SCOPE OF WORK
§ Framing for steel
stairs, galleries and platforms.
§ Grating and grating
treads, including abrasive nosing.
§ Safety floor plate (checkered
plate).
§ Handrails.
§ Ladders.
§ 1.7 Guard plates.
§
Banding
of all openings in grating occasioned by field run piping.
§
All
materials necessary, including Type 316 stainless steel studs for grating hold‑down
clips to connect the gallery work to structural steel and other parts of the
structure already in place.
§
All
brackets, hangers and bracing necessary to support the Work rigidly and keep it
in free from vibration and excessive deflection
CODES AND STANDARDS
The Contractor shall
comply with the requirements of Book II, refers to "Codes and
Standards".
The
codes and standards of the following organizations extracted from Book II
refers to "Codes and Standards" are specifically applicable to the
design, manufacture and testing of the work included in this Specification:
ASTM ............. American Society for Testing
and Materials
AISC ............. American Institute of Steel
Construction Manual
AWS ............. American Welding Society
SSPC ............ Steel Structures Painting Council, USA
SAE ..........… Society of Automotive
Engineers, USA
UBC ………… Uniform Building Code of USA
OSHA
……….. Occupational Safety and
Health Administration, USA
Code Requirements: All stair riser
heights, stair tread depths, stair widths, ladders, ladder guards, hand railing
heights etc. shall conform to the latest UBC and OSHA code requirements that
may apply.
The gallery work shall
also conform to the mandatory requirements of all Indonesian authorities having
jurisdiction. It shall be Contractor's responsibility to investigate such
requirements and determine the applicable provisions. These provisions shall be
current to the date of contract award.
WORKMANSHIP, SEQUENCE AND FINISH
Workmanship and finish
shall be equal to the best shop and field practice. All material shall have
clean surfaces before being worked. Fabricated members shall be free from
twists, bends or open joints. Shearing and clipping shall be
neatly and accurately
done. All work shall be neatly finished.
As much of the work as
possible, including connections and joints between members, attachment of clip
angles, punching of holes etc. shall be shop fabricated so as to reduce the
amount of field erection work to a minimum.
The Contractor shall be
responsible for proper fit of all materials furnished, including railing and
post clearance with other equipment, piping, grating, checkered plate etc.
including field check for clearances.
The Contractor shall
fabricate and erect the gallery work in the sequence desired by the Owner if
requested.
MATERIAL
Grating shall be
galvanized steel unless otherwise specified. Steel grating shall be fabricated
from welding quality steel equal to SAE 1015 for bearing bars and SAE‑1010 for
cross bars.
Structural steel and all
other steel including floor plates, ladders, cages, guard plates etc. shall
conform to applicable requirements of ASTM A36- Standard Specification for
Structural Steel.
Bolts shall be of ASTM
A325 Type 1 steel.
Handrails
and posts shall be butt welded steel pipe of standard weight (Schedule 40) or steel structural tubing of
equal or greater weight unless galvanized
pipe is called for in the specification. The pipe shall conform to ASTM A120 with its steel meeting a minimum
tensile strength of 3000 kg/cm and a
yield point of 1750 kg/cm on actual physical tests. The structural tubing shall conform to ASTM A501, F‑36 or better
material. The Contractor shall retain
final responsibility for spacing of handrail posts. All handrails shall be shop
prime and field finish painted.
Areas exposed to
chemical attack shall have Fiberglass Reinforced Polyester (FRP) grating with
FR gray grit top.
DESIGN REQUIREMENTS
GRATING
Grating, except where
noted otherwise on the approved drawings, shall have a minimum thickness of 38
mm with 38 mm x 5 mm main bars on 30 mm center‑to‑center bar spacing and
crossbars on not greater than 100 mm center‑to‑center spacing. Deflection of
grating shall not exceed L/300.
STAIRS
Channel stringers and
grating tread stairs shall be used in all plant areas to service equipment or
to travel from one gallery level to another.
This type of stairs
having a Maximum slope of 400, a maximum and a minimum riser of 190
mm and 165 mm respectively and a maximum and a minimum tread of 250 mm and 225
mm respectively is considered gallery stairs. The stair treads shall be rigidly
bolts to stringers with bolt heads on the outside and nuts on the inside faces
of stringers. The stair width shall not be less than 75 cm.
