Home › Blog › Aerospace, Defense & Space › FST-Compliant Materials › How to spec an FST part
How to Spec an FST-Documented Part: What to Send H-O for a Quote
The fastest way to a useful FST quote is to answer the questions a converter is going to ask anyway. FST material selection turns on where a part lives and which regulatory clause its drawing references, and a quote built on guesses about either is a quote you will revise. Here is the short list of facts that move an FST part from a vague request to a real, manufacturable scope, and what our engineering team does with each one.
Request a quote for your project →
The nine facts to send, and what each one decides
FST material selection turns on where a part lives and which clause its drawing references, so a quote built on guesses about either is a quote you will revise. The nine facts below are exactly what our applications engineering team needs to move an FST request from a vague description to a manufacturable scope. Send what you have; we will tell you what is still open.
- The regulatory clause the drawing references. FAR 25.853, 25.856(a), 25.856(a)(1), or 25.855 each points at a different method context and a different family shortlist. This is the single most load-bearing line; if you are unsure, tell us where the part lives and we will talk through it.
- Where the part lives. Cabin interior finish, fuselage thermal-acoustic insulation, lower-fuselage burnthrough zone, cargo liner, wire-way, or a fire path beside a hot component. Location is what maps a part to its clause.
- The mechanical job. Insulate, seal or gasket, pad and anti-rattle, line a wire-way, fire-block a path, or add acoustic mass. A part that is a gasket first and a fire question second shortlists differently from one that is insulation first.
- Service temperature and hot-zone adjacency. Continuous and peak temperature, and whether the part sits next to a duct, bleed-air run, or other heat source, decide whether an elastomeric foam, an inorganic facing, or a layered stack is appropriate.
- Geometry. A drawing or DXF is ideal; a dimensioned sketch works to start; an existing part we can measure works too. Tell us thickness, tolerances, and whether the part is flat, formed, or a multi-layer lay-in.
- Adhesive and lamination needs. Whether the part needs a pressure-sensitive adhesive backing, a specific liner, or lamination of a fire-side facing to a thermal core as one converted part.
- Smoke and toxicity requirements. Any smoke-density (commonly ASTM E662) or toxicity screens your program layers on top of the flame requirement, since these can be the gate that decides the family.
- The documentation you need on the order. Technical data sheets, the maker's fire documentation for the grade, and lot-coded traceability. Tell us what your certification chain expects to receive with the parts.
- Quantities and cadence. Sample needs, estimated annual usage, and whether the part is a one-off, a kit, or a recurring shipset. This drives nesting, tooling, and lead-time planning.
From Request to Manufacturable Scope
| What you send | What it decides |
|---|---|
| Clause reference | The method context and the family shortlist (25.853 vs 25.856(a) vs 25.856(a)(1) vs 25.855) |
| Part location | Which clause applies and whether a single material or a layered stack is the right form |
| Mechanical job | Insulate, seal, pad, line, fire-block, or add acoustic mass: sorts the candidate families |
| Temperature and adjacency | Elastomeric foam, inorganic facing, or laminated stack |
| Geometry | The converting method: die-cut, waterjet, laminate, or kit |
| Smoke and toxicity needs | Often the gate that removes a flame-passing grade (ASTM E662 and program screens) |
| Documentation and quantities | The data package shipped with the parts and the nesting, tooling, and lead-time plan |
Qualitative guidance only; clause assignments describe common usage, not compliance findings. Confirm each grade on its current technical data sheet.
What engineering does with the list
With the clause and location in hand, we map the part to the method context that clause points at, then shortlist families that carry documentation for that context: SOLIMIDE polyimide foam and ManniGlas inorganic facings for insulation duty, the documented silicone sponges and ENSOLITE 25.853-context grades for cabin gaskets and trim, and Nomex aramid paper for liners.
The mechanical job and temperature narrow the grade, the geometry sets the converting method (die-cut, waterjet, laminate, kit), and the documentation requirement confirms which grade's TDS package matches your certification chain. The output is a family-and-grade direction plus a converted-part quote, not a compliance finding.
What happens after you send it
We confirm the family-and-grade direction and the converting approach, quote the converted part to your drawing, and identify any open questions (a missing clause reference, an undefined adhesive, a tolerance that drives tooling). For common configurations on materials we keep on hand, samples typically ship in three to five business days; standard production runs about two weeks after drawing approval, with expedited service available.
