Q: Have the requirements for becoming a certified pervious concrete installer changed?
A: We asked Scott Erickson to respond to this question: Not exactly, but the new ACI 522.1-13, Specification for Pervious Concrete, now requires that pervious concrete must be placed and finished by a National Ready Mixed Concrete Association-certified Pervious Concrete “Installer” or “Craftsman.” The previous edition of the ACI 522 specification only required that contractors have an NRMCA-certified Pervious Concrete “Technician” on a project. So now on any project where the ACI 522.1-13 specification has been referenced in the contract documents, the contractor must employ at least one certified Craftsman “who must be onsite, overseeing each placement crew during all concrete placement,” or three certified Installers “who must be onsite working as members of each placement crew during all concrete placement.” The differences among the three levels of certification are significant:
- Certified Technicians are only required to pass a written test—there are no experience requirements and no hands-on performance exam.
- Certified Installers must:
- pass the Technician written test, and
- have pervious installation experience of at least three projects with total area exceeding 10,000 square feet, and
- pass a hands-on Performance Evaluation.
- A Certified Craftsman must:
- pass the Technician written test, and
- hold a current ACI Flatwork Finisher certification, and
- have documented evidence of work experience constructing pervious concrete projects—a minimum of 1500 hours of work experience if he also passes the hands-on Performance Evaluation or 3000 hours without the Performance Evaluation.
To help contractors qualify their workers for these higher levels of certification, most contract documents allow contractors to hire a certified Craftsman as a consultant to supervise during construction. There are, however, only 32 NRMCA-certified Craftsmen in the U.S.
The Performance Review that must be passed in order to upgrade to Installer requires the applicant to demonstrate the ability to recognize proper mix hydration, to describe how to adjust improperly hydrated mixes, and to demonstrate a thorough knowledge of proper placing, compaction, and curing. Performance reviews are being offered by many NRMCA local chapters and will also be offered during the 2014 World of Concrete.
ACI Committee 522 upgraded the qualifications for pervious concrete installers based on the conviction that inexperience and pervious concrete are a dangerous combination. Pervious concrete is not difficult to place and finish, but it is different. Some Technician-level classes do not include hands-on pervious placement as a requirement for passing the exam. The new ACI 522.1 requirements assure that pervious contractors will have experienced personnel on the job. The industry wants to make sure the contractor will be able to recognize the right moisture content and understand the consequences of ignoring improperly hydrated mixes. The proper moisture content is critical to a successful pervious installation and is not something that can be learned from a video or book.
Certified Technicians should schedule an upgrade now, since future pervious projects that adopt ACI 522.1-13 will no longer allow Technician-only certifications. According to NRMCA, there are currently 6625 certified Technicians in North America, but only 189 Installers and 32 Craftsmen.
For more information on NRMCA training programs, including performance reviews, contact one of the local sponsoring groups listed at www.NRMCA.org/certifications.
Scott Erickson has personally been involved in more than 200 pervious installations. He is a principal with Evolution Pervious Paving Resources, and owner of Quality Concrete, Salem, Ore., a ready-mixed concrete producer; he is an NRMCA-certified Pervious Craftsman, current president of the National Pervious Concrete Paving Association, and a voting member of ACI Committee 522, Pervious Concrete.