1 Scope
NOTE This specification covers the design coordination, materials, fabrication, finishing, and installation of shop-fabricated metal stairs and the handrail and guard systems that serve them. (1.1)
NOTE The work includes egress and convenience stairs constructed as steel pan stairs filled with concrete, formed steel plate stairs, and bar-grating-tread stairs, together with their stringers, treads, risers, landings, landing framing, and the hangers, struts, and brackets that support and connect the assembly to the building structure. (1.2)
NOTE It also includes the handrails and guards — pipe, tube, and picket systems of carbon steel, aluminum, and stainless steel — that protect the stair runs, landings, and adjacent floor openings, including their posts, infill, brackets, anchorage, and the by-reference coordination of glass infill panels. (1.3)
NOTE A metal stair is simultaneously a structural element governed by the building code's structural provisions and a means-of-egress element governed by the building code's life-safety provisions, and this standard keeps the two distinct so that neither is overlooked: a stair that is structurally adequate but has 8 in. risers, or a guard that carries its design load but admits a 5 in. sphere, is a defective stair regardless of its strength. (1.4)
1.5The stringers and landings shall be designed for load like any framing member, while the tread geometry, nosing, handrail height, and guard opening limitations are dictated by the means-of-egress chapter and are not subject to engineering discretion.
1.6The means-of-egress and structural requirements apply at the same time to the same assembly.
NOTE The governing documents are the International Building Code (IBC) for the structural loads (Chapter 16) and the means-of-egress geometry and protection (Chapter 10), ANSI/AISC 360 for the design of the steel members and connections, AWS D1.1/D1.1M for welding, and — where the project requires accessible routes — the accessibility provisions referenced by the code (ICC A117.1 and, for federal and many public projects, the ADA Standards for Accessible Design). (1.7)
NOTE The recommended fabrication and quality practices of the NAAMM/NOMMA metal stair and pipe railing manuals (AMP 510 and AMP 521) inform the workmanship requirements without being a substitute for the code. (1.8)
NOTE The boundary of the work is the stair assembly itself, its railings and guards, the connection hardware that joins it to the structure, and the field finishes applied to it. (1.9)
1.10The primary building frame to which the stair connects, and the connections of that frame, are governed by Structural Steel Framing. 1.12Glass infill panels shall be specified to Glazing and set into frames furnished under this standard. 1.13The concrete fill placed in steel pan treads and the cast-in anchorage of stair and railing supports shall be coordinated with Cast In Place Concrete. 1.14Shop-primed surfaces that receive a finish paint system in the field shall be coordinated with Interior Painting. 2 Referenced Standards
2.1Materials, design, fabrication, welding, finishing, and installation shall comply with the latest adopted edition of the following standards and codes.
| Standard |
Title |
| IBC |
International Building Code (locally adopted edition) — Chapter 10 (Means of Egress) and Chapter 16 (Structural Design) |
| ANSI/AISC 360 |
Specification for Structural Steel Buildings |
| ANSI/AISC 303 |
Code of Standard Practice for Steel Buildings and Bridges |
| AWS D1.1/D1.1M |
Structural Welding Code — Steel |
| AWS D1.2/D1.2M |
Structural Welding Code — Aluminum |
| AWS D1.6/D1.6M |
Structural Welding Code — Stainless Steel |
| ICC A117.1 |
Accessible and Usable Buildings and Facilities |
| ADA Standards |
ADA Standards for Accessible Design (where applicable) |
| NAAMM/NOMMA AMP 510 |
Metal Stairs Manual |
| NAAMM/NOMMA AMP 521 |
Pipe Railing Systems Manual Including Round Tube |
| ASTM A36/A36M |
Standard Specification for Carbon Structural Steel (plates, bars, angles) |
| ASTM A992/A992M |
Standard Specification for Structural Steel Shapes (wide-flange stringers and framing) |
| ASTM A1011/A1011M |
Standard Specification for Steel, Sheet and Strip, Hot-Rolled (formed stair pans and risers) |
| ASTM A1008/A1008M |
Standard Specification for Steel, Sheet, Cold-Rolled (formed pans and closures) |
| ASTM A53/A53M |
Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless (steel pipe railings) |
| ASTM A500/A500M |
Standard Specification for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing (steel tube railings and posts) |
| ASTM B221/B221M |
Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes (aluminum railings) |
| ASTM B241/B241M |
Standard Specification for Aluminum and Aluminum-Alloy Seamless Pipe and Seamless Extruded Tube (aluminum pipe railings) |
| ASTM A312/A312M |
Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes (stainless railings) |
| ASTM A554 |
Standard Specification for Welded Stainless Steel Mechanical Tubing (stainless tube railings) |
| ASTM A123/A123M |
Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products |
| ASTM A153/A153M |
Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware |
| ASTM A780/A780M |
Standard Practice for Repair of Damaged and Uncoated Areas of Hot-Dip Galvanized Coatings |
| ASTM F3125/F3125M |
High Strength Structural Bolts and Assemblies |
| ASTM A307 |
Standard Specification for Carbon Steel Bolts, Studs, and Threaded Rod (60 ksi) |
| SSPC / NACE |
Surface preparation standards for shop priming (SSPC-SP and abrasive-blast standards) |
| AISC Design Guide 11 |
Vibrations of Steel-Framed Structural Systems Due to Human Activity (serviceability reference) |
2.2Where the contract documents, the adopted building code, a referenced standard, or the delegated design conflict, the more stringent requirement shall govern unless the Structural Engineer of Record (SER) or the Architect directs otherwise in writing.
