I have an architect that wants me to write a specification for fall arrest anchors but make them bidder design. He wants to move the liability over to the contractor.
I have always worked on projects where the structural engineer designs the anchor and works with the architect to locate them over structural elements.
What is your experience?
I’ve done it both ways, but the architect usually has to determine the layout to meet Code and establish the loads that they have to be designed to if delegating design
I routinely specify fall-arrest and other facade access systems as delegated design. This is the one case where I cite OSHA requirements in the specs, since they govern the design. Performance criteria are also spec’d, to indicate the req’d loads the equipment must withstand in use.
We also specify fall-arrest & building maintenance access systems as delegated design, usually with a deferred approval by the AHU.
But you really need to work with a vendor during your design phase to define and layout a workable schematic design. This will insure that the structural design is in place for bidding and that you have other miscellaneous scope items covered.
There is nothing more painful and avoidable than paying a big surcharge to add additional structural steel because the decision on fall arrest system design came too late.
I agree with Steven - a layout based on input from the Owner’s building maintenance provider or a similar entity should be shown on Bid Documents. The structural steel to which the fall-arrest anchor is secured needs to be designed by the Project Structural Engineer in order to bear the required forces. The Architect should indicate flashing, thermal breaks and other features required for the integrity of the roofing assembly where anchors cause penetrations.
The delegated design should only be for how the anchors themselves are constructed and fastened, based on performance criteria clearly indicated in the specifications.
Have you read this?
https://www.xsplatforms.com/osha-final-rule-walking-working-surfaces/
Its a synopsis of this: https://www.govinfo.gov/content/pkg/FR-2016-11-18/pdf/2016-24557.pdf
Interesting information that affects our fall arrest, window washing, and metal ladder specs.
Make the contractor responsible for any additional steel framing required by the fall arresting system.
Require the delegated design address the connection of the arrestors to the steel.
The structural engineer still needs to make sure that the steel frame has the overall capacity needed to resist the loads. In general you will want to coordinate the locations of the arrestors with the engineer so the engineer can locate framing members under the arrestors.