2.4 Prevention through Design (PtD) Concepts (ANSI Z590.3)

The Concept of Prevention through Design (PtD)

Historically, occupational safety often operated reactively. A facility was designed, built, and put into operation; only then, when workers encountered hazards or suffered injuries, were safety professionals called in to figure out how to protect them. This approach led to heavy reliance on administrative controls and PPE, or vastly expensive retroactive engineering modifications.

Prevention through Design (PtD) represents a paradigm shift. PtD is the practice of anticipating and "designing out" occupational hazards and risks early in the lifecycle of a facility, piece of equipment, process, or tool. By addressing safety during the conceptual and design phases, hazards are eliminated before they ever physically exist. This aligns perfectly with the top tier of the Hierarchy of Controls (Elimination).

The ANSI/ASSP Z590.3 Standard

The American National Standards Institute (ANSI) and the American Society of Safety Professionals (ASSP) developed the ANSI/ASSP Z590.3 standard: Prevention through Design Guidelines for Addressing Occupational Hazards and Risks in Design and Redesign Processes.

This standard provides a comprehensive framework for integrating safety and health into the design process. It outlines the responsibilities of various stakeholders (including owners, design engineers, and safety professionals) and provides a structured methodology for conducting design risk assessments. The standard emphasizes a life-cycle approach, ensuring that safety is considered not just for normal operations, but also for construction, maintenance, decommissioning, and eventual disposal of the asset.

The Financial and Operational Case for PtD

One of the most compelling arguments a Safety Management Professional can make for PtD is the massive return on investment. The cost to implement a safety change follows an exponential curve based on the project lifecycle phase.

• Concept/Design Phase: Changing a blueprint or a CAD model to move a valve from a confined space to an easily accessible ground-level location costs virtually nothing (perhaps a few hours of engineering time).
• Construction Phase: Moving that same valve while the facility is being built requires change orders, material delays, and rework, costing thousands of dollars.
• Operational Phase: Attempting to relocate the valve once the plant is running involves costly process shutdowns, cutting and welding existing pipework, and intensive safety oversight, costing tens or hundreds of thousands of dollars. Alternatively, leaving the valve in the confined space forces the facility to bear the perpetual, ongoing costs of confined space entry permits, specialized rescue training, and specialized PPE for the next 30 years.

By investing time in hazard identification during the design phase, organizations avoid immense lifecycle costs and significantly improve operational efficiency and reliability.

Practical Application of PtD

Implementing PtD requires early and active involvement from the SMP. Safety professionals must secure a seat at the table during design reviews, bringing their field experience to the engineering team.

Key PtD strategies include:

1. Designing for Maintainability: Recognizing that maintenance tasks are historically high-risk. PtD strategies include providing permanent, safe access platforms to elevated equipment, ensuring adequate clearance around machinery to avoid awkward postures, and designing modular equipment that can be safely swapped out rather than repaired in place.
2. Designing for Ergonomics: Selecting tools and designing workstations that accommodate a wide range of human body sizes (anthropometry). This includes adjustable-height workstations, reducing required reach distances, and designing parts to limit manual lifting weight.
3. Material Substitution in Design: Specifying non-toxic building materials or specifying processes that operate at lower temperatures or pressures to inherently reduce the energy potential of the system.
4. Standardization: Designing facilities using standard layouts and equipment. If multiple pump stations are designed identically, operators face less cognitive load and confusion, reducing the likelihood of human error.

Overcoming Barriers to PtD

Despite its clear benefits, PtD faces several barriers in industry. The most common is the siloed nature of organizations. Design engineers are often incentivized by minimizing capital expenditure (CAPEX) and meeting tight project deadlines, whereas safety professionals are focused on reducing operational risk and operating expenditure (OPEX).

To overcome this, SMPs must act as bridge-builders. They must educate engineering teams on safety standards, facilitate collaborative design hazard reviews (like early-stage HAZOPs or Design FMEAs), and clearly articulate the long-term financial benefits of safe design to executive leadership. According to ANSI Z590.3, a successful PtD program requires a strong, visible commitment from top management to integrate safety objectives seamlessly with performance, cost, and schedule objectives.