pre-certified by NSF 61 have been readily available in California.
Pre-certification requires coordination testing and routine facility
inspection by NSF to maintain certification. Another reason
admixture certification has been required is because formulas
for admixes change frequently with advances in materials and
products.
Section 5.1 Barrier materials
Concrete aggregate sampling is required only if the method for
testing for individual concrete components is used. Aggregate
sampling is not required if concrete cylinders are tested for the
constituents in Portland and hydraulic cements.
As municipalities have two common ways to confirm
concrete compliance: confirm constituent compliance or soak
testing, language was developed to provide clarification on
testing procedures that apply to each case. This clarification
was incorporated because the previously developed guidance
gaining compliance through testing individual components that
make up the concrete, i.e., aggregate, cement, admixtures, did
not explicitly state that soaking of the final concrete would not
be required. This assumes that the individual components are
found to be compliant. The revised guidance also clarified that
when confirming compliance with the concrete cylinder soak test
method, the agency was not required to also test the constituents
of the mix, including aggregate.
The option of analyzing individual constituents of the
concrete was designed to overcome the logistics and impracticality
of certifying concrete cylinders prior to construction or cores after
the concrete was poured in the field. Pre-construction concrete
cylinder testing on some projects was found to require eight to
12 weeks to produce analytical results. Testing cylinders prior
to construction posed significant schedule impacts, and testing
cores after the concrete was placed in the field posed a significant
risk to the agency. For constituent testing it is typically found that
the concrete supplier has NSF certified cement and admixtures
available, allowing for the aggregate to be sent to an ANSI
certified laboratory to test for compliance.
Section 5.7.2 Normalization for concrete aggregate
Clarification of the formula for normalization that recognizes
only 10 percent of the aggregate exposed within the top one-inch
surface of the concrete is exposed to drinking water in low-pressure
situations found in storage tanks. (The previous assumption
Tyson Neely Appointed to SWRCB Wastewater Operator Certification Program
ORANGE COUNTY WATER DISTRICT Operations Manager Tyson Neely has been appointed by the State Water Resources Control Board to serve
as an advisory committee member on its Wastewater Operator Certification Program (WWOCP). Neely fills the seat recently added by Assembly
Bill 2890, which was approved by Gov. Jerry Brown in 2016, placing one water recycling operator on the committee to represent water recycling plants.
The committee examines and certifies wastewater treatment plant operators and registers contract operators. There are currently approximately 6,000 active certified
wastewater treatment plant operators.
Neely joined OCWD in January 2007 as an operations shift supervisor and was promoted to operations manager in 2008 to provide operational oversight of
the Groundwater Replenishment System’s Advanced Water Purification Facility and the Green Acres Project Title 22 recycled water plant. He was the subject of The
SOURCE Interview, SOURCE, Winter 2017. S
18 SOURCE fall 2017
was that 80 percent of all aggregate was exposed.)
Table 5.6 Lists calculated values of surface area-to-volume ratios
for tanks or storage vessels for tanks from five million to 10 million
gallons.
Table 5.8 Lists values for calculating the aggregate field use for
tanks from 1,000 to 250,000 gallons.
This clarification refined the constants found within the
normalization formulas and simplified calculations in ap-plications
where tanks are too small to meet the threshold for
the 350,000-gallon exemption. The tables and complete lan-guage
are available in the ballot summary that can be found at
http://ca-nv-awwa.org/canv/CNS/Advocacy/NSF_ANSI%20Std%20
61/CNS/Advocacy/NSF_ANSI_61_.aspx?hkey=f9adf49e-94f0-4b0b-a859-
6c470609b2c6.
The ballot has been adopted, approved and took effect
March 17, 2017. The revised NSF/ANSI Standard 61 is scheduled
for publication in Fall 2017.
Where to From Here
The next step is to continue to gather data and monitor
newly constructed tanks and structures, focusing on tanks
and structures smaller than 350,000 gallons, and determine
whether the exemption can be applied to a smaller threshold
of vessels. This will take time, and the Ad Hoc Committee on
Standard 61 would greatly appreciate receiving data from
projects of this size so it can determine whether the threshold can
safely be lowered. Send information to Jeldredge@cityofnapa.org or
Kevin Peacock at kevinpeacock@dntanks.com.
Special thanks to industry representative Kevin Peacock
of DN Tanks, who assisted by gathering data and analyses
performed on recent projects and providing it to the analytical
team at NSF, and to Eugene Leung at DDW who managed the
interim data-centric monitoring approach to achieve compliance
with the standard when certified products were not available
in the market. Mr. Leung also served as a resource within
DDW to advise and review the interim alternate method the
ad hoc committee established. Also thank you to Charley Rea
of California Construction and Industrial Materials Association
(CalCIMA), who assisted in addressing this problem, raised
awareness among CalCIMA members, including large material
suppliers, and facilitated understanding of the roadmap for
performing analyses that addressed the lack of ANSI/NSF 61
certified materials available in the California materials market.S
OPERATIONS