HANDRAILS
Handrail shall be
provided for the following areas and where required:
Around every stairway
floor opening.
Around every floor opening
into which personnel could accidentally trip or fall, except when provided with
an opening cover.
On all flights of stairs
having four or more risers.
At all open sided
floors, walkways and platforms.
Adjacent to dangerous
equipment.
All temporary openings
shall be guarded by temporary handrails.
Handrails shall be
placed at 105 cm above the nosing of treads, or above the top of platform
grating or checkered plate. They shall be continuous the full length of the
stairs. Ends shall be returned or shall terminate in newel posts or safety
terminals.
Handrails shall be
standard pipe handrails 40 mm diameter, welded construction.
The handgrip portion of handrails shall have a continuous smooth surface with
no sharp corners.
Handrails projecting from a wall shall have a
space of not less than 40 mm between the wall and the handrail.
GUARD PLATES
Guard plates shall be 6
mm thick and shall extend a minimum of 100 mm above the finished floor line,
unless otherwise required.
Guard plates shall be
fastened to steel framing members or concreter slabs.
All guard plates shall
be attached to framing members in the shop, where possible, in order to
minimize the amount of field erection work.
LADDERS
Ladders shall be
provided in all pits, manholes, and entrances to tunnels, to all roofs over 6 m
above the ground where there is no access by a stair, or to the floors where no
stair system is provided.
The following types of
ladders shall be used in the design of the power plant:
Ladders that consist of
individual round steel rungs.
Ladders that consist of
steel side rails and steel rungs attached to side rails.
Ladders equipped with a
cage.
Ladder service platforms
or landings 3.6 m or higher above ground shall have a safety cage. Ladders over 6 m in height that are equipped with a
cage must have a rest platform at intervals not exceeding 10 m.
DETAILED REQUIREMENTS
GRATING
Grating shall be a
standard make of fabricated galvanized grating of a type acceptable to the
Owners however grating of the pressure locked type is not acceptable. The
welding requirements hereinafter specified do not apply to weld grating that
shall be produced in accordance with standard manufacturing practice.
Grating panels shall be
of uniform width as far as possible. Grating bars on grating areas adjacent to
each other shall run in the same direction, if economically possible, and
grating panels shall in other respects be so fabricated that the design will
match when panels are assembled. Ends of panels shall be cut off neatly. Ends
that have become bent must be straightened before acceptance. All grating shall
be straight and not warped and shall have full bearing on the supporting steel.
In order to obtain a
firm bearing on the supporting steel, each section of grating shall be fastened
near each corner to the supporting steel. The method of fastening shall be by
either tack welding, fasteners or a combination of both.
Fasteners shall be
permanently fastened to the grating sections so as not to become detached and
lost when removing and replacing grating sections.
Special care shall be taken to anchor
overhanging grating sections securely by means of fasteners. Grating shall be
provided with stops to prevent any section from slipping off the supporting
steel when an adjacent panel is removed.
All gallery steel connecting to structural steel
shall be continuous fillet welded.
Grating sections shall
fit snugly with not more than 3 mm clearance between adjacent sections of
grating, and 8 mm clearance between grating and curb angles or guard plates.
Holes in grating for
pipes, where required by Contractor's design, shall be cut and banded in the
shop, unless otherwise specified.
All other holes that are
not specifically located and dimensioned on the Contractor's design drawings
shall be cut and banded in the field in accordance with field measurements of
pipes in place.
When laying out holes in
grating for piping, consideration must be given to clearances required to
accommodate pipe covering (if any) and movement of the piping due to thermal
expansion.
Grating shall be split
around all pipes where possible and shall be made into easily removable
sections. Location of junction lines between grating sections shall be
determined from actual field measurements of pipes insofar as it is possible.
All holes for pipes shall clear the pipe (or pipe covering as the case may be)
by not less than 50 mm or more than 75 mm. Furthermore, the arrangement shall
allow for the displacement of pipes due to their expansion or contraction
without contact between grating and pipe (or pipe covering).
