This article is based on a presentation Tyler Sease, PE, SE gave at NASCC: The Steel Conference 2026 in Atlanta. Miscellaneous steel design covers the structural components that fall outside the primary building frame. These include stairs, railings, ladders, platforms, and the connections that tie them together. These items are typically handled through delegated design, which means detailers, fabricators, and specialty engineers carry most of the coordination load. Small decisions on a miscellaneous steel package routinely become the biggest schedule and constructability problems on a project, which is why we keep coming back to this topic with our team and at industry events.
We will cover this project in more depth in a future article. We designed a monumental switchback stair at a university student center with a 38-foot, 4-inch clear span between slab edges and roughly 45-foot stringers. The total design live load across the stair was 145 kips, equivalent to about 50 Honda Civics or twelve African bull elephants. The project sat in a high-seismic region.
The W27x94 stringer connection to the supporting wide-flange beam introduced a 30-kip axial load into a beam that was not originally designed for it. We added a note on our drawings telling the engineer of record that shear studs needed to be added to that beam to transfer the axial load into the slab. This is the type of coordination detailers are well positioned to catch.
Miscellaneous steel design pulls from at least four code bodies, and detailers should be able to recognize when each one applies:
The most common mistake we see is treating IBC and OSHA as interchangeable. They are not. A stair designed only to OSHA geometry will not satisfy IBC means-of-egress requirements, and a stair designed to IBC alone may not satisfy OSHA where workers are accessing equipment.
Stair design starts with selecting the right stringer for the geometry and the aesthetic. The common options are channel and miscellaneous channel (C and MC) shapes, HSS, plate, built-up sections, and wide-flange beams. The drivers behind that choice are strength, span, deflection, aesthetics, and how the infill attaches. Long spans usually push toward HSS or built-up sections; short, repetitive runs do well with MC channels. We covered this in more detail in our earlier article on steel stair types and design considerations.
Common tread and landing infill options include:
For loads, IBC stairways carry a 100 psf uniform live load plus a 300-lb concentrated load applied non-concurrently on a 4 in² area. The allowable stress increase that older codes once permitted for stair design was removed in the 2009 IBC, which detailers should know if they are working from older reference details.
Railing design splits cleanly along the IBC versus OSHA line:
Loading is where miscellaneous steel railings get interesting. Per the NAAMM Pipe Railing Systems Manual, a 200-lb concentrated load applied to a continuous railing system does not end up entirely at any one post. End posts on a two-span rail take roughly 85 percent of the load; intermediate posts on a three-or-more-span rail take about 60 percent. Designing every post for the full 200 lbs is conservative but often unnecessary, and it occasionally makes a connection look impossible when it is not.
A common detailing trap is mounting a 1.66-inch outside-diameter pipe post on the 1.5-inch flange of an MC12x10.6 stringer. The post is wider than the flange. Practical alternatives include switching to MC12x14.3, which has a 2.12-inch flange, or moving to an HSS12 stringer with a small gap to clear the radius.
Other recurring guardrail challenges to flag during detailing:
The takeaway: railing post connections are not a place to copy a typical detail. The connection load almost always governs, and good connection design is the difference between a railing that works in the field and one that bounces back as an RFI.
The first question to answer on any ladder is whether the access really wants a stair, a ships ladder, or a fixed ladder. Angle from horizontal makes the call. Stairs run roughly 30 to 45 degrees, ships ladders 50 to 70 degrees, and fixed ladders 75 to 90 degrees. Ships ladders require grab rails; standard fixed ladders require side rails and uniform rung spacing.
Geometry detailers should be familiar with on fixed ladders:
The biggest ladder-related rule change in recent years comes from 29 CFR 1910.28(b)(9). Fixed ladders installed on or after November 19, 2018, that climb more than 24 feet from the lower level must be equipped with a personal fall arrest system or ladder safety system. Cages alone no longer satisfy the requirement on new installations.
When a fall arrest system is added, the rungs that support the system need to be upsized, typically to 1-inch or 1-1/4-inch diameter, and the weld detail changes from a standard rung weld to a stronger configuration. The standard design load for a fall arrest system is 3,100 lbs ASD (5,000 lbs LRFD), and that load typically distributes across the two or three rungs nearest the support point. Detailers should not size every rung for the full fall arrest load by default. Coordinate with the engineer on which rungs carry the system.
Stairs are usually not part of the building's lateral system. They run between floors that move independently during a seismic event, which means a rigidly connected stair can either become an unintended brace or tear itself apart trying to resist that movement.
The standard solution is a slip connection at one end of the stringer, such as a slotted bolted connection or a stringer on bearing pads. The detail allows in-plane movement without engaging the stair as a brace. Coordination with the engineer of record on expected floor displacements is non-negotiable. A slot that is too short does not help anyone.
Free-standing stairs are a different category. They are designed as non-building structures because they do not share the building's lateral system at all.
A short list of the references our team uses regularly:
We design hundreds of stairs, railings, and ladders every year as part of our miscellaneous steel design and steel stair design practice. The volume and variety of that work, from straightforward egress stairs to monumental architectural pieces, is what shapes how we approach miscellaneous steel detailing. The patterns become clear when you have seen enough connections, geometries, and coordination items across enough projects. That experience is why we cover this territory carefully with our team and why we present on it at NASCC.
This article is the cornerstone of a series. We will be following up with separate deep dives on the monumental stair case study above, ladder design and the 24-foot fall-arrest threshold, and seismic detailing for stairs. If your next project includes miscellaneous steel design, we are ready to support you. Reach out to us. This is where we thrive.
