Overview
ISO 8334:2007 specifies laboratory test methods to determine the balance and the maximum holding moment of portable combustion‑engine, hand‑held chain‑saws used in forestry and tree service. The standard defines how to measure longitudinal and lateral balance in typical operating configurations and how to calculate the maximum holding moment from the saw’s mass and centre of gravity. ISO 8334 helps manufacturers, test houses and safety assessors evaluate ergonomic stability and handling characteristics of portable chain‑saws.
Key topics and technical requirements
- Test configurations
- Saw tested in a new, clean condition with fuel and oil tanks half full.
- Two guide‑bar configurations: shortest/lightest (without spiked bumper if detachable) and longest/heaviest (with spiked bumper if available). Guide bar tightened to its uppermost position.
- Longitudinal balance
- For forest‑service saws: supported on the front handle so the guide‑bar plane is vertical; measure angle α between guide‑bar centreline and horizontal.
- For tree‑service saws: supported on a 10 mm diameter rod near the rear throttle trigger; measure angle β.
- Lateral balance (tree‑service saws)
- Saw balanced on a steel support pin located close behind the released throttle trigger; pin conical to max 45° with contact radius ≤ 1 mm. Measure angle δ between guide‑bar plane and vertical.
- Maximum holding moment (tree‑service saws)
- Determine mass m and centre of gravity (CG) with longest guide bar and half‑filled tanks. Measure distance R from the reference point (inside of rear handle intersecting back of released throttle trigger) to the CG.
- Calculate holding moment M in N·m using the specified formula converting R (mm) to metres:
- M = m × g × R × 10^-3, where g = 9.81 m/s².
- Test report requirements
- Reports must reference ISO 8334 and record date/place, saw identification (manufacturer, model, serial), guide‑bar lengths/masses, measured angles (α, β, δ), mass and CG data, calculated holding moment, and test equipment and personnel.
Applications and who uses it
- Chain‑saw manufacturers: design validation, ergonomic tuning and product development.
- Independent test laboratories and certification bodies: performance verification and conformity testing.
- Safety engineers and procurement teams in forestry and arborist sectors: comparing handling characteristics and selecting equipment that meets occupational safety requirements.
- Regulatory and standards organizations: establishing product standards and acceptance criteria based on measured balance and holding moment.
Related standards
- ISO 6531 (vocabulary for portable hand‑held chain‑saws) is normative for terms and definitions.
- Product standards and specific certification schemes set acceptance limits; ISO 8334 defines the measurement method rather than pass/fail limits.
Keywords: ISO 8334:2007, portable chain‑saws, balance testing, holding moment, forestry machinery, longitudinal balance, lateral balance, centre of gravity, chain‑saw test method.
Open preview (PDF)Forestry machinery — Portable chain-saws — Determination of balance and maximum holding moment
