Fiberglass Air Duct Liners | A Serious Indoor Air Quality Concern

Most commercial air duct systems are internally lined with fiberglass duct liners.  Deteriorating fiberglass duct liner is a very common cause for indoor air quality complaints and adverse health effects.

Fiberglass Duct Liner

Fiberglass internal duct liner is commonly used in many commercial heating, ventilation, and air conditioning (HVAC) system.  Fiberglass duct liner provides sound attenuation by dampening noise from HVAC equipment, and sound from adjacent office spaces.  Fiberglass duct liner provides thermal insulation for air ducts, preventing the air ducts from losing expensive conditioned air.

Fiberglass Duct Liner Deterioration

Over time internal fiberglass duct liner is exposed to varying degrees of air turbulence, temperature and humidity.  These environmental changes take its toll on the duct liner, breaking down its primary seal.

The primary seal is a black gritty coating on the surface of the duct liner which locks down the fiberglass fibers.  Deteriorated primary coating migrates through the ventilation system depositing within HVAC components and eventually entering the indoor air.

After the primary seal has fully deteriorated, it allows raw fiberglass fibers to be exposed to the airstream.  Turbulent airstreams wick the raw fiberglass fibers through the ventilation system, creating additional deposits within HVAC components and exposing building occupants to raw fiberglass fibers.

Health Effects of Fiber Glass Fibers

Health effects from exposure to fiberglass can be different depending on the fiber size and type of exposure.  Fiberglass, at a minimum, is an acute physical irritant to the skin, eyes, and upper respiratory tract.

  • While no long-term health effects should occur from touching fiberglass. Rashes can appear when the fibers become embedded in the outer layer of the skin.
  • Eyes may become red and irritated after exposure to fiberglass as occupants touch horizontal surfaces with deposits of fiberglass fibers, and rub their eyes.
  • Soreness in the nose and throat can result when fibers are inhaled. Asthma and bronchitis can be aggravated by exposure to fiberglass.
  • Temporary stomach irritation may occur if fibers are swallowed.

How Can Fiberglass Air Ducts Be Repaired?

If caught in the early stages of deterioration the internal fiberglass duct liner can be repaired.  Fiberglass duct liner can be resurfaced with an encapsulate specifically designed for HVAC systems.   Initially a commercial air duct cleaning needs to be performed to remove the foreign debris from the air duct surface to ensure for a proper bond.  After the air duct system is cleaned, the encapsulate is applied to the air duct surface locking down the fiberglass fibers.

If the internal fiberglass lining to too deteriorated, the lining must be removed and replaced.  If the damage is localized,  new internal internal insulation can be installed within the ducting.  If the damage is extensive, consider removing the damaged insulation and wrapping the air ducts with an external fiberglass insulation.

Pigeons Cause Devastating Indoor Air Quality and HVAC Problems

Pigeon problems have devastating effects on the heating and cooling components and indoor air quality of a commercial facility.  Pigeon problems affect employees, maintenance personnel and potentially customers.

HVAC Systems Make Perfect Pigeon Coups

Unfortunately, rooftop heating and cooling units are a perfect place for pigeons to nest.  To seek shelter from the elements, pigeons typically enter air handler units through the fresh air intakes and build their nests within the HVAC unit.  A single pair of pigeons can generate up to 18 new pigeons per year.  Once a nest is established, pigeons are extremely territorial.

Indoor Air Quality

An HVAC system distributes the air throughout a facility.  The bacteria, fungi and parasites that live and grow in pigeon droppings can carry and transmit any of 60 known diseases.  Exposure to pigeon feces and other organic matter such as feathers carcasses and nesting material from the HVAC system may pose a considerable health threat to people who come in contact with them or inhale the airborne particles from them.  Every precaution should be taken to ensure that building occupants and maintenance personnel are protected from pigeon feces.

Damage to HVAC Systems

As pigeons live in the air handler units they peck through filter material allowing unfiltered air and pigeon contaminants to freely enter the ventilation system.  There are numerous damaging effects to an HVAC system.

  • Filter banks: Pigeons peck though filter banks allowing for unfiltered air and pigeon contaminants to be drawn into HVAC components and supply air ducts.
  • Fan Blower: Pigeon debris builds within the fan blades decreasing airflow.
  • Air conditioner coils: Pigeon debris compacts within air conditioner coils and clogs the drain pan.
  • Insulation: Pigeons peck at insulation to create nesting material allowing for raw fiberglass fibers to enter the airstream.

How Do You Correct Pigeon Problems?

 

Hire a professional wildlife service or animal control contractor to relocate existing pigeons, and install devices to prevent future intrusions.  Have the pigeon debris removed by a professional air duct cleaning contractor.  Be sure to have the air duct cleaning contractor inspect the supply air ducts downstream of the HVAC unit.