Standard Manholes shall be four feet in inside diameter. The walls shall be built of 8-inch brick work and plastered on exterior surfaces with a one-half inch coat of mortar; interior joints shall be carefully pointed. Brick work shall conform to requirements of "Brick Masonry." Item 36. Castings shall conform to the requirements of "Cast Iron," specified under Item 27. Manholes shall conform to the standard plans on file in the office of the Engineer, and the channels shall be constructed as ordered.

Steps. - The manhole steps required shall be of good quality wrought iron. Test pieces shall exhibit a minimum tensile breaking strength of 50,000 lbs. per square inch, and shall endure without signs of distress, cold bending 180 degrees about a curve whose diameter is equal to that of the test piece. The material used shall be sound and free from mechanical defects. Steps shall conform to plans on file in the office of the Engineer. They shall be straight and after thorough cleaning shall be painted with two coats of red lead.

Payment. - The price bid per manhole complete shall include all excavation and backfill and furnishing and placing of all masonry materials, furnishing, painting and setting of all castings and steps.