- benchmark: silica_fibre_purity
label: Silica fibre purity, raw fibre used in the patented composite
value: 99.6
unit: '%'
scope: material
conditions:
fibre: silica fibre (Microquartz 108 type)
basis: minimum purity printed for the raw fibre before tile forming
method: Printed in the patent description of raw materials; a raw-fibre specification, not a tile test
status: ground
source: patent-frci
where: Description, paragraph on suitable raw materials (sentence beginning 'Silica fibers, at least 99.6% pure')
corrosion: []
risks:
hazards:
- text: 'PubChem''s silica record (CID 24261, a generic silica entry) lists ''H315 (56.3%): Causes skin irritation'' and states ''This chemical does not meet GHS hazard criteria for 35% (889 of 2540) of reports.'' It is not a record for the bound fibre tile.'
ghs: []
source: pubchem-silica
where: GHS Classification section, CID 24261
- text: 'PubChem''s boron oxide record (CID 11073337, B2O3) lists ''H360FD: May damage fertility; May damage the unborn child'' as Danger for reproductive toxicity. The FRCI tile contains boron oxide only as bound aluminoborosilicate fibre, so this is a constituent-level hazard.'
ghs: []
source: pubchem-b2o3
where: GHS Classification section, CID 11073337
- text: 'PubChem''s alumina record (CID 9989226) lists ''H335 (100%): May cause respiratory irritation'' for the reports that give a hazard code, and states that most reports say the chemical does not meet GHS hazard criteria.'
ghs: []
source: pubchem-alumina
where: GHS Classification section, CID 9989226
failure_risks:
- mode: Tile damage during ascent or landing
trigger: Debris strikes or other impacts during launch, and handling after landing
consequence: The Wikipedia summary says the tiles, 'originally specified never to take debris strikes during launch, in practice also needed to be closely inspected and repaired after each landing'.
severity: moderate
source: wiki-tps
where: Overview section on tile inspection and repair
handling:
- text: The Wikipedia summary says the tiles were glued to Nomex felt strain-isolation pads with room temperature vulcanizing (RTV) silicone adhesive rather than mechanically fastened, to avoid heat transfer through attachment points.
source: wiki-tps
where: Tile attachment paragraph
uses:
- application: heat-shields
device: Space Shuttle orbiter reusable insulation tiles
example: NASA TPSX says FRCI-12 'was baselined for use on all of the shuttle orbiters' and 'has been flying successfully on the shuttle since its adoption shortly after the second orbiter Challenger was built'.
source: tpsx-frci
where: Description section of the FRCI-12 Rigid Tile record
- application: heat-shields
device: Orbiter underside tiles, replacing some HRSI tiles
example: Wikipedia says 'Fibrous refractory composite insulation (FRCI) tiles, used to provide improved strength, durability, resistance to coating cracking and weight reduction. Some HRSI tiles were replaced by this type.'
source: wiki-tps
where: Materials section, FRCI tiles entry
- application: heat-shields
device: Tiles around door penetrations (replacing LI-2200 tiles)
example: AZoM reports that LI-2200 tiles around door penetrations were replaced by FRCI, which helped reduce the overall weight of the Space Shuttle.
source: azom-pirolini
where: Article text on LI-2200 tiles
supply:
- subject: Boron (boric oxide in the aluminoborosilicate fibre)
producers: []
critical_lists:
- list: USGS 2025 Final List of Critical Minerals (boron added in the 2025 revision)
listed: true
recycling: Not found in the USGS boron chapter we hold.
substitutes: []
source: usgs-boron-2026
where: 'Import Sources line (''All forms: Turkey, 90%; Bolivia, 6%; and other, 4%'', 2021-24) and the 2025 critical minerals paragraph. The chapter gives import shares for the United States, not fibre makers.'
- subject: Aluminium (alumina, Al2O3, in the aluminoborosilicate fibre)
producers: []
critical_lists: []
recycling: Not found in the USGS bauxite and alumina chapter we hold.
substitutes:
- 'USGS: ''Bauxite is the only raw material used in the production of alumina on a commercial scale.'''
source: usgs-alumina-2026
where: Substitutes paragraph; Import Sources line for alumina. Critical-list status not checked in this run.
