A reinforced, foil-faced textile for external duct insulation facings, pipe insulation wrap and converter-ready HVAC rolls. Specify the foil, woven glass backing and lamination as one system—then check usable width, joint sealing and moisture performance.
For HVAC material distributors, mechanical insulation contractors and pipe-cover fabricators. Discuss custom roll formats, sampling, bond-strength acceptance and project documentation with DERFLEX.
It is a laminate of aluminum foil, an adhesive or bonding layer, and woven fiberglass cloth. Used outside a separately specified insulation core, the foil/glass facing provides a reinforced protective skin and may serve as part of the vapor-control system when the selected grade and all joints are properly qualified and sealed.
The fiberglass supplies textile reinforcement for handling and conversion; the foil layer provides a metallic facing. The insulation beneath supplies most of the thermal resistance. A foil surface alone does not establish an insulation R-value, and reflective performance depends on how it is installed.
This page is specific to duct-facing and pipe-wrap procurement. For the broader range of reflective structures, see DERFLEX's aluminum foil fiberglass fabric manufacturing page.
HVAC buyers often encounter aluminum foil fiberglass cloth, foil-scrim-kraft (FSK), and metallized-film laminates under similar product descriptions. Their backing structure, mechanical behavior, moisture control and conversion methods can differ significantly.
| Construction | Typical make-up | Procurement fit | What to verify |
|---|---|---|---|
| Aluminum foil + woven fiberglass cloth | Discrete foil, approved bond system and continuous woven glass backing. | Converter-ready facing or protective wrap where glass-fabric handling strength and finish matter. | Weave, foil gauge, fold resistance, bond strength and usable width. |
| FSK foil / scrim / kraft | Foil, fiberglass reinforcing yarn or scrim, adhesive and kraft paper. | Common facing for factory-made duct wrap and insulation products. | Type under ASTM C1136, vapor permeance, kraft moisture sensitivity and joint compatibility. |
| Metallized-film facing | Thin metal deposit on polymer carrier with textile or other backing. | Selected light-duty laminates when polymer-film temperature and handling behavior are suitable. | Carrier polymer, whole-laminate heat limits, vapor performance and aging. |
No performance equivalence is implied. Review the separately published foil-laminated insulation material families when comparing possible alternative backings.
Cold and hot mechanical services have different failure modes. Select the facing and joining system based on the local environment, the base insulation and the way installers or fabricators will handle the material.
Use reinforced foil/glass as an external facing over the specified duct insulation. Confirm the rectangular duct perimeter, seam placement, corners, inspection access and tape or adhesive compatibility. For chilled ducts, uninterrupted vapor-retarder detailing is critical.
For pipes and preformed insulation sections, determine the finished outside diameter after insulation, wrap width, spiral or longitudinal overlap, elbows, branch connections and the intended sealing sequence. Do not assume a roll membrane is a finished vapor-tight pipe jacket.
Control width, corner folding, seam location and tape adhesion to the foil surface.
Prioritize low permeance where specified, fully sealed joints and penetrations to reduce condensation risk.
Verify actual laminate-layer temperature and bond stability; foil brightness is not a heat rating.
Plan slitting, cut-edge finishing, approved joining tapes and repeatable roll identification.
A comparable RFQ starts with the complete laminate—not only finished GSM. DERFLEX can review the requested construction and commercial feasibility; exact values, tolerances, certificates and test data are agreed for the offered grade.
