SECTION 05510

METAL STAIRS

PART 1 GENERAL

SECTION INCLUDES

Steel stair frame of structural sections, with [open] [closed] risers.

[Open grate] [Checkered plate] [Pan to receive concrete fill] [Shop cast concrete] stair treads[.] [and landings.]

Integral balusters and [plastic covered] handrailing.

PRODUCTS FURNISHED BUT NOT INSTALLED UNDER THIS SECTION

Section 03300 - Cast-In-Place Concrete: Placement of metal anchors in concrete.

Section [______-____________]: Placement of metal anchors in [precast] [post tensioned] [_____________] concrete.

Section [04300 - Unit Masonry System] [_____-__________]: Placement of metal anchors in masonry.

RELATED SECTIONS

Section 03300 - Cast-In-Place Concrete: Concrete fill in stair pans [and landings]; [mesh reinforcement for landings].

Section [______-____________]: Bearing [plates] [angles] [and] [________] for metal stairs, including anchorage.

Section 05520 - Handrails and Railings: Handrails and balusters other than specified in this Section.

Section 06200 - Finish Carpentry: Wood handrail.

Section 09900 - Painting: Paint finish.

REFERENCES

ANSI A117.1 - Buildings and Facilities - Providing Accessibility and Usability For Physically Handicapped People.

ASTM A36 - Structural Steel.

ASTM A53 - Hot-Dipped, Zinc-coated Welded and Seamless Steel Pipe.

ASTM A153 - Zinc Coating (Hot-Dip) on Iron and Steel Hardware.

ASTM A202.1 - Metal Bar Grating Manual for Steel and Aluminum Gratings and Stair Treads.

ASTM A283 - Carbon Steel Plates, Shapes, and Bars.

ASTM A307 - Carbon Steel Externally Threaded Standard Fasteners.

ASTM A325 - High Strength Bolts for Structural Steel Joints.

ASTM A386 - Zinc-Coating (Hot-Dip) on Assembled Steel Products.

ASTM A446 - Steel Sheet, Zinc-Coated (Galvanized) by the Hot-Dip Process, Structural (Physical) Quality.

ASTM A500 - Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Round and Shapes.

ASTM A501 - Hot-Formed Welded and Seamless Carbon Steel Structural Tubing.

AWS A2.0 - Standard Welding Symbols.

AWS D1.1 - Structural Welding Code.

SSPC - Steel Structures Painting Council.

DESIGN REQUIREMENTS

Fabricate stair assembly to support live load of [100] [_____] lb/sq ft ([4.7] [_____] KPA) with deflection of stringer or landing framing not to exceed [1/180] [1/240] [_____] of span.

Railing assembly, wall rails, and attachments to resist lateral force of [75] [_____] lbs ([333] [_____] N) at any point without damage or permanent set.

SUBMITTALS

Submit under provisions of Section [01300.] [________.]

Shop Drawings: Indicate profiles, sizes, connection attachments, reinforcing, anchorage, size and type of fasteners, and accessories.

Indicate welded connections using standard AWS A2.0 welding symbols. Indicate net weld lengths.

Sample: Submit [two] [_____], [_____] inch ([_____] mm) long samples of plastic handrail covering.

QUALIFICATIONS

Prepare Shop Drawings under direct supervision of a Professional Structural Engineer experienced in design of this work and licensed [at the place where the Project is located.] [in the State of [____________].]

Welders' Certificates: Submit under provisions of Section [01300] [________], certifying welders employed on the Work, verifying AWS qualification within the previous 12 months.

FIELD MEASUREMENTS

Verify that field measurements are as [indicated on [Drawings] [shop drawings]] [instructed by the manufacturer].

PART 2 PRODUCTS

MATERIALS

Steel Sections: ASTM [A36.] [____.]

Steel Tubing: [ASTM A500, Grade B.] [ASTM A501.]

Plates: [ASTM A283.] [________________.]

