The introduction of HVAC systems established the need for pipe insulation. Forced ventilation ducting systems are designed to supply and return fresh air and regulate air to occupied Spaces in a building. Insulation is used to control noise propagated by pipes, reduce heat loss or gain through pipe walls, and minimize water vapor condensation. The lined piping system delivers fresh and regulated air quietly and safely throughout the occupied space at the correct design temperature.

1. What is glass fiber duct lining?

Fiberglass acoustic pipe linings are fiberglass insulation materials used as sound absorption and thermal insulation linings for the inner surfaces of pipes, plenum chambers and other air handling equipment, and can handle air up to 121 ° C.

2. Where is the air duct lining used?

Acoustic comfort, thermal comfort, and safety are key to many types of systems, buildings, and Spaces within high-occupancy commercial buildings, including: conference rooms, hospitals and healthcare, performance halls/theaters, churches/temples/houses of worship, recording studios, office Spaces, hospitality/accommodations, educational facilities, high-speed air distribution systems, and more. Plumbing systems that meet the space conditioning needs of these uses are prime candidates for buildings and systems using fiberglass acoustic and thermal pipe linings.

3. Why is glass fiber used in pipeline lining?

Fiberglass acoustic and thermal pipe linings provide high-performance sound absorbers that are durable, do not react to metals commonly used in HVAC pipe construction, and provide a high level of fire safety. Fiberglass pipe linings provide these functions while being extremely cost effective and highly versatile.

4, proper use/function

Fiberglass pipe linings are often misunderstood by the construction community (owners, designers and installers). Products that make good sound energy control materials can usually also make good thermal energy control materials. This is especially true for fiberglass products, including pipe linings.

One of the functions of the pipe lining is sound insulation, designed to reduce the transfer of sound energy from one location to another. This feature involves eliminating sound transmission from an operating HVAC air distribution system and enhancing the acoustic part of the indoor Environmental Quality (IEQ).

Another function of the pipe lining is insulation, designed to slow heat gain and loss, with the main goals being energy saving, condensation control and enhanced thermal comfort for IEQ. Pipe lining is generally a less cost-effective method of providing thermal energy control. If acoustic control in an HVAC air distribution system is not required, another form of insulation may be considered to provide thermal control functions.

A very common practice for air distribution piping is to line and externally insulate the air distribution components to provide the most cost-effective combination of the two materials. For example, if a piping system requires R-8 insulation for acoustic and thermal control, a designer might choose a 2.5cm pipe liner with an R-value of 4.2 after installation, then add a layer of fiberglass pipe wrap to the outer surface of the pipe, providing an R-value of 3.8 or greater for installation. The combined heat value will meet or exceed the need for insulation values while providing high quality and cost-effective acoustic comfort. This combination provides efficient sound and thermal energy control.

Based on the fiberglass air duct lining products currently on the market, fiberglass air duct lining can be used in HVAC pipes and equipment to serve HVAC air distribution systems with airflow speeds up to 1829 meters per minute. As mentioned earlier, not all pipe linings have the same speed level. Confirm the performance of the product under consideration. Fiberglass pipe linings are only suitable for HVAC air distribution systems with a maximum operating temperature of 121 ° C. It does not apply to kitchen exhaust, fume hood exhaust, solid delivery systems, or other similar plumbing.

Glass fiber pipe lining products can be lined with rectangular/square, spiral round, spiral flat oval geometry in single or double wall pipe structures. Other air distribution system components for which pipe linings may be installed include air processors, integral equipment cabinets, fan coils, VAV boxes, sound attenuators, hydrostatic ventilation systems, and transmission ducts, as well as air termination equipment such as boots, boxes, and diffusers.

5, the form of pipe lining material

Glass fiber pipe lining material is supplied in roll form and rigid form in sheet form. Blanket/roll products are available in a variety of thicknesses and widths to meet performance and application requirements. Rigid/plate forms are somewhat limited in meeting the needs of large static pressure Spaces.

6, pipeline sound transmission and acoustic performance

The types of uncomfortable sounds that plumbing systems may encounter or produce include:

(1) Crosstalk noise: airborne noise, transmitted from one room to another using gas waves, such as sound or music transmitted through a diffuser in an adjacent room located on the same pipe

(2) Insertion noise: airborne and/or structural transmission sources that travel from one room to another through vibration, such as noise generated by fans of HVAC systems

(3) Other noise/system noise: howling noise, rumbling noise, popping noise

Sound or noise attenuation is the loss of sound wave energy or sound damping, which is an interruption that reduces the volume and quality of sound waves, that is, the loss of sound energy. Sound or noise attenuation for HVAC air distribution can take the form of sound diffusion, sound absorption, and vibration reduction (noise management).

The effectiveness of pipe linings is typically measured in one of three ways:

(1) Sound absorption coefficient (SAC) - the sound energy absorbed when striking a specific surface. SAC represents the percentage of sound energy absorbed at a particular frequency.

(2) Noise reduction factor (NRC) - the average SAC for the octave center frequencies of 250, 500, 1000, and 2000 Hz.

(3) Sound insertion loss - a reduction in sound pressure level due to the placement of a pipe liner in the sound path between the sound source and the receiver. The value is measured in decibels.

7, density and thickness performance

It is generally believed that increasing density is the best way to improve the sound absorption performance of glass fiber pipe lining. However, increasing the thickness of the pipe lining generally provides a higher reduction in sound transmission than increasing the density. It is important to know the range of frequencies considered, as increasing density may be more effective at higher frequencies.