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READ AND **REMOVE THIS PAGE** BEFORE PLACING

THE SPECIFICATION SECTION IN THE CONTRACT

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[DIVISION 10: SPECIALTIES]{.underline}

SECTION 10274 ‑ SNAP‑ON STRINGER ACCESS FLOOR SYSTEM

USE: Construction and installation of a snap‑on stringer access floor
system for computer room application which includes pedestals, floor
panels, edge strips, cutouts, grilles, dampered perforated panels,
plenum dividers, steps and risers, ramps, railings, fascias, lateral
bracing, cove bases, and lifting devices. Unique job requirements may
require specific coverage.

**NOTES TO SPECIFIER:**

A. Options within paragraphs are identified by enclosure in brackets;
blank spaces enclosed by brackets \[\_\_\_\_\_\] provide for information
to be inserted, as appropriate, to individual projects.

B. **TO AVOID CONFLICTING REQUIREMENTS AND COSTLY MISTAKES,** the
specifier must edit (delete, substitute or add to the text). The
remaining paragraphs must be renumbered.

C. DELETE FOR FINAL COPY: Notes to the Specifier, located between lines
of asterisks; all \[brackets\], [underlining]{.underline}, **boldface**,
and *italics*, within the paragraphs; and this page. (Open Reveal Codes
\[alt F3\] to do this accurately.)

D. [To Edit "(Footer B)":]{.underline} (Corel 8). **ENTIRE FOOTER SHOULD
BE BOLDED.** Click in the footer and delete the "Project Name (ftr B)"
text and replace it with the **Name of the Project (upper and lower
case)**. Replace date with current MM/YY (WITHOUT BRACKETS).

E. The Guide Specifications are intended to be continuously reviewed and
revised. User's technical comments are appreciated. Also, other related
or similar specification that are written "from scratch" that could
benefit others, or other questions can be sent to NSTC A/E Group, ST
110, or call (303) 987-6868.

**DRAWING DATA REQUIRED:**

**REQUIRED SPEC MODIFICATIONS:**

[GENERAL NOTES]{.underline}

A. Whenever entire articles, paragraphs or subparagraphs are not
applicable, the articles, paragraphs or subparagraphs should be deleted;
if necessary, reletter or renumber articles, paragraphs or
subparagraphs.

B. THIS GUIDE IS NOT INTENDED AS A SUBSTITUTE FOR READING THE ENTIRE
SECTION.

[TECHNICAL NOTES]{.underline}

A. 1.01C: Select or add applicable specification sections. Do not list
specification sections from Division 10.

B. 1.02: Select or add applicable references.

C. 1.04A: Select applicable specification section.

D. 1.04B: Insert number of copies of the manufacturer\'s descriptive
data required. Normally 5 copies are required. Distribution after review
is normally 1 copy to the COR, 3 copies to the Contractor, and 1 copy to
the project file.

E. 1.04C: Insert number of copies of shop drawings required. Normally 5
copies are required. Distribution after review is normally 1 copy to the
COR, 3 copies to the Contractor, and 1 copy to the project file.

F. 1.04D: Insert number of copies of reports required. Normally 5 copies
are required. Distribution after review is normally 1 copy to the COR, 3
copies to the Contractor, and 1 copy to the project file.

G. 1.04E: Insert number of copies of Certificates of Conformance
required. Normally 3 copies are required. Distribution after review is
normally 1 copy to the COR, 1 copy to the Contractor, and 1 copy to the
project file.

H. 1.04F: Insert number of samples required. Normally 2 samples are
required. Distribution after review is normally 1 sample to the COR, and
1 sample to the Contractor.

I. 1.05A: Insert number of hours.

J. 1.05B: Select applicable phrase.

K. 1.05C: Select applicable phrase.

L. 4.01 and 4.02: When a \"lump sum\" Contract is used, delete the title
PART 4: MEASUREMENT AND PAYMENT, and both articles from this section.
Measurement and payment will be addressed in Part 4 of \[Section 01009 -
General Information and Requirements\] \[or\] \[Section 01010 - Summary
of Work\].