3 Submittals
3.1 Action Submittals
3.1.1The Contractor shall submit the following for review before fabrication begins:
- Shop drawings (stair geometry, framing, connections, railings, embeds)
- Delegated-design structural calculations (PE-sealed)
- Tabulated support reactions for SER coordination
- Product data — pipe/tube/bar/plate/grating
- Product data — abrasive and photoluminescent nosings
- Product data — primer and galvanizing
- Welding procedure specifications (WPS) and welder qualifications
- Finish samples (railing finish, nosing, ground weld sample)
- Glass infill panel data (coordinated with glazing standard)
☐ Shop drawings (stair geometry, framing, connections, railings, embeds)
☐ Delegated-design structural calculations (PE-sealed)
☐ Tabulated support reactions for SER coordination
☐ Product data — pipe/tube/bar/plate/grating
☐ Product data — abrasive and photoluminescent nosings
☐ Product data — primer and galvanizing
☐ Welding procedure specifications (WPS) and welder qualifications
☐ Finish samples (railing finish, nosing, ground weld sample)
☐ Glass infill panel data (coordinated with glazing standard)
3.1.2No stair or railing element shall be fabricated until the corresponding submittals have been reviewed and returned.
3.1.3Submittals shall be internally coordinated and shall be coordinated with the structure to which the work connects, established under Structural Steel Framing, so that support reactions, embed locations, and edge conditions are consistent with the approved frame. 3.2 Shop Drawings
3.2.1Shop drawings shall show each stair and railing in plan, elevation, and section at a scale sufficient to detail the work.
3.2.2Shop drawings shall show the layout of stringers, treads, risers, landings, and supporting framing; the tread and riser dimensions and the nosing profile; all welds with AWS weld symbols, weld sizes, and joint geometry; all bolted and field connections; the type, size, location, and orientation of every embed, anchor, hanger, and bracket; the railing post spacing, infill layout, and bracket and base details; the expansion and isolation provisions; and the finish on each surface.
3.2.3Where the work connects to concrete, the shop drawings shall show the cast-in anchorage to be furnished under Cast In Place Concrete. 3.3 Structural Design Calculations
3.3.1Where design of the stair, its framing, its connections, or the railings is delegated to the fabricator, signed and sealed calculations shall be submitted, prepared by a professional engineer licensed in the jurisdiction of the project.
3.3.2Calculations shall demonstrate compliance with the IBC stair live load and concentrated load, the deflection limits, the handrail and guard concentrated, uniform, and infill loads, and — where stipulated — the vibration serviceability criterion.
3.3.3The reactions delivered to the supporting structure shall be tabulated for the SER's coordination.
3.4 Product Data and Samples
3.4.1Product data shall be submitted for pipe, tube, bar, plate, grating, nosings, primers, and galvanizing.
3.4.2Where the appearance of exposed railings or stairs is a specified deliverable, samples shall be submitted: a sample of each abrasive or photoluminescent nosing, a sample of each railing finish, and a representative welded and ground railing corner where exposed welds are to be ground smooth.
3.4.3Glass infill panels shall be submitted to and coordinated with Glazing. 3.5.1The Contractor shall submit the following informational submittals:
- Welding procedure specifications (WPS) and welder/operator qualification records under AWS D1.1 for steel, AWS D1.2 for aluminum, and AWS D1.6 for stainless steel, for the processes and positions used
- Mill certifications for structural steel, pipe, tube, and bar
- The fabricator's and erector's quality-control procedures and relevant experience
☐ Welding procedure specifications (WPS) and welder/operator qualification records (AWS D1.1/D1.2/D1.6)
☐ Mill certifications for structural steel, pipe, tube, and bar
☐ Fabricator and erector quality-control procedures and experience
3.6 Closeout Submittals
3.6.1The Contractor shall provide the following at project closeout:
- As-built records noting any field-authorized connection or dimensional modifications
- Galvanizing certificates and shop-priming records, including surface preparation and dry film thickness
- Touch-up and field-finish records
- Operation and maintenance data for any specified coatings and warranty documentation
☐ As-built records of field-authorized modifications
☐ Galvanizing certificates and shop-priming records (surface prep, DFT)
☐ Touch-up and field-finish records
☐ Coating O&M data and warranty documentation
4 Quality Assurance
4.1 Fabricator and Erector Qualifications
4.1.1The stair and railing fabricator shall be a firm regularly engaged in the fabrication of architectural and structural metal stairs and railings of comparable type and scale, with welders qualified for the work.
