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Small fiberglass fragment in airDetection & Hazards of Large vs Ultra-small Airborne Fiberglass & Fiberglass Dust Fragments in buildings

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Detection of airborne fiberglass:

How Airborne particle size effects on air quality testing: This document provides information about the role of particle size and lab procedures in the detection of small particles of fiberglass fragments and indoor air quality fiberglass contamination issues in residential and light-commercial buildings.

This article describes risks of inaccuracies in airborne fiberglass and similar particle studies if the forensic analyst fails to use procedures that can detect very small particles & fragments.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Sources & Detection of Sub-Micron Sized Fiberglass Fragments in Building Air

Certainteed blown in fiberglass (C) Daniel FriedmanExperienced forensic microscopists will almost certainly agree that it is very common to find fiberglass insulation fragments in indoor dust and air samples. Most often analysts recognize and identify large fiber particles - lengths considerably longer than other indoor dust analytes such as mold or pollen.

Here we will discuss: Large Non-Respirable Fiberglass Insulation Particles. Special problems with very small fiberglass fragment particles down to sub-micron size. Basic Dust Cleanup Advice for Indoor Fiberglass Fragments or other Small Particles. Prudent Avoidance Advice About Fiberglass Insulation Dust.

Larger Non-Respirable Fiberglass Insulation Particles - 3.5u & larger

These comparatively large fiberglass particles are typically low enough in frequency and large enough in size that experts will agree that they are unlikely to pose a health risk to building occupants.

Indeed manufacturer MSDS sheets indicate that "There are no known health effects from the long term use or contact with non respirable continuous filament fibers.

As manufactured, PPG glass fibers are non respirable.

Nonrespirable fibers cannot reach the deep lung because they have a diameter of greater than 3.5 micrometers."[2]

Small, Respirable Fiberglass Insulation Particles - 1u - 2.5u range & possibly smaller

But what about the level of ultra-small [and respirable] fiberglass fragments that might be present in some buildings where insulation has been tramped-on, stomped about, or otherwise damaged and abused?

Kilburn (1992) found

Commercial rotary spun fibreglass used for insulating appliances appears to produce human disease that is similar to asbestosis.

Kilburn's findings were critiqued by Rossiter (1993).

In 2018 the level of exposure in normal buildings to and the hazards of such exposure to "small" fiberglass particles remain a topic of disagreement even when other studies have supported the assertion that there can be serious health hazards beyond dermatitis.

It would appear that "if you don't look for a particle, you won't find it and you won't report the particle" is a common problem with certain particles that may be present but not tested-for. That's particularly true if the mountant fluid used by the microscopist has a refractive index similar to glass (as in fiberglass) - the particles are there but they simply disappear from view under the microscope, regardless of magnification. (Fiberglass, even when you can see it in the microscope, also disappears under polarized light).

In our experience small fiberglass fragments in the 1u range may be present in a dust sample but will not be found unless the microscopist uses specific mounting media and scanning methods to detect these materials.

If a lab only notices and reports on large fiberglass fragments, unless the lab also specifically looked for very small fiberglass particles, the conclusion that no such particles were present is unreliable.

See DUST ANALYSIS for FIBERGLASS for a description of lab analysis of fiberglass in dust.

About these small fiberglass fragments, one manufacturer explains:

Chopped, crushed or severely mechanically processed fiber glass installed in a building and that has not been otherwise damaged may contain a very small amount of respirable fibers that could reach the deep lung.

The measured airborne concentration of these respirable fibers in areas where severe processing of fiberglass occurred has been shown to be extremely low and well below the TLV.

Repeated or prolonged exposure to respirable glass fibres may cause fibrosis, lung cancer and mesothelioma. PPG fiber glass in the form supplied, [italics ours] does not contain respirable fibers.[2]

Possible Hazards of Intact vs. Damaged Fiberglass Insulation Particles

Small fiberglass fragment in airWe agree that in proper and normal installations the assumption that intact fiberglass insulation sheds very little into the indoor environment, that the particles are large enough not to be inhaled deep into the lungs, and that at normal levels fiberglass is not likely to be hazardous to occupants.

The concern for the carcinogenicty of fiberglass is not new, and was cited by Stanton's rat study back in 1977.

A decade later McCurdy (1988) concluded:

If the potential of these fibers to cause lung cancer is dose-related, as is the case for asbestos, then it is likely that less risk accrues to today's workers and that the danger to homeowners with attic insulation of synthetic mineral fiber is negligible.

Interestingly that work cited long fibers as more-hazardous than short ones (for some vitreous fiber types) based on the observation that the body is able to break down small vitreous fiber particles.

Researchers generally agree that the most-common hazard to workers or others exposed to significant fiberglass dust is a form of dermatitis.

