HMS I offered should conform to following standards set by ISRI. ( download ISRI specifications circular)

ISRI 200  No. 1 heavy melting steel.

Wrought iron and/or steel scrap 1/4 inch and over in thickness. Individual pieces not over 60 x 24 inches (charging box size) prepared in a manner to ensure compact charging.

ISRI 201  No. 1 heavy melting steel 3 feet x 18 inches.

Wrought iron and/or steel scrap 1/4 inch and over in thickness. Individual pieces not over 36 x 18 inches (charging box size) prepared in a manner to ensure compact charging.

ISRI 202 No. 1 heavy melting steel 5 feet x 18 inches.

Wrought iron and/or steel scrap 1/4 inch and over in thickness. Individual pieces not over 60 x 18 inches (charging box size) prepared in a manner to ensure compact charging.