4.1.2The erector shall be experienced in setting metal stairs and anchoring railings to the building structure.
4.1.3Where the stair is part of the structural framing certification scope, the fabricator and erector qualifications established in Structural Steel Framing apply. 4.2 Welder Qualification
☐ AWS D1.1 (carbon and low-alloy steel)
☐ AWS D1.2 (aluminum) — where aluminum railings are welded
☐ AWS D1.6 (stainless steel) — where stainless railings are welded
4.2.1Welders and welding operators shall be qualified under AWS D1.1 for steel, AWS D1.2 for aluminum, and AWS D1.6 for stainless steel, for the processes, positions, and base-metal groups they will weld.
4.2.2Aluminum and stainless welding shall be performed only by welders qualified on those materials; carbon-steel qualification does not extend to aluminum or stainless.
NOTE Welding dissimilar metals or welding aluminum with steel-contaminated consumables produces defective, corrosion-prone welds. (4.2.3)
4.3 Mockup
4.3.1Where the contract documents require it, a representative full-height railing assembly or a single stair run mockup shall be erected and reviewed before fabrication of the remaining work, to establish the standard of fit, weld appearance, finish, and dimensional conformance.
4.3.2The accepted mockup shall be retained for comparison and may be incorporated into the work if it conforms.
4.4 Pre-Installation Conference
4.4.1A pre-installation conference shall be held before the first stair is set, attended by the Contractor, the fabricator, the erector, and the parties responsible for the supporting structure and the concrete fill.
4.4.2The conference agenda shall cover the support conditions and embed verification, the erection sequence and temporary support, the welding and bolting at connections, the concrete pan-fill placement and curing, the railing anchorage, and the protection of finished surfaces.
5 Environmental and Service Conditions
5.1 Service Environment and Corrosion
NOTE The service environment determines the steel finish and railing material. (5.1.1)
Interior, dry, conditioned, finished space — shop-primed steel, field-painted
Interior, unfinished/service space — shop-primed steel
Exterior or wet/humid interior — hot-dip galvanized steel
Corrosive, coastal, or pool environment — galvanized, aluminum, or stainless
5.1.2Interior, dry, conditioned stairs in finished spaces may use shop-primed carbon steel that receives a field paint finish under Interior Painting. 5.1.3Stairs and railings in unconditioned, wet, exterior, or corrosive locations — exterior egress stairs, parking structures, plant and process areas, and pool or coastal environments — shall be hot-dip galvanized, or aluminum or stainless steel construction.
NOTE A shop-primed-and-painted carbon-steel stair in a wet environment will corrode at every weld, edge, and connection that the paint film cannot durably protect. (5.1.4)
5.2 Accessibility
○ IBC means-of-egress handrails only (not an accessible route)
○ IBC plus ICC A117.1 accessible handrails
○ IBC plus ICC A117.1 and ADA Standards (federal/public accommodation)
5.2.1Where the stair is on an accessible route or otherwise subject to accessibility requirements, the handrail geometry, extensions, and graspability shall comply with ICC A117.1 and, where applicable, the ADA Standards.
5.2.2Where both the IBC and the accessible-handrail provisions apply, the more restrictive provision shall govern.
NOTE Accessible handrail provisions are more restrictive than the base IBC handrail provisions in several respects: continuous graspable profile, extensions at the top and bottom of runs, and clearance to the wall. (5.2.3)
6 Structural Design
6.1 Design Responsibility
NOTE The stair and railing structural design is commonly delegated to the fabricator's engineer, who designs the members, connections, and railings for the loads and reactions and seals the calculations, while the SER coordinates the support points and reactions into the building structure. (6.1.1)
○ Delegated to fabricator's engineer (loads and reactions shown; PE-sealed)
○ Fully detailed by the Structural Engineer of Record
6.1.2The contract documents shall state, for the stairs and railings, whether the design is fully detailed by the SER or delegated, consistent with the design-responsibility provisions of ANSI/AISC 303.
6.1.3Where delegated, the design forces, the support locations, and any geometric constraints shall be shown so the delegated design is bounded.
○ 100 psf (IBC stairs and exit facilities)
6.2.1Stairs and their supporting framing shall be designed for the IBC uniform live load on stairs and exit facilities of 100 psf applied to the walking and landing surfaces.
