Because few design professionals possess the site safety expertise necessary to perform effective design for construction safety, one key component of the DfCS process is to secure expertise on construction hazards during the design process. Ideally, design firms will have in-house employees who possess the required knowledge, but this is not practical for small- and medium-sized firms. A solution for all firms is to have safety expertise be provided by trade contractors or an outside site safety consultant.
While site safety ideally should be considered throughout the design process, the fact that design firms will likely require the services of outside individuals makes it more practical to have safety constructability knowledge provided at specific points of time, namely at the 30%, 60% and 90% design stages. The graphic below indicates some of the specific review tasks that are most appropriate at each stage. It is important to keep the diminishing returns curve in mind: Having safety explicitly considered at the 30% stage is more important than at the later stages. For example, using prefabricated modules can offer significant safety and cost advantages, but such modules are likely not possible if they are not discussed until the later stages of design.
A second key component of the DfCS process is equipping designers with appropriate DfCS tools. Discipline-specific design checklists have been developed by several large design-build and owner firms, by Gambatese and Hinze for the Construction Industry Institute, and by the UK and Australia. Another important set of tools are decision support tools for appropriately weighing the safety benefits of a specific design decision with the resulting cost, time and quality effects, i.e., multi-attribute decision tools. Such a tool is a typical component of a Lean Construction project.
Will drawings and specifications resulting from a DfCS process look any different from typical construction documents? The answer is probably not initially. DfCS documents will likely at first look like typical documents but reflect an inherently safer construction process. That is, the documents will look the same but be safer for construction workers than if DfCS were not used. Ideally, DfCS construction documents will include safety enhancing details and notes. For example, drawings will include the locations of tie offs for fall protection, excavation shoring details when appropriate, perhaps even critical excerpts from OSHA standards.