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Posts Tagged ‘gypsum’

Theoretical Gypsum Requirement (TGR) Models

Friday, July 6th, 2012

By John Ashworth,  ALS Environmental – Canada

ALS Environmental Lab TestingGypsum is often applied as an amendment to soils that exhibit a high sodium adsorption ratio (SAR).  The addition of gypsum can reduce a soil’s clay plasticity, thus improving drainage and ease of cultivation. Estimating the correct amount of gypsum required to remediate a particular site is an inexact science requiring experience and consideration of specific site history and conditions, but models described in the literature can produce theoretical estimates to provide guidance.  As a service to our clients, ALS now offers two theoretical calculations for gypsum requirement that are suited to two common categories of salt-impacted soil on the Canadian prairies.

How a Laboratory Can Help You Identify Problem Chinese Drywall

Tuesday, April 6th, 2010

by Alyson Fortune, Air Quality Scientist; Michael Tuday, Director of R&D; Nicole Pannone, Air Service Specialist

Identify Problem Chinese Drywall

For the past four years, the U.S. Consumer Product Safety Commission (CPSC) has been receiving complaints from homeowners regarding corrosion and odors in their homes linked to imported drywall. The problem drywall, which was installed in homes between 2004 and 2007 and is commonly referred to as “Chinese drywall,” has resulted in more than 2,500 complaints to the CPSC. The complaints originated from homeowners primarily in the southeastern part of the United States, but have since been reported throughout the country.

Homeowners have linked their Chinese drywall to corrosion in their air conditioner coils, corrosion in copper wiring, and emission of foul odors. The odors have been described as smelling like rotten eggs, burnt matches, and other sulfurous smells.

Chinese Drywall Columbia Analytical has been studying this issue and testing both foreign and domestic drywall samples since February 2008. Laboratory tests have been developed to aid in the identification of defective drywall products. These tests may be used to verify visual home inspections and determine if corrosion effects are from drywall and not from other household items, such as carpets, cleaners, paints, or personal care products.

This article presents a chronology of how Columbia Analytical established their test methods for determining problem drywall and how each of the issues that arose was resolved with a laboratory solution.

See Chinese drywall lab tests and results…