MPS Master
SECTION 05 51 00
METAL STAIRS
PART 1 – GENERAL
1.01 SUMMARY
A. This Section includes Specifications for steel stairs with poured-in-place concrete pan
treads and landings; structural steel stair framing and supports; steel pan landings to
receive concrete fill; and specifies engineering design of fabricated stairs and
components.
1.02 SYSTEM DESCRIPTION
A. Design and fabricate stair system from steel or aluminum to support a uniform live load of
100 pounds per square foot (lb/sq ft) and a concentrated load of 300 pounds (lb.)
Deflection of treads, stringers or landing framing shall not exceed 1/360 of span under
design live loading.
B. Stair systems shall include stairs, landings, handrails, guardrails, nosings, floor edge
channels or angle, and all supports and anchors to adjacent construction. Handrails as
indicated on Drawings. Where handrails are attached to walls, include metal backing
within walls.
C. Design, fabricate, and test railing assemblies in accordance with the most stringent
requirements of ASTM E985 and applicable local code.
D. Design details indicated may be modified by the fabricator subject to the specified
requirements.
E. Fabricate metal stairs to comply with NAAMM AMP 510, Class: Architectural.
F. Floor construction, as indicated on the Contract Drawings, includes bearing capacity to
support steel stairs and design live loading, except for slab edge supports which are to be
provided under the work of this Section. Stair system shall accommodate the
surrounding construction indicated. All modifications to structure as required to support
or otherwise accommodate the design/build stairs shall be the responsibility of the
Contractor. Changes in dimension or location of finish surfaces indicated are subject to
prior approval by Resident Engineer.
G. Railing Reactions:
1. Railing attachments shall be capable of resisting a force of 200 lbs at all points in
any direction without damage or permanent set.
2. Railing attachments shall be capable of resisting a force of 50 lbs per lineal foot
in any direction without damage or permanent set.
H. Interior stair treads, nosings, and landing surfaces shall be concrete-filled steel pans or
shop-cast concrete treads as indicated and detailed on Contract Drawings. Risers shall
have closed design as detailed. Exterior treads and landings shall be concrete as
detailed or indicated on Contract Drawings
I. Regulatory Requirements:
1. Pre-engineered Metal Stairs shall meet the requirements of the Minnesota Building
Code for service stairs.
2. Furnish all calculations, engineer's stamps, drawings, and other items required
by the code authorities to obtain approval of the installation.
1.03 SUBMITTALS
A. Procedures: Section 01 33 00, Submittal.
B. Shop Drawings: Indicate profiles, sizes, connection attachments, reinforcing, anchorage,
size and type of fasteners, and accessories.
1. Indicate welded connections using standard AWS A2.4 welding symbols.
Indicate net weld lengths.
2. Shop drawings for bidder-designed elements shall include stamp or seal of a
Professional Engineer registered in the State of Minnesota on each sheet of the
shop drawings.
C. Delegated Design Data:
D. Certifications:
1. Welders and welding procedures: Submit certifications as required.
E. Closeout Submittal:
1. Submit certification by the registered Professional Engineer responsible for this
work that all products and all installations for bidder-engineered metal stair items
comply with all design requirements.
1.04 QUALITY ASSURANCE
A. Structural Designer Qualifications: Professional Structural Engineer experienced in
design of this work and licensed in the State of Minnesota, or personnel under direct
supervision of such an engineer.
B. See Section 05 xx xx Metals for requirements for welders, weldingprocedures, and inspections.
C. Testing and Inspection: All metal fabrications are subject to special inspection as
specified in Section 01 xx xxGeneral Requirements.
D. Regulatory Requirements:
1. Design structural elements to meet all requirements of the Minnesota Building Code.
2. Furnish all calculations, engineer's stamps, drawings, and other items required
by the code authorities to obtain approval of installations.
