Administrative Controls
Administrative controls are changes in work procedures such as written safety policies, rules, supervision, schedules, and training with the goal of reducing the duration, frequency, and severity of exposure to hazardous chemicals or situations. They are one component the Industrial Hygiene program uses to protect tank farm workers.
Administrative controls are established based on Chemicals of Potential Concern (COPCs). COPCs are chemicals that have been identified in the tank farm headspaces, and classified according to their carcinogenicity, concentration compared to their Occupational Exposure Limits, prevalence in tanks and toxicity.
Types of administrative controls established at the tank farms include Chemical Worker Training, Industrial Hygiene Technician direct-reading instrument (DRI) monitoring, and boundaries/posting - Exclusion Zones (EZ) and Chemical Contamination Reduction Zones (CRZ).
Exclusion Zones (EZ)
An administrative control boundary established around emission points (temporary or permanent) where Tank Vapors have the potential to exceed 50% of their OEL(s) (Tank Vapor COCs). The EZ boundary is to be identified using a physical barrier and signage, unless controlled as outlined in TFC-ESHQ-IH-C-48 Section 4.5 (e.g., by continuous monitoring). EZs can be inside or outside of a Tank Farm.
Chemical Contamination Reduction Zones (CRZ)
An administrative control boundary established around EZ(s). Chemical CRZs are areas where the potential for Tank Vapors exposure is less than 50% of the OEL(s). Additional training requirements are needed to access the area. Typically, this area will be designated as the Tank Farm fence line but may be larger or outside of a Tank Farm, as necessary.
Action Limit (AL)
The airborne concentration of a chemical contaminant above which required actions (e.g., additional controls, monitoring, or response procedures) are implemented. Unless otherwise established by regulation, an action limit is set at 50% of the 8-hour Time Weighted Average (TWA) of the Occupational Exposure Limit.
Automation & Process Control
We've worked diligently to implement innovative solutions and maximize the use of existing and new automation capabilities and technologies to safely and accurately monitor, control, and diagnose conditions within a tank farm remotely to minimize personnel physically entering the farm.
Remote capabilities include, but are not limited to:
- Tank farm monitoring
- Alarms and indications
- Characterization and sampling
- Operations and maintenance
Defining the Unrestricted Work Boundary
The Washington River Protection Solutions (WRPS) Industrial Hygiene (IH) Department released a white paper on the IH basis for defining the Unrestricted Boundary related to tank farm vapors at Hanford. The Unrestricted Boundary will be established where practical at a tank farm fence line. The area from the Unrestricted Boundary to the Hanford Site Boundary will be considered the unrestricted area for which general workers or members of the public (with escort) can be assured that they will not be exposed to tank vapor hazards at levels that could place them at risk of exceeding an occupational exposure limit (OEL). Inputs to defining the Unrestricted Boundary included tank farm source data, dispersion modeling, stack and fence line monitoring, and IH rounds and routines, in addition to regulations governing the Tank Farms Operation Contract (TOC). The white paper also defines work boundaries within and outside of the Unrestricted Boundary that will be used moving forward within the IH program, including Exclusion Zone (EZ), Contamination Reduction Zone (CRZ), Support zone, and Industrial Zone. For the full text, please follow this link.
Central Control Room
In 2014, WRPS built a Central Control Room (CCR) which provides a central location where control systems are consolidated allowing for easy access to data and information.
The vision of the Central Control Room (CCR) is to have double-shell tank (DST) process automation systems available to facilitate daily rounds monitoring, transfer operations, and facility control. Entry into a tank farm to record local readings will be minimized with the use of wireless infrastructure and the connection of all instruments, valves, and transfer equipment to the distributed control system.
Currently, the CCR supports 24/7 control and monitoring of Hanford tank farms and the 242-A Evaporator. With eight workstations, the CCR supports three main tank farm control and monitoring systems, including the following:
- DST waste transfer control
- DST vapor instrumentation monitoring
- DST ventilation control
- 242-A Evaporator monitoring
- Single-Shell Tank (SST) and DST monitoring
- DST balance of plant control