How to Write a Commercial Window Film Specification

How do you write a commercial window film specification?

Write it as a standard three-part section in Division 08: the film’s purpose, submittals and qualifications in Part 1; the named product and its performance on stated glass in Part 2; and examination, film-to-glass approval, attachment and visual inspection in Part 3. What makes a film specification work is film-specific: the existing glass, the manufacturer’s film-to-glass approval, the attachment for security film, and the glass every performance number was measured on.

Most major film manufacturers publish three-part guide specifications to start from, including 3M, Eastman (LLumar), Madico and Solar Gard. They organize them the same way, under 08 87 13 for solar control films, 08 87 23 for safety and security films and 08 87 33 for decorative films, but they differ in the details that decide acceptance: which glass their numbers are measured on, how installed film is inspected, and what they require of the installer. A guide specification is a starting point, not a finished section. It has to be edited for the actual glass, the goal and the project, and it should not carry one manufacturer’s assumptions into a section that allows others.

Key points

• Window film belongs in MasterFormat Division 08 under 08 87 00, Glazing Surface Films. Manufacturers’ guide specifications use 08 87 13 for solar control, 08 87 23 for safety and security and 08 87 33 for decorative films.
• Every performance number should name the glass it was measured on. Eastman publishes LLumar safety film values on 1/8 inch single pane clear glass; 3M and Solar Gard publish theirs on 1/4 inch clear glass, so the numbers cannot be compared directly.
• The glass changes the result. Solar Gard lists its Ecolux 70 Low-E film at a winter U-factor of 0.60 on 1/4 inch clear single pane glass and 0.34 on 1/4 inch clear insulated glass.
• Require a film-to-glass or glass stress analysis as a submittal. 3M and Solar Gard both include one in their guide specifications.
• Specify one inspection method. The IWFA guideline views film from the room side at not less than 6 feet; Eastman’s guide views it from 10 feet against a bright sky; 3M’s allows 30 days for the film to dry before final inspection.
• Security film needs a sized attachment, and safety film should be specified by its tested performance on glass, not by raw film properties.
• Check the warranty clause against the manufacturer’s current warranty document, and leave ASTM F3561 out of a retrofit film specification.

Which CSI section does window film go in?

MasterFormat places window film in Division 08, Openings, under 08 87 00, Glazing Surface Films. The sections manufacturers use for their guide specifications are:

Not every project uses these numbers. We see written film specifications on architect, general contractor and public work, and the section number varies from project to project, so what the section says matters more than its number. Safety film guide specifications list solar performance values too, so a security film with solar requirements can be specified in one section. Madico and Solar Gard, for example, place anti-graffiti film in their safety and security and general film sections respectively, so check where each manufacturer puts the product you are naming.

What goes in Part 1, General?

The CSI three-part format puts administrative and procedural requirements in Part 1. For window film:

• Summary and purpose. State what the film is for: solar heat and glare, Low-E retrofit, glass safety, forced-entry delay, blast hazard mitigation, privacy, bird collision deterrence or graffiti protection. The purpose decides the product, the attachment and the tests that apply.
• Existing glass. Describe the glass type, thickness, construction (single, double or triple pane), heat treatment and any Low-E coating and its surface, or require the installer to verify them. This is what the manufacturer needs to approve the film.
• References. List only the standards the section actually uses (see the table below).
• Submittals. Product data sheets with independent test reports; a film-to-glass or glass stress analysis of the existing glass with the proposed film (both 3M’s and Solar Gard’s guides include one); shop drawings of the film, anchoring accessories and sealant for security film; verification samples (Solar Gard’s guide asks for two at least 6 inches square, Eastman’s for two 12 inches square); and the warranty form. Some guides also offer Environmental Product Declarations (EPDs) to ISO 14025 and ISO 21930 for projects with sustainability goals.
• Quality assurance. Manufacturers set the installer bar differently: 3M’s guide asks for at least five years of demonstrated experience and manufacturer authorization, Eastman’s for a firm authorized by the film seller, and Solar Gard’s for at least three applications of similar size and complexity, approved by the manufacturer. Pick a requirement you can verify and that does not lock out an approved equal by accident.
• Mock-up. All three guides provide for a mock-up to evaluate surface preparation and workmanship, on a window the architect designates, before the rest of the work proceeds. For security film, include the attachment in the mock-up.
• Project conditions. Temperature, humidity and ventilation within the manufacturer’s limits, and the schedule: occupied building phasing, after-hours work, school calendars and, for exterior film, the season.
• Warranty. The manufacturer’s current written limited warranty for the exact product (see below).