All holes shall be
banded with a 5 mm bar projecting 25 mm above top of grating. The grating bars
shall be neatly welded to the band. All bands shall be divided on the junction
line between adjacent panels.
When it is
necessary in the installation of a floor grating panel to cut the grating t
right angles to the bars at a point of support, suitable means of permanently
holding the ends of the bar in alignment shall be provided.
Nosing
Edges of
grating at head of stairs shall, have a 40 mm wide and not less than 8 mm thick
abrasive nosing.
Where
grating junction lines occur at head of stairs, the nosing shall be cut at the
junction line so as to permit removal of each section of grating.
Provide
manufacturer's standard paint finish on metal areas of treads as nosing.
Abrasive areas shall not be painted. Any discolorations, etc., on the treads
and nosing shall be cleaned off with a solvent after erection, and before
completion of the work.
Install stair tread nosing in the shop but
only after the grating treads have been galvanized.
The
projecting edges of longitudinal grating bars at openings not protected by
guard plates shall be banded with 6 mm thick bar of same depth as the grating.
Outdoor grating and
stair treads shall have serrated top. All exterior (grating shall be clipped
down with a minimum of two saddle clips per grating section.
STAIRS AND TREADS
Stairs shall be
constructed and attached to galleries or concrete work as indicated on the
standard drawings.
Stair treads shall
be 32 mm x 5 mm standard galvanized grating of the same pattern as the floor
grating. Grating treads shall have abrasive noising.
Stair treads shall be
rigidly bolted to stringers with bolt heads on outside and nuts on inside faces
of stringers.
CHECKERED STEEL FLOOR
PLATES
Checkered steel
floor plate shall be rolled steel galvanized plate of a type and design
suitable for the floor loading. Steel floor plates shall have a nominal
thickness of 6 mm unless otherwise required.
The pattern center lines
on all checkered steel floor plate sections shall match and line up in both
directions on adjacent sections.
All floor plate sections
shall fit snugly into place with not more than 1.5 mm space between.
All
steel floor plates shall be amply reinforced by means of steel angles along all edges of each plate and in intermediate
locations where necessary. Each stiffener
shall be welded to underside of plate along both edges of the stiffener. Each section shall be provided with two
lifting holes located in opposite corners.
Floor plates shall be straight and flush with the surrounding floor. Each floor plate section shall be provided with
grinding bars, for aligning faces of
plate sections with each other and with adjacent flooring. Grinding bars shall
have bearing over their entire area.
Steel floor plates,
where curb angle construction is required shall also be reinforced with
stiffeners except for narrow trenches where stiffeners may not be required. All openings for pipes shall be
neatly cut so as to clear the pipe (or pipe
covering) 12 mm all around. The
arrangement shall be such that any section can be readily removed.
HANDRAILS
All railings and railing
post connections shall be in accordance with the details shown on the approved
drawings.
All railing and post
intersections shall be welded. Pipe or tubing posts shall be welded to the top
rail, the rail being continuous. The
center rail shall be welded to the posts, the posts being continuous.
The railing and post
sections shall be completely fabricated in the shop in as large sections as is
practicable and that can be conveniently handled and erected.
Field railing splices
where required shall be welded and shall in all cases be located near a pipe post or point of support. No screwed
couplings will be permitted in rails or posts.
After shop and/or field welding is done, all rough weld metal
projections shall be neatly ground off so
that the joint will present a smooth
appearance. Neat appearing welds with no
rough projections will not require grinding. All sharp corners shall be
rounded.
The Contractor shall cut
handrails and guard plates and weld them (except galvanized steel) in field to
clear diagonal bracing where required.
Ends of handrails at
building columns or other vertical steel may be attached to the steel by means
of a collar welded to the steel.
Where gates are
required, swing gates shall be provided. No chain gate shall be used.
GUARD PLATES
Guard plates shall be
furnished in as long lengths as possible. Ends of adjoining guard plates shall
be welded together. Joints shall be no closer than 1 m to handrail post.
Guard plates used at
edges of floors and galleries and meeting at angles at corners shall have corners welded. If necessary, an extra piece of
plate shall be welded to the outside of
guard plates to close the gap between plates that do not join.
