STANDARD AND SPECIFICATION FOR
THE U.S. MUNICIPAL DRAINAGE AND CONSTRUCTION CASTINGS
MATERIAL: Grey Iron castings shall conform to ASTM
A48-2003 (A48M) Class 35B, AASHTO M105,
and/or AASHTO-M306 unless
otherwise specified. Ductile Iron castings shall conform to ASTM
A536-84(2004) and A536 Grade 80-55-06. Castings shall conform to ASTM
A48 Class 30/35B
or ASTM A536.
MANUFACTURING: Castings supply will be free from
pouring faults, shrinkage, cracks, cold shuts, sponginess, blow-holes,
and other defects. Bearing surfaces shall be machined, if necessary,
so that the grates and covers sit firmly on the frames without
rocking. The cover or grate shall not rock when rotated to any
position in the frame. Circular manhole frames, covers, and grates
shall be furnished with machined horizontal bearing surfaces unless
otherwise specified. All square and rectangular units shall be
furnished with an as-cast bearing surface unless otherwise
specified.
TOLERANCES: As cast dimensions may vary by ± 1/16
inch per foot in critical areas relating to fit, load bearing capacity
and drainage openings. Dimension Tolerances:
a) 300 mm or less +/- 3 mm
b) Up to and including 900 mm +/- 6mm
Non-critical dimensions may be modified to facilitate proper casting
techniques, performance and value, without notice. Notwithstanding
these tolerances, all rings, covers, frames, grates and curb hoods of
the same nominal size are interchangeable.
WEIGHTS: Casting weights shall be within ± 5% of the
specified weight and/or as shown on
customer drawing.
PAINT: Castings are supplied unpainted as a standard,
unless specified. If paint is required, all surfaces shall be painted
with one shop coat of asphalt or at base black paint having a minimum
softening point of 71 degree centigrade. All joints and crevices shall
be thoroughly coated.
CAST IRON LOAD RATING
All castings to have load tested in accordance with the destructive
testing protocol below, and are assigned one of the following four
load rating designations:
Non-Traffic: These castings are intended for areas
such as sidewalks, terraces and other areas not subject to vehicular
traffic loads.
Medium Duty: Castings bearing this designation are
able to withstand occasional vehicular loading,
but are not
intended to receive heavy highway traffic. Applications include
driveways, parking lots,
and ramps.
Heavy Duty: These castings are manufactured to
withstand highway traffic loads, exceeding AASHTO H-20/HS-20
specifications (wheel loads of 16,000 pounds with a tyre contact area
of 10” x 20”) 25,000 pounds proof load in accordance with CID A-A
60,005 or 40,000 pounds proof load per AASHTO M-306.
QUALITY ASSURANCE
Upon request, two type 'C' test bars for each lot of castings as
described in ASTM A48 shall be supplied.
Failure of the test bars to meet the specified tension requirements
will be reported within two weeks from receipt of the test bars.