Iron castings shall be either gray iron castings meeting the requirements of ASTM A48 or ductile (nodular) iron castings meeting the requirements of ASTM A536 as specified in the contract documents.


Unless otherwise specified gray iron castings bridge rockers and shoes shall meet the requirement of class (ASTM A 48) 35B, ductile iron castings shall meet the requirements of Grade 65-45-12 (ASTM A-536) and steel castings shall meet the requirements of Grade 65-35 (ASTM A 27), Class 1 or Class 2.


Aluminum alloy castings shall conform to the requirements of ASTM B26 Alloy, ANSI 356.0.


Acceptance shall be on the basis of certification from approved sources. An imprint on the cover may show “Storm Sewer”. The manufacturer may also imprint marks or trade names on the castings. Weighing and verification may be required as directed by the Engineer. Castings shall conform to the shape, weight and dimensions of the standard plan. Surfaces of the castings shall be free from burnt-on sand or adhering sand, scale, cracks, hottears and shall be removable smooth as determined by visual examination. Welding, painting or plugging will not be accepted.


The finished casting shall show careful finished workmanship, true to pattern in form and dimension.  Castings which have been damaged either during manufacture or shipping shall be rejected.  Any defects such as cracks, sponginess, blow holes, cold joints, porosity, sand inclusions, scabs, or slags shall be basis for rejection.


Minor defects may be accepted with prior engineer’s approval of the:

  1. Length is not greater than 25% of the thickness at the point of occurrence.
  2. Depth is not greater than 5% of the thickness at the point of occurrence.
  3. Defects did not impair the strength at critical locations.


Bearing surfaces between manhole rings and covers or grates and frames shall be cast or machined to produce a uniform bearing throughout the parameter area of contact.


Castings that will be subjected to roadway traffic (heavy) shall have fully machined bearing surfaces as indicated on the standard road plan. Machined portion of the frame shall completely accommodate the machined portion of the cover so that only machined surfaces come in contact. Pairs of machined castings shall be matched and marked to facilitate subsequent identification at installation.


Field inspection personnel may verify dimensional requirements and perform visual inspection for acceptance and/or rejection on project site.


Permissible Variations - Frame


·         Cover opening diameter + 1/16 in. (+ 1.6 mm)

·         Cover opening depth + 1/32 in. (+ 0.8 mm)

·         Height + 1/8 in. (+ 3.2 mm)

·         Flange + 1/4 in. (+ 6.4 mm)


Permissible Variation-Cover


·         Diameter + 1/16 in. (+ 1.6 mm)

·         Seat Depth  -1/32 in. (+ 0 mm, -0.8 mm)


All other dimensions + 1/8 in. (+ 3.2 mm)

Casting which has been damaged either during manufacture or in shipping may be rejected. Repairing shall not be allowed without prior approval of the engineer.



Iowa DOT Standard (Reference)



Neenah Foundry


Deeter Foundry



Proof Load Requirements

Combined Weight

Frame and Cover






Fixed Casting






40,000 Pounds








Floating Castings






40,000 Pounds











1158 or







Note – SW-602 Type G = R-5902 = RA55 (discontinued)


Manufacturer’s certification shall state that the castings representing each furnished casting have been tested and inspected and has been found to meet the specification requirements including a report of test results furnished at the time of shipment.  Authorized personnel shall sign the certification statement.


Note:  All iron castings shall be from domestic origin, melted and manufactured in the USA.


* Cast utility access cover for use with Precast Concrete Handhole (Standard Road Plans)


**Casting for storm sewer manholes (Standard Road Plans)


Certification Statement – Required


The certification statement shall read as follows:


The material itemized in this shipment is certified to meet the requirements of the applicable specification, the ASTM requirements for the type specified and the requirements of this IM.


The certification statement must be signed by an authorized representative of the manufacturer.