NOTE The uniform load governs the design of the stringers, landing beams, hangers, and supporting framing that carry the accumulated load of a crowd on the stair. (6.2.2)
6.3 Concentrated Load
○ 300 lb on 4 in² (IBC, non-concurrent with uniform load)
6.3.1Each tread and each landing shall additionally be designed for the IBC concentrated load of 300 lb applied on an area of 4 in² at the location producing the maximum effect.
6.3.2The concentrated load need not be applied concurrently with the uniform load.
NOTE The concentrated load governs the design of an individual tread and the local design of the walking surface, where a single heavy footfall or a point load controls rather than the distributed crowd load. (6.3.3)
6.4 Deflection Limits
L/360 (standard)
L/480 (reduced deflection / monumental stairs)
6.4.1Stringers, treads, and landing framing shall satisfy the deflection limits of the IBC and AISC 360.
6.4.2Live-load deflection of stringers and landing framing shall not exceed L/360, and total-load deflection shall not exceed L/240, unless the contract documents impose a tighter limit.
6.4.3Treads shall be designed so that the deflection under the concentrated load does not produce a perceptible springiness.
NOTE Excessive tread deflection is a serviceability and perceived-safety defect even where the strength is adequate. (6.4.4)
6.5 Vibration Serviceability
○ Not required (concrete-filled pan stair on stiff supports)
○ Required — target minimum fundamental frequency per AISC Design Guide 11
○ Required — peak acceleration limit per project criteria
6.5.1Where the contract documents stipulate it, or where the configuration warrants, the stair shall be evaluated for walking-induced vibration, with a target fundamental frequency or acceleration limit consistent with AISC Design Guide 11.
NOTE Slender, long-span, or lightly framed stairs — particularly steel stairs without concrete-filled pans and stairs with intermediate landings hung from above — can be perceptibly springy or can resonate under the rhythmic loading of descending foot traffic, even when they satisfy strength and static-deflection limits. (6.5.2)
NOTE Concrete-filled pan treads and stiff stringer-to-structure connections raise the natural frequency and damping and are the most effective means of controlling stair vibration. (6.5.3)
7 Stair Geometry and Means of Egress
7.1 Riser Height and Tread Depth
○ 7 in. (IBC means-of-egress maximum)
○ Less than 7 in. as required by run geometry
○ 11 in. (IBC means-of-egress minimum)
○ Greater than 11 in. as required by run geometry
7.1.1Stair risers and treads shall conform to the means-of-egress provisions of the IBC.
7.1.2For stairways serving an occupant load and not within an individual dwelling unit, the maximum riser height shall be 7 in. and the minimum tread depth shall be 11 in.
7.1.3Risers within a flight shall be of uniform height and treads of uniform depth; the tolerance between the largest and smallest riser, and between the largest and smallest tread, within a flight shall not exceed 3/8 in.
NOTE Nonuniform risers are a leading cause of stair falls because a user's gait adapts to the rhythm of the first few steps and a single odd riser is not anticipated. (7.1.4)
7.2 Stair Width
7.2.1The clear width of the stair between handrails, and the required width based on occupant load and the egress-capacity factor, shall be as indicated on the egress plans. 7.2.2Handrail and stringer projections into the required width shall be within the limits the IBC permits.
7.3 Nosing Projection and Profile
○ Solid (closed) risers — required for accessible routes and most egress
○ Open risers (where permitted; no 4 in. sphere passage)
7.3.1Where solid risers are provided, the nosing projection beyond the riser below shall not exceed 1-1/4 in.
7.3.3The nosing projection shall be uniform throughout the flight.
7.3.4Open risers, where permitted, shall not allow passage of a 4 in. sphere.
7.4 Slip Resistance and Nosing Marking
Cast-metal abrasive nosing (aluminum/iron carrier with abrasive fill) — cast into concrete-filled pan
Extruded aluminum abrasive nosing with abrasive insert
Checkered/raised-pattern integral nosing (formed plate or grating treads)
Photoluminescent abrasive nosing (egress-path marking applications)
○ Not required (occupancy/height below IBC luminous-marking threshold)
○ Required — photoluminescent or listed luminous marking at nosings, handrails, and obstacles
7.4.1The walking surface of treads and landings shall be slip-resistant.
7.4.2Each tread shall have a visually contrasting, slip-resistant nosing strip; the nosing shall be marked or finished so its leading edge is distinguishable from the rest of the tread, as the IBC requires for the marking of the leading edge.
7.4.3In interior exit stairways and ramps serving as a required egress path, the markings, handrails, and obstacles shall be identified with the luminous or photoluminescent egress-path marking the IBC requires where applicable.
