Bagaimana cara mengidentifikasi dan menghindari underground utilities saat excavation?

Underground utility strike adalah leading cause of excavation fatality - gas explosion, electrocution, atau infrastructure damage. Prevention requires systematic approach.

Types of Underground Utilities:

• Gas: Natural gas, LPG - high pressure, explosive
• Electric: Power cable - high voltage, fatal electrocution
• Telecom: Fiber optic, phone line - expensive damage
• Water: Supply pipe - flooding, service disruption
• Sewer: Wastewater, storm drain - health hazard
• Industrial: Steam, chemical pipeline

Universal Color Code (Indonesia follows International Standard):

• RED: Electric power cable
• YELLOW: Gas, oil, petroleum pipeline
• ORANGE: Telecommunication, fiber optic
• BLUE: Water supply
• GREEN: Sewer, drain
• PURPLE: Reclaimed water, irrigation
• PINK: Survey marking, temporary
• WHITE: Proposed excavation limit

PRE-EXCAVATION PLANNING (Mandatory Steps):

Step 1: Call Before You Dig (Minimum 3 Working Days Before)

• Indonesia: Contact local utility companies:
• PLN untuk electric
• PGN untuk gas
• PDAM untuk water
• Telkom, ISP untuk telecommunication
• Provide info:
• Excavation location (map, GPS coordinate)
• Planned depth, area
• Start date
• Contact person
• Utility locate service: Company send technician untuk mark utility location

Step 2: Obtain Utility Plans/As-Built Drawings

• Request dari utility owner
• Review untuk understand:
• Utility type, size
• Depth below surface
• Horizontal location
• CAUTION: Plans often inaccurate - treat as guide, not absolute

Step 3: Physical Utility Locate & Marking

• Ground marking: Utility company representative mark di surface dengan:
• Spray paint (color-coded)
• Flag atau stake
• Marking tape
• Marking indicate:
• Centerline of utility
• Width/diameter
• Depth (annotated)

Step 4: Verify dengan Technology (Highly Recommended)

• Ground Penetrating Radar (GPR): Detect buried object
• Electromagnetic locator: Trace metal pipe/cable
• Acoustic detection: For plastic pipe (water)

Step 5: Hand Digging Trial Hole (Potholing)

• CRITICAL STEP: Before excavator operation, manually dig trial hole untuk visually confirm utility location/depth
• Method:
• Use hand shovel atau vacuum excavation (air spade)
• Dig within tolerance zone (defined distance dari marked utility)
• Expose utility untuk positive identification
• Tolerance Zone (Safe Approach Distance):
• Indonesia standard: 0.5 meter dari marked utility centerline
• Within zone - HAND DIG ONLY

EXCAVATION PROCEDURE:

General Rules:

• Stay outside tolerance zone dengan mechanical excavation
• Slow, controlled digging saat approaching marked depth
• Spotter assigned untuk monitor dan guide operator
• Frequent checking - stop periodically untuk visual inspect

Excavator Technique Near Utilities:

• Parallel approach: Dig parallel to utility line direction (not across)
• Shallow bites: Small bucket load, 15-20cm depth increment
• Smooth operation: No aggressive digging
• Stop 30cm above marked depth: Final 30cm hand expose only

Spotter Role:

• Position dengan clear view dari excavation dan operator
• Monitor bucket position relative ke marked utility
• Signal operator untuk adjust atau stop
• Check exposed soil untuk evidence of utility (discoloration, bedding sand)

IF UTILITY EXPOSED:

• STOP excavation immediately saat utility visible
• Assess condition:
• Damaged? - activate emergency response
• Intact? - proceed with caution
• Hand excavate to fully expose utility 1 meter each side of crossing point
• Provide support: Utility harus adequately supported - tidak boleh suspended/sagging
• Use wooden plank, bag, atau engineered support
• Protect dari damage:
• Cover dengan padding (foam, carpet)
• Barricade around exposed utility
• Warning sign
• Mark clearly: Paint, flag untuk prevent accidental contact by other worker/equipment

EMERGENCY - UTILITY DAMAGE:

Gas Line Strike:

1. EVACUATE area immediately - 100+ meter radius
2. No ignition source: Engine off, no phone, no smoking
3. Call emergency: Fire department, gas company emergency line
4. Establish perimeter: Prevent entry
5. Account for all personnel
6. DO NOT attempt repair

Electric Cable Strike:

1. STAY in equipment jika contact ongoing - cabin insulated
2. If must exit: JUMP clear (no simultaneous contact equipment-ground), shuffle away
3. Warn others: Stay back, assume energized
4. Call PLN emergency - request de-energize
5. DO NOT approach sampai utility company confirm safe

Water Line Strike:

• Immediate flooding likely
• Evacuate low area - flood risk
• Call PDAM untuk shutoff
• Protect excavation dari collapse (water erode soil)

Documentation:

• Photograph utility marking sebelum start
• Daily log - depth, observation
• Any damage - formal incident report

Operator Responsibility:

• Never assume "no utility here" - always verify
• If in doubt - STOP dan clarify
• Respect marked tolerance zone - no shortcut
• Challenge unsafe instruction - if told dig without proper clearance, refuse dan report

One strike can kill people, cost millions, shut down operation - prevention worth effort!