Several factors contribute to the betterment of Indoor Environmental Quality (IEQ). Poor IEQ is almost every time blamed on HVACR systems, particularly on the insulation materials used. In the second and concluding part, we find out how insulation materials actually help improve the quality of indoor environment and why preventive maintenance and system cleaning still remain relevant. Jerome Sanchez reports.

In recent years, there has been an increased focus on the quality of indoor air. The heightened attention was due to the surfacing of cases of “sick buildings” reportedly attributed to construction materials, interior furnishings and volatile organic compounds, among others.

According to a publication of the North American Insulation Manufacturers Association (NAIMA), entitled “An Essential Component of Indoor Environmental Quality: Fibreglass HVAC Insulations”, National Institute for Occupational Safety and Health (NIOSH) of the US, identifies inadequate ventilation as the major source of poor Indoor Environmental Quality (IEQ). For this reason, the publication highlights that whenever IEQ problems arise, the primary focus is often on the HVACR system.

Causes of poor IEQ

One of the primary components of an HVACR system that is usually the target of poor IEQ complaints is insulation, particularly fibreglass insulation. In defense of fibreglass insulation, the same NAIMA publication points out that air being distributed through the ducts may also contain contaminants that are completely disparate from insulation. “It is important to note that the air handling systems have many other components besides duct work, including heating units, air conditioners, vents, fans, fan coil units and others,” the report cites. It adds that faulty operation and maintenance of HVACR systems can also be a cause of poor IEQ.

The report admits that formaldehyde gas is another potential source of poor IEQ. “Fibreglass insulations are manufactured with a phenol formaldehyde resin,” it says, but clarifies that the resins used in the manufacture of fibreglass are cured and emit little formaldehyde (CH2O). This claim is supported by a study sponsored by the US Consumer Product Safety Commission that reveals that fibrous glass insulation products appear to be weak CH2O emitters with a minimal impact on indoor CH2O concentrations.

Some industry players also point out that glass fibres from fibreglass insulation materials can erode from the airstream surface and can cause irritation and allergies to occupants. An article from the NAIMA Air Handling Committee, entitled “Glass Fibre Air Transmission Systems: The Facts about Airborne Fibres”, however, contradicts the claim, saying that studies conducted over a period of 25 years, including UL 181 tests and a World Health Organisation report, show that fibreglass duct liner and fibreglass duct board exhibit insignificant signs of fibre erosion on surfaces in typical HVACR ducts.

Building occupants themselves are reported to be possible causes of poor IEQ. The occupants may release cigarette smoke, perfume, human cells, viruses and bacteria into the air on a daily basis. If the occupied space is poorly designed or unmonitored, these contaminants can reportedly severely compromise a person’s health.

How insulation can help the cause

Thermal and acoustical occupant comfort is a salient component of IEQ. Insulation products like fibreglass insulation are claimed to be able to help maintain a consistent air temperature throughout the system; reduce condensation, and consequently, repress the growth of microbes and moulds; absorb noise from the system’s operation; and conserve energy.

According to “An Essential Component of Indoor Environmental Quality: Fibreglass HVAC Insulations”, fibreglass insulation materials can help maintain consistent air temperature by reducing heat transfer across the duct system. This, says the publication, allows the building’s HVACR system to deliver conditioned air at designed temperatures. Moreover, by maintaining consistent air temperature, insulation materials can help increase occupant comfort and reduce consumption of electricity. Insulation materials like fibreglass can also reduce the chances of microbial growth and proliferation, as well as other moisture-related building damage by eliminating preconditions for microbial growth, including condensation and moisture, the publication claims.

Fibreglass insulation materials can help in the reduction of transmission of equipment and air flow generated noise through the duct system. It is can also contribute to lessening cross-talk from one room to another through the duct system, according to the above-mentioned article.

In addition to the afore-mentioned benefits of fibreglass insulation materials to the betterment of IEQ, the same report points out that “cleanability” and integrated anti-microbial protection in the material are additional benefits of using this type of insulation.

Cleaning and preventive maintenance

According to industry players, the best way to maintain efficiency, quiet air delivery, occupant comfort and cost effectiveness of an HVAC system still lies in following a regular system operation and maintenance schedule. Maintenance procedures include inspection, detection and remediation of probable sources of airborne contaminants and moisture, affirms “An Essential Component of Indoor Environmental Quality: Fibreglass HVAC Insulations”.

There may, of course, be times when cleaning may be needed. Currently, there are several cleaning methods available. But the three most common are reportedly contact vacuuming, air washing and power brushing.

Contact vacuuming involves the use of a portable vacuum with High-Efficiency Particulate Air (HEPA) filtration. Explaining how the cleaning is done, the same report says that there is direct contact between the brush head and the interior of duct surfaces to remove dirt and debris.

Air washing, on the other hand, is said to involve the introduction of compressed air into the duct through a hose terminated with a “skipper” nozzle. The dislodged dirt and debris reportedly become airborne, and are drawn downstream through the duct and out of the system by the vacuum collection equipment.

Power brushing, the report explains, entails the use of pneumatically or electrically powered rotation bristle brushes to loosen dirt and debris which are drawn downstream into a vacuum collector.

Conclusion

Insulation materials play a vital role in achieving IEQ. Insulation material such as fibreglass helps in the maintenance of air temperature, reduction of condensation, repression of moulds and microbes and absorption of sound from equipment operation. The use of fibreglass insulation has been questioned by a few industry players due to its potential threat to the health of occupants.

NAIMA, an association of insulation manufacturers, however, has conducted studies and the results show that fibreglass insulation is safe to manufacture, install and use when recommended work practices are followed. In addition, industry players still recommend regular cleaning and preventive maintenance of HVACR systems to ensure its efficiency, its cost-effectiveness and to ensure comfort of occupants.