ISO 6535:2015

Overview

ISO 6535:2015, "Portable chain-saws - Chain brake performance," specifies standardized methods for measuring the braking time and release force of manually operated chain brakes on portable hand‑held chain‑saws. The standard defines test objects, required apparatus, preparation and stepwise procedures to produce repeatable performance data used for safety assessment, design validation and conformity testing.

Key topics and requirements

• Test objects: Measurements are performed on three new production saws of the same model, fitted with the manufacturer‑recommended guide bar and chain.
• Measured parameters:
  • Braking time - interval from the pendulum impact to when chain motion has ceased (defined by two successive drive links/sprocket teeth taking >5 ms to pass a reference point).
  • Release force - static force required to activate the brake on the front hand‑guard.
• Apparatus specifications:
  • Rotational speed indicator (±2.5% reading accuracy).
  • Time recording device with ±2.5 ms accuracy and appropriate pick‑ups for brake activation and chain motion.
  • Force gauge (±1 N).
  • Pendulum with 50 mm ±1 mm flat strike face, 700 mm ±5 mm arm length, producing 1.4 J ±0.2 J impact energy from a 200 mm ±5 mm drop.
• Procedure highlights:
  • Release force measured three times before and three times after dynamic tests (six results reported).
  • Braking time measured across three measurement series: initial (5 actuations), after a 300‑actuation preliminary running plus fuel‑tank cutting sequence, and a final (5 actuations) following interim actuations; average of 10 measurements (from second and third series) reported.
  • Engine running conditions: racing speed defined as manufacturer’s rated max power speed +33% or full throttle, whichever is less. Strict speed tolerances and cooling/rest intervals are prescribed.
• Reporting: All braking times recorded; average braking time (ms) from specified measurements; six release force values (N); chain lubrication oil type.

Applications

ISO 6535:2015 is used to:

• Validate chain brake performance during product development and design iterations.
• Support type‑approval, certification and conformity assessments for portable chain‑saws.
• Provide repeatable test methods for laboratory testing, quality control and forensic safety investigations.
• Inform procurement specifications and regulatory compliance checks for forestry equipment.

Who will use it:

• Chain‑saw manufacturers and R&D engineers
• Test laboratories and certification bodies
• Safety regulators and standards committees
• Forestry equipment purchasers and maintenance organizations

Related standards

• ISO 6531 - Portable chain‑saws - Vocabulary
• ISO 6533:2012 - Portable chain‑saw front hand‑guard - Dimensions and clearances

Keywords: ISO 6535:2015, portable chain‑saws, chain brake performance, braking time, release force, chain‑saw safety testing, forestry machinery standards.