Chipper Knife Guard
Does WorkSafeBC explicitly define 'chipper knife guard' as a term?
No. WorkSafeBC defines 'guard' generally as a physical barrier preventing worker access to moving parts or the point of operation. It provides specific chipper requirements, such as a barrier or baffle on the feed side of the rotor for hand-fed chippers, and a table or apron with high sides for self-feeding chippers. The phrase 'chipper knife guard' is a functional descriptor combining these guarding requirements around chipper knives.
What minimum geometric requirements apply to chipper knife guarding in BC?
For self-feeding chippers, the table or apron must extend at least 1.5 m (5 ft) back from the rotor, with sides high enough to prevent reaching and contacting rotating knives. Hand-fed mobile chippers must have a barrier or baffle on the feed side to prevent ejection of chipped material. All guard designs must conform to CSA Z432, which specifies maximum permissible openings based on distance from the hazard and reach-envelope criteria.
Is it ever permissible to remove a chipper knife guard for operational reasons?
Under WorkSafeBC, removal of guards is only permitted where use of a guard is clearly impracticable for a specific operation, and only if alternate devices (e.g., pushsticks) are used and the guard is replaced immediately after the operation. For chippers, guards are integral safeguarding elements, not optional; removing them would typically be non-compliant.
A chipper knife guard is a physical barrier or guarding arrangement on a wood chipper that prevents workers from reaching or being exposed to rotating chipper knives or rotor, and from being struck by ejected material, while allowing safe feed of wood. It includes fixed or interlocked guards, barriers, baffles, tables, aprons, and side structures compliant with CSA Z432 and WorkSafeBC regulations.
On a shop floor or sawmill yard, a chipper knife guard system includes a table or apron extending at least 1.5 m back from the rotor on self-feeding chippers, with high side walls to prevent reaching the knives. Hand-fed mobile chippers require a barrier or baffle on the feed side to contain ejected material. Fixed guards cover the rotor housing, secured with tools-removable fasteners, while interlocked guards stop the machine if opened. Spare knives are stored in guarded containers. Workers inspect guards before use, feed material from behind the table, and only access the rotor under lockout/tagout.
Guard removal or bypass to improve throughput, violating the requirement that safeguards remain in place and effective at all times.
Non-compliant reach distances and opening sizes in guards, such as table length less than 1.5 m or openings allowing hand access to knives, failing CSA Z432 criteria.
Poor maintenance or damage to barriers and baffles, like cracks or missing sections, reducing their ability to contain ejected material and meet safeguard performance expectations.