7.4.4Abrasive nosings shall be cast or filled with an aggregate that provides durable slip resistance and shall not depend on a surface coating that wears off under traffic.
8 Stair Types and Construction
8.1 Stair Type Selection
NOTE The stair type determines the tread construction, the finish, and the appropriate environment. (8.1.1)
Steel pan stair, concrete-filled treads and risers (standard interior egress)
Steel pan stair, concrete-filled treads with steel risers
Formed steel plate stair (service/architectural)
Bar-grating-tread stair (exterior/industrial)
NOTE A steel pan stair has formed steel pans for treads (and usually risers) that are filled with concrete in the field to form the finished walking surface; it is the standard for interior commercial egress stairs because the concrete fill provides mass, slip resistance, vibration damping, and a durable surface, and because the finish floor (resilient, terrazzo, or tile) can be carried onto the tread. (8.1.2)
NOTE A formed steel plate stair uses bent and welded plate treads, often with a raised pattern or applied nosing, and suits service stairs and exposed-metal architectural stairs. (8.1.3)
NOTE A bar-grating-tread stair uses welded or pressure-locked bar grating treads and suits exterior, industrial, and wet environments where drainage and an open surface are wanted. (8.1.4)
8.2 Stringers
Steel channel stringers (service and most egress stairs)
Steel plate stringers (exposed/architectural)
Wide-flange stringers (long spans / heavy loads)
8.2.1Stringers shall be steel channels, plates, or wide-flange sections sized for the design loads and deflection limits, with the tread and riser pans or treads welded or bolted to the stringers.
NOTE Exposed-stringer (architectural) stairs typically use plate stringers with concealed tread connections; service stairs typically use channel stringers with tread support clips or welded pans. (8.2.2)
8.2.3Stringer-to-structure connections shall transfer the stair reactions to the supporting framing or to cast-in embeds without relying on the concrete fill for support.
8.3 Pan Treads and Risers
16 ga (light service, short span)
14 ga (standard commercial egress pan)
12 ga (heavy load / longer span)
1.53
1.522.53
Default: 2 in.
8.3.1For steel pan stairs, the tread and riser pans shall be formed from steel sheet of a gauge adequate to support the wet concrete and the design loads without permanent deformation, with the pan formed to retain the concrete fill and to engage the nosing.
8.3.2The pan shall be detailed to the required fill depth so that the finished tread surface aligns with the nosing and produces the uniform riser and tread dimensions specified above.
8.3.3Light-gauge pans that deflect under the wet concrete produce uneven treads and a wavy finished surface and shall not be used; the pan gauge shall be coordinated with the fill depth and the span between stringers.
8.3.4The concrete fill for pan treads shall be placed, finished, and cured under Cast In Place Concrete after the stair is set and the pans are stable. 8.3.5The nosing shall be set and aligned before the fill is placed so that the abrasive leading edge is at the finished surface.
NOTE The fill mix, reinforcement (where required), and surface finish are coordinated with
Cast In Place Concrete.
(8.3.6) 8.4.1For formed steel plate stairs, treads shall be bent or welded from plate of adequate thickness to carry the concentrated load without perceptible deflection, with a raised pattern (checkered or treadplate) or an applied abrasive nosing for slip resistance.
8.4.2Plate treads shall be welded or bolted to the stringers and shall be detailed to drain where exposed to moisture.
8.5 Grating Treads
○ Welded bar grating with serrated/abrasive nosing
○ Swage-locked bar grating with abrasive nosing
○ Pressure-locked (dovetail) bar grating
8.5.1For bar-grating-tread stairs, treads shall be welded, swage-locked, or pressure-locked bar grating with an integral nosing (serrated or abrasive) and end carrier plates for connection to the stringers.
8.5.2Grating bar depth and spacing shall be selected for the span and the design load.
8.5.3Grating treads shall comply with the open-riser sphere limitation where they serve as means of egress, and the grating opening dimension shall be coordinated with any accessibility requirement, since wide grating openings can catch a cane tip or heel.
8.6 Landings
8.6.1Landings shall be constructed of the same tread type as the stair (concrete-filled pan, plate, or grating) on landing framing designed for the uniform and concentrated loads and the deflection limits.
8.6.2Landing framing shall connect to the building structure or to cast-in embeds and shall not transfer load through the railing or through the concrete fill.
8.6.3Intermediate landings hung from the structure above shall be designed and detailed so that the hangers carry the load and the connections control sway and vibration.
