Introduction to Construction Quality
Assurance-Inspectors Certification Program
(CQA-ICP)
The Construction Quality
Assurance-Inspectors Certification Program (CQA-ICP) is administered by the
Geosynthetic Certification Institute which is a branch of the Geosynthetic
Institute. It is located in Folsom,
Definition of CQA (as opposed to CQC)
Construction quality assurance (CQA) and construction
quality control (CQC) are widely recognized as critically important factors in
overall quality management for waste containment facilities of all types. This includes geosynthetic materials as well
as natural soil materials. The best of
designs and regulatory requirements will not necessarily translate to
facilities that are protective of human health and environment unless they are
properly constructed. Additionally, for
geosynthetics, both manufacturing quality assurance (MQA) and manufacturing
quality control (MQC) are equally important.
Geosynthetics refer to factory fabricated polymeric materials like
geomembranes, geotextiles, geonets, geogrids, geosynthetic clay liners,
etc. The natural soils involved are compacted
clay liners and drainage soils of various types. In this context, the definitions of CQA as
contrasted to CQC are as follows:
- Construction Quality
Assurance (CQA): A planned system
of activities that provides the owner and permitting agency assurance that
the facility was constructed as specified in the design. Construction quality assurance includes
inspectors, verifications, audits, and evaluations of materials and
workmanship necessary to determine and document the quality of the
constructed facility. Construction
quality assurance (CQA) refers to measures taken by the CQA organization
to assess if the installer or contractor is in compliance with the plans
and specifications for the project.
- Construction Quality
Control (CQC): A planned system of
inspections that is used to directly monitor and control the quality of a
construction project. Construction
quality control is normally performed by the geosynthetics installer, or for natural soil materials by the
earthwork contractor, and is necessary to achieve quality in the
constructed or installed system.
Construction quality control (CQC) refers to measures taken by the
installer or contractor to determine compliance with the requirements for
materials and workmanship as stated in the plans and specifications for
the project.
The
certification program to be described herein focuses entirely on CQA. Two different programs are offered; one is
focused on geosynthetic materials and the other on compacted clay liners. A candidate can take both programs if
desired. A complimentary, but completely
separate, program on CQC is available through the International Associate of
Geosynthetic Installers (IAGI). Their
Website is as follows:
<<www.iagi.org>>.
The
following flow chart describes the interactions of MQA/CQA and MQC/CQC as they
apply to a particular project so as to produce an appropriate level of quality.
Figure 1 - Organizational Structure of Quality
Control and Quality Assurance Activities
*Note
that this certification program focuses on both geosynthetic and compacted clay
liner construction quality assurance (CQA) and not directly on manufacturing
quality assurance (MQA).
The Value of CQA
The electrical leak location survey (ELLS) method
was developed in 1984 and was slow to initially be implemented but for the past
10-years provided a wealth of data on leaks of geomembranes placed in the
field; both uncovered, and after soil covering.
For uncovered geomembranes the water puddle technique (ASTM D6747 and
D7002) is used and for soil covered geomembrane the dipole technique (ASTM
D6747 and D7007) is used. The following
photographs (compliments of A. Rollin) show each technique being used.
(a) Water Puddle Technique (b) Dipole Technique
Figure 2 - Electric Leak Location Survey Techniques
In a paper by Forget, Jacquelin
and Rollin (2005) a comparison of exposed geomembrane leakage without CQA and
with CQA has been generated. Figure 3
shows the incidence of holes for these two situations. The result is that an average of 22 leaks/ha (9.0
leaks/acre) occurred in 14 projects without CQA; whereas an average of 4
leaks/ha (1.6 leaks acre) occurred in 43 projects with CQA.
Figure 3 - Exposed Geomembrane Leakage Without and
With CQA
The situation for covered geomembranes [usually with
300 mm (or 12. in.) of sand or gravel] is even more dramatic. The result from 42-projects is that an
average of 16 leaks/ha (6.5 leaks/acre) occurred without CQA; whereas an
average of only 0.5 leaks/ha (0.20 leaks/acre) occurred with CQA.
This reference, and others,
indicate that there is a direct
relationship between leak occurrence and the presence or absence of a credible
CQA program. Of course, the tacit
assumption is that a “credible” CQA program is being offered and it is this
program being described that will hopefully fill this need.