Asbestos Detection in Vermiculite Spray-on Fireproofing

Asbestos Detection in Vermiculite Spray-on Fireproofing (SOF-V)

Item No. 198.8

Presenter: Craig Huntington

January 28, 2015

Part 1: History of Vermiculite with Asbestos

Part 2: RJ Lee Group LAB.055.1 • Determination of Asbestos in Spray-on Fireproofing containing

Vermiculite (SOF-V)

• Matrix reduction achieved through ashing, mild acid treatment, water washing and aggressive acid / base dissolution.

• PLM is used to identify and quantify chrysotile asbestos.

• PLM/SEM/EDS is used to identify and quantify both regulated and non-regulated amphibole asbestos.

2 Webinar Series – Item No. 198.8 RJ Lee Group

Item No. 198.8 Polarized-Light Microscopy method for identifying and quantitating asbestos in SOF-V bulk samples.

• Matrix reduction achieved through ashing, mild acid treatment, water flotation and heavy liquid mineral separation.

• PLM analysis identifies and quantifies chrysotile asbestos.

• PLM quantifies all amphibole asbestos together, but does not differentiate between regulated and non-regulated amphibole asbestos minerals.



The “New Approved Methods” include RJLG LAB.055.1 and Item No. 198.8

Introduction



Microscopic exam to check for vermiculite

Subsampling and crushing

Ashing to remove organics / cellulose

PLM analysis for amphibole asbestos

Heavy liquid centrifugation for amphibole asbestos

PLM analysis for chrysotile

Acid / Water treatment to dissolve carbonate and gypsum

If chrysotile % is >1%, then process complete

“Item No. 198.8 incorporates a two-step approach for the identification and quantitation of chrysotile and amphibole asbestos, including Libby amphiboles, in SOF-V.”

Organic material, hydrated calcium sulfates and carbonates are eliminated

from the sample through low temperature ashing, mild acid treatment

and water flotation.


Vermiculite Identification

• Vermiculite is a clay mineral produced by the low temperature

hydrothermal alteration and weathering of mica.

(Mg,Ca)0.7(Mg,Fe+3,Al)6.0[(Al,Si)8O20](OH)4.8H2O

• Vermiculite exfoliates when heated suddenly due to steam generation which forces the structural layers apart.


• Prior to the introduction of asbestos regulations in the 1970s, chrysotile was added to the fireproofing to provide mechanical strength and spalling resistance. Chrysotile does not occur naturally in vermiculite deposits.


Fiberglass bundle

• After the asbestos regulations were introduced, fiberglass was substituted for chrysotile.

Chrysotile: an asbestiform serpentine mineral mined and used extensively in North America.

Mg3[Si2O5](OH)4


35x Binocular photo

Occurs as a rolled sheet, which forms hollow fibers

Preliminary Examination of Spray-on Fireproofing as Received


The sample is ground, then ashed in a muffle furnace at 485 ± 5°C for a minimum of 10 hours.


Sample ground in mortar and pestle Sample ashed in muffle furnace


250ml conical flask with sample in 150 ml solution of hydrochloric acid and filtered water and stirred for 15 minutes.

Additional filtered water is added to bring the water surface to the top of the flask.

Float is removed from surface

The ashed sample is acid treated to remove carbonate and gypsum.


Dried float material Filtered sink material

Microscopic Analysis of Chrysotile



Filtered sink fraction

Ground sink fraction ready for PLM analysis

In Polarized Light Microscopy, chrysotile is Colorless

Occurs in fiber bundles

Exhibits asbestiform morphology

Refractive indices are typically nα=1.548 nγ=1.556


Plane Polarized Light 1.550 RI oil Cross Polarized Light 1.550 RI oil


Plane Polarized Light Cross Polarized Light

PLM photomicrographs of a vermiculite flake and chrysotile bundle (arrows) in 1.630 refractive index oil from ground sink fraction.

Heavy Liquid Centrifugation is used

to separate less dense minerals from amphibole for asbestos

determination.