9 Handrails and Guards
9.1 Distinction Between Handrail and Guard
NOTE A handrail is the graspable rail provided for support along a stair or ramp, set at the height the means-of-egress provisions require. (9.1.1)
NOTE A guard (guardrail) is the barrier provided at the open side of a walking surface, stair, landing, or floor opening to prevent a fall, and it has its own height and opening-limitation requirements. (9.1.2)
NOTE The two functions are distinct and frequently combined in one assembly — a stair guard with a graspable top or intermediate handrail — but each requirement applies independently: a 42 in. guard that has no graspable handrail at the right height does not satisfy the handrail requirement, and a graspable handrail that does not also meet the guard opening limitation at an open side does not satisfy the guard requirement. (9.1.3)
9.2 Handrail Height
3438
343638
Default: 34 in.
9.2.1Handrails shall be mounted so the top of the gripping surface is 34 in. to 38 in. measured vertically above the leading edge of the tread nosings and above the finished landing surface.
9.2.2Where two handrails are provided or where a guard also serves as a handrail, each handrail shall be within this range.
NOTE Handrail height is measured to the top of the graspable surface, not to the top of a guard above it. (9.2.3)
9.3 Handrail Graspability and Extensions
Round, 1-1/4 in. to 2 in. outside diameter (Type I graspable)
Non-circular, perimeter and dimension per IBC/A117.1 (Type I)
Type II graspable profile per IBC (where permitted)
○ Top and bottom extensions per ICC A117.1 / ADA (accessible route)
○ Extensions/terminations per IBC means-of-egress only
9.3.1Handrails shall provide a continuous graspable gripping surface along the full length of each stair flight and ramp run, free of obstruction by newels, fittings, or brackets that would interrupt the grip.
9.3.2The graspable profile (a circular cross-section of the required diameter, or a non-circular profile within the required perimeter and dimension) shall comply with the IBC and, where applicable, ICC A117.1.
9.3.3Where the route is accessible, handrails shall extend horizontally and then continue or turn at the top and bottom of each run by the distance ICC A117.1 and the ADA Standards require.
NOTE The extension gives a user something to hold while completing the transition off the stair. (9.3.4)
9.4 Guard Height
○ 42 in. minimum (IBC standard)
○ Greater than 42 in. (architectural / fall-protection requirement)
9.4.1Guards shall be not less than 42 in. high, measured vertically from the leading edge of the tread nosings or from the adjacent walking/landing surface to the top of the guard, except where the IBC permits a reduced height for specific conditions (such as the guard height at the open side of a stair measured to the handrail).
9.4.2Guards shall be provided at every open-sided walking surface, stair, ramp, and landing located more than 30 in. above the surface below, and at the perimeter of floor openings, as the IBC requires.
9.5 Guard Opening Limitations
○ 4 in. sphere maximum (public/standard occupancies)
○ Larger opening per IBC for restricted industrial occupancies (not public)
9.5.1Required guards shall be constructed so that the open spaces between intermediate rails, balusters, pickets, or other infill do not allow passage of a 4 in. diameter sphere up to the height the IBC specifies, with the more permissive limits the code allows at the triangular opening below the bottom rail at a stair and (in some occupancies) above a defined height.
9.5.2The 4 in. sphere limitation shall be verified on the shop drawings for every guard configuration, because it governs the picket spacing, the cable spacing, and the infill panel layout.
9.5.3Guards in certain industrial occupancies not accessible to the public may use the larger opening the code permits for those occupancies.
NOTE The 4 in. sphere limitation is a child-safety provision. (9.5.4)
9.6 Guard and Handrail Structural Loads
○ 200 lb in any direction at any point (IBC)
○ 50 plf in any direction (IBC; not concurrent with the 200 lb load)
○ 50 lb on 1 ft² horizontal (IBC infill load)
9.6.1Handrails and guards shall be designed for the structural loads of the IBC.
9.6.2The top rail of a handrail or guard shall resist a concentrated load of 200 lb applied in any direction at any point along the top, and a uniform load of 50 plf applied in any direction along the top; the two need not act concurrently.
9.6.3Guard infill components — balusters, pickets, panel fillers, and intermediate rails other than the top rail — shall resist a horizontal concentrated load of 50 lb applied on an area of 1 ft².
9.6.4The post spacing shall be set so that both the 200 lb concentrated load and the 50 plf uniform load are satisfied with the selected rail and post sizes.
NOTE The 200 lb concentrated load almost always governs the post and base-anchorage design, while the 50 plf uniform load can govern the top rail between posts. (9.6.5)
9.7 Railing Material
Carbon steel pipe (ASTM A53), galvanized — exterior/wet
Carbon steel pipe (ASTM A53), shop-primed and field-painted — interior
Carbon steel tube (ASTM A500), shop-primed and field-painted
Aluminum pipe/tube (6063/6061) — exterior, low maintenance
Stainless steel, Type 304 — interior architectural
Stainless steel, Type 316 — coastal/corrosive
1-1/4 in. NPS (1.660 in. OD) — handrail standard
1-1/2 in. NPS (1.900 in. OD) — handrail/posts
2 in. NPS (2.375 in. OD) — posts and top rails, heavy duty
9.7.1Railings shall be carbon steel pipe or tube (galvanized or shop-primed and painted), aluminum pipe or tube, or stainless steel pipe or tube, selected for the service environment and appearance.
