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  2. Duct (flow) - Wikipedia

    en.wikipedia.org/wiki/Duct_(flow)

    Kinks in flexible ducting must be avoided. Some flexible duct markets prefer to avoid using flexible duct on the return air portions of HVAC systems, however flexible duct can tolerate moderate negative pressures. The UL181 test requires a negative pressure of 200 Pa. To use flexible ducting in a system, make sure to pull the duct tight so you ...

  3. HDPE pipe - Wikipedia

    en.wikipedia.org/wiki/HDPE_pipe

    HDPE pipe is a type of flexible plastic pipe used to transfer fluids and gases.It is often employed for replacing aging concrete or steel main pipelines.Constructed from the thermoplastic HDPE (high-density polyethylene), it has low permeability and robust molecular bonding, making it suitable for high-pressure pipelines.

  4. Piping and instrumentation diagram - Wikipedia

    en.wikipedia.org/wiki/Piping_and_instrumentation...

    Pipe classes and piping line numbers; Flow directions; Interconnections references; Permanent start-up, flush and bypass lines; Pipelines and flowlines; Blinds and spectacle blinds; Insulation and heat tracing; Process control instrumentation and designation (names, numbers, unique tag identifiers), including:

  5. Drain-waste-vent system - Wikipedia

    en.wikipedia.org/wiki/Drain-waste-vent_system

    Double trapping is prohibited by plumbing codes due to its susceptibility to clogging. In the U.S., every plumbing fixture must also be coupled to the system's vent piping. [1] Without a vent, negative pressure can slow the flow of water leaving the system, resulting in clogs, or cause siphonage to empty a trap. The high point of the vent ...

  6. Ductile iron pipe - Wikipedia

    en.wikipedia.org/wiki/Ductile_iron_pipe

    [3] [16] A 2003 report by researchers from the National Research Council of Canada noted that "both good and poor performances" of polyethylene sleeving had been reported. [10] However, a study in the Ductile Iron Pipe Research Association's Florida test site found that, compared with uncoated pipes exposed to a corrosive environment, pipes ...

  7. Copper tubing - Wikipedia

    en.wikipedia.org/wiki/Copper_tubing

    Soft (or ductile) copper tubing can be bent easily to travel around obstacles in the path of the tubing. While the work hardening of the drawing process used to size the tubing makes the copper hard or rigid, it is carefully annealed to make it soft again; it is, therefore, more expensive to produce than non-annealed, rigid copper tubing.

  8. Duct leakage testing - Wikipedia

    en.wikipedia.org/wiki/Duct_leakage_testing

    A duct leakage tester is a diagnostic tool designed to measure the airtightness of forced air heating, ventilating and air-conditioning (HVAC) ductwork. A duct leakage tester consists of a calibrated fan for measuring an air flow rate and a pressure sensing device to measure the pressure created by the fan flow.

  9. Risk-based inspection - Wikipedia

    en.wikipedia.org/wiki/Risk-based_inspection

    Risk-based inspection (RBI) is an optimal maintenance business process used to examine equipment such as pressure vessels, quick-opening closure - doors, heat exchangers, and piping in industrial plants. RBI is a decision-making methodology for optimizing inspection plans.