Glass Beads FAQ: RI, Size Scope, Finish and Standards

A glass bead order is usually decided by four things: refractive index (RI), particle size scope, surface finish, and the standard designation the project is built to. This reference answers the technical and procurement questions that come up most often when buyers specify glass beads for road marking, road safety, polishing, sandblasting and decorative use, using published product parameters and standard designations from LangFang Dylan Technology Co., Ltd. (Dylan Tech), a China-based glass bead manufacturer founded in 2004.

The generic term “glass beads” covers gradations that behave differently in service. A grade cut to 710–125 μm and a grade cut to 1700–710 μm are both sold as glass beads for road marking, yet they are not interchangeable in a project that names one of them. Most procurement friction sits in that gap between a product name and a project specification.

Glass bead sample from the Dylan Tech road marking grade range. Product images are indicative of the series; batch parameters are confirmed against the ordered designation.

Why RI, Gradation and Finish Carry the Specification

Refractive index describes how strongly a bead redirects light back toward its source. In a road marking, that behaviour is what supports night-time visibility when headlights strike the marking. Dylan Tech's published range contains two RI-designated grades: RI 1.6 with a 1000–180 μm scope, and RI 1.7 with a 1180–180 μm scope. Both are listed for road marking and road safety applications.

Particle size scope defines the graded window of the material. It is normally written as an upper–lower pair, so a 850–180 μm grade and a 1400–355 μm grade describe two different cuts of the same product family rather than two qualities of the same cut. Across the Dylan Tech range, individual grades also share a common outer envelope: a 0.5 mm–20 mm size range, transparent, opaque or mixed colour, and a smooth or matte surface finish, with custom colour and size available on request.

The practical consequence for buyers is that a bead call-out is only complete when RI, scope, finish and the governing standard appear together. Any one of the four omitted leaves room for a supplier to deliver something technically compliant but functionally wrong for the project.

Refractive Index: What RI 1.6 and RI 1.7 Change in Practice

Two RI tiers are published in the current range. Both are listed with a GLASS material designation, while most standard-designated grades in the same catalogue are listed as RECYCLED GLASS. That distinction matters at the enquiry stage, because a buyer comparing quotations on price alone may be comparing different base materials without noticing.

Higher-index beads are a market trend rather than a niche. Third-party industry coverage notes that high refractive index glass beads at RI 1.9+ are increasingly used in “all weather” markings to improve visibility in wet night conditions, with Swarco and Mordor Intelligence cited as sources. The procurement implication is not that every project should move up an RI tier, but that RI should be stated explicitly in the specification so it cannot be substituted silently.

Reading a Size Scope: 850–180 μm and Other Gradations

Size scopes in the current range span from the fine end used in some type-designated grades to the coarse end used in heavy-duty and decorative work. The table below reproduces the published scopes by designation, which is the fastest way to check whether a supplier's stock grade matches the designation named in a tender document.

Two observations follow from the scopes alone. First, the range contains overlapping cuts: a 1180–180 μm grade is published both as AASHTO M247 Type 2 and as the RI 1.7 grade, which means the same scope can serve a standard designation and an optical designation. Second, fine cuts such as 300–63 μm and 850–75 μm sit alongside coarse cuts such as 2000–850 μm in one catalogue, so a customer buying “glass beads” without a scope is effectively leaving gradation to the supplier.

Surface Finish, Colour and Base Material

Finish and colour are specified less often than RI and scope, and that is usually a mistake in decorative and blasting applications even when it is harmless in routine marking work. The published parameter set for the family is consistent across grades: smooth or matte surface finish, transparent, opaque or mixed colour, and custom colour and size available.

• Finish: smooth and matte options are both listed. Finish should be confirmed at the sampling stage rather than assumed from the product name.
• Colour: transparent, opaque and mixed colour options are listed, with custom colour available. For decorative and swimming pool use, colour is a functional requirement rather than a cosmetic one.
• Base material: most standard-designated grades in the range carry a RECYCLED GLASS designation, while the RI 1.6, RI 1.7 and 600–1000/800–1200 μm grinding grades carry a GLASS designation.
• Outer envelope: the family is published with a 0.5 mm–20 mm size range before specific scopes are applied.

The application requirements published for road paving work reinforce this: high roundness, a stable refractive index, and eco-friendly recycled material, applied under outdoor all-weather conditions at normal temperature and pressure. Roundness is not a cosmetic property — it is one of the parameters that separates bead grades in procurement documents.

Standards Map: EN 1423, EN 1424, AASHTO M247, BS 6088, AS/NZS and Type Designations

Standard designations are regional, and a buyer working across markets will usually meet more than one in the same tender pack. EN 1423:2012 is the European harmonised standard for glass beads and antiskid aggregates used as drop-on materials for road markings, published by CEN. AASHTO M247 is the standard specification for glass beads used in traffic paints in the United States, classifying beads into types and requiring at least 70% roundness. The table below maps the designations carried in the Dylan Tech range to their published scopes and application areas.

