Fibre Reinforced Facade Encyclopedia: Manufacturing
Quality control in a facade panel factory is the set of documented checks that prove each panel was made from the specified materials, by the specified process, to the specified dimensions and finish. For glass fibre reinforced concrete (GRC, GFRC) it is formalised as factory production control under BS EN 1169, with test methods in the BS EN 1170 series and mix and strength requirements in the GRCA specification, usually inside an ISO 9001 quality management system. Its output is a paper trail that can be checked against the panels on the building.
Every panel should be traceable back to a batch, and every batch back to a set of test coupons and the certificates for the cement, sand, fibre and admixtures that went into it.
At a glance
| Property | Typical value | Note |
|---|---|---|
| Factory production control | BS EN 1169 | The FPC standard for GRC manufacture |
| Test methods | BS EN 1170-1 to 1170-8 | Boards, coupons, MOR, LOP, density, fibre content |
| Mix and strength requirements | GRCA Specification for the Manufacture, Curing and Testing of GRC Products | Grade designations by 28 day MOR |
| Quality system | ISO 9001 | The management framework the FPC sits inside |
| Test board frequency | Per batch or per shift, commonly daily | |
| Coupon tests | MOR and LOP at 7 and 28 days | Four-point bending to BS EN 1170-5 |
| Hold points | Mould sign-off, first-off panel, pre-delivery inspection | Written into the inspection and test plan |
Incoming materials
Everything that goes into a panel is checked before use, because a defect introduced here cannot be found later without destroying the panel.
- Cement: batch certificate against the relevant standard, delivery date and silo allocation recorded
- Sand: grading, silica content, moisture content, and a check that the source has not changed, since a change of quarry changes colour across an elevation
- Alkali resistant glass fibre: roving type and a certificate of zirconia content for the delivered batch, since AR glass below the specified zirconia level is the historic cause of long-term strength loss
- Steel for stud frames and anchors: mill certificates, grade and coating or stainless designation
- Admixtures and acrylic polymer: batch number, expiry date, storage temperature record, and a pigment dosing record where the mix is coloured
- Resins and catalysts for FRP work: batch, shelf life, gel time check on receipt
Batch records and traceability
A batch record is created for each mix and carries the mix identification, date and time, operator, equipment settings, the lot numbers of every constituent, ambient conditions and the curing regime. For sprayed work the spray rate, fibre feed rate and chopper length are set at the start of a shift, verified by a bag test and recorded with it. Every panel carries a permanent identification mark on the back face linking it to that record and to the mould it came from.
That link is what makes the system useful. If a panel shows a defect at year three, the batch record identifies every other panel made from the same materials on the same day. Without traceability, one suspect panel puts every panel on the facade in question.
Test boards and coupons
The central control on sprayed GRC is the test board. At the start of a batch, and at the frequency agreed for the project, the operator sprays a flat board using the same gun, settings and material as the panels. It is cured with them and cut into coupons.
The coupons go to four-point bending to BS EN 1170-5 to give the limit of proportionality, the first crack stress used for serviceability design, and the modulus of rupture, the peak flexural stress. Results are recorded at 7 and 28 days against the specified grade. Density is measured to BS EN 1170-6 and fibre content by the wash-out method. For fibre reinforced polymer work the equivalent controls are laminate thickness, glass content by ignition loss, cure verification by hardness and flexural coupons.
Dimensional and finish control
Panels are checked against the approved shop drawings, not against the architect’s elevation. Each is measured on a jig or against a template for overall dimensions, diagonals to confirm square, bow, twist, edge straightness, and the position of every cast-in fixing and anchor relative to a stated datum, against a tolerance table agreed before manufacture starts. Cumulative tolerance is the thing to watch: thirty panels each within tolerance can still fail to fit if the tolerances all run the same way, which is why tolerance and joint width are designed together.
Finish is controlled against retained physical samples rather than against words. A signed control sample is agreed at the start and kept in the factory for the job, and where the finish varies naturally, as acid etched and exposed aggregate finishes do, a range of samples defines the acceptable spread. Panels are assessed against those samples under agreed lighting and at the agreed viewing distance, with the approved mock-up as the overall benchmark. Judging a panel at arm’s length under factory lighting when it will be seen from 20 metres produces rejections that mean nothing.
What a specifier should require
- An inspection and test plan accepted before manufacture begins, listing every check, its frequency, its acceptance criteria and its hold and witness points
- ISO 9001 certification for the factory and factory production control to BS EN 1169 for GRC production
- Batch test results for MOR, LOP, density and fibre content, issued with the delivery
- A traceability register linking panel identification marks to batch records and mould numbers
- Hold points the specifier can attend: mould sign-off, first-off panel inspection and pre-delivery inspection
- A written non-conformance and concession procedure with a visible register
- Material certificates, including the zirconia content certificate for the AR glass fibre, and the retained control and range samples
Specifying the tests without specifying that the results are delivered is the common failure. Ask for the records as a deliverable and treat a missing record as a non-conformance in its own right.
Standards and references
- BS EN 1169 Precast concrete products: general rules for factory production control of glass fibre reinforced cement
- BS EN 1170-1 to 1170-8 Test methods for glass fibre reinforced cement, including 1170-5 bending and 1170-6 glass content
- GRCA Specification for the Manufacture, Curing and Testing of GRC Products, and the GRCA Practical Design Guide
- ISO 9001 Quality management systems
- ISO 1172 and ASTM D2584 fibre content by ignition loss for fibre reinforced polymer laminates
- AS 1530.1 and AS 5637.1, where the fire evidence must match the product and thickness supplied
Related terms
Questions specifiers ask
What is a test board?
A flat board sprayed at the same time, with the same equipment and material, as production panels. It is cured alongside them and cut into coupons for bending, density and fibre content tests.
What is EN 1169?
The European standard for factory production control of glass fibre reinforced cement. It sets out the control system a factory must operate, with the test methods themselves given in the EN 1170 series.
What hold points should be in the inspection and test plan?
At minimum: mould sign-off before the first pour, first-off panel inspection against the shop drawings and the control sample, and pre-delivery inspection.
How are finishes judged?
Against a signed control sample retained in the factory, and a range of samples where the finish varies naturally, judged under agreed lighting at the agreed viewing distance.
Specifying batch testing on a facade package? ShapeShell-RC is batch tested for modulus of rupture and limit of proportionality to the GRCA specification, with records issued against each delivery. Request our inspection and test plan
Reviewed by Richard Halvorsen, General Manager, ShapeShift Technologies. Last updated September 2026.