can include exposure frequency and duration, or dose–response and exposure assessments, and is generally related to a unit of time, an activity or event, number of units produced, or life cycle of a system.
Initial risk. The initial risk including existing controls is evaluated using the risk criteria and matrix selected to determine if it is acceptable or in need of further risk reduction.
Risk reduction and control methods. For risk levels that exceed acceptability, further risk reduction measures using the hierarchy of controls are selected.
Residual risk. A second assessment considering the new risk reduction measures is made to determine the remaining risk or “residual risk.” For risk levels that remain unacceptable, additional assessments and new risk treatments are applied until the risk is reduced to a level acceptable to the organization. If this cannot be achieved, the “high‐risk” operation shall not continue, except in unusual and emergency circumstances or as a closely monitored and limited exception circumstance with approval of the person having authority to accept the risk (11).
Risk acceptance. Using the organization's own defined “ALOR,” decision‐makers can determine if the risk is acceptable or if additional reduction is required. Higher risks may be tolerated temporarily by management in certain situations by using interim controls until more permanent measures can be fully implemented. This must be a risk‐based decision made by senior management.
Documentation. Information regarding the assessment, members involved, dates, methods, risks identified, treatments implemented to reduce risk, and other pertinent information should be documented and communicated to affected stakeholders and decision‐makers.
Follow up. Following implementation of control measures, an evaluation should be performed to determine their effectiveness and reliability, that no new hazards were inadvertently created, and that the risk level was adequately reduced. If the residual risk level is not acceptable, or if unintended consequences were created by the control measures, steps should be taken to reassess the risk and consider other risk treatment options.
Table 3 Listed methods from ISO 31010, ANSI Z590.3, and ANSI Z10.
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6 PD IN CONSTRUCTION
In 2018, the ASSP prepared a technical report published by the ANSI on “PtD – A Life Cycle Approach to Safety and Health in the Construction Industry. As stated in its Foreword, ASSP TR‐A10.100‐2018 was developed to provide information and guidance to the construction industry with the goal of reducing or eliminating injuries, illnesses, and fatalities throughout the entire process of building construction, operation, maintenance, retrofit, and demolition.
6.1 Concept
In construction, successful PtD efforts have processes and specific PtD related responsibilities for various stakeholders associated with capital projects. The report describes the “Concept‐30%‐60%‐90%” design review process which should be used in construction. The process begins during the “concept” design stage and involves the owner, architect/engineer (AE) and general contractor (GC) or construction manager (CM) explicitly stating and communicating to stakeholders that PtD concepts are to be incorporated into the design. This requires an established process for identifying hazards in the design using design reviews, checklists, safety specifications, and other tools. Primary construction materials selected should conform to the stated safety specifications and be reviewed for any deviations. The design team should consider using prefabricated or modular construction where possible to reduce risk cost and time in erection and assembly activities, while maintaining quality of finished product.
6.1.1 30% Design
In this phase, subcontractors, suppliers, operators, and maintenance personnel become involved in the review of designs to identify or anticipate any critical site hazards and needed risk reductions. Discussions for prefabrication options, specific design tools, or specialists needed are made along with design options that will result in an inherently safer construction process.
6.1.2 60% Design
At this stage, for those hazards that cannot be avoided, risk reduction measures are incorporated into the design including hazard alerts, locations for safe work platforms, built‐in fall protection anchorages, parapet heights to provide fall protection on roof tops, and other measures.
6.1.3 90% Design
As the design reaches 90% completion, safety constructability of plans, specifications, materials, and work methods are reviewed. Safety expectations are clearly identified in all contract documents and safety parameters for subcontractors identified and communicated. All trade contractors are invited to provide input on improvements for reducing residual risks.
Some of the tools used to incorporate PtD into construction projects include hazard analysis and design checklists, sustainability practices, prefabrication and modularization, building information modeling (BIM), lean design and construction, and decision tools such as risk assessments, benefit‐cost models, and design risk calculators.
7 PD ANALYSIS AND ASSESSMENT METHODS
For each situation, methods should be selected and applied that are suitable for the context and needs of the organization. ANSI Z590.3, Addendum G lists eight methods commonly used for hazard analysis and risk assessment which are
Preliminary Hazard Analysis (PHA)
What‐If Analysis
Checklist Analysis
What‐If/Checklist Analysis
Hazard and Operability Analysis (HAZOP)
Failure Mode and Effects Analysis (FMEA)
Fault Tree Analysis (FTA)
Management Oversight and Risk Tree (MORT)
In most cases, risks can be adequately assessed using PHA, What‐If/Checklist Analysis, and FMEA. Often times, modified and combined techniques are needed to adequately identify, assess, treat, and communicate risks to stakeholders. In pre‐operational stages, a design safety review approach is extremely valuable in anticipating, identifying, and avoiding or reducing risks before they are introduced into a system – the core of PtD. Table 3 provides listed methods from ISO 31010, ANSI Z590.3, and ANSI Z10.
OSH practitioners, for the most part, have not fully engaged in the pre‐operational stage. Reasons that OSH practitioners are not involved in the design process might include job descriptions and daily work demands, lack of notification or invitation to participate in design reviews, status within an organization, or lack of knowledge in the design process. OSH professionals must overcome these barriers and engage in the avoidance and elimination of hazards in new designs in their organizations.
8 PERFORMING DESIGN SAFETY REVIEWS
Design safety reviews are a method used to anticipate and identify hazards during the pre‐operational stage of new facilities, expansions in existing buildings, new or modified processes and systems, equipment and machines, and products. The purpose of a design safety review is to avoid recognized hazards before they are introduced or embedded in the design of a new system or redesign of an existing system. Design safety reviews will vary in scope based upon the context and the complexity of the system being reviewed.