**REVISIONS OF THIS SECTION:**

CSI format, editorial changes: 11/01

Metric:

Technical Update: 09/92

SECTION 10274

SNAP-ON STRINGER ACCESS FLOOR SYSTEM

[PART 1: GENERAL]{.underline}

1.1 SUMMARY:

A. Section Includes: Providing and installing an assembly of panels
mounted on adjustable pedestals to provide an underfloor space for the
accommodation of electrical conduit, mechanical service lines and, when
required, to serve as an air supply or return plenum.

B. Temporary Requirements: Whenever the drawings do not indicate
placements required for perforated panels, Contractor shall include in
his bid provision for 5 percent of the number of total panels required
for dampered perforated floor panels, 95 percent solid floor panels.
These totals will be adjusted by Change Order when the exact number of
required dampered perforated panels becomes known. Contractor shall
indicate in Bid Schedule his unit costs for (1) Dampered Perforated
Panels and (2) Solid Floor Panels.

1.2 REFERENCES:

A. American Society for Testing and Materials:

ASTM A 525 REV A-91 General Requirements for Steel Sheet, Zinc Coated
(Galvanized) by the Hot Dip Process

ASTM A 525 M-91 General Requirements for Steel Sheet, Zinc Coated
(Galvanized) by the Hot Dip Process (Metric)

ASTM B 85‑90 Specification for Aluminum-Alloy Die Castings

ASTM E 84 REV A-91 Test Method for Surface Burning Characteristics of
Building Materials

B. National Electrical Manufacturers Association:

NEMA LD 3-85 High‑Pressure Decorative Laminates

C. Underwriters\' Laboratories, Inc.:

UL 992-71 Outline of Investigation for the Test for the Flame
Propagation Classification of Flooring and Floor Covering Materials

1.3 SYSTEM DESCRIPTION:

A. Design Requirements: One size modular prefabricated structural floor
panel supported by a rigid pedestal‑stringer system. The system shall
permit self‑alignment of floor panels, provide adjustable pedestals, and
provide readily removable floor panels and floor covering.

1\. Supports: Support system shall allow for 360‑degree freedom in
laying out cable and cutouts for service to machines. Base access floor
system on a 24‑inch square module which provides at least 6-3/4 inches
clearance between the structural floor and the lowest pedestal supported
component.

2\. Air Leakage: Air leakage through the joints between panels and
around the perimeter of the floor system shall not exceed 2 cubic

feet of air per minute per linear foot of joint subjected to 1/2‑inch
water gauge positive pressure in the plenum.

3\. Design Loads: Access flooring shall be capable of supporting a
uniform live load of minimum 250 pounds per square foot with a
deflection not to exceed 0.040 inches. Floor shall also be capable of
supporting a minimum 1000 pound load concentrated on one square inch at
any point on the panel area without deflecting more than 0.080 inch with
a safety factor of not less than 2 based on ultimate strength of the
material being used. Floor system shall be laterally stable in all
directions whether panels are in place or not. Finished assembly shall
be rigid and free of vibration and rocking panels.

B. Finished Floor System: Finished floor surface shall be smooth and
uniform with all panels free of distortion. Completed floor system shall
be rigid, free of vibration and of rocking panels.

1.4 SUBMITTALS:

A. General: Submittals shall be according to \[Section 01009 - General
Information and Requirements.\] \[and\] \[Section 01300 - Submittals.\]
\[and\] \[Section 01365 - Certificates of Conformance.\]

B. Manufacturer\'s Literature: Submit \[\_\_\_\_\] copies of the
manufacturer\'s descriptive data for floor system to be used on this
project.

C. Shop Drawings: Submit \[\_\_\_\_\] copies of shop \[and erection\]
drawings for the floor system to be used on this project. \[Drawings
shall be prepared by and bear the stamp of a \[registered
\[\_\_\_\_\_\_\_\_\_\_\_\_\_\_\] engineer\] \[licensed architect.\]
\[Shop drawings shall show layout of work stair and ramp framing, sizes,
and details of components, gasketing, return air grills, supply air,
registers and perforated panels, grounding details and method of
installation. \[A bill of materials shall be furnished with the shop
drawings.\] Drawings shall be \[same\] \[larger\] scale as the full size
Contract Drawings.

