@TomSuperO posted:Really Nice George. Amazing how the details make it pop.... the cat... - obviously one of the stray mill cats... but not to scale.
90's: yellow= NG (natural gas), Green = O2 (oxygen), Blue = H20, Purple (hydraulic fluid), Orangish-Yellow (safety railings).
COG ((coke oven gas (which would have been used a fuel in the Open Hearth back in the day)) - I do not remember - mustard yellow / green?
Back in the day there wasn't any standardized color codes for utilities. Each company used the color they designated for that gas or liquid company wide. Starting around the 80's, the industry adopted a standardized system of color coding due to accidents. (taking a cutting torch to an unmarked "dead" line only to find it was an active oxygen line - fatal) You can find these color codes on line. A lot of water pipes were just black pipe and not painted. Steam pipes were always insulated with usually a silver or white (asbestos) hard shell covering and had the typical expansion "hump" in the lines.
Tom
Thank you, Tom!
I'll get to work on that out-of-scale cat. 
George
