Pipe, Duct, and Equipment Insulation Systems
What this domain tests
System questions check whether you know the differences among pipe, duct, and equipment insulation: supports, securement, removable covers, and the effect of compression or air leakage.
Core rules
- Pipe insulation is usually factory-made pipe covering or wrap. Hangers and supports need inserts, shields, or high-density blocks so the insulation is not crushed and the vapor retarder is not broken.
- Duct wrap is installed on the outside of ducts; duct liner is installed inside the airstream. Wrap must be snug but not compressed, with joints sealed and facing continuous. Liner edges must be protected so fibers do not enter the airstream.
- Equipment insulation on tanks, vessels, and air handlers uses board, blanket, or block with bands, studs, or clips. Heads and nozzles need fitted pieces; removable blankets are used where access is required.
- Double-layer application is used when the specified thickness exceeds what one layer can handle, or to break joints and improve performance. Stagger layers.
- Removable covers belong on valves, flanges, filters, and access doors that need service.
Worked example
A 12-inch chilled-water pipe requires 2-inch insulation. Use two 1-inch layers or a 2-inch pipe covering rated for the service, with a continuous vapor retarder. At each hanger, install a high-density insert or shield, then seal the jacket. The reasoning: the hanger is a compression point; if the insulation is crushed, the vapor retarder is damaged and condensation can start.
Traps
Compressing duct wrap at corners; putting duct liner where the airstream will erode it; forgetting removable covers; and breaking the vapor retarder at supports. Also, confusing pipe insulation sizes with actual pipe outside diameter.