- subject: Silicon dioxide (silica fibre)
producers: []
critical_lists:
- list: USGS 2025 Final List of Critical Minerals (silicon added in the 2025 revision)
listed: true
recycling: Not found in the USGS silicon chapter we hold.
substitutes: []
source: usgs-silicon-2026
where: World Resources paragraph ('The source of the silicon is silica in various natural forms, such as quartzite.') and the 2025 critical minerals paragraph. This is the feedstock for silicon, not a fibre supply chain for FRCI.
media: []
documents:
- title: 'NASA Ames TPSX: FRCI-12 Rigid Tile material record (Material id=3)'
type: database
url: https://tpsx.arc.nasa.gov/Material?id=3
year: 2006
- title: 'Wikipedia: Space Shuttle thermal protection system'
type: report
url: https://en.wikipedia.org/wiki/Space_Shuttle_thermal_protection_system
year: 2026
- title: 'US Patent 4,148,962: Fibrous refractory composite insulation (Google Patents)'
type: paper
url: https://patents.google.com/patent/US4148962A/en
year: 1979
- title: 'AZoM: Materials Used in Space Shuttle Thermal Protection Systems'
type: paper
url: https://www.azom.com/article.aspx?ArticleID=11443
year: 2014
- title: 'PubChem: Silica (CID 24261), GHS classification'
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/24261
year: 2026
- title: 'PubChem: Boron oxide (B2O3, CID 11073337), GHS classification'
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/11073337
year: 2026
- title: 'PubChem: Alumina (CID 9989226), GHS classification'
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/9989226
year: 2026
- title: 'USGS Mineral Commodity Summaries 2026: Boron'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-boron.pdf
year: 2026
- title: 'USGS Mineral Commodity Summaries 2026: Bauxite and Alumina'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-bauxite-alumina.pdf
year: 2026
- title: 'USGS Mineral Commodity Summaries 2026: Silicon'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf
year: 2026
gaps:
- The TPSX record prints its density, thermal conductivity, specific heat, emissivity, use-temperature limits, strength, expansion, loss tangent and reuse limit in exponent form (for example 1.92e+02 kg/m^3), so those rows are left out, as the brief requires. The patent's modulus of rupture (6.04 x 10 to the power 6 N/m) is also in exponent form and is left out.
- The properties from the US 4,148,962 patent (strain to failure, density range, boron oxide content, fibre softening temperature, silica fibre purity) and the temperature capability are laboratory tile data from the patent examples, not flight-grade FRCI-12 data. The fibre softening temperature and boron oxide content are property names not in spores/property-canon.yaml, so those names are used as written.
- No plain-number thermal conductivity, emissivity or single-use or multiple-use temperature limit for FRCI-12 was found in a source we could read.
- No ageing, moisture-absorption or coating-degradation data for FRCI-12 was found in any source held; the corrosion section is empty for this reason.
- No flight-grade data sheet was reached. The Lockheed Missiles and Space Co. FRCI-12 data sheet (1987) is cited by TPSX but was not found online.
- The patent's density examples (0.32 g/cc, 0.11 g/cc, 0.24 g/cc) and its family density range are lab batches of the composite and are not recorded as FRCI-12 values.
- No producer or country-share data for FRCI silica fibre or aluminoborosilicate fibre was found. The USGS chapters give feedstock and import shares, not fibre makers.
- Hazard data are for the pure compounds in PubChem (silica, boron oxide, alumina). No safety data sheet for the bound FRCI tile was found.
- 'The Stewart and Leiser paper on FRCI thermal conductivity (NTRS citation 19860030482) was not read: its PDF download returned a not-found response. NASA NTRS report 19830004910 (a 1982 Ames contract report on FRCI) names an FRCI 20-12 composition adopted for the orbiters; that designation is not confirmed to be FRCI-12, so no values were taken from it.'