9.7.2Steel pipe shall conform to ASTM A53 and steel tube to ASTM A500; aluminum to ASTM B221/B241 (typically 6063 or 6061 alloy); stainless to ASTM A312/A554 (typically Type 304 interior, Type 316 corrosive or coastal).
9.7.3Dissimilar metals in contact — aluminum railings on steel embeds, stainless fasteners in aluminum — shall be isolated to prevent galvanic corrosion.
9.8 Railing Infill Type
Vertical pickets at 4 in. maximum clear spacing
Horizontal intermediate rails (where occupancy permits; ladder-effect restrictions apply)
Perforated or mesh panel infill
Tensioned cable infill (spacing to satisfy 4 in. sphere under load)
Glass infill panels (coordinated with glazing standard)
9.8.1Horizontal rail infill shall be used only where the occupancy permits, because it creates a climbable ladder effect and is restricted or prohibited in occupancies where children are present.
9.8.2Tensioned cable infill shall be spaced and tensioned so that the opening does not exceed the 4 in. sphere limit under the design infill load.
9.8.3Glass infill panels shall be specified to Glazing — laminated or laminated-tempered safety glass of the required type and thickness, set into frames or fittings furnished under this standard, with the guard load resisted by the glass and its supports as the glazing standard and the IBC require. NOTE Cable deflects under a pushing load, and an under-tensioned cable can open beyond the limit. (9.8.4)
9.9 Railing Anchorage
Cast-in inserts / sleeves (coordinate with concrete standard)
Core-drilled and non-shrink-grouted posts
Adhesive (epoxy) anchors of rated capacity
Surface base plate with expansion anchors
9.9.1Railing posts and brackets shall be anchored to the stair, landing, or building structure to develop the design loads with the required factor of safety.
9.9.2Anchorage to concrete shall be by cast-in inserts, expansion or adhesive anchors of the rated capacity, or core-drilled and grouted posts, coordinated with Cast In Place Concrete; anchorage to steel shall be welded or bolted. 9.9.3Wall-mounted handrail brackets shall be anchored to blocking or to the structure, not to the gypsum board alone, because the 200 lb concentrated load will pull a bracket out of unblocked board.
9.9.4The anchorage shall be detailed and, where required, tested for the load.
NOTE Base plates and core-drilled connections are the most common points of railing failure. (9.9.5)
10 Fabrication
10.1 Shop Fabrication and Welding
○ Ground smooth and dressed flush (exposed architectural railings/stairs)
○ Welds left as-deposited, cleaned (service stairs / concealed)
10.1.1Stairs and railings shall be fabricated in the shop to the maximum extent practical, with field connections held to the minimum needed for handling and erection.
10.1.2Welds shall be made under qualified WPS by qualified welders, continuous where exposed to weather or moisture, and of the size and type shown.
10.1.3Exposed welds on architectural railings and stairs shall be ground smooth and dressed flush to a uniform finish where the contract documents require, and the grinding shall not reduce the section below the design throat.
10.1.4Joints shall be coped, mitered, and fitted so that members align and the assembly is true to line and plane.
10.2 Bolted Connections
10.2.1Bolted field connections shall use fasteners of the specified grade — ASTM F3125 high-strength bolts where the connection is structural, or ASTM A307 where the connection is not slip- or fatigue-critical — protected against corrosion to match the assembly.
10.2.2Connections shall be detailed so that fasteners are accessible for installation and inspection and are concealed on exposed architectural work where the design requires.
11 Finishes
11.1 Galvanizing
○ Zinc-rich coating per ASTM A780 (standard field repair)
○ Thermal-sprayed (metallized) zinc per ASTM A780 (severe exposure)
11.1.1Steel stairs and railings in exterior, wet, or corrosive service shall be hot-dip galvanized after fabrication in accordance with ASTM A123 for assemblies and shapes and ASTM A153 for hardware and fasteners.
11.1.2Members shall be detailed for galvanizing with vent and drain holes at closed sections so that the molten zinc fills and drains and trapped gas does not cause an explosion or an unfilled cavity in the kettle.
11.1.3Field welds, field-cut edges, and abraded areas in galvanized work shall be repaired in accordance with ASTM A780 using a zinc-rich coating or a thermal-sprayed zinc repair to restore the coating thickness.