Pipe: [ASTM A53, Grade [B] [____] Schedule [40] [____]] [________________].

Sheet Steel: ASTM A446, Grade B Structural Quality with [0.25] [1.25] [_____] oz/sq ft ([75] [380] [_____] g/sq m) galvanized coating.

Gratings: ANSI A202.1, Type [__________.]

Plastic Handrail Cover: Extruded PVC, [________] profile, [__________] color; [_________] manufactured by [__________.]

Infill Panels: [Tempered glass] [Polycarbonate] [Acrylic] [__________]; [clear.] [__________.]

Stair Treads: [Shop cast] concrete [in metal pan]; [_____] inches ([_____] mm) deep; [smooth] [__________] surface; [non-slip] [__________] edge.

Shop Cast Concrete Treads: [_____x_____] inch ([_____x_____] mm) profile, [width as detailed] [__________], reinforced with [__________]; [smooth] [__________] finish, radiused nosings.

Concrete for Treads and Landings: Portland cement Type [I] [_____], [3000] [_____] psi ([20] [_____] MPa) 28 day strength, [2 to 3] [_____] inch ([50 to 75] [_____] mm) slump.

Tread and Landing Concrete Reinforcement: [Mesh] [Bar] type [as detailed], [galvanized.] [unfinished.]

Bolts, Nuts, and Washers: ASTM [A325] [A307] [galvanized to ASTM A153 for galvanized components].

Exposed Mechanical Fastenings: Flush countersunk screws or bolts; consistent with design of stair structure.

Welding Materials: AWS D1.1; type required for materials being welded.

Shop and Touch-Up Primer: [SSPC 15, Type 1, red oxide.] [________.]

****** [OR] ******

Touch-Up Primer for Galvanized Surfaces: Zinc rich type.

FABRICATION - GENERAL

Fit and shop assemble in largest practical sections, for delivery to site.

Fabricate components with joints tightly fitted and secured.

Continuously seal jointed pieces by [intermittent welds and plastic filler.] [continuous welds.]

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.

Exposed Mechanical Fastenings: Flush countersunk screws or bolts; unobtrusively located; consistent with design of component, except where specifically noted otherwise.

Supply components required for anchorage of fabrications. Fabricate anchors and related components of same material and finish as fabrication, except where specifically noted otherwise.

Accurately form components required for anchorage of stairs [and] [landings] [and] [railings] to each other and to building structure.

[Install continuous plastic handrail cover. Heat weld joints and trim smooth.]

FABRICATION - PAN STAIRS [AND LANDINGS]

Fabricate stairs [and landings] with [closed] [open] risers and treads of metal pan construction, ready to receive concrete.

Form treads [and risers] with minimum [_____] gage ([_____] mm thick) sheet steel stock.

Secure [reinforced] tread pans to stringers with [clip angles] [__________]; [welded] [bolted] in place.

Form stringers with rolled steel [channels] [rectangular hollow sections] [__________], [10] [12] [_____] inches ([250] [300] [_____] mm) deep. [Weld facia plates to channels using [14] [_____] gage ([1.8] [_____] mm thick) steel sheet across channel toes.]

Form landings with minimum [_____] gage [(_____] mm thick) sheet stock. Reinforce underside with [angles] [metal T's] [__________] to attain design load requirements.

Form balusters with [_____] inch ([_____] mm) [diameter] [square] [rectangular] steel sections, [welded] [bolted] to stringers.

[Prime paint] [____________________] components.

FABRICATION - CHECKERED PLATE STAIRS [AND LANDINGS]

Form treads with minimum [_____] gage ([_____] mm thick) checkered steel plate; [prime paint] [galvanized] finish. [Weld] [Bolt] to stringer support clips. [Bend nosing to a [_____] inch ([_____] mm) radius and return down [_____] inch ([_____] mm).]

Form stringers with rolled steel [channels] [rectangular hollow sections] [_______________], [10] [12] [_____] inches ([250] [300] [_____] mm) deep; [prime paint] [galvanized] finish.

