Technical data
Technical data, and how to read a film datasheet
A datasheet is only useful if it tells you which glass the number was measured on. The same film on 6 mm clear float and on a coated sealed unit gives two different answers — and the second one is usually the one your client owns.
Detail
The fields that actually matter
VLT tells you how much daylight survives. TSER and SHGC tell you how much solar energy is rejected or admitted — they are related but not interchangeable, and a SHGC is what an energy model needs. UV rejection matters for fading, not for heat.
Ask for the glass build-up the figures were measured on. A datasheet without that line is a marketing document.
Getting the numbers
Request the sheet for your construction
We issue a technical data sheet per series, and measured figures for the batch where a project needs them. Tell us the series and the glass and we will send the sheet that applies.
Where a number has not been measured, the sheet says “not tested” rather than carrying an estimate forward.
Method
How the numbers are measured, and why it matters
Two films can publish the same visible light transmission and behave differently on your glass, because the number was measured on a laboratory sample of clear float at a standard thickness. Your building is tinted, laminated, or a sealed unit, and none of those match the sample.
The optical properties of a film are a property of the film. The performance of an installation is a property of the assembly. Confusing the two is the most common technical error in this industry, and it is why a supplier who asks about your glass is more useful than one who sends a PDF.
Our datasheets state the method and the substrate for each figure. Where a figure depends on the glass it is applied to, it is not published as a single number.
| Figure | Describes | Use it for |
|---|---|---|
| VLT | Visible light passing through | Glare and daylight, and legal limits on vehicles |
| TSER | Total solar energy rejected | Cooling load comparison |
| SHGC | Fraction of solar energy admitted | Building energy modelling |
| IR rejection | Rejection in the infrared band | Marketing comparison only — not a load figure |
| UV rejection | Rejection below 400 nm | Fading and material protection |
Specification
Sending a glass schedule instead of an enquiry
The fastest quotation comes from a glass schedule, not from a message asking for the price list. Five columns do most of the work: location or elevation, pane size, glass build-up, quantity, and the requirement — heat, glare, privacy, safety, or a combination.
With that, the reply is a specification: which series, which thickness, which fixing if any, and the documents that go with it. Without it, the reply is a price range and a list of questions, which costs both sides a week.
For safety and security work, add the frame type and glazing method. For exterior work, add the storey height and any shading. Those two additions change the answer more often than the film choice does.
Questions
Before you ask
The three questions that come up on almost every enquiry.
Do you publish SHGC?
Where it has been measured for the construction, yes. Otherwise the sheet says so — an invented SHGC is worse than a blank field in an energy model.
Can you send a datasheet before we order?
Yes, per series. Batch-specific figures come with the order.
Are the figures third-party tested?
Some are, some are in-house. The sheet states which; ask if it matters to your customer.
Why are some figures marked "on request"?
Because they are measured per batch. Publishing a single figure for a product made in several constructions would be less accurate than saying nothing until the batch is defined.
Can you model the energy saving?
We can supply the measured optical data your engineer needs to model it. The modelling itself belongs with the building services engineer, who knows the plant, the loads and the tariff.
Do you provide BIM or CAD files?
Not currently. We supply the specification text and the datasheet, which is what most schedules need.
How do I compare TSER between two suppliers?
Check the substrate and method first. A TSER measured on 3 mm clear float is comparable to another measured the same way, and not comparable to one measured on a laminated sample.
Related
Keep reading
Send the specification
Tell us the glass, the quantity and the destination port. You get film grade, documents and MOQ in one reply.