Use of Cable Avoidance Tools (CAT) and Signal Generators (Genny) in NRSWA Operations

Use of Cable Avoidance Tools (CAT) and Signal Generators (Genny) in NRSWA Operations

The New Roads and Street Works Act (NRSWA) mandates that any work carried out on public highways, roads, and streets must ensure the safety and integrity of existing underground utilities. Cable Avoidance Tools (CAT) and Signal Generators (Genny) are crucial in this context. They help in detecting and avoiding buried utilities, thereby preventing accidental damage and ensuring compliance with NRSWA regulations.

Job Site Procedures for Using CAT and Genny

Pre-Work Planning and Risk Assessment

Site Survey and Documentation Review:

• Site Plans and Utility Maps: Review existing site plans and utility maps to identify known underground utilities. This initial step helps to cross-reference and validate the findings during the actual detection process.
• Risk Assessment: Conduct a thorough risk assessment to identify potential hazards associated with underground utilities. Determine the areas that need detailed scanning using CAT and Genny.

Initial Site Marking

Marking Out the Site:

• Physical Markers: Use physical markers like paint or flags to outline the area where excavation or roadwork will take place. This helps in systematically scanning the area.
• Grid System: Implement a grid system to ensure comprehensive coverage and systematic scanning of the area.

Using the CAT and Genny

Step-by-Step Process:

1. Visual Inspection and Site Preparation:

• Initial Visual Check: Conduct an initial visual inspection of the area for any visible signs of utilities or markers left by previous surveys.
• Safety Gear: Ensure all operators are wearing appropriate Personal Protective Equipment (PPE) such as gloves, safety boots, and high-visibility clothing.

2. Operating the CAT:

Power Mode:

• Initial Scan: Start with the CAT in Power Mode to detect any live power cables that may be emitting electromagnetic fields.
• Marking Locations: Mark the detected locations on the ground using paint or flags.

Radio Mode:

• Secondary Scan: Switch to Radio Mode to detect utilities re-radiating radio signals. This helps in identifying utilities that may not be live but still pose a risk.
• Cross-Verification: Cross-verify the marked locations to ensure consistency and accuracy.

3. Using the Genny:

Direct Connection:

• Application of Signal: Connect the Genny directly to an accessible part of the utility, such as a valve or exposed pipe, to apply a strong and clear signal.
• Tracing the Signal: Use the CAT in Genny Mode to trace the signal emitted by the Genny along the utility’s path.

Induction:

• Signal Induction: Place the Genny on the ground above the suspected path of the utility to induce a signal.
• Detection and Marking: Follow the signal with the CAT and mark the detected utilities.

Clamp Method:

• Clamp Application: Use a signal clamp to apply the signal to utilities without direct contact, especially useful for live cables.
• Path Tracing: Trace the path of the signal with the CAT and mark accordingly.

Depth Estimation and Verification

Depth Estimation:

• Depth Functionality: Use the depth estimation feature of the CAT to determine the approximate depth of the detected utilities.
• Mark Depths: Mark the estimated depths on the ground to aid in safe excavation planning.

Cross-Verification:

• Double Checking: Perform multiple scans using different modes and angles to cross-verify the accuracy of the detected utilities.
• Consultation: Consult with utility companies if there are discrepancies or uncertainties in the findings.

Documentation and Reporting

Recording Findings:

• Detailed Records: Maintain detailed records of all detected utilities, including their locations, depths, and types.
• Site Maps: Update site maps with the newly detected utilities for future reference and compliance documentation.

Compliance Reporting:

• NRSWA Compliance: Ensure that all findings and procedures are documented to demonstrate compliance with NRSWA requirements.
• Reporting: Prepare and submit reports to relevant authorities or stakeholders as required.

Excavation and Work Execution

Controlled Excavation:

• Hand Digging: In areas with detected utilities, use hand digging or vacuum excavation to safely expose the utilities before using mechanical equipment.
• Continuous Monitoring: Continuously monitor for utilities during the excavation process using CAT and Genny to avoid accidental damage.

On-Site Adjustments:

• Real-Time Adjustments: Make real-time adjustments to the excavation plans based on newly detected utilities or changes in site conditions.
• Utility Protection: Implement protective measures, such as shoring or temporary covers, to protect exposed utilities during the work.

Post-Work Procedures

Final Inspections:

• Post-Work Scan: Conduct a final scan of the site using CAT and Genny to ensure no utilities have been overlooked or newly exposed.
• Utility Marking Removal: Remove any temporary utility markers once the work is completed and the site is restored.

Reporting and Documentation:

• Final Report: Prepare a final report documenting the work carried out, including any incidents or changes to the planned procedures.
• Compliance Documentation: Ensure all documentation is up-to-date and compliant with NRSWA requirements for future reference.

Using Cable Avoidance Tools (CAT) and Signal Generators (Genny) in NRSWA operations is crucial for the safety and efficiency of roadworks and street works. These tools help in accurately detecting and avoiding underground utilities, ensuring compliance with regulations, and protecting both workers and infrastructure. Proper training, systematic procedures, and thorough documentation are essential for the effective use of CAT and Genny, contributing to the successful execution of construction and maintenance projects.