Form landings with minimum [_____] gage ([_____] mm thick) checkered steel plate; [prime paint] [galvanized] finish. Reinforced underside with [angles] [metal T's] [__________] to attain design load requirements.

Form balusters with [_____] inch ([_____] mm) [diameter] [square] [rectangular] steel sections, [welded] [bolted] to stringers; [prime paint] [galvanized] finish.

FABRICATION - OPEN GRATING STAIRS [AND LANDINGS]

Fabricate treads [_____] inch ([_____] mm) thick [in accordance with ANSI A202.1] of [welded] [mechanically clinched] [__________] steel bars, [welded] [bolted] to supports; [prime paint] [galvanized] [__________] finish.

Form hollow stringers with rolled steel [channels] [rectangular hollow sections] [__________] [prime paint] [galvanized] finish.

Form landings [_____] inch ([_____] mm thick [in accordance with ANSI A202.1] [same as treads]; [prime paint] [galvanized] finish. Reinforce underside with [angles] [metal T's] [__________] to attain design load requirements.

Form balusters with [_____] inch ([_____] mm) [diameter] [square] [rectangular] steel sections, [welded] [bolted] to stringers; [prime paint] [galvanized] finish.

FABRICATION - UNIT STAIR TOWERS

Fabricate self-supporting steel stair towers with formed treads [and risers]; steel [channel] [__________] stringers; landing platforms; sectioned for transport; corner structural support members designed to support full weight of complete stair tower plus design live load; with [steel railings,] [newel posts,] [and] [balusters].

Fabric stair towers to height not exceeding [40] [_____] feet ([12] [_____] m) for transportation purposes; designed for stacking to height of building as a self-supporting structure.

FINISHES

Prepare surfaces to be primed in accordance with SSPC SP [2.] [____.]

****** [OR] ******

Clean surfaces of rust, scale, grease, and foreign matter prior to finishing.

Do not prime surfaces in direct contact with concrete or where field welding is required.

Prime paint items with [one coat.] [two coats.]

Galvanized items to minimum [1.25] [2.0] [_____] oz/sq ft ([380] [360] [_____] g/sq m) zinc coating[.] [in accordance with ASTM A386.]

PART 3 EXECUTION

EXAMINATION

Verify that field conditions are acceptable and are ready to receive work.

Beginning of installation means erector accepts existing conditions.

PREPARATION

Clean and strip primed steel items to bare metal where site welding is required.

Supply items required to be [cast into concrete] [and] [or] [embedded in masonry] with setting templates, to appropriate sections.

INSTALLATION

Install items plumb and level, accurately fitted, free from distortion or defects.

Provide anchors, [plates] [angles] [hangers] [and] [struts] required for connecting stairs to structure.

Allow for erection loads, and for sufficient temporary bracing to maintain true alignment until completion of erection and installation of permanent attachments.

Field weld components indicated on [Drawings.] [shop drawings.] Perform field welding in accordance with AWS D1.1.

Field bolt and weld to match shop bolting and welding. Conceal bolts and screws whenever possible. [Where not concealed, use flush countersunk fastenings.]

Mechanically fasten joints butted tight, flush, and hairline. Grind welds smooth and flush.

Obtain Architect/Engineer approval prior to site cutting or making adjustments not scheduled.

After erection, prime welds, abrasions, and surfaces not [shop primed] [galvanized], except surfaces to be in contact with concrete.

ERECTION TOLERANCES

Maximum Variation From Plumb: [1/4] [____] inch ([6] [____] mm) per story, non-cumulative.

Maximum Offset From True Alignment: [1/4] [____] inch ([6] [____] mm).

SCHEDULE

Stairs A and B: Pan stairs and landings, plastic handrail cover, primed finish.

Stair C: Checkered plate stairs and landings, galvanized finish. Pipe handrails specified in Section 05521.

END OF SECTION