PART 2 – PRODUCTS
2.01 MANUFACTURERS
A. Metal Stair and Stair Tower Fabricators:
1. The Sharon Companies Ltd. (Medina OH; 330-723-3225).
2. American Stair Corporation (Romeoville, IL; 800-872-7824).
3. O’Keeffe’s, Inc. (San Francisco, CA; 415-822-4222).
4. Substitutions: See Section 01 60 00, Product Requirements.
2.02 DESIGN-BUILD METAL STAIRS - GENERAL
A. Metal Stairs: Provide stairs of the design specified, complete with landing platforms,
vertical and horizontal supports, railings, and guards, fabricated accurately for anchorage
to each other and to building structure.
1. Regulatory Requirements: Provide stairs complying with the most stringent
requirements of local, State, and federal regulations; where requirements of the
contract documents exceed those of regulations, comply with the Contract
Documents.
2. Structural Design: Provide complete stair assemblies complying with the
following:
a. Stair Capacity: Uniform live load of 100 lb/sq ft and a concentrated load
of 300 lb with deflection of stringer or landing framing not to exceed
1/360 of span for live loads.
b. Seismic importance factor for stairs is 1.25.
3. Dimensions: As indicated on Contract Drawings.
4. Shop-assemble components; disassemble into largest practical sections suitable
for transport and access to site.
5. No sharp or rough areas on exposed travel surfaces and surfaces accessible to
touch.
6. Separate dissimilar metals using paint or permanent tape.
B. Metal Jointing and Finish Quality Levels:
1. Architectural: All joints as inconspicuous as possible, whether welded or
mechanical.
a. Welded Joints: Continuously welded and ground smooth and flush.
b. Mechanical Joints: Butted tight, flush, and hairline; concealed fastenings
only.
c. Exposed Edges and Corners: Eased to small uniform radius.
d. Metal Surfaces to be Painted: Sanded or ground smooth, suitable for
highest quality gloss finish.
2. Service: Exposed joints tight with face surfaces aligned; underside of stair not
covered by soffit is not considered exposed to view.
a. Welded Joints: Welded on back side wherever possible.
b. Welds Exposed to View: Ground smooth; not required to be flush.
c. Bolts Exposed to View: Countersunk flat or oval head bolts; no exposed
nuts or screw threads.
d. Metal Surfaces to be Painted: Sanded smooth, suitable for satin or
matte finish.
C. Fasteners: Same material or compatible with materials being fastened; type consistent
with design and specified quality level.
D. Anchors and Related Components: Same material and finish as item to be anchored,
except where specifically indicated otherwise; provide all anchors and fasteners required.
2.03 METAL STAIRS WITH CONCRETE PAN TREADS
A. Jointing and Finish Quality Level: Architectural, as defined above.
B. Risers: Closed.
C. Metal Pan Treads: Metal pan with field-installed concrete fill.
1. Concrete Depth: 2 inches, minimum.
2. Tread Pan Material: Steel sheet.
3. Tread Pan Thickness: As required by design; 14 gage, 0.075 inch minimum.
4. Pan Anchorage to Stringers: Continuously welded, from top or bottom.
5. Concrete Reinforcement: Welded wire mesh.
6. Concrete Finish: Steel-troweled.
D. Risers: Same material and thickness as tread pans.
1. Riser/Nosing Profile: Sloped riser with rounded nosing of minimum radius.
2. Nosing Depth: Not more than 1-1/2 inch overhang.
3. Nosing Return: Flush with top of concrete fill, not more than 1/2 inch wide.
E. Stringers: Hot-Rolled steel channels or plates.
1. Stringer Depth: As indicated on Contract Drawings but not less than 12 inches.
2. End Closure: Sheet steel of same thickness as risers welded across ends.
F. Landings: Same metal pan construction as treads, supported and reinforced as required
to achieve design load capacity.
G. Under-Side of Stair: Where exposed to view, to be finished same as specified for other
exposed to view surfaces.