| Specification item | Information to request from DERFLEX | Why the buyer needs it |
|---|---|---|
| Facing construction | Real aluminum foil + woven fiberglass cloth, or clearly identified alternative by request. | Prevents substituting film-backed or scrim/kraft products without approval. |
| Foil thickness | Specified aluminum gauge in micrometers (µm), with accepted tolerance. | Affects creasing, foil continuity and comparison between quotations. |
| Fiberglass substrate | Glass type, weave, yarn and fabric weight; backing-side finish if any. | Determines strength, dimensional behavior and fraying during cutting. |
| Finished mass / thickness | Composite g/m² and total thickness with test method and tolerances. | Supports pattern handling, roll yield and repeatability. |
| Lamination bond | Bond-system declaration or agreed performance threshold; peel test method and conditioning. | Prevents foil lift or delamination during wrapping and use. |
| Usable roll width | Nominal and minimum usable width, edge allowance and slitting availability. | Directly changes duct seam count and pipe sleeve cutting yield. |
| Roll length / core | Length, core diameter, winding direction, roll outside diameter and splice policy. | Ensures compatibility with slitting, cutting and transport equipment. |
| Water-vapor permeance | Required ASTM E96/E96M or project-approved method; measured value of exact grade. | Supports vapor-retarder design for chilled services; laps still need sealing. |
| Fire and smoke | Project-defined surface burning standard, such as ASTM E84 where applicable. | Tests apply to stated specimens and jurisdictions; no generic fire classification assumed. |
| Temperature / humidity | Expected laminate-layer temperature; agreed conditioning and bond-retention tests. | The adhesive can set the service limitation before glass cloth does. |
| Installation joining | Foil tape/adhesive system, lap dimension, substrate cleaning and pressure requirements. | Determines joint continuity on ducts, bends and penetrations. |
| Sampling & packing | Lab samples, conversion-trial roll, labeling, pallet protection and batch records. | Supports approval and clean transfer into repeat procurement. |
Specification framework, not a published DERFLEX grade datasheet. No universal stock thickness, permeance, fire rating, MOQ or lead time is asserted.
A low-permeance facing cannot compensate for open laps, damaged foil, unsealed hangers or gaps around valves and penetrations. The insulation designer sets the vapor-retarder requirement; the material supplier supports selection and evidence for the facing.
Ask for the required test method and result on the exact material construction. Do not convert a competitor's FSK datasheet into a DERFLEX performance claim.
Agree overlap width, approved foil tape and adhesive, minimum application temperature and surface preparation. Demonstrate joint adhesion after appropriate conditioning.
Elbows, tees, supports, branch takeoffs, access doors and termination ends need a project-specific continuity detail.
Pinholes, tears, punctures and foil creases may weaken the vapor-control layer. Define an installation inspection and repair approach.
If the application instead requires a removable maintenance jacket, evaluate the separate insulation-jacket outer fabric options; the required construction may be different from a permanently sealed HVAC facing.
Price per square meter is only one purchasing variable. A wider roll may cover a duct perimeter with fewer joints; a narrower slit roll can reduce pipe-wrapper handling and waste. Compare cost against usable cutting width, not only catalog width.
Estimate wrap width from 2 × (duct width + duct height) plus the approved lap and cutting allowance; adjust for segmented wrapping at fittings.
Start from π × finished insulated diameter plus the joining allowance for a circumferential band. Spiral wrap consumption follows the selected angle and overlap.
These are layout-screening relationships only, not installation dimensions or building-code instructions.
Select tests according to the project specification and end-use. The standards below are relevant industry references, not claims that a particular DERFLEX grade has already passed them.
| Verification area | Possible reference / acceptance route | What to record in the sample approval |
|---|---|---|
| Flexible insulation facing requirements | ASTM C1136, where specified for the applicable product type. | Relevant type and characteristics; do not assume every foil/glass laminate fits the same classification. |
| Water-vapor transmission | ASTM E96/E96M or the project's stated permeance method. | Procedure, specimen conditions, numerical result, units and report date. |
| Surface burning | ASTM E84 or jurisdiction-specific test where required. | Exact tested configuration and report scope; no blanket claim for every thickness or assembly. |
| Foil-to-glass bond | Agreed project peel / bond-retention procedure, before and after conditioning. | Fixture, specimen geometry, force units, conditioning and acceptance criteria. |
| Mechanical converting | Agreed tensile, tear, fold and slit-edge checks on the finished laminate. | Machine/cross direction, bend radius, cycles, fray or delamination observations. |
| Temperature-humidity durability | Project-defined thermal and humidity aging; ASTM C1258 may be relevant to applicable facings. | Layer temperature, exposure duration, foil surface changes and bond retention. |
Request a construction declaration, grade-specific technical data sheet, test reports where available or commissioned, specimen identification, approved reference sample, roll inspection tolerances and packaging specification. Ask DERFLEX what can be supplied for the exact grade before stating compliance in downstream bids.