What goes in Part 2, Products?

Name the product, then state the performance you need on the glass it was measured on. Two rules make Part 2 enforceable.

Tie every number to a named glass. Film performance changes with the glass under it. Solar Gard’s 08 87 13 guide for Ecolux 70 shows how much:

Manufacturers also publish on different reference glass. Eastman’s LLumar safety film values are for single pane, 1/8 inch clear glass; 3M’s and Solar Gard’s are for 1/4 inch clear glass, with separate figures for insulated glass. A side-by-side comparison of two products is only meaningful on the same glass, which is one more reason to state the glass in the specification and require submittals on it.

“Visible light transmittance 67 percent” means nothing on insulated glass. “Visible light transmittance 67 percent on 1/4 inch clear single pane glass, calculated with NFRC methodology” can be checked at submittal. Where available, ask for NFRC-certified ratings: NFRC rates applied film on six reference glazing systems, none of them Low-E, and lists certified films in its Certified Products Directory. Data published on clear glass does not describe the film on a Low-E unit; we explain why in How Do Low-E Coatings Affect Window Film?

Specify safety film by its performance on glass. Raw film properties such as tensile and tear strength describe the film, not the window. Solar Gard’s 08 87 23 guide says plainly that its nominal physical property values “should NOT be used for specification purposes,” because performance testing on filmed glass is what reflects a real installation. Specify the safety glazing classifications and any blast results the manufacturer reports for a named glass and configuration instead. Eastman’s guide refers blast, windstorm and forced-entry projects to its technical team rather than covering them in the standard text.

Then add what the purpose needs:

• Solar control (08 87 13): visible light transmittance and reflectance inside and out, solar heat gain coefficient, total solar energy rejected and glare reduction on stated glass, and whether the film is interior or exterior.
• Low-E retrofit (08 87 13): emissivity and winter U-factor on stated glass. We compare Low-E film with new windows in Low-E Window Film vs. Window Replacement.
• Safety and security (08 87 23): film thickness; ANSI Z97.1 and CPSC 16 CFR 1201 classifications as reported for stated glass; any GSA TS01 blast result with its full tested configuration; and the attachment system and sealant.
• Bird control (08 87 26): pattern, dot size and spacing, exterior application, and an American Bird Conservancy threat factor if a rule or goal requires one. We explain spacing and threat factors in Bird Collision Window Film for Existing Buildings.
• Decorative (08 87 33): product or pattern, colors, artwork approval and seam layout.
• All films, where required: surface burning characteristics and VOC content. Eastman’s and Solar Gard’s guides both list ASTM E84 Class A, with a flame spread index of 0 to 25 and a smoke developed index of 0 to 450, and Solar Gard’s adds VOC compliance with California Department of Public Health, CHPS and LEED v4 low-emitting criteria.

How should a specification handle security film attachment?

Name it, size it and test it. Film alone holds broken glass together but does not hold the filmed glass in the frame. The attachment details come from the film manufacturer, so the specification should require the manufacturer’s attachment guidelines and state the dimensions. Solar Gard’s 08 87 23 guide, for example, sets minimum wet glaze dimensions for structural silicone:

• Blast mitigation: at least 1/2 inch of overlap on film and frame, not counting the glazing stops, or 3/8 inch of depth at the center of the bead.
• Impact resistance or glass retention: at least 3/8 inch of overlap, or 1/4 inch of depth at the center of the bead.

Attachment dimensions must be selected for the intended performance requirement and supported by the manufacturer’s applicable testing or installation guidance; they do not by themselves establish forced-entry performance for every glazing system.

The same guide calls for the wet glaze to be applied to the manufacturer’s guidelines by an authorized applicator; allows open cell backer rod where gaskets are removed, or gaskets cut back with the architect’s approval, with a sealant compatibility test; recommends a triangular bead profile to maximize depth; and describes an adhesion test on the frame: a 1 inch by 6 inch bead, cured at least 7 days and pulled at 90 degrees, where the result should be cohesive failure, with sealant left on the surface. Our standard system for forced-entry delay is 8 mil clear Armorcoat with a four-sided DOWSIL 995 wet glaze attachment. We compare attachment systems in Security Film Attachment Systems Explained.

If the frame cannot take an attachment, the specification should say what the film is then for: glass safety and fragment retention, not forced-entry delay. We cover the limits in What Security Window Film Can and Cannot Do.

How do manufacturers’ guide specifications differ?

