N.Y. Comp. Codes R. & Regs. tit. 1, § 2.38 – Sanitary piping—Item 10p.

(a) All sanitary piping, fittings and connections which are exposed to milk or milk products, or from which liquids may drip, drain or be drawn into milk products, consist of smooth, impervious, corrosion-resistant, nontoxic, easily cleanable material.
(b) All sanitary piping, connections and fittings consist of:
1. (1) stainless steel of the AISI (American Iron and Steel Institute) 300 series; or
2. (2) equally corrosion-resistant metal which is nontoxic and nonabsorbent; or
3. (3) heat-resistant glass; provided, that plastic, or rubber and rubberlike materials, which are relatively inert, resistant to scratching, scoring, decomposition, crazing, chipping and distortion under normal use conditions; which are nontoxic, fat-resistant, relatively nonabsorbent; which do not impart flavor or odor to the products; and which maintain their original properties under repeated use conditions, may be used for gaskets, sealing applications, and for short flexible takedown jumpers or connections where flexibility is required for essential or functional reasons.
(c) Sanitary piping, fittings and connections are designed to permit easy cleaning, kept in good repair, and free of breaks or corrosion, and contain no dead ends of piping in which milk may collect.
(d) All interior surfaces of demountable piping, including valves, fittings and connections are designed, constructed and installed to permit inspection and drainage.
(e) All cleaned-in-place milk pipelines and return-solution lines are rigid, self-draining and so supported to maintain uniform slope and alignment. Return-solution lines shall be constructed of material meeting the specifications of subdivision (b) of this section. If gaskets are used, they shall be self-positioning, of material meeting the specifications outlined in subdivision (b) of this section, and designed, finished and applied to form a smooth, flush interior surface. If gaskets are not used, all fittings shall have self-positioning faces designed to form a smooth, flush interior surface. All interior surfaces of welded joints in pipelines shall be smooth and free from pits, cracks or inclusions.
In the case of welded lines, the commissioner may require that the installer provide a boroscope or other suitable inspection device to determine the acceptability of interior surfaces of welded lines. All welded surfaces shall be approved by the commissioner. Each cleaning circuit shall have access points for inspection in addition to the entrances and exits. These may be valves, removable sections, fittings or other means or combinations that are adequate for inspection of the interior of the line. These access points shall be located at sufficient intervals to determine the general condition of the interior surfaces of the line. Detailed plans for welded pipeline systems shall be submitted to the commissioner for written approval prior to installation. No alteration or addition shall be made to any welded milk pipeline system without prior written approval from the commissioner.
(f) Pasteurized milk and milk products are conducted from one piece of equipment to another only through sanitary milk piping.
(g) All stainless steel lines and vessels used to convey or store any of the products included in section 2.1 of this Part or any ingredients used in the manufacture of such products, cleaning solutions or water shall be color coded so as to provide easy identification of the material contained therein. The following color scheme shall be used:
Raw product lines red
Pasteurized product lines blue
Cleaning solution lines green
Water lines (SS only) yellow
Sugar and dairy food ingredients orange
Additional color coding of stainless steel lines to denote ingredients of special products is permitted provided it does not duplicate the color coding scheme described above.

Raw product lines	red
Pasteurized product lines	blue
Cleaning solution lines	green
Water lines (SS only)	yellow
Sugar and dairy food ingredients	orange