NOTE A galvanized stair welded in the field and not repaired will corrode at every field weld. (11.1.4)
11.2 Shop Priming
SSPC-SP 3 power tool cleaning (interior, mild exposure)
SSPC-SP 6 commercial blast cleaning (standard for exposed/painted)
SSPC-SP 10 near-white blast cleaning (severe service / high-performance coating)
11.2.1Steel that will receive a field paint finish shall be cleaned to the specified SSPC surface-preparation standard and shop-primed with a primer compatible with the finish coats to be applied under Interior Painting. 11.2.2Surfaces to be field-welded shall be left unprimed within the weld zone, and surfaces to be embedded in concrete (pan interiors receiving the concrete fill) shall be left unprimed or shall receive only a coating compatible with concrete bond.
11.2.3The shop primer shall not be applied to galvanized surfaces without the surface preparation a paint-over-galvanizing system requires.
11.3 Aluminum and Stainless Finishes
Not applicable — railing is not aluminum
Clear anodized (AA-M12C22A41)
Color anodized
Powder coat / organic finish
Mill finish (service/concealed)
11.3.1Aluminum railings shall receive the specified finish — mill, clear or color anodized, or a powder-coat or organic finish — and aluminum in contact with concrete, masonry, or dissimilar metal shall be isolated with a protective coating or barrier to prevent galvanic and alkaline attack.
11.3.2Stainless steel railings shall receive the specified surface finish (brushed, satin, or polished) applied uniformly, and shall be passivated and kept free of carbon-steel contamination from grinding or handling that would cause rust staining.
12 Installation
12.1 Survey and Coordination
12.1.1Before erection, the installer shall verify the supporting structure, embed locations, opening dimensions, and floor-to-floor heights against the shop drawings, and shall reconcile any out-of-tolerance condition with the SER before fabricating field-fit pieces.
NOTE Floor-to-floor height controls the riser count and dimension; an unverified height that differs from the drawings produces nonuniform risers at the top or bottom of the run, which is the most common stair field error. (12.1.2)
12.2 Setting and Connection
12.2.1Stairs shall be set in the sequence shown, supported and braced until their permanent connections to the structure are complete, and shall not be released from rigging until stable on their connections.
12.2.2Stringer-to-structure connections shall be completed before the stair carries construction traffic, and the concrete pan fill shall be placed only after the stair is permanently connected and the pans are supported.
12.2.3Railings shall be set plumb, true to line, and at the specified heights, with posts anchored as detailed before any infill load is applied.
12.3 Tolerances
12.3.1Erected stairs and railings shall be set within commercial fabrication and erection tolerances: variation from plumb, level, and line shall not be conspicuous, riser and tread dimensions shall be held within the 3/8 in. uniformity limit, and handrail and guard heights shall be within the code range at every point.
12.3.2Adjacent railing segments shall align in height and face so that a continuous run reads as a single line.
12.4 Protection
12.4.1Finished stairs and railings shall be protected from construction damage, weld spatter, mortar, and staining.
12.4.2Galvanized and finished metal shall be protected from contact with wet concrete and dissimilar-metal runoff.
12.4.3Treads shall be protected from construction traffic until the building is ready for occupancy, and the field paint or finish shall be applied or touched up after the protection is removed and the surface is cleaned.
13 Testing and Inspection
13.1 Welding Inspection
13.1.1Welds shall be visually inspected for size, profile, fusion, and freedom from cracks and undercut.
13.1.2Structural welds at stringer-to-structure connections and at landing framing, and any weld the contract documents or the building code designate for special inspection, shall be inspected as the IBC special-inspection provisions require.
13.1.3Field welds in galvanized work shall be inspected and the coating repaired before the connection is concealed or exposed to weather.
13.2 Railing Load Verification
○ Not required (anchorage designed and detailed; visual verification only)
○ Required — apply 200 lb design load to a representative sample of posts and rails
13.2.1Where the contract documents require it, completed guards and handrails shall be field-tested by applying the design concentrated load and confirming that the assembly resists the load without permanent deformation or anchorage failure.
NOTE Anchorage to existing or field-poured concrete is the most common failure point and is the anchorage most worth verifying by test. (13.2.2)
14 Warranty
1 year from substantial completion
2 years from substantial completion
14.1The Contractor shall warrant the metal stair and railing work against defects in materials and workmanship — including weld failure, connection or anchorage failure, coating failure, nonuniform or out-of-tolerance treads and risers, perceptible vibration or springiness beyond the specified criterion, and corrosion of inadequately protected steel — for a period of not less than one year from substantial completion, or for the period stated in the contract documents if longer.
14.2Anodized, powder-coat, and other applied finishes shall carry the finish manufacturer's standard warranty against fading, chalking, and adhesion failure, passed through to the Owner.
14.3The warranty shall not limit the right to require correction of nonconforming life-safety conditions — handrail or guard height, guard opening, or nosing — discovered at any time.