D. Reports: Submit \[\_\_\_\_\] copies \[of written documentation\] of
the bonding strength of pedestal adhesive, air leakage, deflection under
loading, and non-combustibility of edge strips to be used on this
project.

E. Certificates of Conformance: Submit \[\_\_\_\_\] copies of written
certification from the supplier of the \[following\]
Contractor-furnished \[items\] floor panels to be used on this project
that \[it conforms\] \[they conform\] to the design load requirements of
this specification section. If floor panels are composed of more than
one structural material, the certification shall indicate that the
bonding strength of the adhesive(s) used is adequate.

F. Samples: Submit \[\_\_\_\_\] samples of each \[color\] \[and\]
\[pattern\] \[style\] of each component of the floor system, including
floor covering to be used on this project. Samples shall be actual
material in\] \[colors required\] in this specification.\]

1.5 QUALITY ASSURANCE:

A. Manufacturer Qualifications: A company regularly engaged in the
manufacture of the floor systems to be used on this project, and who
issue\'s a complete catalog of data on such products. The manufacturer
shall have parts and service available to commence correction of the
deficiency, within \[\_\_\_\_\_\] hours after verbal notification by the
Contracting Officer, through factory representatives, franchised
dealers, or factory certified maintenance service shops.

B. Contractor Qualifications: A specialist with successful installation
experience on projects with similar floor systems \[and\] \[approved by
the manufacturer.\]

C. Labeling Requirements: Panels shall have a flame spread rating of 25
or less and be Underwriter\'s Laboratories Inc., (UL) \[labeled\]
\[listed\] \[and\] \[rated\].

1.6 DELIVERY, STORAGE, AND HANDLING:

A. Delivery: Deliver materials to the site in undamaged condition, in
the original containers or packages, complete with all necessary
appurtenances and instructions. Materials shall bear the manufacturer\'s
name and brand designations.

B. Storage: Store materials under cover in a well‑ventilated enclosure
and do not expose to extreme changes in temperature and humidity that
could cause damage to the materials. Do not store materials in the
building until wet‑applied materials are dry. Handle materials in such a
manner as to protect them from damage during the entire construction
period. Defective or damaged materials shall be replaced at the
Contractor\'s expense.

1.7 SEQUENCING AND SCHEDULING:

A. Other Trades: Installation area shall be free and clear of other
trades to permit taking accurate elevations of entire area.

1.8 MAINTENANCE:

A. Extra Materials: Provide one floor panel lifting device standard with
access floor manufacturer for each individual floor area. The lifting
devices shall be a type standard with the raised floor industry for the
selected floor covering used.

[PART 2: PRODUCTS]{.underline}

2.1 MATERIALS:

A. Pedestals: Each capable of carrying a 5000-lb axial load without
permanent deformation. Provide pedestals of steel or aluminum or a
combination thereof. Pedestals made of ferrous materials shall have a
permanent factory‑applied corrosion resistant finish.

1\. Pedestal Bases and Shafts: Each pedestal base shall provide a
minimum of 16 square inches bearing surface upon the structural floor.
Provide base plate not less than 4 inches by 4 inches by 1/8‑inch thick,
and weld to shaft of pedestal. Approved die‑formed bases of equivalent
load spreading capacity and bearing area may be provided in lieu of flat
base plates. Provide rod shafts not less than 7/8‑inch in diameter, pipe
shafts not less than one inch in diameter, or square shafts not less
than one inch square. Provide pedestals with adjusting threads or other
devices that will permit leveling of the access floor system. Threaded
devices used for adjustment purposes shall conform to either the unified
or fine thread series. Provide lock‑nuts, set‑screws, or other locking
devices to positively lock the final pedestal vertical adjustments in
place. Provide a locking device that is effective whether floor panels
are or are not in place.

2\. Pedestal Caps: Design to fit precisely over pedestal shafts by
welding and interlock with panels and stringers in order to preclude
tilting, rocking, or vibrating of panels when a live load is applied.