On the points that decide acceptance, three current guide specifications compare like this:

None of these is wrong; they are written for different products. The risk is copying one into a section that allows several manufacturers, so the inspection method, installer requirement and submittals stop matching what the other approved products can meet. Decide each of these deliberately and write it once.

Which standards belong in a window film specification, and which do not?

Blast results describe the tested assembly, not the film. Solar Gard’s guide reports GSA Performance Condition 3B for clear safety film daylight applied to 1/4 inch single pane annealed glass, 3B with a GE SCS2000 SilPruf attachment on the same glass, and 3A daylight applied to 1/4 inch double pane annealed glass, each at a minimum blast load of 4 psi and 28 psi-msec. In Solar Gard’s earlier 2000 test series, 8 mil film wet glazed with Dow Corning 995 (now DOWSIL 995) on 1/4 inch annealed glass rated 3a. A specification that asks for a Performance Condition should name the configuration it means.

What goes in Part 3, Execution?

• Examination. Verify the glass type, thickness, construction, coating and condition before film is ordered; inspect for scratches and defects that will affect the final appearance; and report broken seals, damaged glass and frame conditions that would prevent an attachment. We identify glass with a meter on every survey.
• Film-to-glass approval. Require documented manufacturer approval for the proposed film and glazing combination before installation. If approval is declined, the design professional should evaluate an approved alternative.
• Preparation and installation. Clean the glass, remove any existing film, install to the manufacturer’s instructions, and install the attachment to the specified dimensions after the film has passed visual inspection.
• Inspection and acceptance. Name one method, because the guides differ. The International Window Film Association’s Architectural Visual Inspection Guideline is the industry document: view at right angles from the room side, at not less than 6 feet, in natural daylight but not direct sunlight, excluding a 2 inch band at the perimeter. Edge gaps are normally 1/32 to 1/16 inch, which is worth stating so a guide specification’s “no gaps between film and frame” is not read literally; Eastman’s guide, for comparison, cuts film to within 1/8 inch of the frame. Water bubbles and haze while the adhesive cures are not defects; IWFA’s typical visual cure times are 30 days for film up to 4 mils, 60 days from 4 to 8 mils and 90 days from 8 to 12 mils.
• Cleaning and protection. Protect installed film from later construction work, and do not clean new film for 30 days, as Solar Gard asks.

What should the specification say about the warranty?

Require the manufacturer’s current written limited warranty for the exact product, registered to the owner, and do not describe more than it covers. Two checks are worth making:

• Match the term to the current warranty. Guide specifications state warranty terms that can lag the warranty documents. Solar Gard’s current clear safety film guide, for example, lists 12 years for Armorcoat Clear, while Solar Gard’s current Armorcoat PremierPlus warranty runs 16 years for commercial use. Eastman’s guide lists 10 years for LLumar and 12 for Vista films, with restrictions. When a guide and a warranty differ, the warranty document is what the manufacturer honors.
• Separate film coverage from glass coverage. The film warranty covers defects such as peeling, bubbling and delamination. Glass breakage and seal failure coverage, where a manufacturer offers it, is separate and limited. In Solar Gard’s solar control warranties, for example, it requires an approved film-to-glass application and excludes single panes over 100 square feet, insulated units over 40 square feet, glass with any edge over 10 feet and glass 3/8 inch or thicker. The Armorcoat PremierPlus commercial warranty is not transferable and excludes theft or break in.

What mistakes do we see most in window film specifications?

• A discontinued or outdated product, or data from an old sheet.
• A film that is not appropriate for the glass, usually a solar film on Low-E or insulated glass the manufacturer does not approve it for.
• Security film with no attachment language. The film is specified, but nothing connects it to the frame.
• Standards that do not fit retrofit film, most often ASTM F3561 on a school entrance.
• Performance numbers with no glass named, which cannot be verified at submittal.

Who should write the window film specification?

The architect or design professional owns it. A window film contractor can help with product selection, film-to-glass approvals and technical language, and the manufacturers’ guide specifications give the structure. AAA Glass Tint works primarily with Solar Gard and also works with other manufacturers, including 3M and SOLYX. We help architects with product selection and technical window film specification language, and supply data sheets, film-to-glass approvals, samples, warranty information and mock-ups. AAA Glass Tint is also an AIA Continuing Education provider. Once the specification is out, How to Compare Commercial Window Film Bids covers what to check in the responses.

Before a section is finalized, have the glass surveyed so the specification describes the building that is actually there. Request a free assessment.