This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol2", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
The iron, both cast and wrought, and the rolled steel to be of the best quality and brands approved by the architect; and, except where bedded in concrete, to be painted two coats of granitic oxide before fixing.
All castings to be perfectly smooth, and free from flaws, sandholes, and other defects.
Provide all requisite patterns.
The wrought iron to bear an ultimate tensile stress of 22 tons per square inch of section, with a contraction of area at fracture of 18 per cent.
The steel to bear an ultimate tensile stress of not less than 27 or more than 32 tons per square inch of section, with a contraction of area at fracture of from 50 to 40 per cent. accordingly.
Suitable samples of the various sections of wrought iron and steel to be provided for testing.