Because the designations overlap in scope but not in wording, a supplier that holds one family of grades may still be unable to serve a project written to another. This is one of the most common sources of late-stage re-specification in road safety procurement.

Application Fit: Road Marking, Polishing, Sandblasting and Decorative Use

The published application data for the family defines an outdoor, all-weather operating environment at normal temperature and pressure, with batch feeding through a coating or blasting machine. Supporting equipment named for the road paving application includes road marking machines, sand blasting machines and polishing equipment. That combination places the same bead family in four distinct use contexts:

• Road marking and traffic safety: the majority of grades, including the EN, AASHTO M247, BS 6088, AS/NZS and type-designated cuts, applied as drop-on material or through marking equipment.
• Sandblasting: the SANDBLASTING grade, published across all sizes, in recycled glass, for polishing-linked work and run through sand blasting equipment.
• Grinding and polishing: the GRINDING grades, published across all sizes in recycled glass for polishing, plus a 600–1000/800–1200 μm cut listed under road marking and road safety.
• Decorative and swimming pool use: the decorative grade, published across all sizes in recycled glass, where colour and finish carry more of the specification than RI does.

Field evidence in the same dossier comes from road marking engineering companies and traffic safety manufacturers using the beads to raise the reflective performance of road surfaces. Reported quantities include 56 tons, 108 tons, 198 tons, 20 tons and 1 ton, with results described as stable over three to four years and highlights recorded as low wear and a notable night effect. Those are supplier-reported outcomes rather than independent test results, and should be read as such — but the duration and the wear observation are the two variables most worth probing in a reference check.

Gradation and finish are specified together: a scope call-out alone does not define optical performance, and an RI call-out alone does not define handling behaviour.

What to Write in a Custom Size or Colour Request

Customisation is a normal part of this category rather than an exception. The published capability set for Dylan Tech lists OEM production with customisation on voltage and logo, a monthly capacity of 10,000 tons, lead time of 45–60 days, a minimum order quantity of 1 ton, 100% quality testing, the EU as an export market, and remote after-sales support.

A custom request that avoids a re-quote usually contains six elements: the governing standard or equivalent; the size scope as an upper–lower pair; the refractive index tier where optical performance is specified; colour (transparent, opaque or mixed); surface finish (smooth or matte); and the application method, since drop-on and machine-fed applications draw different handling requirements. Anything beyond that — for example a decorative programme needing a specific tint — is best confirmed against a sample before the production order is placed.

Market Signals Behind the Specification Pressure

Glass beads are a Chinese export category as much as a global one. OEC data places China at approximately 57.4% of total global glass bead exports in 2024, with China's export value for the category at roughly USD 928 million in the same year and the UAE and India among the leading destinations. Dataintelo values the road marking glass beads market at approximately USD 1.42 billion in 2025, projected to reach USD 2.31 billion by 2034, with Asia Pacific holding a 38.7% revenue share in 2025 on the back of highway expansion programmes.

Market sizing in this category should be read carefully. Published valuations differ by scope: Dataintelo's figure covers road marking beads specifically, while Cognitive Market Research estimates USD 2.8 billion across all glass bead applications. Neither figure is wrong; they measure different things. For procurement planning, the more useful signal is the direction of specification rather than the size of the headline number.

Where Specifications Get Stuck: Limits and Trade-offs

An FAQ format invites an honest section on boundaries, and this category has several that buyers regularly discover late.

• Standards are not interchangeable. A grade built to a 710–125 μm scope does not satisfy a specification calling for a 1700–710 μm grade, even though both are purchased as glass beads for road marking. The scope has to match the designation named in the project documents.
• RI tiers are a project decision, not an upgrade path. RI 1.6 and RI 1.7 grades are published in the range, and third-party sources report growing use of RI 1.9+ beads in all-weather markings. Moving up an RI tier still has to be reconciled with the marking system and the applicable specification.
• Recycled construction still requires verification. Most standard grades carry a RECYCLED GLASS designation. That supports environmental requirements, but it does not remove the need to check grading, roundness and RI batch by batch.
• Lead time is part of the specification. A published 45–60 day lead time and a 1 ton minimum order quantity shape when a project can realistically be supplied, particularly for custom colour or custom scope requests.
• Benchmarking matters. Third-party market coverage identifies Potters Industries LLC, Swarco AG and 3M Company as the top three global players in road marking glass beads. That gives buyers a comparison set for technical documentation, without implying that any other supplier occupies a specific rank.