- 'Designation: only the trade name FRCI-12 is printed in the sources held. No UNS, EN or ASTM code applies.'
sources:
tpsx-frci:
title: FRCI-12 Rigid Tile, NASA Ames Thermal Protection Materials database record (Material id=3)
id: TPSX Material id=3; record last modified 2001-10-01, property rows 2006-01-05
url: https://tpsx.arc.nasa.gov/Material?id=3
year: 2006
kind: database
license: US government work (NASA)
wiki-tps:
title: Space Shuttle thermal protection system (Wikipedia)
id: en.wikipedia.org, accessed in this run (composition and history only)
url: https://en.wikipedia.org/wiki/Space_Shuttle_thermal_protection_system
year: 2026
kind: web
license: CC BY-SA 4.0 (Wikipedia)
patent-frci:
title: 'US 4,148,962: Fibrous refractory composite insulation (Leiser, Goldstein, Smith)'
id: US patent 4,148,962 (1979); TPSX reference 12
url: https://patents.google.com/patent/US4148962A/en
year: 1979
kind: web
license: public domain (US patent)
azom-pirolini:
title: Materials Used in Space Shuttle Thermal Protection Systems (AZoM, Alessandro Pirolini)
id: AZoM article 11443; byline 10 October 2014, updated 13 June 2019
url: https://www.azom.com/article.aspx?ArticleID=11443
year: 2014
kind: web
license: AZoM website terms
pubchem-silica:
title: PubChem compound record, Silica (CID 24261), GHS classification
id: CID 24261
url: https://pubchem.ncbi.nlm.nih.gov/compound/24261
year: 2026
kind: database
license: public domain (NCBI)
pubchem-b2o3:
title: PubChem compound record, Boron oxide (B2O3, CID 11073337), GHS classification
id: CID 11073337
url: https://pubchem.ncbi.nlm.nih.gov/compound/11073337
year: 2026
kind: database
license: public domain (NCBI)
pubchem-alumina:
title: PubChem compound record, Alumina (CID 9989226), GHS classification
id: CID 9989226
url: https://pubchem.ncbi.nlm.nih.gov/compound/9989226
year: 2026
kind: database
license: public domain (NCBI)
usgs-boron-2026:
title: 'Mineral Commodity Summaries 2026: Boron'
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-boron.pdf
year: 2026
kind: report
license: public domain (USGS)
usgs-alumina-2026:
title: 'Mineral Commodity Summaries 2026: Bauxite and Alumina'
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-bauxite-alumina.pdf
year: 2026
kind: report
license: public domain (USGS)
usgs-silicon-2026:
title: 'Mineral Commodity Summaries 2026: Silicon'
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf
year: 2026
kind: report
license: public domain (USGS)
license: CC-BY-4.0
updated: '2026-11-01'
review:
status: draft
method: assistant
checked_values: 12
unreachable: 0
caveats: 2
note: 'Read by an AI assistant on 2026-11-01 and deepened on 2026-11-02: 12 property values taken from the TPSX record (plain-number rows only), the Wikipedia density table and the US 4,148,962 patent examples and description; all TPSX numeric rows printed in exponent form were left out.'
story:
recipe:
line: FRCI-12 is a fibre composite, not a single compound. NASA's TPSX record describes it as a silica fibre body with an aluminoborosilicate fibre component, and gives the exact split in its composition line. The patent describes making the tile by washing the silica fibres, dispersing the aluminoborosilicate fibres, mixing both into a water slurry, pressing a billet, drying it and firing it.
parts:
- name: Silica fibre
symbol: SiO2
share: 78% wt, per the TPSX composition line
role: The bulk of the tile. The patent describes the silica fibres as highly pure, at least 99.6% pure.
- name: Aluminoborosilicate fibre
share: 22% wt, per the TPSX composition line
role: Adds strength and durability. It carries the boron oxide listed in the TPSX composition line.
risk_groups:
- title: For people
level: 0
verdict: Irritant codes in the PubChem silica record
lead: The safety information found here is for the pure compounds, not for the bound tile. No safety data sheet for FRCI-12 was found.
points:
- label: Silica
line: PubChem's silica record lists skin, eye and respiratory irritation codes from company reports, and says most reports do not meet GHS criteria.
