Geosynthetics August/September 2020 - 12

IAGI CERTIFICATION
Q: What is IAGI certification and can we
get it through GSI?
A: Nice to hear from you and thanks for
reaching out to us at the Geosynthetic
Institute (GSI). Unfortunately, I think you
want to get in touch with the International
Association of Geosynthetic Installers (IAGI)
instead of GSI. They have two different
programs, which are described below,
that may be of interest to your firm.
Program #1: IAGI's Certified Welding
Technician (CWT) program recognizes the
knowledge, experience and skill of those
technicians who hold the certification.

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Engineers benefit from IAGI's CWT program
because certification verifies that the welders
on their job have experience in geomembrane
welding and meeting industry standards
of skill for those geomembranes they are
certified in. IAGI encourages all engineers
to require that any welding done on their
jobsite be done with CWTs.
Member companies who have invested
resources in training and testing their
welding technicians take pride in the skill of
their welding technicians. IAGI encourages
you to use companies that have made this
commitment to quality on your next job.
Program #2: IAGI's Approved Installation
Contractor recognizes geosynthetic
installation companies that meet a minimum
level of professionalism, ethics and business
practices. Approved Installation Contractors
must meet requirements in the following
areas: corporate history and business
practices, insurance verification, safety
training, and professional competence and
experience. Click on the links below for
additional AIC program information.
If you have any additional questions or
comments regarding the IAGI International
program, please contact the IAGI office at
iagi@iagi.org or +1 (720) 353-4977.

ULTRAVIOLET RADIATION
AND GEOMEMBRANES
Q: We are currently assessing some
geomembrane products for simulated
lifetime exposure for use in central Australia
and have been comparing values with the
Arizona example provided in your multiple
geomembrane test studies (GRI Report #44
and #47).

12

I have a query related to the value adopted
for the site-specific ultraviolet (UV) radiation.
Our source for our site indicates approximately
20 MJ/m2/day (Source: http://www.bom.gov
.au/jsp/ncc/climate_averages/solar-exposure/
index.jsp).
I understand the source adopted for the
GRI example is https://www.nrel.gov/gis/
solar.html.
Where the Arizona figure indicates
approximately 7.9 kWh/m2/day, which
equates to approximately 28.1 MJ/m2/day.
I wish to understand how the value of 28
MJ/m2/month (as used in your example)
is obtained. If you could please provide
some clarity on the matter it would be
greatly appreciated.
A: In short, these values have been handed
down by the equipment manufacturers of
weathering devices. Attached is GSI's best
present correlation.
Lifetime Equivalency from Laboratory
Weatherometers
GM1: UV fluorescent
half-life in lab=2100 hours
field lifetime=2.2 years
Thus: 1000 hours QUV=1.05 years
field (9.2 ×)
GM2: UV fluorescent
half-life in lab=8700 hours
QUV 1000 hours=1 year in field
field lifetime=8 years
Thus: 1000 hours QUV=0.92 years
field (8.1 ×)
GM3: Xenon arc
half-life in lab=4500 hours
Xenon 1000 hours=0.5 year in field
field lifetime=2.2 years
Thus; 1000 hours xenon=0.49 years
field (4.3 ×)
Conclusion: UV fluorescent is twice the
strength of xenon arc 1000 hours in QUV
at ASTM D7238 conditions equals a year
in Phoenix, Ariz.; 1000 hours in xenon arc
at ASTM D4355 conditions equals a year in
Phoenix, Ariz., field conditions.

Geosynthetics | August September 2020

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7/22/20 11:21 PM
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Geosynthetics August/September 2020

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