Every order carries the maker's TDS and fire documentation for the exact grade and lot, under our ISO 9001:2015 certified quality management system.
The mistakes this checklist prevents
The list exists to head off the failures that cost the most time. Without a clause reference, a part gets quoted against the wrong method and revised later. Without the installed location, a flame-propagation foam can be proposed where a burnthrough-resistant stack is needed. Without smoke and toxicity requirements, a mechanically ideal grade can be shortlisted and then removed at documentation review.
And without a clear documentation request, parts can ship with a data package that does not match what the certification chain expects. Nine facts up front replace four revisions later.
Frequently asked questions
What is the single most important thing to put on an FST part drawing?
The regulatory clause the part is certified against: FAR 25.853, 25.856(a), 25.856(a)(1), or 25.855. The clause determines the method context, and the method determines the family shortlist, so it is the most load-bearing line on the drawing. If you are not sure which clause applies, tell us where the part lives and we will help map it before quoting.
Do I need to send a full drawing, or is a sketch enough?
A drawing or DXF is ideal, but a dimensioned sketch is enough to start a quote, and we can also measure an existing part to reverse-engineer it. What we need early is thickness, key tolerances, and whether the part is flat, formed, or a multi-layer lay-in, plus the clause and location so we can confirm the family before refining geometry.
What documentation will H-O provide with the parts?
The maker's technical data sheet and fire documentation for the exact grade supplied, plus lot-coded traceability under our ISO 9001:2015 certified quality management system. Tell us what your certification chain expects to receive so the package matches. H-O supplies the converted part and its documentation; the compliance finding itself belongs to your program.
Can H-O reverse-engineer an existing FST part?
Yes. Send the existing part and any drawing you have, and we will measure geometry and identify a documented family and grade direction that matches the original's duty and clause context. We confirm the converting method and quote the converted part; we do not make airworthiness or compliance determinations, which remain with your certification process.
How fast can I get FST samples?
For common die-cut configurations on materials we keep on hand, samples typically ship in three to five business days. Standard production runs about two weeks after drawing approval, with expedited service available. Lead time depends on the grade, the geometry, and whether the part is a single material or a laminated stack, so confirm specifics with your quote.
Send the checklist, get an FST part quote
Send the clause, the location, and whatever geometry you have, and we will confirm a family-and-grade direction and quote converted parts to your drawing.
Samples typically ship in 3 to 5 business days for common die-cut configurations on materials we keep on hand; standard production runs about two weeks after drawing approval; expedited service is available. MOQ varies by material and part.
Family-owned in Winsted, Connecticut since 1971 · ISO 9001:2015 certified · OEMs worldwide send us a drawing — and get back their part.
Related reading
Request a quote for your FST-compliant material part
Send H-O your drawing or describe the part—engineering reviews every RFQ and converts samples on your geometry.
Last updated · Reviewed by H-O Products engineering (ISO 9001:2015 certified converter, Winsted, CT).
References
- FAR 25.853 (compartment interiors); FAR 25.855 (cargo and baggage compartments); FAR 25.856 (thermal/acoustic insulation, including 25.856(a) flame propagation and 25.856(a)(1) burnthrough). Cited by designation; compliance findings belong to program certification.
- ASTM E662 (specific optical density of smoke); ASTM E162 (surface flammability under radiant heat); UL 94 (flammability classes, per grade TDS); ASTM C177 / C518 (thermal conductivity); ASTM D1056 (flexible cellular materials).
- Manufacturer technical data sheets: SOLIMIDE polyimide foam, ManniGlas glass-fiber paper and inorganic facings, BISCO RS and flame-retardant V-0 silicone sponge grades, ENSOLITE vinyl nitrile, Nomex aramid paper.
This article describes the information H-O uses to quote FST-documented converted parts, using the families and method designations cited on the parent application page. Regulatory clauses are named for orientation only; compliance findings belong to your program's certification process, and H-O makes no airworthiness or compliance determinations. Comparisons are qualitative; classes and values are per each grade's current technical data sheet.
All parts are custom manufactured to order; minimum production run quantities vary by material and part. H-O is a converter, not a raw-material producer.