The microscope photo shown above, taken at relatively low magnification, perhaps 120x, shows indoor dust fragments including skin cells (pink) and also some long fiberglass fragments.

[Click to enlarge any image]

These particular fiberglass fragments are large enough to see easily.

DJF Opinion: Frequent presence of high levels fiberglass fragments in air and some dust samples, might suggest that damaged insulation inside an HVAC duct system or exposed and mechanically-damaged fiberglass insulation in the building may be contributing unwanted and potentially unsafe levels of these fibers.

Small Fiberglass Particles May Not Have Been Detected Nor Adequately Studied

However it is possible that the presence of and level of small fiberglass particles has not been adequately studied, perhaps because those particles do not normally occur in intact fiberglass materials and perhaps because, as I've argued, they go un-detected even when damaged fiberglass is present and being distributed in indoor air.

But having inspected several thousand buildings, we have certainly encountered conditions in which insulation has been installed or damaged in a manner risking an increased level of these small fragments.

Opinion: I frequently found fiberglass fragments in indoor air samples, particularly where fiberglass HVAC duct material are in a building and where fiberglass insulation has been left exposed in a living or occupied area (such as in the ceiling above an unfinished basement being used as an office or family play area).

It is perfectly normal to find some fiberglass in most indoor air and dust samples.

But sometimes we find a notable increase in the volume or number of fiberglass fragments in air and dust samples, and we may, if we look with care, find a high frequency of ultra-small micron-level fiberglass fragments - almost always in an environment where fiberglass insulation or duct liner has been mechanically damaged.

How does this happen? If someone has attempted to mechanically "clean" HVAC duct work which was lined with fiberglass insulation, it is likely that I'll find a higher presence of fiberglass fragments in indoor air and in settled dust.

The skin, eye, and respiratory irritant effects of exposure to fiberglass dust and particles has been widely acknowledged and appears, for example, in the MSDS for various fiberglass products. [1][2][3][4][5]

But in our opinion a concern regarding abnormally-high ultra-small fiberglass fragments are present.

"Abnormally high" would benefit from a quantitative definition but given the current fiberglass exposure standards focus on large particles, we don't have a definition nor an exposure level for small fiberglass fragments.

Causes of Ultra-Small Fiberglass Particles: mechanical damage to insulation

What may be the sources of these fiberglass fragments? Here are some examples:

Heath Risks from Small Fiberglass Fragments? Maybe.

Watch out: While the fiberglass industry does not necessarily agree these particles in homes constitute a hazard, independent studies and warnings at US government health-related websites suggest that there may be carcinogenic or respiratory health hazards from exposure to high levels of fiberglass particles in some buildings and/or work environments.

Really? The exposure level of small airborne fiberglass particles is likely to depend on

Small particles in the 2.5u and below range are easily breathed deeply into the lung where they can be hard to expel. Some studies cited the ease with which the body dissolves or handles these ultra-small particles.

Yet small particulates are considered an indoor air pollutant. Airborne particles in the PM 2.5 size range (fine particles defined as 2.5 u and smaller in diameter ) to PM 10 (coarse particles) have been identified as a air pollution and as a human health hazard.

Basic Dust Cleanup Advice for Indoor Fiberglass Fragments or other Small Particles

If we find frequent presence of fiberglass fibers in air or interior dust samples further investigation, cleaning, and particularly investigation of air handling equipment and duct systems in the building would be appropriate.

If fiberglass HVAC duct work has been installed I very often find significant fiberglass levels in interior air and dust samples.

Because these materials cannot be mechanically cleaned and because I do not recommend encapsulant sprays, replacement could be in order.

We would not expect and do not usually find evidence of movement of significant levels of fiberglass fragments from insulated attics, nor from enclosed (finished) walls, ceilings into living areas under normal conditions.

Prudent Avoidance Advice About Fiberglass Insulation Dust

It is possible that small fiberglass particles in air may constitute a meaningful health risk (obviously depending on the overall exposure level) which has not been explored.

We suggest that that prudent avoidance would be appropriate. Improper cleaning or treatment of fiberglass ducts with biocides may in fact increase rather than decrease indoor air quality problems in a building, particularly if occupants have other respiratory or pulmonary concerns/vulnerabilities.

Small vs Large Fiberglass Particle Hazard Research

Research of health hazards associated with fiberglass exposure have focused on specific industries such as boat building, and catastrophic events such as bombings in London that disturbed fiberglass in buildings. See REFERENCES, FIBERGLASS HAZARDS for more detailed citations.

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Or see LAB IDENTIFICATION OF FIBERGLASS for forensic lab procedural notes about fiberglass particles.

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Articles on Fiberglass Hazards in Buildings

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