In Ontario’s industrial establishments, compliance is not a matter of preference—it’s a legal requirement grounded in the Occupational Health and Safety Act (OHSA) and Ontario Regulation 851. One of the most essential obligations under this regulation is the PSHSR, a technical engineering review completed before machinery or processes are brought into service.
At SAFE Engineering Inc., we see firsthand how critical a pre-start up safety review is for keeping workers safe, preventing costly delays, and ensuring equipment is commissioned properly. These reviews are not optional, and ignoring them can lead to serious compliance issues.
Legal Mandate for PSHSRs Under OHSA & O.Reg 851
A pre-start review is mandated when certain types of machinery, processes, or protective elements are introduced or modified within an industrial establishment. OHSA requires employers to ensure equipment is safe before operation, and Ontario Regulation 851 outlines the specific situations where a licensed professional engineer must complete a PSHSR.
Because these reviews are tied directly to regulatory compliance, the work must be thorough, documented, and aligned with the standards enforced by the Ministry of Labour.
Triggers for a PHSR (New Equipment, Modifications, Layout Changes)
PSHSR triggers vary, but most fall into three common categories:
- New Equipment Installation
When new machinery is installed, guarding, interlocks, electrical systems, and access points must meet current standards. Even equipment considered “safe” by the manufacturer may not satisfy Ontario’s requirements. - Modifications to Existing Equipment
Changes to guarding, control systems, drive mechanisms, or electrical interfaces can create new hazards. Any modification that affects worker exposure typically requires a PSR assessment. - Layout or Process Changes
Moving equipment or reconfiguring production areas may reduce safe access, change egress routes, or expose workers to new risks. These changes must be assessed to ensure compliance is maintained.
In every scenario, the PSHSR ensures the installation or modification has been engineered and verified to prevent harm.
What a PSR Assessment Covers
A PSR assessment is a detailed engineering evaluation. When we conduct a review, we examine machine guarding, control systems, interlocks, electrical safety, hydraulic or pneumatic hazards, and equipment layouts.
The assessment also includes:
- Evaluating exposure to moving parts
- Reviewing safeguarding devices against standards
- Assessing emergency stop access and reliability
- Verifying that worker approach distances are met
- Checking guarding for strength, location, and bypass prevention
We document all findings in a written report that outlines compliance status and lists any required corrective actions. This documentation is essential for regulatory audits and for maintaining internal accountability.
Avoiding Project Delays With Early Reviews
One of the biggest challenges we observe in Ontario facilities is the tendency to initiate a pre-start up safety review too late in the project. When equipment has already been installed or production schedules are fixed, discovering non-compliance can lead to rework, delays, and unexpected costs.
Early PSHSR planning eliminates these problems. When we are involved in the design or early procurement stages, we can identify hazards before they become embedded in the layout. This allows the project to move forward smoothly, without last-minute changes or production interruptions.
The Role of SAFE Engineering Inc. in Regulatory Compliance
As engineering specialists focused on regulatory compliance, we support Ontario manufacturers by integrating PSHSR requirements directly into project planning. Through our pre-start review services, we ensure that equipment installations, retrofits, and modifications satisfy OHSA and O.Reg 851 before commissioning.
When we perform a PSHSR, our team:
- Evaluates hazards using engineering principles
- Verifies guarding, control reliability, and safe access
- Confirms compliance with Ontario Regulation 851
- Prepares complete engineering documentation for audits
- Reduces the risk of orders or shutdowns
By working closely with facility teams, contractors, and project managers, we help prevent compliance gaps that lead to enforcement action.
Conclusion
In Ontario, a pre-start review is not optional—it is a legal safeguard that ensures machinery and processes can operate safely. When completed early and thoroughly, a PSHSR protects workers, maintains compliance, and prevents costly delays.
At SAFE Engineering Inc., we take pride in supporting industrial establishments across Ontario through precise, engineering-driven PSR assessment services that keep projects safe, compliant, and efficient. Contact us today!
