Visual Quality Standard For Applied Window Film As Adopted By
The IWFA May 15, 1999
1. Installed film on flat
glass surfaces is not expected to have the same level of
visual quality as glass. The following criteria apply to the
installed film only and not to any defect inherent in the
glass.
2. Installed film has a discrete time for full adhesion to be
effected since installation utilizes a detergent solution in
the water to float the film onto the glass: the excess water
is squeegeed out, but inevitably residual water will remain
between the film and glass. The time to achieve full adhesion
is often referred to as "the adhesive cure time".
Adhesion will be increasing from a lower value during this
time. Visual and adhesive cure time is related to thickness of
the film and various metallic coating on the film. Typical
visual cure times may be extended or shortened according to
climatic conditions.
3. Inspection for optical quality can be made before full
visual cure is attained. Table 1 provides a guide for typical
visual cure times. It should be noted that effects during
cure, such as water bubbles, water distortion, and water haze
are not to be regarded as defects.
4. The glass with applied film shall be viewed at right angles
to the glass from the room side, at a distance of not less
than 6 feet (2 meters). Viewing shall be carried out in
natural daylight, not in direct sunlight, and shall assess the
normal vision area with the exception of a 2 inch (50mm) wide
band around the perimeter of the unit.
5. The installation shall be deemed acceptable if all of the
following are unobtrusive (effects during visual cure should
be disregarded): Dirt Particles, Hair and Fibers, Adhesive
Gels, Fingerprints, Air Bubbles, Water Haze, Scores and
Scratches, Film Distortion, Creases, Edge Lift, Nicks and
Tears. Inspection may by made within 1 day of installation.
Obtrusiveness of blemishes shall be judged by looking through
the film installation under lighting conditions described in
4.
6. The 2 inch (50mm) wide band around the perimeter shall be
assessed by a similar procedure to that in 3 and 4, but a
small number of particles is considered acceptable where poor
frame condition mitigates against the high quality standards
normally achieved.
7. Edge gaps will normally be 1/32 - 1/16 inch (1-4mm). This
allows for the water used in the installation to be squeegeed
out. This ensures that film edges are not raised up by contact
with the frame margin. Contact with the frame margin could
lead to peeling of the film.
8. For thicker safety films the edge gaps will normally be
1/32 - 1/16 inch (1-4mm), with 1/32 - 1/8 inch (1-5mm) being
acceptable for films of (7 mil (175)). Combination solar
control safety films will also fall within this standard.
An edge gap of up to 1/16 inch (2mm) is recommended,
especially for darker (tinted, metallized, tinted/metallized,
and sputtered) films, to minimize the light line around the
edge of the installed film.
9. Splicing of films is necessary when larger panels of glass
are treated, where both length and width of the glass exceed
the maximum width of film. The splice line itself should not
be viewed as a defect. This line should be straight and should
be parallel to one edge of the frame margin. The two pieces of
film may be butt jointed. The maximum gap at any point in the
splice line should be 1/64 inch (1mm). Film may be overlapped,
spliced or butt jointed.
10. Certain films with special high performance coating may
have lengthened cure times. Consult the manufacturer for cure
times of these films.
Table 1 - Typical Cure Times
| Film
thickness in mils |
Film
thickness in
microns(µ) |
Typical
Cure
Time (days) |
| Up
to 4 |
Up
to 100 |
30 |
| 4
to 8 |
100
to 200 |
60 |
| 8
to 12 |
200
to 300 |
100 |
| Over
12 but not more than 17 |
Over
300 but not more than 425 |
140 |
*Special adaptation of
information received from the Glass and Glazing Federation;
reproduced with their permission.
Copyright© 1999 International Window Film Association
All Rights Reserved
International Window Film Association
P.O. Box 3871
Martinsville, VA 24115-3871
Ph: (540) 666-4932
Fax:: (540) 666-4933
Email: Information@iwfa.com
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