What are the main types of sheeting covered in IS 15684?

It covers three types of micro-prismatic sheeting: Type IV (High-Intensity Prismatic), Type IX (Very High-Intensity Prismatic), and Type XI (Superior Intensity Prismatic).

What is the specified service life for sheeting under this code?

The standard specifies a minimum 10-year durability for all types (IV, IX, XI) when properly processed and applied (Clause 6.1.1).

Which code tells me which type of sheeting to use for a highway sign?

IRC:67 (Code of Practice for Road Signs) specifies the design and application of signs, which in turn dictates the minimum required sheeting type based on the road category and sign type.

Does this standard include requirements for fluorescent colors?

Yes, Annex C and related tables provide colorimetric and photometric requirements for fluorescent yellow-green, fluorescent yellow, and fluorescent orange sheeting.

IS 15684

: 2018

Retro-Reflective Sheeting for Road Signs - Specification

CurrentFrequently UsedSpecificationTransportation · Roads and Pavement

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This standard specifies the requirements for micro-prismatic retro-reflective sheeting used for traffic signs, delineators, and other traffic control devices. It classifies sheeting into high-performance types (IV, IX, XI) and details the photometric, colorimetric, physical, and durability properties to ensure nighttime visibility and longevity.

Specifies requirements for retro-reflective sheeting materials used for the fabrication of permanent and temporary road signs to ensure visibility.

Quick Reference Values

Minimum Coefficient of Retroreflection (Type XI, White, 0.2° Obs, -4° Ent)700 cd/lux/m²

Minimum Coefficient of Retroreflection (Type IV, White, 0.2° Obs, -4° Ent)250 cd/lux/m²

Durability/Service Life (Type XI)10 years

Durability/Service Life (Type IV)10 years

Shrinkage (Max)0.8 mm in any direction after 24h at 70°C

Flexibility Mandrel Diameter2.8 mm

Impact ResistanceNo cracking or peeling beyond 3 mm from impact point

Practical Notes

This standard is aligned with modern ASTM D4956 types, focusing on high-performance micro-prismatic sheetings (Type IV, IX, XI) and phasing out older, less efficient glass-bead sheetings (like Type I).

The choice between Type IV, IX, or XI depends on the road category and required conspicuity, as specified by the client or in IRC:67. Higher types offer better angularity and brightness but at a higher cost.

Ensure the sheeting is applied according to the manufacturer's instructions on a properly prepared substrate (e.g., aluminum composite panel) to achieve the specified 10-year durability.