- label: Boron oxide
line: PubChem's boron oxide record lists a reproductive toxicity hazard (H360FD) for the pure oxide. Its presence in the tile is as bound fibre.
- title: If a tile is damaged
lead: These are handling and inspection points from the sources, not from test data.
points:
- label: Ascent damage
line: The Wikipedia summary says the tiles needed close inspection and repair after each landing, because they could be damaged during ascent.
why: FRCI-12 is a rigid reusable insulation tile made of fibrous refractory composite insulation (FRCI). It was used on the Space Shuttle orbiters and was designed to be stronger than the original silica tiles while keeping a low density. TPSX says it is 'substantially stronger than the original' silica tile at a low density.
uses:
- where: Space Shuttle orbiters
line: NASA TPSX says FRCI-12 was baselined for use on all of the shuttle orbiters and has flown on the shuttle since shortly after the second orbiter Challenger was built.
- where: Orbiter underside tiles
line: Wikipedia says FRCI tiles improved strength, durability and resistance to coating cracking, reduced weight, and replaced some HRSI tiles.
- where: Door penetrations
line: AZoM reports that FRCI replaced LI-2200 tiles around door penetrations, which helped reduce the orbiter's weight.
can_do:
- label: Density
benchmark: density
line: Insulate the hot underside of a re-entry vehicle at a density of 192 kg/m3 (12 lb/ft3) per the Wikipedia density table.
- label: Dielectric
benchmark: dielectric_constant
line: Keep a dielectric constant of 1.2 at 10GHz and room temperature, per the TPSX record.
- label: Strength limit
benchmark: mechanical_stability_limit_temperature
line: Keep its tensile properties relatively constant up to 1144K (1600F), per the TPSX notes.
compare: FRCI-12 is lighter than the LI-2200 tiles it was used beside and was used to replace some HRSI tiles, according to the Wikipedia and AZoM sources. TPSX says it is 'equivalent in strength to LI-2200 at a lower density'. The compare rows below show its density, dielectric constant and the patent's laboratory temperature comparison. No comparable figures for other tile grades are recorded here.
compare_rows:
- label: Density
benchmark: density
- label: Dielectric constant
benchmark: dielectric_constant
- label: Temperature capability (patent lab tile)
benchmark: temperature_capability
handling:
- Expect the tile to need inspection and repair after each flight, according to the Wikipedia summary.
good_for:
- Low density. The Wikipedia table lists the tile at 192 kg/m3 (12 lb/ft3).
- Reusable insulation on a re-entry vehicle. TPSX says it flew on the Space Shuttle.
watch_out:
- Most flight property values for this grade are printed in exponent form in the TPSX record and are not recorded here.
- The patent temperature figure is for a laboratory tile, not the flight tile.
- Inspection and repair were needed after flights, according to the Wikipedia summary.
verdict: FRCI-12 is a documented flight tile with limited plain-number data in the sources we could read. The file is a partial draft.
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.
| # | Source | Type | Year | Used for |
|---|---|---|---|---|
| FRCI-12 Rigid Tile, NASA Ames Thermal Protection Materials database record (Material id=3) | database | 2006 | 6 values | |
| Space Shuttle thermal protection system (Wikipedia) | web | 2026 | 5 values | |
| US 4,148,962: Fibrous refractory composite insulation (Leiser, Goldstein, Smith) | web | 1979 | 6 values | |
| Materials Used in Space Shuttle Thermal Protection Systems (AZoM, Alessandro Pirolini) | web | 2014 | 1 value | |
| PubChem compound record, Silica (CID 24261), GHS classification | database | 2026 | 1 value | |
| PubChem compound record, Boron oxide (B2O3, CID 11073337), GHS classification | database | 2026 | 1 value | |
| PubChem compound record, Alumina (CID 9989226), GHS classification | database | 2026 | 1 value | |
| Mineral Commodity Summaries 2026: Boron | report | 2026 | 1 value | |
| Mineral Commodity Summaries 2026: Bauxite and Alumina | report | 2026 | 1 value | |
| Mineral Commodity Summaries 2026: Silicon | report | 2026 | 1 value |
Updated