Per Unit Method
How does the per unit method align with WorkSafeBC requirements for health & safety programs?
WorkSafeBC requires employers to develop health & safety programs with written safe work procedures, hazard identification, incident investigation, and documented reviews. The per unit method operationalizes this by defining units (workers, tasks, machines, CUs, work areas) and attaching hazards, risk assessments, safe work procedures, incident records, and hazard ratings to each unit. SafeDesk should treat these units as primary relational entities and enforce linkages between incidents, inspections, training records, and units.
How should SafeDesk support the per unit method for occupational noise measurement under CSA Z107.56-18 / WorkSafeBC?
WorkSafeBC's noise measurement guide specifies measuring Lex for at least five workers in a group and calculating Lgroup and standard deviation, or for single workers taking at least five representative measurements. SafeDesk must store raw Lex measurements per worker, define exposure groups, and calculate Lgroup, standard deviation, and precision P. Automated rules should trigger corrective actions when Lgroup or individual Lex exceeds 85 dBA and alert when exposure variability is high.
How is the per unit method applied to respirator and PPE compliance under WorkSafeBC / CSA Z94.4-18?
WorkSafeBC requires each respirator user to perform a user seal check before each use per CSA Z94.4-18. Per unit method means each worker unit must have assigned respirator type, fit test history, and seal check records. Each respirator model unit must have standard compliance and maintenance history. SafeDesk should bind PPE records to worker units, provide workflows for fit test scheduling and seal check acknowledgements, and report compliance per shift or job.
The per unit method is a measurement and control approach in a safety program where hazards, exposures, incidents, and compliance requirements are quantified and managed for each defined unit—typically individual workers, specific tasks, machines, or classification units—to meet regulatory requirements and make controls and documentation traceable and auditable. It operationalizes WorkSafeBC, OSHA, and CSA standards by linking data to discrete operational units.
On the shop floor, the per unit method applies to exposure and hazard assessment per worker or task, such as measuring noise exposure for each worker in a group and splitting groups when exposures differ significantly. It also applies to incident investigation by linking incidents to specific workers, machines, and tasks for root-cause analysis. First-aid coverage and hazard ratings are managed per classification unit (CU), ensuring resources match operational risks. PPE compliance is tracked per worker and per equipment unit, with respirator seal checks and fit tests documented individually. This structured approach enables defensible compliance documentation and targeted corrective actions.
Treating group averages as sufficient and ignoring high-risk individuals, leading to undetected overexposure and missing hearing conservation triggers.
Aggregating incident data without unit-level linkage to machines, tasks, or workers, preventing trend analysis and superficial investigations.
Misalignment between classification units and actual operations, causing insufficient first-aid coverage or non-compliance when hazard ratings are not updated.