2.04 MATERIALS
A. Steel Sections: ASTM A36/A36M.
B. Steel Plates: ASTM A283.
C. Ungalvanized Steel Sheet: ASTM A1008/A1008M, Designation SS, Grade 33, Type 1.
D. Galvanized Steel Sheet: ASTM A653/A653M, Structural Steel (SS) Grade 33/230 with
G40/Z120 coating.
E. Gratings: Bar gratings complying with NAAMM MBG 531 or NAAMM MBG 532,
whichever applies based on bar sizes.
F. Concrete Fill: Minimum 28-day compressive strength of 3,000 psi as specified in Section
03 xx xx Concrete.
G. Concrete Reinforcement: Mesh type as specified in Section 03 20 00, Concrete
Reinforcing.
H. Steel Bolts, Nuts, and Washers: ASTM A325 (ASTM A325M), Type 1, galvanized to
ASTM A153/A153M where connecting galvanized components.
I. Welding Materials: AWS D1.1; type required for materials being welded.
2.05 SHOP FINISHING
A. Shop finishing of ferrous metal items is specified in Section 05 xx xx Metals. No shop finishing, other than cleaning is required for aluminum
items.
2.06 COMPONENTS
A. Metal Pan Stair Treads: Concrete in metal pan; 2 inches deep; smooth surface; non-slip
edge.
2.07 FABRICATION - GENERAL
A. Fit and shop assemble components in largest practical sections, for delivery to site.
B. Fabricate components with joints tightly fitted and secured.
C. Continuously seal joined pieces by intermittent welds and plastic filler (bondo).
D. Grind exposed joints flush and smooth with adjacent finish surface. Make exposed joints
butt tight, flush, and hairline. Ease exposed edges to small uniform radius.
E. Exposed Mechanical Fastenings: Flush countersunk screws or bolts; unobtrusively
located; consistent with design of component, except where specifically noted otherwise.
F. Supply components required for anchorage of fabrications. Fabricate anchors and
related components of same material and finish as fabrication, except where specifically
noted otherwise.
G. Fabricate components accurately for anchorage to each other and to building structure.
2.08 FABRICATION - PAN STAIRS AND LANDINGS
A. Fabricate interior stairs and landings with closed risers and treads of metal pan
construction using ungalvanized steel sheet, ready to receive concrete.
B. Fabricate exterior stairs and landings with closed risers and treads of metal pan
construction using galvanized steel sheet, ready to receive concrete.
C. Form treads and risers with minimum 18 gage sheet steel stock.
D. Secure reinforced tread pans to stringers with clip angles; welded in place.
E. Form stringers with hot-rolled steel channels, 12 inches deep. Weld fascia plates to
channels using 14 gage steel sheet across channel toes.
F. Form landings with minimum 18 gage sheet stock. Reinforce underside with angles to
attain design load requirements.
PART 3 – EXECUTION
3.01 EXAMINATION
A. Verify that field conditions are acceptable and are ready to receive work.
3.02 PREPARATION
A. When field welding is required, clean and strip primed steel items to bare metal.
B. Supply items required to be cast into concrete and embedded in masonry with setting
templates.
3.03 INSTALLATION
A. Install components plumb and level, accurately fitted, free from distortion or defects.
B. Provide anchors, plates, angles, hangers, and struts required for connecting stairs to
structure.
C. Allow for erection loads, and for sufficient temporary bracing to maintain true alignment
until completion of erection and installation of permanent attachments.
D. Provide welded field joints where specifically indicated on Contract Drawings. Perform
field welding in accordance with AWS D1.1.
E. Other field joints may be either welded or bolted provided the result complies with the
limitations specified for jointing quality levels.
F. Obtain approval prior to site cutting or creating adjustments not scheduled.
G. After erection, prime welds, abrasions, and surfaces not shop primed or galvanized,
except surfaces to be in contact with concrete.
3.04 ERECTION TOLERANCES
A. Maximum Variation from Plumb: 1/4 inch per story, non-cumulative.
B. Maximum Offset from True Alignment: 1/4 inch.
END OF SECTION