UL 1685 — Electrical and Optical Fiber Cable Smoke-Release Test

The UL 1685 standard is used for testing electrical and optical fiber cables. Cables are useful, but they can be hazardous if their flame retardant and fire resistant capabilities are unknown. As a result, the wire and cable industry analyzes cable flame propagation using flame tests. Cable manufacturers, electrical distributors, and other users can all benefit from this testing.

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<strong>UL 1685 — Electrical and Optical Fiber Cable Smoke-Release Test</strong>

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Overview
Scope, Applications, and Benefits
Test Process
Specifications
Instrumentation
Results and Deliverables

Overview

UL 1685 is used to determine the flame propagation and smoke release properties of electrical and optical fiber cables subjected to vertical-tray fire conditions. The test procedure involves the reaction of cables to the ignition source, focusing on the spread of flame, smoke production, and the height of damaged cables.

UL 1685 is commonly used to assess the fire performance of cables in industrial, commercial, and infrastructure applications. The standard can be used to establish the suitability of cables for applications where limiting flame spread and controlling smoke release are critical safety considerations.

Scope, Applications, and Benefits

Scope

UL 1685 tests the fire performance of electrical and optical fiber cables laid in a vertical tray configuration when exposed to controlled flames. The test result reveals the flame propagation characteristics, smoke release, and the level of damage sustained by the cables during the test.

UL 1685 evaluates:
● Vertical tray flame propagation of cables
● Smoke-release behavior during fire exposure
● Cable damage height after flame application
● Peak and total smoke generation
● Suitability of cables for fire-sensitive installations

Applications

● Electrical power cables
● Control and instrumentation cables
● Communication and data cables
● Optical fiber cables
● Commercial cable tray installations
● Industrial cable fire performance evaluation

Benefits

● Provides standardized fire performance evaluation for cables
● Helps assess flame spread in vertical tray installations
● Measures smoke-release behavior under fire exposure
● Supports safer cable selection for enclosed environments
● Assists in evaluating compliance with fire performance requirements

Test Process

Sample Preparation

Cable specimens are installed vertically on a tray in the required arrangement for testing.

Flame Application

A standardized ignition source is applied to the cable tray assembly for the specified duration.

Smoke and Flame Observation

Flame spread, smoke release, and cable damage height are monitored during the exposure period.

Data Recording & Evaluation

The measured fire and smoke performance values are recorded and evaluated according to the acceptance criteria.

Technical Specifications

Parameter	Details
Applicable Materials	Electrical and optical fiber cables
Test Orientation	Vertical tray configuration
Fire Exposure	Standardized flame source
Evaluation Criteria	Flame spread, smoke release, and cable damage height
Smoke Metrics	Peak smoke release and total smoke generation
Measured Outputs	Flame propagation and smoke-release performance

Instrumentation Used for Testing

UL 1685 vertical cable tray test apparatus with defined tray configuration
Calibrated flame exposure burner system with defined heat output
Optical density photometer system for smoke concentration measurement
Specimen mounting and cable fill installation fixtures per UL 1685 requirements
Temperature and environmental monitoring instrumentation throughout test exposure
Data acquisition and test reporting system

Results and Deliverables

Smoke optical density measurements throughout defined flame exposure period
Smoke-release index data and peak optical density values for all tested cable specimens
Flame exposure and cable tray installation records per UL 1685 test conditions
Test compliance result assessed against defined UL 1685 maximum smoke-release criteria
UL 1685 smoke-release test report for product approval, building code submissions, and regulatory authority review

Why Choose Infinita Lab for UL 1685?

Infinita Lab is a trusted USA-based testing laboratory offering UL 1685 testing services across an extensive network of accredited facilities across the USA. Infinita Lab is built to serve the full spectrum of modern testing needs—across industries, materials, and methodologies. Our advanced equipment and expert professionals deliver highly accurate and prompt test results, helping businesses achieve quality compliance and product reliability.

Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you. Request a Quote

Frequently Asked Questions

UL 1685 assesses how flames spread and how much smoke electrical and optical fiber cables release. It helps determine if cable designs limit smoke production and fire spread during standard vertical tray fire tests.

Smoke-release testing helps find cables that lower visibility risks and toxic exposure during fires. UL 1685 helps select safer cables for buildings, tunnels, and industrial sites where getting people out quickly is essential.

UL 1685 is often used for electrical power cables, control cables, communication cables, and optical fiber cables that are placed in trays. This standard evaluates how well these cables perform in terms of flame spread and smoke generation.

UL 1685 testing places vertically mounted cable trays in front of a controlled flame source. It monitors how the flames spread and how much smoke is released. This setup helps evaluate how well cables perform in a fire under consistent lab conditions.

UL 1685 tests how cables spread flames and release smoke in a controlled lab setting. It may not fully reflect the complicated conditions of real fires, which can vary due to ventilation, installation differences, or the presence of various combustible materials.