3\. Leveling: Leveling feature shall allow for overall floor adjustment
within plus or minus 0.10 inch and finished access floor surface level
within 0.062‑inch in every 10 feet in all directions. Provide positive
locking device.

B. Floor Panels: Fabricate so that accurate job cutting and fitting may
be done, using standard sizes, for fitting at perimeters and around
columns. Metal shall not be exposed on the finished top surface of the
panels. Provide vinyl trim or vinyl end bars along the four edges of the
panels. Provide cutouts and cutout closures to accommodate utility
systems and equipment intercabling. Reinforce cutouts to meet design
load requirements. Cut panels that do meet specific design load
requirements shall have extra support pedestals at each corner of cut.
Use panels uniform in face dimensions within a tolerance of plus or
minus 0.015‑inch. Use interchangeable panels which maintain a uniform
close fit, of one of the following types:

1\. Steel Panels: Die‑formed construction. Weld a flat steel top sheet
to one or more formed steel stiffener sheets. The panels shall have
zinc‑coating conforming to ASTM A 525, G 90 with baked enamel finish
standard with access floor manufacturer.

2\. Wood Core Panels: Not less than one inch thick and faced on both
sides with structurally bonded, thermosetting adhesive under pressure to
zinc‑coated steel sheets and sealed on all edges and corners with
zinc‑coated steel or extruded aluminum. Steel sheets shall be no lighter
than 26‑gauge, and zinc coatings shall conform to ASTM A 525, G 90.
Extruded aluminum edging shall be not less than 1/8 inch thick. The
completed panels shall have a flame spread rating of 25 or less when
tested in accordance with ASTM E 84. Provide zinc‑coated steel or
extruded aluminum edging to protect shop and field edge cuts and cutouts
through the face of panels in a manner to meet the flame spread
requirements specified.

3\. Aluminum Panels: Die cast conforming to ASTM B 85, SC 84A.

4\. Size: Individual floor panels 24 x 24 inches and of such weight that
they may be readily removed and handled by one person using a lifting
tool furnished by the access floor manufacturer.

C. Floor Finish:

1\. Floor Panels: Surfaced with Grade HW 120 high pressure plastic
laminate conforming to NEMA LD‑3. Floor finish colors and patterns from
manufacturer\'s standard selection shall be as selected by Contracting
Officer. Bolt heads or similar attachments shall not pierce the traffic
surface.

2\. To preclude static electricity charge buildup, the floor covering
shall have volume resistivity no greater than 2 x 10 to the tenth power
ohms per cubic centimeter or no less than 5 x 10 to the fifth power ohms
per cubic centimeter, and the electrical resistance shall remain stable
over the life expectancy of the floor covering. If an anti‑static agent
is used in the manufacturing process, it shall not be surface applied,
but shall be an integral part of the material.

D. Edge Strips: Provide perimeter of panels with extruded vinyl edge
strips with top edge flush with panel floor finish. Metal edge strips
will not be acceptable.

E. Accessories:

1\. Provide registers, grilles, dampered perforated panels, and plenum
dividers of the manufacturer\'s standard type, designed to meet required
weight support requirements specified herein. Provide isolation pads
from steel and floor under registers and grilles if such practice is
standard with the manufacturer. Design perforated panels to support the
same load as the typical floor panel. Install top surfaces of perforated
panels flush with adjacent finished surfaces. \[Provide perforated
panels with operable dampers.\]

2\. Steps: Steps and risers shall be fabricated of standard components
used for construction of the primary raised floor, fabricated of custom
components, or fabricated of a combination of standard and custom
components. Steps shall include supports, brackets, clamps, plates,
edging, threads, non‑slip nosing, risers, closures, fasteners, and other
appurtenances. Height of risers shall not exceed 7 1/2 inches. Design
steps to support a minimum uniform load of 150 pounds per square foot.
Surface treads with same material as specified for floor panels.

3\. Ramps: Surface with same material as specified for floor finish
\[except when nonslip surface is required\]. Ramps shall include
supports, brackets, clamps, plates, edging, closures, nose pieces,
fasteners, and other appurtenances. Fabricate ramps of the same
materials as the floor panels.

