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Level 2: Isolation

Separate People from Hazard​

Isolation means separating people from the hazard using distance or physical barriers.

If people can't reach the hazard, they can't be harmed by it.

Why Isolation is Effective​

Advantages:

  • Controls hazard at source (doesn't require eliminating it)
  • Physical separation provides reliable protection
  • Protects multiple workers simultaneously
  • Doesn't rely heavily on worker behavior

Limitations:

  • Doesn't remove hazard (unlike elimination)
  • Requires maintaining barriers/separation
  • May interfere with work access

Types of Isolation​

Physical Separation (Distance)​

Increase distance between workers and hazard:

Construction Examples:

Relocate Hazardous Operations:

  • Mixing/batching area away from main work areas (dust, noise, chemical exposure)
  • Concrete cutting area separated from other work (dust, noise)
  • Fuel/chemical storage remote from accommodation and ignition sources

Exclusion Zones:

  • Barricaded area around operating plant (excavators, cranes)
  • Marked zones around overhead work (falling object risk)
  • Restricted areas near electrical hazards

Buffer Distances:

  • Stockpiles away from excavation edges (prevent surcharge loading)
  • Scaffolding from powerlines (electrical safety distances)

Practical Example: Concrete batching plant located 50 meters from main construction area. Cement dust, noise, and truck movements isolated from other workers.

Physical Barriers​

Install barriers between workers and hazard:

Permanent Barriers:

  • Fencing around plant and equipment
  • Machine guards (fixed guards over moving parts)
  • Screens separating work areas
  • Enclosures for noise sources

Temporary Barriers:

  • Barricades around hazards
  • Hoarding/fencing around construction sites
  • Mesh screens on scaffolding (falling objects)
  • Curtains/partitions separating work zones

Construction Examples:

Site Hoarding:

  • 1.8m+ fencing around construction site perimeter
  • Separates public from construction hazards
  • Prevents unauthorized entry

Guardrails/Edge Protection:

  • Barriers at edges of floors, roofs, excavations
  • Physically prevents falls
  • Most reliable fall protection

Scaffold Debris Netting:

  • Mesh attached to scaffold
  • Catches falling tools/materials
  • Protects workers and public below

Acoustic Barriers:

  • Temporary walls/screens around noisy equipment
  • Reduces noise exposure to nearby workers

Segregation​

Separate incompatible hazards:

Chemical Storage:

  • Separate flammable liquids from oxidizers
  • Acids stored separately from bases
  • Incompatible chemicals in separate cabinets/areas

Work Areas:

  • Hot work separated from flammable materials
  • Painting/coating area separate from spark-producing operations

Traffic Management:

  • Pedestrian routes separated from vehicle routes
  • Dedicated walkways with physical barriers

Practical Example: Site layout with dedicated fenced pedestrian walkways separate from vehicle routes. Workers physically isolated from mobile plant and delivery vehicles.

Enclosure​

Enclose the hazard:

Complete Enclosure:

  • Acoustic enclosure around compressor/generator (noise control)
  • Enclosed booth for spray painting (vapor/overspray control)
  • Covered enclosure for dust-producing work

Partial Enclosure:

  • Guards on power tools (blade guards, vacuum shrouds)
  • Splash shields on grinding wheels
  • Extraction hoods over welding stations

Construction Example: Diesel generator in acoustic enclosure (shipping container with ventilation and sound insulation). Noise reduced from 95dB to 70dB at 10 meters. Workers can work nearby without hearing protection.

Isolation vs. Engineering Controls​

Overlap exists - many isolation methods also engineering controls.

General distinction:

  • Isolation: Emphasis on separating people from hazard (barriers, distance)
  • Engineering Controls: Emphasis on controlling the hazard itself (ventilation, equipment modification)

Practically: Both are Level 2 controls and often used together.

Maintaining Isolation​

Critical requirements:

Barriers Must:

  • Remain in place and intact
  • Be strong enough to resist impact, loads
  • Be clearly marked/visible
  • Not be easily bypassed or removed

Distance Must:

  • Be maintained (don't move hazard closer)
  • Be enforced (workers don't enter exclusion zones)
  • Be marked clearly

Inspections:

  • Regular checks barriers undamaged
  • Exclusion zones respected
  • Signage visible

Practical Construction Examples​

Example 1: Excavation Work​

Hazard: Workers or public falling into excavation (2m deep).

Isolation Controls:

Barriers:

  • Temporary fencing 1.5m from excavation edge (prevents approach)
  • Orange mesh fencing with high visibility
  • "DANGER - OPEN EXCAVATION" signs

Result: Physical barrier prevents falls. Anyone who needs to approach (e.g., for inspection) must deliberately open/bypass barrier - conscious decision, not accidental approach.

Example 2: Overhead Powerlines​

Hazard: Crane boom contacting 11kV powerlines (electrocution risk).

Isolation Controls:

Goal Post Barriers:

  • Physical frame installed around work area
  • Height/position prevents crane reaching powerlines
  • Highly visible (painted yellow/black)

Spotter:

  • Dedicated person monitors clearances
  • Stops work if approach too close

Result: Physical barrier and human monitoring isolate crane from powerlines.

Example 3: Noisy Equipment​

Hazard: Concrete saw generating 110dB noise.

Isolation Controls:

Acoustic Barrier:

  • Temporary noise screens (3m high) around cutting area
  • Absorptive/reflective panels reduce noise transmission

Distance:

  • Cutting area 20m from other work
  • Reduces noise at distance (inverse square law)

Exclusion Zone:

  • 5m barricaded exclusion zone around saw
  • Only operator in zone (wearing hearing protection)
  • Other workers kept at distance

Result: Noise reduced to <85dB for workers outside zone. Operator protected by hearing protection and limited exposure time.

Example 4: Chemical Storage​

Hazard: Incompatible chemicals (flammable liquids and oxidizers).

Isolation Controls:

Separate Storage:

  • Flammable liquids cabinet in one location
  • Oxidizers cabinet 5 meters away
  • Physical separation prevents contact if leak/spill

Bunding:

  • Each cabinet in separate bunded area
  • Spills contained, cannot mix

Signage:

  • Clear labels on cabinets
  • Hazard warnings

Result: Incompatible chemicals isolated from each other. If leak occurs, cannot cause dangerous reaction.

When Isolation Not Sufficient​

If isolation reduces but doesn't adequately control risk, add:

Additional Level 2 Controls:

Level 3 Controls:

Example: Isolating spray painting in separate booth (isolation) + extraction ventilation (engineering control) + respirators for painter (PPE) = layered protection.

Common Isolation Applications in Construction​

Site Security:

  • Perimeter fencing (public from hazards)
  • Locked gates (unauthorized entry)

Edge Protection:

  • Guardrails at fall edges
  • Covers over penetrations

Exclusion Zones:

  • Around operating plant
  • Below overhead work
  • Near energized equipment

Traffic Management:

  • Pedestrian/vehicle separation
  • Barricaded walkways

Hazardous Materials:

  • Chemical storage areas (fenced, signed)
  • Asbestos removal zones (barricaded, signed)

Noise/Dust Sources:

  • Screened or remote locations
  • Timed for minimum worker exposure