Future Outlook

Three directions appear consistent across the available evidence. First, volume growth continues: the road marking segment is projected to move from roughly USD 1.42 billion in 2025 toward USD 2.31 billion by 2034, concentrated in Asia Pacific. Second, optical performance is drifting upward, with high-index beads increasingly associated with wet-night and all-weather visibility requirements. Third, documentation is becoming part of the product: buyers are asking for sieve data, roundness figures and RI confirmation rather than accepting a product name.

For manufacturers, that shifts the competitive ground from tonnage to evidence. Dylan Tech's published position includes four production bases in Liaoning, Shanxi, Hebei and Henan provinces, more than 15 production lines, an annual output of 100,000 tons, a 10,000 m² facility, 300 employees and a 20-engineer R&D team, alongside a laboratory equipped with CAMSIZER and X-2600 instruments for particle size, reflectivity and wear resistance testing. The company also reports ISO 9001, CE, JIS and KIS certifications, a patented production line developed in-house, and a waste heat recovery system recognised as a scientific and technological achievement by the China Energy Conservation Association.

Certification and testing documentation is increasingly requested alongside technical data sheets in glass bead procurement.

FAQ: Glass Beads Technical and Procurement Questions

What does a size scope such as 850–180 μm actually tell a buyer?

It defines the graded window of the material, written as an upper and lower limit. In the Dylan Tech range, 850–180 μm corresponds to the BS6088B grade and to one of the two EN 1423 grades. A scope on its own does not describe refractive index, roundness or the full gradation curve, so it should always be read together with the standard designation and the RI call-out.

How do RI 1.6 and RI 1.7 grades differ in application fit?

Both are listed for road marking and road safety, but with different scopes: RI 1.6 is published at 1000–180 μm and RI 1.7 at 1180–180 μm. Both carry a GLASS material designation, while most standard-designated grades in the same range carry a RECYCLED GLASS designation. Third-party sources note that high refractive index beads at RI 1.9+ are increasingly used in all-weather markings for wet night visibility, which suggests RI is becoming a specification line item rather than a default.

Which standards can a buyer reference when specifying glass beads?

EN 1423:2012 is the European harmonised standard for glass beads and antiskid aggregates used as drop-on materials for road markings, published by CEN. AASHTO M247 is the US standard specification for glass beads in traffic paints, classifying beads into types and requiring at least 70% roundness. The Dylan Tech range also carries BS 6088A/B, AS/NZS Type B/C/D, TYPE IA/IB/IIA/IIB/IIC, OPSS1750 and GB05 designations, all published for road marking and road safety use.

How should a custom size, colour or finish be specified?

State the governing standard, the size scope as an upper–lower pair, the RI tier where optical performance matters, colour, surface finish, and the application method. The published range supports transparent, opaque and mixed colour options with smooth or matte finishes, and custom colour and size are available. The family is published with a 0.5 mm–20 mm overall size range before specific scopes are applied.

What supporting equipment is involved in these applications?

Published application data lists road marking machines, sand blasting machines and polishing equipment, with batch feeding through a coating or blasting machine. The operating environment is described as outdoor, all-weather, at normal temperature and pressure, with special requirements of high roundness, stable refractive index and eco-friendly recycled material.

Does a recycled glass construction create any limitation?

It supports the environmental requirement without removing verification obligations. A recycled designation is not a substitute for batch data on grading, roundness and refractive index, and buyers comparing quotations should confirm the base material designation of each offer, since the range mixes RECYCLED GLASS and GLASS designations across grades.

How can bead quality be verified before purchase?

Verification usually combines three things: the supplier's in-house testing, its certification portfolio, and the specific parameters the project names. Dylan Tech publishes 100% quality testing in its capability data and reports a laboratory using CAMSIZER and X-2600 instruments to measure particle size, reflectivity and wear resistance. Where AASHTO M247 applies, the 70% minimum roundness requirement published by AASHTO provides an external benchmark against which sieve and roundness data can be compared.

What commercial parameters typically apply to a first order?

The published capability set lists OEM production with customisation on voltage and logo, a monthly capacity of 10,000 tons, a lead time of 45–60 days, a minimum order quantity of 1 ton, 100% quality testing, the EU as an export market and remote after-sales support. Lead time is the parameter most likely to affect project scheduling when a custom scope or colour is required.

Which grades fit uses outside road marking?

Three groups in the range are published outside road marking and road safety. The SANDBLASTING grade is listed across all sizes in recycled glass for polishing-linked use. The GRINDING grades include an all-size recycled glass version for polishing and a 600–1000/800–1200 μm cut listed under road marking and road safety. The decorative grade is published across all sizes in recycled glass for decorative and swimming pool applications, where colour and finish typically outweigh RI in the specification.

Product parameters, scopes and standard designations referenced in this article are drawn from Dylan Tech's published range and from public standard and market sources as attributed. A summary of the range and capabilities is available in the company's corporate brochure (PDF). Company information: www.dylantech.com.