4\. Railings: Double rail and post type, fabricated of aluminum,
designed to present a pleasing appearance, and to perform as a safety
barrier. Provide railings complete with anchorages, floor plates, and
end caps, with a satin clear natural anodized finish.

5\. Fascia and Lateral Bracing: Provide aluminum or steel fascia plates
at open ends of floor, at sides of ramps, at sides of steps, and
elsewhere as necessary to enclose the free area under the raised floor.
Provide a factory‑applied baked enamel finish.

Provide appurtenances including angles, trim, and fasteners, with the
plates.

6\. Bases: Provide vinyl or rubber base at all vertical intersections.
The cove base shall be 4 inches high, 1/8 inch thick.

[PART 3: EXECUTION]{.underline}

3.1 PREPARATION:

A. Retro‑fit Condition: Ascertain that the formerly existing floor
material has been completely removed, including its adhesive, if any.

B. General Requirements: Inspect the area to receive access flooring,
rails and ramp to determine that the floor surface is smooth and clean,
wall surfaces completed, and light fixtures installed sufficient to
illuminate the area.

C. Wall‑Mounted Electrical Outlets:

1\. Ascertain that the outlets have been installed 24 inches to
centerline above existing base floor.

2\. In retro‑fit condition, those outlets chosen to be retained shall
have been raised to 24 inches to centerline above existing floor and
wall patched and finished. Those outlets to be abandoned shall have been
removed and wall patched and finished.

D. Wall Construction: All wall construction shall have been completed
including doors and hardware.

1\. In retrofit condition, any wall demolition shall have been completed
and former wall intersection completely finished. Area of base floor
formerly under removed partitions shall be flush with adjacent floor.
Protruding fasteners, etc. shall be removed and base floor patched.

3.2 INSTALLATION:

A. General: Install all components and accessories in accordance with
the requirements as specified herein and manufacturer\'s
recommendations. Free ends of floor, where floor system does not abut
wall or other construction, shall have positive anchorage and rigid
support, and closed with fascia plates. Where pedestals shall be
installed with adhesive, do not apply sealer, hardener, or paint
specified for the structural floor supporting the pedestals until the
pedestals have been installed and adhesive has cured.

B. Fasteners and Fastening: Apply fasteners and fastening for pedestals
and stringers, as applicable. Do not use self‑tapping screws or
spring‑action lock‑nuts. Thoroughly clean floor surfaces and remove all
dust before the work is started.

C. Grounding: Ground access floor system for safety hazard and static
suppression. Total system resistivity from the wearing surface of the
floor to the building ground shall be within the range of 1.5 x 10 to
the fifth power ohms minimum to 2 x 10 to the tenth power ohms maximum.
When metal registers and grilles are provided, insulate as required to
provide the same grounding resistivity as the wearing surface. The
electrical joint resistance between individual stringer and pedestal
junctions shall be less than 0.1 milliohms. The electrical resistance
between stringers and floor panels as mounted in normal use shall be not
greater than 3 ohms. Make acceptance tests after the access floor system
has been installed as specified herein. Make at least one test for each
500 square feet of floor area. Conduct tests in accordance with NFPA
56A, Section 4628, except for the required limits of resistivity as
stated above in this paragraph. Conduct testing in the presence of the
Contracting Officer and the representatives of the manufacturer and the
installer. Should the access floor system fail the initial tests, make
necessary and approved modifications to the grounding system until the
tests are passed. Exposed metal shall not be allowed at the wearing
surface of the access floor system, except at metal grilles and
registers.

D. Pedestals: Secure bases of pedestals to the structural floor with
approved mechanical fasteners or specified adhesive and provide full and
firm contact with the structural floor. Set pedestals plumb and in true
alignment. Adjust pedestal height to within approximately 2 inches.

E. Stringers: Where pedestal‑stringer system is used, firmly anchor the
stringers and other framing members to the pedestals with threaded
fasteners, spaced uniformly in parallel lines, and place at the required
elevation. Stagger abutting joints of longitudinal stringers (6 feet or
longer in length) in a staircase pattern to provide increased lateral
strength.