The sink residue which remains following chrysotile examination is dispersed into two centrifuge tubes containing density-adjusted heavy liquid 2.75 g/cc and placed in centrifuge.



PLM Analysis for Amphibole Asbestos


• Amphibole minerals

May be asbestiform, non-asbestiform, or both.

Asbestiform amphiboles found in SOF-V typically occur as individual bundles or naturally intergrown into the vermiculite sheets; they are not added as a separate constituent to the fireproofing.

The amphibole asbestos minerals typically associated with vermiculite deposits:

• anthophyllite asbestos - regulated

• tremolite-actinolite asbestos - regulated

• richterite-winchite asbestos - non-regulated


35x binocular image of filtered sink fraction


Filtered sink fraction from heavy liquid separation showing abundant sheet structures in sink fraction

Item No. 198.8 utilizes PLM for analysis of amphibole asbestos. PLM is unable to determine the species of amphibole asbestos due to overlapping optical characteristics. Therefore:

Results are quantified as “amphibole asbestos,” but are not distinguished between regulated and non-regulated minerals.


PLM photos of amphibole asbestos between the sheets from heavy liquid sink fraction in 1.630 RI oil.


Plane Polarized Light Cross Polarized Light

Summary of Results


The total asbestos content is calculated as:

Total percent asbestos = %Chrysotile + %Amphibole Asbestos *The percentage of asbestos will be rounded to two significant digits.

The SOF-V sample is classified as ACM (asbestos-containing material) if the total percent asbestos is

greater than 1%.

28 RJ Lee Group Webinar Series – Item No. 198.8

• “No asbestos detected” – samples contained no asbestos points or trace asbestos by PLM.

• “Trace chrysotile / amphibole asbestos detected” –samples contained no asbestos points out of the 400 (or more) non-empty points, but did contain asbestos positively identified by PLM.

• “Chrysotile / amphibole asbestos detected at ___%” – percentage given for each type of asbestos if asbestos was identified at the point(s) being counted.


A Comparative Summary


RJLG LAB.055.1 vs. Item No. 198.8

RJLG LAB.055.1 Item No. 198.8 Both methods utilize two step matrix reduction processes prior to determining chrysotile and

amphibole asbestos content in SOF-V.

Utilizes ashing and mild acid dissolution prior to PLM analysis for chrysotile.

Utilizes ashing, mild acid dissolution and water flotation prior to PLM analysis for chrysotile.

Utilizes PLM to identify and quantify chrysotile using a 400 point count method.

Utilizes a 400 point count process to quantify chrysotile only if its presence is confirmed during the initial PLM scan of 8 slides.

Dissolves vermiculite matrix prior to PLM and SEM analysis for amphibole asbestos; liberates amphiboles trapped between the vermiculite sheets.

Utilizes heavy liquid (2.75 g/cc) and centrifuge to separate low from high density minerals prior to PLM analysis for amphibole asbestos.

Utilizes both PLM and SEM to quantify amphibole asbestos and EDS to speciate the amphibole mineral(s). Distinguishes between regulated and non-regulated amphibole species.

Utilizes PLM to quantify amphibole asbestos, but is unable to speciate the amphibole or determine whether it is regulated or non-regulated amphibole species.


VermicuLine: 724.387.1972

or

[email protected]

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Be sure to watch for our future webinars!


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The 19th Annual PACNY Environmental Conference

February 25, 26, 27, 2015 Turning Stone Resort and Casino, Verona, NY

Annual Joint NYC AIHA/ASSE/SENY Meeting

February 24, 2015 (9:30AM – 12:00AM) Lennox Hill Hospital - Training Center

100 East 77th Street, New York, NY

RJ Lee Group

VermicuLine: 724.387.1972

or

[email protected]

All webinars are available for download at http://hubs.ly/y0tdxM0.

Be sure to watch for our future webinars!




Documents

Asbestos Detection in Vermiculite Spray-on Fireproofing