High-temperature equipment and industrial thermal shields have different design needs; the coated-fiberglass temperature rating guide explains why the complete laminate temperature matters more than the bare glass limit.
Approve real foil, glass construction, bonding and any reverse finish as a written bill of materials.
Cut, bend and tape the sample around corners, bends and fitting penetrations.
Review laminate adhesion after the project-defined temperature and humidity exposure.
Record usable width, roll length, winding, damage/splice policy and edge fray limits.
Ensure reports apply to the quoted construction, not another supplier's FSK grade. Agree test and inspection deliverables before confirming the production schedule.
A different foil gauge, fiberglass weave, adhesive or width can change cutting, joint and bond behavior. Re-approve meaningful changes, even when the face still looks silver.
DERFLEX's established reflective-laminate and technical-textile programs provide a starting point for discussing custom-facing structures and international wholesale supply. Availability of a particular foil/glass specification and any associated test certificate must be verified before purchase.
The project conversation should cover the insulation system, required facing build, slit widths, batch labeling, shipping method and documentation—not only a quote for “silver insulation cloth”. Where your use concerns radiant shielding rather than normal HVAC facings, review aluminized heat-shield roll material for the different design questions.
Request a declared layer stack and enough sample area to test the chosen tape, joining procedure, folding and insulation surface.
Specify quantity, finished width, grade, roll length, maximum outer diameter, packing and inspection record requirements.
Confirm core support, winding tension, edge guards, rolls-per-pallet, moisture protection and shipping marks.
Practical answers for HVAC importers, insulation contractors and OEM roll converters.
Yes, a qualified foil-faced woven glass laminate can be used as an external facing over the specified duct insulation. Select the roll for mechanical handling, required vapor-permeance performance and compatibility with the planned joints. It does not replace the core thermal insulation or establish the finished duct assembly's fire performance.
It can form part of a vapor-retarder system when the exact material meets the specified water-vapor permeance and all laps, tape seams, terminations and penetrations are sealed correctly. The foil face alone does not prove a finished pipe system is vapor-tight.
Foil fiberglass cloth uses a woven fiberglass fabric backing. FSK typically laminates foil, reinforcing fiberglass scrim or yarn and kraft paper. They may serve related insulation-facing roles but differ in backing structure, drape, handling and possible test classifications.
DERFLEX can review custom roll widths, slit dimensions, roll lengths, core size and packaging through a project-based quotation. Confirm feasibility, dimensional tolerances, sample requirements, minimum order quantity and delivery schedule for the selected structure.
Set an agreed peel or bond-retention test with defined specimen width, conditioning, procedure, units and pass criterion. Check the actual sample after bending and relevant heat/humidity exposure. A visual foil shine is not proof of adhesion durability.
Do not assign an R-value to this facing alone. Most thermal resistance comes from the specified insulation core and complete assembly. A reflective facing can affect radiant exchange under appropriate air-space conditions, but the actual system rating must be assessed separately.
Begin with the exact facing construction, product data sheet, foil gauge, substrate declaration, usable width tolerances and sample approval. Add applicable ASTM C1136, ASTM E96/E96M, ASTM E84 and other project-specific test evidence only where the standard fits the grade and can be supported by relevant reports.
State whether the material will face rectangular ducts, spiral ducts or insulated pipes; provide insulation type and service temperature, chilled or warm duty, required vapor/fire performance, foil and glass construction, finished mass, width, roll length, estimated order volume, joining method, destination and documentation requirements.
Send the duct or insulated pipe dimensions, target vapor requirement, foil/glass construction, usable width, roll length, adhesive or tape method, quantity and destination. DERFLEX can review suitable sample and quotation options for your project.
No on-page form; the button opens DERFLEX's dedicated quote page.
Technical illustrations are explanatory, not photographs or certifications of an available grade. Product drawings, actual material photos and any test values should be confirmed against DERFLEX's approved offering before release.