Cutouts
shall be provided where necessary to clear piping or other equipment.
The Contractor shall
provide guard plates around all column penetrations and moment connections.
Gratings shall be coped and fitted with cover plates so as to prevent openings greater than 25 mm in width around these
penetrations.
LADDERS
Unless otherwise
specified, ladders shall be galvanized and made of steel bar stringers and
round steel bar rungs.
Suitable guards or cages
shall be furnished for ladders for locations and conditions stated in mentioned
before or where required by OSHA or UBC. Guards shall be of type and design as
required by these codes.
Access from platforms,
floors or landings to all ladders going to a lower elevation shall be provided with a pipe swing gate, as may be
indicated, or as may be required by OSHA or UBC.
FABRICATIONS AND ERECTION
Fabrication and erection
shall be in accordance with the applicable provisions of the AISC Manual of
Steel Construction (latest edition) and the following:
SHOP CONNECTIONS
All shop connections
shall be made by welding or with bolts.
Gallery members
connecting to existing work or to steel work by others shall be welded. For
welding requirements, see Clause as mentioned before. All other gallery work
shall be bolted. For bolted connection requirements, see Clause in mentioned
before.
Welded connections shall
conform to Tables III and IV, "Framed Beam Connections", of the AISC
Manual, using E70XX electrodes unless otherwise indicated.
The connection angle
length shall be the maximum for each size beam.
Bolted connections shall
conform to Table IIA, "Framed Beam Connections", of the AISC Manual,
using double angle connections with minimum 19 mm diameter bolts of ASTIM A325 Type
1 for friction‑type connections unless otherwise
indicated. Number of bolts and connection angle length shall be the maximum for each size beam. The minimum
projection of the installed bolt beyond the nut shall be 6 mm.
BEARING PLATES
Beams bearing on masonry
or concrete work shall be provided with bearing plates and clip angles.
FABRICATION
Structures shall be
plumbed or leveled such that the deviations for the complete work do not exceed
the requirements of the AISC Code of Standard Practice. Erection drawings shall
be marked accordingly.
WELDING
Welding shall be in
accordance with the applicable provisions of the AISC Manual, AWS DIA,
"Structural Welding Code” and Specification Welding in Steel structures.
CLEANING AND PAINTING
Shop cleaning and
painting of gallery steel shall be in accordance with the Technical
Specification Prime Coat and Shop finish painting.
The field finish coat of
paint for surfaces other than grating, ladder stringers and bar rungs shall be
applied per Technical Specification Field finish painting.
GALVANIZING
Grating, stair treads,
ladders (except cages), floor plates and stop bars shall be complete shop fabricated and galvanized after
fabrication unless noted otherwise. The galvanizing
shall be compatible to the environmental conditions.
All parts to be
galvanized shall be designed for erecting with bolts, pins, and anchor bolts,
clips etc. and shall not require field welding, field riveting, field drilling
or any operation that would damage galvanizing.
All bolts, clips, nuts,
washers, anchors, stops, banding and other appurtenances required for
galvanized parts shall also be galvanized or stainless steel and shall be
furnished and installed by Contractor.
Galvanizing shall
conform with the applicable requirements set forth in the latest editions of
the ASTIVI Standard Specifications Al 23, Al 5‑3), A384, A385 and A386.
Bolts shall be
galvanized after threading. Nuts shall be galvanized before threading. Members
that are being punched or drilled shall be galvanized after punching or
drilling.
Any grating that is
warped or bent after galvanizing wills Le rejected and shall not be used.
Galvanized grating shall
be tested in accordance with the requirements set forth in the latest edition
of the ASTM Standard Specification A239.
The Contractor will be
required to regalvanize all gallery work that has had galvanizing damaged. If
it becomes necessary to alter any galvanized stair treads or grating in the
field, such work shall be regalvanized before installing at no cost to the
Owner.
QUALITY ASSURANCE/QUALITY CONTROL (QA/QC)
Quality
assurance/quality control shall conform to the requirements in Book II.
The quality control
procedures and documentation shall include but not be limited to the following
Welding.
Nondestructive testing.
Packaging and shipping.
Shop test procedures.
Cleaning, painting and
galvanizing.