My knowledge base does not contain specific documentation that outlines how to differentiate between polybutylene (poly-v) and cross-linked polyethylene (PEX) piping materials. However, I can provide general safety guidance based on industry best practices for working with piping.

General safety guidelines for working with piping include:

• Always wear appropriate personal protective equipment (PPE), including eye protection and gloves.
• Ensure proper ventilation when working in enclosed spaces.
• Identify the contents of the pipe before working on it. Where, in any one establishment, one or more hazardous substances are transported through pipe lines, all above ground piping systems used to transport gases, vapors, liquids, semi-liquids, or plastics shall be identified at points where confusion would introduce hazards to employees.
• Relieve pressure before disconnecting any pipes. When dismantling or opening closed pressurized or gravity fed systems, internal pressure shall be relieved or other methods utilized to prevent sudden release of pressure or spraying of liquid.
• Inspect pipes for damage or corrosion before handling.
• Use appropriate tools and techniques for cutting and joining pipes.
• Follow all safety regulations and guidelines.
• Make joints liquid-tight. Welded or screwed joints or approved connectors shall be used. Threaded joints and connections shall be made up tight with a suitable lubricant or piping compound.

Regulatory compliance requires that piping systems be properly identified to prevent hazards to employees. Methods of identification include complete color painting, color bands, names or abbreviations stenciled on the pipe, or tags securely fastened to the system. [1] [1]

All pressure piping shall be designed, constructed, installed, and maintained in accordance with good engineering practice. Piping which meets the requirements of the applicable ANSI B31 standard shall be considered as providing reasonable safety. [2]