Specifications for Traffic Beads for Waterborne Traffic Paints
This specification covers glass beads to be gravity dropped upon 8-25 mils (1.4-4.4 M2 /L, 57-179 ft2 /gal) of
waterborne traffic paint. These beads shall be applied at a rate of 0.67-1.33 Kg/L or (9-12 lb/gal) of traffic
2.1 The following documents, of the issue as stated on date of invitation to bid or request for proposal,
form a part of this specification to the extent specified herein:
2.1.1 Federal Specifications
TT-B-1325 - Beads (Glass Spheres) Retro reflective
2.1.2 Nevada Specifications
Nevada Department of Transportation Standard Specifications for Road and Bridge
Construction 2014 Edition or latest Edition and applicable Pull Sheets.
2.2 Other Publications - The following documents form a part of this description to the extent specified
herein. Unless a specific issue is identified, the issue in effect on date for invitation for bids or
request for proposal shall apply.
2.2.1 American Society for Testing and Materials (ASTM) Standards:
D 1155 - Standard Test Method for Roundness of Glass Spheres
D 1214 - Standard Test Method for Sieve Analysis of Glass Spheres
3.1 Quality Assurance Control:
The beads shall be segregated into maximum lots of 20,000 Kg (44,000 lb). The manufacturer shall
test each lot for compliance to the specification requirements listed in Table II, entitled ‘Test
Methods”. Lot analysis shall be retained for at least two (2) years.
When tested as specified in Paragraph 4.3, the glass spheres shall be colorless; clean; transparent;
free from milkiness or excessive air bubbles; and essentially clean from surface scarring or
When tested as specified in Paragraph 4.4, the traffic beads shall have a minimum of eighty percent
(80%) rounds overall.
3.4 Embedment Coating:
When tested as specified in Paragraph 4.5, the traffic beads shall be embedment coated with a
material, which enhances adherence of these beads in the waterborne traffic paint.
3.5 Specific Gravity:
When tested as specified in Paragraph 4.6, the traffic beads shall have a specific gravity of two and
forty-four one-hundredths (2.44) to two and fifty-six one hundredths (2.56) at twenty-five degrees
Centigrade (25°C) (seventy-seven degrees Fahrenheit (77°F)).
3.6 Visual Requirements:
3.6.1 Referee Method:
When tested as specified in Paragraph 4.3, the glass beads shall have a minimum of eighty
percent (80%) rounds and shall satisfy the specification requirements described in Paragraph
3.2 - Appearance.
3.6.2 Alternate Method:
When tested as specified in Paragraph 4.4, the traffic beads shall comply with the
specification requirements described in Paragraph 3.3 Roundness.
3.7 Moisture Content
When tested as specified in Paragraph 4.7 the moisture content shall not exceed one one-hundredth
3.8 Moisture Resistance:
When tested as specified in Paragraph 4.8, the traffic beads shall flow freely with minimal
3.9 Refractive Index:
When tested as specified in Paragraph 4.9, the Index of Refraction shall be a minimum of one and
3.10 Reduction in Luster or `Reflective Power
When tested as specified in Paragraph 4.10, the reduction in luster or reflective power of the beads
shall be minimal.
When tested as specified in Paragraph 4.11, the traffic beads delivered shall comply with the
gradation requirements specified in Table I, entitled “Gradation Requirements for Type A Traffic Beads"
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