September 18, 2006

Opinion

There are benefits to performance-based systems

GIB McINTEE

special to DCN

The recent announcement by the Ontario Government regarding the release of the 2006 Ontario Building Code (OBC) formally ushers in performance based standards and specifications for all sectors of the Ontario construction industry.

While performance specifications are really nothing new to the ICI construction sector, the recognition of this specification method provides a number of benefits to both owners and contractors.

One of the key benefits to performance based systems is the fact that the construction team has the greatest degree of flexibility in achieving the performance requirements the owner and their consultants have identified in the contract documents. This allows for greater innovation and creativity that benefits everyone involved in the project.

Now, for performance systems to be effective, specifiers must identify quantifiable performance criteria that the construction team can meet. This requires both a strong knowledge of all the materials and building systems that are available for use, and the identification of specific test methods and minimum/maximum criteria that will be used for acceptance purposes.

To illustrate this fact, the compressive strength of concrete, tested in accordance with CSA A23.1/.2 requirements, has been one of the standard performance requirements used to evaluate concrete.

When a designer specifies the use of 32 MPa compressive strength concrete and references CSA A23.1/.2, they have defined both the test methods and set the performance limits for the concrete’s strength. In recent years we have seen the development of more advanced concrete test methods such as permeability measurements (via ASTM C1202), hardened air void testing (via ASTM C457) and linear shrinkage (via ASTM C157).

The challenge for the construction industry is to continue to develop new test methods and to set the appropriate performance criteria for each testing system.

Given the fact that performance based systems typically require more testing, since it is the results of the testing program rather than the following of prescriptive specifications that dictate both acceptance and rejection, the requirement for high quality testing takes on an even more important focus in a performance based world.

The issue of the importance of proper concrete material evaluation was a topic of significant importance at the Ontario General Contractors Association’s spring seminar where the proposed Canadian Council of Independent Laboratories’ (CCIL) new concrete correlation and field testing certification program was first discussed.

CCIL, working in conjunction with the Ready Mixed Concrete Association of Ontario (RMCAO) and a number of major owners such as the Ontario Ministry of Transportation (MTO), the Municipal Engineers Association (MEA) and representatives from the Consulting Engineer’s of Ontario, have spent the last 18 months developing a new certification system to improve the quality of concrete testing throughout the province.

This working group has developed a new concrete certification system that addresses the performance concerns of all the stakeholders.

The new certification program has been modelled on the existing CCIL Asphalt and Aggregate certification programs and, when fully implemented, will include two new CCIL certification classes for concrete: Type H – Concrete Compressive Strength Testing and Type J – Concrete Field Testing.

The Type H certification will be strictly for concrete testing laboratories and is based on the lab holding a current CSA A283 laboratory qualification and the laboratory successfully participating in a concrete strength correlation program.

Since the MTO is currently conducting concrete correlation programs for compressive strength, hardened air void system determination (AVS), rapid chloride permeability (RCP) and producing qualified lists of testing laboratories that can complete this work, the certification program will be phased in by CCIL at a later date.

The Type J certification will be phased in immediately for all concrete field testing personnel in Ontario and will be based upon the technician holding either CSA or ACI certification. This classification will apply equally to both testing laboratories and construction industry field personnel alike (contractors, concrete producers, owners). This certification system uses the existing CSA and ACI certification systems as the initial program requirements and then adds the following components:

• Annual concrete performance testing verification;

• Random technician qualification inspections;

• A formal reporting mechanism to address improper concrete testing practices;

• Verification that all concrete field testing equipment has been calibrated at the minimum frequencies identified in CSA A283;

• A complete listing of all CCIL Type J certified concrete technicians on the CCIL website.

The development of this new concrete certification system represents a monumental step forward for the Ontario construction industry. It provides a positive and proactive means for all members of the construction team to work together to improve the quality of concrete testing.

It also addresses potential risks general contactors, sub-contractors and concrete producers face as the industry transitions into a greater use of performance based specifications. The system has been identified as one of the key components in the OGCA/RMCAO “Best Practices Guidelines for Concrete Construction”.

Gib McIntee is the Chairman of CCIL Concrete Certification Committee, St. Lawrence Testing & Inspection Co.

References:: CSA A23.1/.2 – Concrete Materials and Methods of Concrete Construction/Methods of Test and Standard Practices for Concrete – 2004 edition; CSA A283 – Qualification Code for Concrete Testing Laboratories – 2000 edition; Best Practices Guidelines for Concrete Construction – OGCA & RMCAO publication, Jan. 2006.

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