A Help4Access Video demonstrating the product features of the Naturally Occurring Asbestos (NOA) Air Monitoring Database System.
Black & Veatch is a global engineering, construction, and consulting company headquartered in Walnut Creek, California. The company has been helping create tailored infrastructure solutions for clients for more than 100 years. Black & Veatch is working with the San Francisco Public Utilities Commission (SFPUC) on a Calaveras Dam Replacement Project. The Project involves a significant earth-moving component. A portion of the earth and rock moved during construction contains Naturally Occurring Asbestos (NOA). A detailed air monitoring program has been undertaken which generally consists of a series of samples taken each day to document conditions on the construction site and within the general population. There is a risk during the course of the project that construction activities will cause an increase to air pollutants that are harmful to the community.
In order to mitigate this risk, Black & Veatch and the SFPUC put a comprehensive air monitoring program in place. The overall purpose for monitoring is to confirm that dust suppression operations remain adequate to assure that asbestos does not escape the site at concentrations capable of causing an unacceptable risk. In order to administer this monitoring program, a data-driven solution was needed for capturing, tracking, and reporting on the results of air monitoring tests.
Product Demo Part 2
The following types of samples are collected during the CDRP to monitor airborne asbestos concentrations:
- Construction Activity Area (CAA) Samples – These samples are collected within the construction site and are intended to provide an indication as to which construction operation is generating asbestos dust. These samples are generally collected during a 10-hour period scheduled to match the construction schedule.
- Perimeter Samples – These samples are collected at the perimeter of the construction site and are intended to document asbestos levels in the air at a control boundary surrounding the construction site. These samples are collected during a 24 or 48 hour period and are typically analyzed with greater sensitivity relative to the CAA samples.
- Ambient Air Samples – These samples are collected at selected locations in the surrounding area and are generally expected to represent levels potentially experienced by receptors at those locations. They are also collected on 24 to 48 hour schedules. Both ambient and perimeter samples are typically analyzed with greater sensitivity than the CAA samples.
- Personal Breathing Zone Samples – These samples are collected by attaching an air sampling device to a construction worker to document air conditions near a worker’s actual breathing zone.
Approximately 10 to 20 or more samples are collected daily and the project is expected to continue for another four years through to the end of 2017. An on-going analysis of the data is required to monitor the performance of the contractor and to comply with the Comprehensive Air Monitoring Program (CAMP) created for the Project.
Two techniques for microscopic examination (one associated with multiple methods) are used to analyze CDRP air samples, namely:
PCM (Phase Contrast Microscopy) – A light-enhancing microscope technology that creates the images of asbestos fibers and bundles at a magnification of ~400X. Historically, this method was used to measure airborne fibers in occupational environments to monitor worker exposures; however, it has several key limitations:
- It cannot differentiate asbestos fibers from non-asbestos fibers.
- It cannot differentiate one type of asbestos fiber from another.
- It does not support visualization of asbestos fibers or bundles thinner than approximately 0.25 u min diameter.
- A minimum length of 5 µm is defined for countable fibers by the method.
TEM (Transmission Electron Microscopy) – A microscope technique that allows for imaging of sub-microscopic asbestos structures using the properties of electrons, which provides more detailed images and is capable of achieving magnifications of 250,000x or better. It is also able to overcome other limitations of the PCM technique by providing the ability to differentiate and identify even the smallest hazardous asbestos structures. Multiple TEM analytical methods are used, as described below, and each uniquely defines how asbestos fibers, bundles, and structures are to be identified and counted in a sample; different methods are applied depending upon the type of information desired.
Three TEM Methods are being employed during the CDRP. These are:
- National Institute of Occupational Safety and Health (NIOSH) Method 7402, which was specifically created for determining the concentrations of asbestos structures with dimensions similar to those counted by PCM. Method 7402, however, also facilitates distinguishing the identity and types of structures counted so that concentrations of specific types of asbestos structures can be individually determined. To assure comparability to historical PCM measurements, Method 7402 formally requires applying the ratios of asbestos to total structures derived by TEM to absolute concentrations derived by PCM (using Method 7400).
- A modified California Air Resources Board – Asbestos Hazard Emergency Response Act (CARB-AHERA) Method, which was specifically created for the analysis of air samples collected at Naturally Occurring Asbestos sites in the State of California. This method is used to count asbestos structures both visible by PCM, and to image and count asbestos structures more than 10 times smaller, down to the limit at which asbestos structures are considered to be of a hazardous size. This method is applied during “routine” analysis of samples. In some cases, both the CARB-AHERA Method and NIOSH Method 7402 are applied to the same sample at the same time.
- A modified International Standards Organization (ISO) Method 10312, which is the method employed during “extended” analysis. This international method is typically used to fully characterize the full range of both the morphological and mineralogical characteristics of asbestos structures in a sample.
It is anticipated that more than 10,000 samples will be collected and analyzed over the course of the project.
Product Demo Part 3
A QA/QC program is being used to track the performance of the monitoring program. The QA checks required for data reporting under the CDRP are incorporated into the database to automate the process for checking data entry. Also, the calculations used to interpret QC analyses and run QC tests are incorporated into the database to automate the process of data validation. The historical record of QA/QC results also needs to be maintained within the database to facilitate a first round of corrective action calculations.
Results from both the overall program and the QA/QC program are tracked to confirm validity and test for the adequacy of dust control. Results also need to be archived both to maintain a record of dust releases and to facilitate additional data evaluation to support dust management decisions at the site. Queries will be incorporated into the database to allow filtering and reporting of the data in a manner facilitating such additional data evaluation.
Help4Access business analysts worked closely with the Black & Veatch subject matter experts teams in order to get down to the detail in the business requirements and Help4Access engineering quickly turned the specifications to a rock-solid system customized to unique requirements enabling Black & Veatch to store, track and report on air monitor testing data that was critical to the success of their overall air monitoring program. The custom application developed by Help4Access, made it possible for Black & Veatch to deploy a comprehensive analytical solution that provided the flexibility and control needed to effectively monitor the air quality around the job site and identify any potential problems with air quality long before they became a public health concern.