SliDeRulE (Safety in Design Risk Evaluator) assists building designers with assessing the construction safety risk associated with their designs. SliDeRulE is intended for use during the design phase of a building. As a building is being designed, architects and engineers can use SliDeRulE to: determine the level of safety risk associated with their design; compare prospective designs based on construction safety risk; and create building designs that minimize the risk of construction worker injury.

SliDeRulE uses risk factors to calculate safety risk. The risk factors are based on the frequency of an incident occurring, severity of a potential incident, and duration of worker exposure to the hazards associated with constructing each design element. SliDeRulE includes risk factors for all of the design elements listed here.

For each design element contained in a building design, the user enters the quantity of the design element into SliDeRulE. SliDeRulE then uses the entered quantities to calculate the safety risk associated with each design element, building system, and the entire building.

Getting started

To begin assessing the safety risk associated with a project design:

  • Click on “Assess a Project” on the SliDeRulE homepage (Figure 1).


    Figure 1. SliDeRulE Homepage

At the start of a project, SliDeRulE then asks that a project title and brief description be provided along with an e-mail address (Figure 2). The title and description are saved with the project data so that the project can be identified at a later date. Also, an e-mail address is required to which SliDeRulE will send a project access code.  Similar to a password, the unique access code is used when returning to and accessing the project data at a later date.


Figure 2. New Project Information Page

If this is a new project:

  • Enter a project title, brief project description, and valid e-mail address in the fields provided. You will be able to modify the title and description at a later time while assessing the project if desired.
  • Read through the Terms of Use and Statement of Liability, and check the box indicating that you have read and agree with these documents.
  • Click on the “Get Started!” button to proceed to the Project Assessment page.

If the project has already been started:

  • Where it says “You can resume it here”, click on “here”
  • On the following page, enter the access code for the project that was previously sent to you from SliDeRulE via e-mail, and click on “Resume Project” to proceed to the Project Assessment page.

Entering project data

Assessing a project entails entering the quantities of each of the design elements included in the project or just the design elements you wish to assess. On the Project Assessment page:

  • Using the links on the left side of the screen, select a system for which to enter data.  Figure 3 shows the Project Assessment page for the Structural Frame system. Similar Project Assessment pages are provided for the other building systems.

Figure 3. Project Assessment Page for the Structural Frame System

  • Next, for each design element included in the building design, enter the required quantity(ies) for each design element. For example, for cast-in-place (CIP) concrete shear walls, enter the total number of cubic yards of concrete in all shear walls on the project.
    • Place the cursor over the blue information symbol () to show a description of the design element and the required input value(s).
    • Click on the blue calculator icon () to open up an on-line calculator. The calculator is provided to assist with calculating the design element quantities.
  • After quantities are input for all design elements within the selected system, click on the “Save and Continue” button at the bottom of the page to save the data entered and proceed to the next system.

At any time, the system links on the left side of the screen can be used to jump to another project system. Progress indicators are provided for each system:

  • When data has been entered for all of the design elements listed in SliDeRulE for a system, a check mark in a green circle () is shown next to the system title.
  • When data has been entered for only some of the design elements listed in SliDeRulE for a system, a check mark in a yellow circle () is shown next to the system title.
  • When no data has been entered for a system, no check mark appears next to the system title.

Calculating safety risk

After entering quantities for all of the design elements included in all of the systems on the project:

  • Calculate the total safety risk by clicking on the “Calculate Risk” button at the bottom of any Project Assessment page.  By doing so, SliDeRulE calculates the safety risk and proceeds to the Assessment Results page (Figure 4).

Figure 4. Assessment Results Page

The Assessment Results page shows the safety risk calculated for each subsystem along with the total safety risk for each system and for the entire project.  The units of the safety risk are “severity”, in which a higher value indicates greater risk.

The words “Not included” are shown for those subsystems in which no data has been entered.

  • Click on any design element or system title to return to the Project Assessment page for that design element or system.
  • Click on the red exclamation point icon () to view a list of specific features related to each of the included design elements which increase/decrease risk of injury. Figure 5 shows an example list for structural frame elements. Some design elements may not have special design considerations.

Figure 5. Example Special Design Considerations Page: Structural Frame Design Elements

Interpreting the results

SliDeRulE calculates and reports a numerical risk value. A lower risk value indicates a safer design for construction workers who are constructing the building. The risk value for one design may then be compared to that of another design in order to select the best possible design for preventing construction worker injuries and fatalities.

SliDeRulE can calculate risk to a level of precision that is likely more than needed in practice. The design is just one of many factors on a project which influence safety. As a result, a small difference in the calculated risk values of two designs may not translate into a difference in safety on the jobsite. A large different in risk values, however, would indicate to the designer that a safety concern is likely present and that the design should be reviewed accordingly.

Printing the results

To print the Assessment Results and Special Design Considerations:

  • Click on the “Print” button at the bottom of the respective pages. A print window will open up from which the results can be printed.

Closing project file

To close the project file:

  • Click on “Logout” in the top, right corner of the Project Assessment, Assessment Results, or Special Design Considerations page. All project data and assessment results will be saved and available for viewing when the project is re-opened.


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