Current through Reg. 50, No. 187; September 24, 2024
(1) Light
transmittance measuring devices shall be provided with a standardized reference
sample and procedure for taking readings utilizing the reference sample. The
device light source shall be mid-range in the visible spectrum (560 nanometers
plus or minus 20 nanometers) and shall exclude the ultraviolet and infrared
portions of the spectrum. The accuracy of reference samples shall be verifiable
with instrumentation calibrated to standards traceable to the National
Institute of Standards and Technology (NIST), whose standards applicable to
this rule are hereby incorporated by reference. A copy of National Bureau of
Standards Special Publication 250-6, "NBS Measurement Services: Regular
Spectral Transmittance" may be ordered from the National Technical Information
Services (NTIS), 5285 Port Royal Road, Springfield, Virginia 22161,
1(800)553-6847.
(2) Light
transmittance measuring devices shall comply with the following criteria:
(a) Single unit light transmittance measuring
devices shall be compact and designed to be operated by one person on vehicle
glass with up to 1/4 inch glass thickness.
(b) Two-piece unit light transmittance
measuring devices shall be designed to be operated by one person on front
windows, side windows and rear windows up to 3/8 inch glass thickness. The
two-piece unit shall have a digital readout to the nearest percent and an
alignment aide feature to maintain stable alignment throughout the period of
measurement. Activation may be manual or automatic.
(c) Measuring devices shall maintain unit
accuracy within plus or minus three percentage points of reference samples and
shall have a repeatability within plus or minus one percentage point from
reading to reading. If the supply voltage is outside of the device's operating
range, the device shall either produce a low battery signal or shall not
produce an output reading, or both.
(d) Measuring devices affected by outside
"stray" or "ambient" light sources of 2% or greater shall not be
acceptable.
(e) Measuring device
readings that are affected by temperature and humidity changes shall not be
acceptable. Operating humidity range shall be 0 to 85 percent and operating
temperature range shall be 20 to 100 degrees Fahrenheit. Acceptable units shall
be capable of demonstrating both published accuracy and repeatability of
transmittance readings throughout the operating temperature and humidity
ranges.
(f) Reference samples shall
be either glass or plastic based with a thickness of 1/8 inch to 1/4 inch and
stable for at least one year. Reference samples shall provide a uniform surface
reading with a variation not to exceed 1.0 percentage point as measured by a
calibrated Spectrophotometer. Reference samples shall be permanently labeled or
inscribed with the manufacturer's name and address, specific identification
number, percent of light transmittance and preparation date. Reference samples
shall be recalibrated at least once per year by a qualified
laboratory.
Rulemaking Authority 316.2955 FS. Law Implemented 316.2951
- 316.2956 FS.
New 1-2-96.
