Timber Dimension Measuring Device Specifications

Summary#

The government has published the Specifications Relating to Timber Dimension Measuring Devices, a set of technical rules for machines that measure log length and diameter. The specifications come into force on October 23, 2024 and replace the previous “terms and conditions” used to temporarily approve these machines.

What it does#

• Sets performance limits: measurement error must stay within ±1 d (one interval) for the axis and range in use.
• Defines environmental and electrical conditions the devices must handle, for example:
  • default temperature range -10°C to +40°C
  • up to 85% relative humidity
  • ambient light between 100 lx and 100,000 lx for optical systems
  • up to 100 dB acoustic interference for ultrasonic systems
• Requires devices to handle off‑center log positions and certain electrical disturbances without giving a wrong result. If affected, devices must either give a correct result, produce a blank or error message, or an obviously unreadable result.
• Bans “tare” adjustments that reduce the gross measured size (for example subtracting bark).
• Requires the device to:
  • show the software name and version,
  • let an inspector observe or test it (including with test objects),
  • provide a portable second indicator in some installations so measurements can be seen during inspection,
  • have seals (physical or electronic) to show if metrological settings were changed,
  • mark permanent identification info (manufacturer, model, serial, measuring ranges, intervals, etc.) and any use limits near the device.
• Measurement and records rules:
  • Devices must not report derived calculations such as area or volume.
  • Each measuring range must have intervals that are 1 × 10^n, 2 × 10^n or 5 × 10^n units of length.
  • Minimum measurable value for a measuring range is 10 d.
  • If a customer is not present when logs are measured, the device (or connected equipment) must record each log’s length and diameter measurements and any lot identifiers, and keep those records for 90 days.
• Installation and use: devices must be installed and used so they remain accurate, do not enable fraud, and allow customers and operators to see the measurement taking place.
• These specifications are issued under the Weights and Measures Act and the Weights and Measures Regulations.

Who's affected#

• Manufacturers and importers of timber dimension measuring devices who want permanent approval under the Weights and Measures Act.
• Owners and operators of these measuring machines at sawmills, log yards, pulp operations and transport yards.
• Measurement and enforcement officials at Measurement Canada who examine and approve devices.
• Customers whose logs are measured and who may request stored records.
• The notice notes there were temporary approvals for four device models and that two manufacturers responded to earlier consultation; the specification consolidates the previous terms and conditions into a permanent ministerial specification.

Why it matters#

• It gives a clear, government-backed technical standard for machines that measure logs. That helps ensure measurements used in buying and selling timber are consistent and trustworthy.
• Existing devices approved under the old terms should meet these rules, and manufacturers can now apply for permanent approval. The change is meant to reduce uncertainty in the market without adding new technical requirements.
• For customers and businesses, the rules aim to protect against measurement errors and fraud, and to make it easier to get measurement records (kept for 90 days) if needed.