F. Auxiliary Framing: Provide auxiliary framing around columns and other
permanent structures, at sides of ramps, at free ends of floor, and
beneath floor panels that are substantially cut to accommodate utility
systems and provisions for equipment mounting, air, and cable entry.
Auxiliary framing shall consist of additional pedestals and stringers
designed to specific heights and lengths to meet structural
irregularities and design loads. Connect auxiliary framing to main
framing.

G. Floor Panels: Floor panels shall lie flat without warp or twist and
shall bear uniformly on supports without rocking and without edges or
corners projecting above the floor plane. Interlock panels with
pedestals in a manner that will preclude lateral movement. Modular size
panels shall be interchangeable without releveling. Fasten perimeter
panels, cutout panels, and panels adjoining columns, stairs, and ramps
to the floor framing.

H. Floor Finish: Firmly bond floor finish in place with a waterproof
adhesive so as not to pull loose by use of the lifting tool or by moving
caster loads up to 1000 pounds.

I. Edge Strips: Mechanically lock edge strips and adhesive bond in
place.

J. Cutouts and Edge Cuts: Edge with the same material as the panel
edges. Bush and close cut‑outs with sponge rubber to prevent abrasion of
cables and entrance of dust and debris. Use self‑extinguishing sponge
rubber. Paint cut panel edges with primer or sealer recommended by panel
manufacturer prior to installing edging

materials. Provide cutouts to service all equipment of 4 inches minimum
diameter each.

K. Ramps: Slope of ramps shall not exceed one inch rise to 12 inches of
run. Provide non‑slip inserts on all ramps. Securely fasten ramps to the
raised floor system and subfloor.

L. Railings: Install top rail and bottom rail approximately 3 feet and 1
1/2 feet, respectively, above the finished panel surface. Slope railings
at \[stairs\] \[and\] \[ramps\] from the horizontal and parallel to the
incline. Space posts a maximum of \[5\] \[or\] \[6\] feet on center.

M. Fascia and Lateral Bracing: Reinforce fascia on the back to prevent
warping. Install manufacturer\'s standard adjustable lateral bracing
system behind fascia at maximum 4 feet on center.

N. Base: Install base after access floor system has been installed. Fill
cracks and voids in walls and other vertical surfaces to receive cove
base with an approved crack filler recommended by the cove base
manufacturer. Apply cove base adhesive to the back of the base with a
notched trowel, leaving approximately 1/4‑inch base space along the top
edge of the base. Immediately press cove base firmly against the wall
and move gently into place, making sure that the toe is in contact with
the raised floor. Roll entire surface of the cove base with a hand
roller, and then firmly press the toe or the base against the wall with
a straight piece of wood. Provide premolded corners in matching size,
shape, and color for all internal and external right angle corners.

O. Repair of Zinc Coating: Repair zinc coating that has been damaged by
welding or in installation and all cut edges of zinc‑coated components
and accessories by the application of a galvanizing repair paint.
Thoroughly clean areas to be repaired and remove slag from welds prior
to application of the paint.

3.3 FIELD QUALITY CONTROL:

A. Supervision: Installation shall be supervised by manufacturer\'s
authorized representative.

B. Tests: Conduct grounding and air leakage tests after installation of
access floor system.

3.4 CLEANING AND PROTECTION:

A. Cleaning: Remove debris accumulated during installation from under
the raised floor system. Immediately after completion of the access
floor installation, thoroughly clean the floor, using a small amount of
an approved cleaner in accordance with the floor covering
manufacturer\'s instructions. Do not permit seepage of cleaner between
individual panels.

3.5 PROTECTION:

A. Finished Floor: Cover cleaned floors with clean building paper before
traffic is permitted. Maintain protection until the access floor system
is accepted.

PART 4: MEASUREMENT AND PAYMENT

4.1 METHOD OF MEASUREMENT:

A. ab Units: The work described in this section will not be measured for
payment.

4.2 BASIS OF PAYMENT:

A. Payment: No direct payment for the work described under this section
will be made. Contractor shall include consideration for this item in
the bid price for other items of the Contract.

END OF SECTION